Teacher of chemistry, biology, ecology
GBOU secondary school No. 402.
BIOGECENOSIS
GRADE 10
The learning objectives of the lesson:
deepen knowledge about biogeocenosis;
to acquaint students with the properties of biogeocenosis;
Developing objectives of the lesson:
to develop in students the ability to highlight the main, essential in the educational material, to compare, generalize and systematize, to establish cause-and-effect relationships;
promote the development of volitional and emotional qualities of the individual;
pay special attention to the development of interest in the subject and speech of students.
Educational objectives of the lesson: contribute to the formation of worldview ideas:
the materiality of the world;
continuity of the process of cognition.
Form of the educational process: cool lesson.
Lesson type: learning lesson.
Lesson structure:
Org. moment
1 min.
Update
2 minutes.
Goal setting
1 min.
Learning new material
25min
reflection
10 minutes
Homework
1 min.
Equipment:
Board;
Projector;
A computer;
Handout;
Way of providing information: Textual, structural-logical, information-technological.
Teaching method: partial search
Technology: Person-oriented.
During the classes.
Stage.
The activities of the teacher.
Student activities.
Organizing time.
Greetings.
Gets the kids ready for the lesson.
Getting ready for the lesson.
Actualization.
What is a biocenosis?
How to translate the prefix "GEO"
Let's connect the prefix "GEO" and the concept of BIOCENOSIS.
Continue the phrase.
They answer questions.
Goal setting.
Today in the lesson we will analyze the concept of BIOGEOCENOSIS.
Write down the topic of the lesson: BIOGECENS.
Learning new material.
In biology, three concepts that are close in meaning are used:
1. Biogeocenosis- a system of a community of living organisms (biota) and its biotic environment on a limited area of the earth's surface with homogeneous conditions (biotope)
2. Biogeocenosis- biocenosis, which is considered in interaction with abiotic factors that affect it and, in turn, change under its influence. Biocenosis is synonymous with community; the concept of ecosystem is also close to it.
3. Ecosystem- a group of organisms of different species, interconnected by the circulation of substances.
Every biogeocenosis is an ecosystem, but not every ecosystem is a biogeocenosis - Justify this phrase.
To characterize biogeocenosis, two close concepts are used: biotope and ecotope (factors of inanimate nature: climate, soil).Define these terms.
Properties of biogeocenosis
1. natural, historically established system
2. a system capable of self-regulation and maintaining its composition at a certain constant level
3. characteristic circulation of substances
4. open system for energy input and output, the main source of which is the Sun
The main indicators of biogeocenosis
1. Species composition - the number of species living in a biogeocenosis.
2. Species diversity - the number of species living in a biogeocenosis per unit area or volume.
In most cases, the species composition and species diversity do not quantitatively coincide, and the species diversity directly depends on the area under study.
Why?
3. Biomass - the number of organisms of biogeocenosis, expressed in units of mass. Most often, biomass is divided into:
a. producer biomass
b. consumer biomass
in. decomposer biomass
Define: Who are producers, decomposers and consumers.
4. sufficiency of living space, that is, such a volume or area that provides one organism with all the resources it needs.
5. richness of species composition. The richer it is, the more stable the food chain and, consequently, the circulation of substances.
6. Variety of species interactions that also maintain the strength of trophic relationships.
7. environment-forming properties of species, that is, the participation of species in the synthesis or oxidation of substances.
8.direction of anthropogenic impact
Make a conclusion on the properties of biogeocenosis.
The joint life of organisms in a biogeocenosis is regulated by five types of biogeocenotic relationships:
Define each type of biogeocenosis and give examples.
Give examples with justifications for each concept.
Justify the phrase
Define the terms:
Biotope - this is the territory occupied by biogeocenosis.
Ecotop - this is a biotope that is affected by organisms from other biogeocenoses.
Write down in a notebook.
Discuss the material with the teacher and ask questions.
They answer the question.
Answer the question:
Producers - organisms, capabletoa photo- orchemosynthesisandbeinginfood. chainsfirstlink, creatororganic. in- infrominorganic, t. e. allautotrophicorganisms. Consumers - organisms, beingintrophicchainsconsumersorganicsubstances. Reducers - organisms, decomposingdeadorganicsubstanceandtransforminghisininorganic, employeefoodothersorganisms.
Summarize the properties of biogeocenosis:
Thus, the mechanisms ensure the existence of unchanging biogeocenoses, which are called stable. A stable biogeocenosis that has existed for a long time is called climax. There are few stable biogeocenoses in nature, more often there are stable - changing biogeocenoses, but capable, thanks to self-regulation, to return to their original, initial position.
Listen and write down the material in a notebook.
Give definitions and give examples.
Reflection.
Let's summarize today's lesson:
Do a test job:
1. Autotrophic organisms include
B) tinder fungus
B) blood-sucking insects
D) red algae
2. The stability and integrity of the biogeocenosis does not depend on
A) geological changes in the Earth's crust
B) diversity of species composition
C) seasonal climate changes
D) the flow of energy and matter
3. Self-regulation in biogeocenosis is manifested in the fact that
A) species multiply rapidly
B) the number of individuals changes
C) some species are not completely destroyed by others
D) the number of populations of individual species is increasing
4. A reservoir is considered a biogeocenosis, since the species living in it
A) located in the same tier
B) food chains are formed
C) belong to the same kingdom
D) not related
5. The adaptability of plants to cohabitation in the biogeocenosis of the forest is manifested in
A) increased competition between species
B) tiered arrangement
B) increase in leaf surface
D) modification of root systems
Test work is discussed and correct answers are given.
Solve test work.
Perform a self-check.
Homework
Steam….., Vopr…. Page…..
Do a test job:
1. A meadow is a more sustainable ecosystem than a wheat field, as it
A) there are producers
B) more fertile soil
C) there are more species
D) there are no predators
2. An example of a biogeocenosis is a set
A) plants grown in a botanical garden
B) oak trees and shrubs
C) all organisms that live in the swamp
D) birds and mammals of the spruce forest
3. The greatest diversity of populations and animal species is characteristic of biocenosis
A) oak trees
B) pine forest
B) an orchard
D) tundra
4. The continuous movement of carbon, nitrogen and other elements in biogeocenoses is carried out largely due to
A) the action of abiotic factors
B) the vital activity of organisms
B) the action of climatic factors
D) volcanic activity
5. The ecosystem becomes more resilient when
A) increasing species diversity
B) the presence of a variety of food chains
B) a closed circulation of substances
D) violation of the circulation of substances.
Write down in a notebook.
114. The greatest diversity of plant and animal species is characteristic of biocenosis
1. tundra;
3. Rainforest +
4. forest-steppe
115. Productivity of ecosystems (in terms of formation of dry matter biomass) from the equator to the poles:
1. decreases +
2. remains unchanged;
3. increases;
4. first decreases and then increases again
5. first increases and then decreases
116. A large ecological group of aquatic organisms that have the ability to move regardless of water currents:
2. plankton
3. nekton +
4. neuston
5. periphyton
117. A large ecological group of aquatic organisms localized at the bottom
1. plankton
2. periphyton
3. neuston
4. benthos +
118. A large ecological group of aquatic organisms that live freely in the water column and passively move in it
1. plankton +
2. periphyton
3. neuston
119. Large ecological group of aquatic organisms attached to aquatic plants
1. plankton
2. periphyton +
3. neuston
120. The ecological group of aquatic organisms living near the surface of the water, on the verge of the aquatic and air environment:
1. plankton
2. periphyton
3. neuston +
121. Freshwater ecosystems that form in stagnant water bodies
1. wetlands
2. lotic
3. lake
4. tape +
5. eutrophic
122. Freshwater ecosystems formed in flowing waters
1. wetlands
2. lotic +
3. lake
4. tape
5. eutrophic
123. The main edificator of communities in the tundra are
1. lichens +
3. shrubs
5. dwarf trees
124. Species that determine the structure and nature of communities in biocenoses, playing an environment-forming role
1. dominants
2. edifiers +
3. subdominants
4. Assectors
5. violets
125. For simple biocenoses of the tundra, under certain conditions,
1. outbreaks of mass reproduction of certain species +
2. very small fluctuations in the number of individual species
3. outbreaks of mass reproduction of individual species are never observed
4. gradual rises in the number of species
5. gradual decline in the number of species
126. The main condition for the sustainability of ecosystems is
1. the presence of formed fertile soil
2. closed ecosystem
3. the presence of large herbivores
4. constant circulation of substances and the influx of energy +
5. high level of biodiversity
127. The scientist who proposed the term biogeocenosis
1. V.N. Sukachev +
2. V.I. Vernadsky
3. Dokuchaev
5. Ch. Darwin
128. The set of environmental factors affecting the composition and structure of biocenoses
1. phytocenosis
2. edaphotop
3. climate top
4. landscape
5. biotope +
129. The concept characterizing the position of a species in the biocenosis, expressed in the features of geographical localization, relation to environmental factors and functional role
1. ecological niche +
2. life form
3. dominance system
4. adaptation
5. life strategy
130. Similar morpho-ecological groups of different types of living organisms, with varying degrees of kinship, expressing the type of adaptation to similar environmental conditions, which occurs as a result of convergent adaptation:
1. ecological niche
2. life form +
3. dominance system
4. adaptation
5. life strategy
131. The resilience of an ecosystem with increasing complexity tends to:
1. varies depending on the nature of the relationship of organisms
2. does not change
3. increases +
4. decreases
5. does not depend on the degree of difficulty
132. The significance of swamps lies in the fact that these ecosystems are capable of ...
1. regulate the temperature regime of ecotopes
2. give a crop of mushrooms
3. to harvest cranberries and lingonberries
4. regulate the water regime of the territory +
5. produce peat
133. The most complex tropical rainforest ecosystems are characterized by:
1. high level of diversity and low abundance of species +
2. high level of diversity and high abundance of species
3. low diversity and low species abundance
4. low diversity and high species abundance
5. high level of diversity and changing abundance of species
134. The highest rate of processing of dead organic matter by decomposers is observed in ecosystems:
2. Tropical rainforests +
3. boreal coniferous forests
5. savannas
135. The abundance of large ungulate phytophages is characteristic of ecosystems
2. Tropical rainforest
3. boreal coniferous forests
5. savannas +
136. The totality of all connections of a species with the environment, which ensure the existence and reproduction of individuals of a given species in nature, are:
1. biocenosis +
3. edaphotop
4. climatetop
5. competitive environment
137. At the level of consumers, the flows of living organic matter transferred to different groups of consumers follow the chains:
1. savings
2. decomposition
3. transformation
4. Eating +
5. synthesis
138. At the consumer level, the flows of dead organic matter transferred to different consumer groups follow the chains:
1. savings
2. expansions +
3. transformation
4. eating
5. synthesis
139. When transferring organic matter to different groups of consumers-consumers, it is divided into two streams:
1. accumulation and decomposition
2. expansions and transformations
3. transformation and synthesis
4. eating away and decomposition +
5. synthesis and accumulation
140. A more complete use of resources at each trophic level of the biocenosis is ensured by:
1. increase in the number of individual species
2. increase in the number of species +
3. increase in the number of all species
4. cyclical changes in numbers
5. increase in predation
141. The amount of biomass and associated energy, at each transition from one trophic level to another, is about:
142. As you ascend the trophic levels, the total biomass, production, energy and number of individuals change:
1. progressively increase
2. increases during the transition from producers to consumers, and then decreases
3. the direction to decrease or increase changes cyclically depending on external factors
4. progressively decrease +
5. remain constant
143. The most important mechanism for maintaining the integrity and functional stability of biocenoses is:
the abundance and diversity of species composition +
increased competition
interaction of all kinds at all levels
reduced competition and species composition
constancy of species composition and reduced competition
144. The sequence of trophic relationships, the end result of which is the mineralization of organic matter:
eating chains
transformation chains
decomposition chains +
mineralization chains
decomposer chains
145. The sequence of trophic links during which the synthesis and transformation of organic matter occurs:
1. Eating chains +
2. chain transformation
3. decomposition chains
4. chains of mineralization
5. circuit synthesis
146. The elementary structural and functional unit of the biosphere is:
biogeocenosis +
phytocenosis
communities of living organisms
147. Areas of the world's oceans, the high productivity of which is due to ascending flows of water from the bottom to the surface
sargasso
rift
convention areas
upwelling +
148. Areas of the world ocean, the high productivity of which is due to the presence of fields of floating brown algae:
1. sargasso +
2. rift
3. conventional areas
4. upwelling
5. reef
149. Areas of high biological diversity in the oceans, localized around hot springs on faults in the oceanic crust and based on primary production supplied by chemotrophic organisms:
sargasso
abyssal rift
offshore
upwelling
reef +
150. Bottom concentrations of biodiversity at great depths of the ocean owe their existence to life
algae
coral polyps
molluscs and echinoderms
chemotrophic bacteria +
151. The factor that determines the geographic distribution in the oceans of areas of thickening of living matter and high productivity around coral reefs is:
1. temperature not less than 20 o +
2. depth no more than 50 m
3. water transparency
4. water salinity
152. Areas of high productivity in the world's oceans, in the communities of which there are no photosynthetic organisms:
sargassum thickenings
abyssal rift +
shelf concentrations
upwelling clusters
reef concentrations
153. The most productive fishing areas of the world's oceans, providing about 20% of the world's fishery, are the areas:
upwelling +
abyssal rift
offshore
sargasso fields
coral reefs
154. The ecological region of the ocean coast, located above the water level at high tide, but exposed to ocean waters during storms and surges:
2. littoral
3. abyssal
4. supralittoral +
5. sublittoral
155. The ecological region of the ocean floor, located in the zone between the water levels at the highest tide and the lowest tide:
A) bathyal
B) littoral +
C) abyssal
D) supralittoral
E) sublittoral
156. The ecological region of the ocean floor, located in the zone from the water level at the lowest ebb to a depth of 200 m:
A) abyssal
B) littoral
C) bathyal
D) supralittoral
E) sublittoral +
157. The ecological area of the ocean floor, located on the continental slopes at depths of 200-2000 m:
A) bathyal +
B) littoral
C) abyssal
D) supralittoral
E) sublittoral
158. Ecological area of the ocean floor at depths exceeding 2000 m:
A) bathyal
B) littoral
C) abyssal +
D) supralittoral
E) sublittoral
159. Ecological groups of marine organisms - nekton, plankton, neuston and pleuston are typical for communities:
A) littoral
B) bathyali
C) abyssals
D) pelagials +
E) sublittoral
160. A community that includes phytocenosis, zoocenosis and microbiocenosis, having certain spatial boundaries, appearance and structure:
A) biocenosis +
E) biogeocenosis
161. The basis of most terrestrial biocenoses, which determine their appearance, structure and certain boundaries, is:
A) zoocenosis
C) edaphotop
D) microbiocenosis
E) phytocenosis +
162. The primary habitat of living organisms, formed by a combination of soil and climatic factors:
A) biotope
B) ecotope +
C) edaphotop
D) climatetop
163. Secondary habitat formed as a result of the active impact of living organisms on the primary habitat:
A) biotope +
C) edaphotop
D) climatetop
164. In the steppe biocenoses, soil formation is dominated by the following processes:
A) mineralization
B) nitrification
C) humification +
D) denitrification
E) ammonification
165. The key factor in the formation of steppe biogeocenoses, which determines the features of the circulation of biogenic elements, is:
A) temperature
B) the level of solar radiation
C) the seasonality of precipitation
D) soil moisture +
E) temperature contrast
166. Among the life forms of plants of steppe biogeocenoses, the most characteristic are:
A) shrubs
B) dwarf shrubs
C) ephemera
D) turf grasses +
E) rhizomatous cereals
167. For the vertical structure of the animal population of the steppe ecosystems, the following is most characteristic:
A) above-ground tier
B) tree layer
C) underground tier
D) tree-shrub layer
E) abundance of burrows +
168. The colonial way of life of various species and groups of rodents is most typical in ecosystems:
A) boreal forests
C) deciduous forests
E) tropical rain forests
169. In the vertical structure of steppe biocenoses there is no:
A) tree layer +
B) tree-shrub layer
C) shrub layer
D) underground tier
E) herbaceous layer
170. In the steppe ecosystems, among the phytophage animals, the following group is practically not represented:
A) frugivorous +
B) seed-eating
C) green-eating
D) rhizophages
E) seed-eating and rhizophagous
171. Steppe ecosystems are geographically localized:
A) in the tropics
B) at high latitudes
C) in the subtropical climate
D) in the inland regions of temperate latitudes +
E) in the mountains
172. The soil cover of steppe biogeocenoses is formed:
A) brown soils
B) serozems
C) podzolic soils
D) chernozems
E) chernozems and chestnut soils +
173. The change of several aspects during the growing season is a pronounced feature of phytocenoses:
A) steppes +
B) tropical rainforests
D) boreal forests
E) deserts
174. Types of edificators among vertebrates in steppe ecosystems are:
A) ungulate mammals
B) carnivorous mammals
C) reptiles
D) amphibians
E) rodents +
175. An important group of vertebrates that contribute to maintaining the stability of steppe phytocenoses are:
B) rodents
C) ungulates +
D) carnivorous mammals
E) insectivorous mammals
176. Of the terrestrial vertebrates in the steppe ecosystems, the worst represented are:
A) reptiles
B) amphibians +
C) mammals
E) carnivorous mammals
177. In the steppe ecosystems of Asia, with an increase in aridity in the direction from north to south in phytocenoses, the importance of life forms increases:
A) semi-shrubs +
B) turf grasses
C) shrubs
D) rhizomatous cereals
E) forbs
178. In accordance with the increase in the moisture gradient from south to north, changes in the phytocenoses of the Asian steppes are expressed
A) in a decrease in species richness and an increase in the value of ephemers and ephemeroids
B) in increasing the value of subshrubs
C) in reducing the value of densely tufted cereals
D) in an increase in species richness and the number of herb species +
E) in increasing the species diversity of rhizomatous grasses and dwarf shrubs
179. The characteristic life forms of plants of tropical rainforests, which have received great development here, are:
A) epiphytes and lianas +
B) dwarf shrubs
C) perennial grasses
D) bushes
E) trees
180. Fruit-eating and insect-eating consumer species prevail in ecosystems:
A) boreal forests
B) deciduous forests
C) tropical rain forests +
E) subtropical forests
181. Termites are the leading group of saprophogi in ecosystems:
A) boreal forests
B) deserts
C) tropical rain forests
D) savannah +
E) subtropical forests
182. Amphibians living mainly in the tree layer are typical for ecosystems:
A) boreal forests
B) deciduous forests
C) subtropical forests
183. Lianas and epiphytes - specific life forms of plants, the most common and characteristic:
A) boreal forests
B) in deciduous forests
C) tropical rainforests +
D) in the savannas
E) in subtropical forests
184. In the ecosystems of tropical rainforests among animals, according to the nature of trophic relationships, the following prevail:
A) frugivorous and insectivorous +
B) seed-eating
C) herbivores
D) rhizophagi
185. Birds that feed on nectar and are effective pollinators of flowering plants are typical for ecosystems:
A) gallery forests
B) deciduous forests
C) subtropical forests
E) tropical rain forests +
186. Complex polydominant communities of plants and animals characterize ecosystems:
B) deciduous forests
C) subtropical forests
E) boreal forests
187. The absence of a clearly expressed layering of phytocenoses and, at the same time, the high complexity of their structure characterizes ecosystems:
A) gallery forests
B) deciduous forests
C) subtropical forests
E) tropical rain forests +
188. Large mammals occupy a very small place among phytophages in ecosystems:
A) boreal forests
B) deciduous forests
C) subtropical forests
E) tropical rain forests +
189. The dynamics of the number of animals, characterized by smooth changes without sharp peaks and declines, distinguishes ecosystems:
A) tropical rainforests +
C) deserts
E) deciduous forests
190. Tree layer communities absolutely dominate among all taxonomic groups of animals in ecosystems:
A) gallery forests
B) deciduous forests
C) subtropical forests
E) tropical rain forests +
191. Phytocenoses of tropical rainforests lack this layer:
A) shrubby +
B) herbaceous plants
C) epiphytes
E) trees
192. Tree layer life forms represent more than 50% of mammal species living in ecosystems
A) boreal forests
B) deciduous forests
C) subtropical forests
E) tropical rain forests +
193. The number of tree species significantly exceeds the number of grass species in phytocenoses of ecosystems:
A) boreal forests
B) tropical rainforests +
C) subtropical forests
E) deciduous forests
194. Efficient direct return of biogenic elements into cycles ensures high productivity of ecosystems:
A) boreal forests
B) deciduous forests
C) subtropical forests
E) tropical rain forests +
195. The main factors that make tropical rainforest ecosystems possible are:
A) rich soils and high rainfall
B) rich soils and high temperatures
C) constancy of temperatures and evenly distributed rainfall +
D) high temperatures and high rainfall
E) rich soils and constant temperatures
196. Low temperatures and a short growing season are the main limiting factors in ecosystems:
A) boreal forests
B) tundra +
D) deciduous forests
E) deserts
197. Snow is the most important edaphic factor affecting the functioning of ecosystems:
A) boreal forests
B) deciduous forests
C) deserts
198. The main edificators of plant communities in the tundra are:
B) shrubs
C) dwarf trees
E) lichens +
199. Tundra phytocenoses have a very simple structure, in which only a few tiers are distinguished:
200. The main phytophages in tundra ecosystems are
A) large ungulates
B) voles and lemmings +
E) insects
201. High productivity of primary production of tundra phytocenoses is ensured by:
A) rich soils
B) optimal temperature conditions
C) a wide variety of producers
D) long summer photoperiods +
E) abundance of moisture
202. Low diversity and high animal populations are a characteristic feature of ecosystems:
A) boreal forests
B) deciduous forests
C) subtropical forests
203. The simplest structure of the fauna of terrestrial vertebrates, including only terrestrial life forms, is characteristic of ecosystems
A) boreal forests
B) deciduous forests
C) tundra +
204. In terms of biomass among animals-saprophages of the soil-litter layer in the tundra, the first place is occupied by
A) earthworms +
B) nematodes
D) springtails
E) larvae of typulid mosquitoes
205. Among vertebrates, the greatest diversity in the tundra is reached by:
A) mammals
B) reptiles
C) freshwater fish
D) amphibians
206. The most common adaptation of vertebrates, which allowed them to adapt to living in extreme conditions of the tundra:
A) hibernation
B) seasonal migrations +
C) food storage
D) life under the snow
E) hibernation and food storage
207. Boreal coniferous forests are geographically localized:
A) in North America
B) in the southern latitudes of South America and Australia
C) in the northern latitudes of North America, Eurasia and the southern latitudes of South America and Australia
D) in the northern latitudes of North America and Eurasia +
E) in the northern latitudes of Eurasia
208. The moisture balance (ratio of precipitation and evaporation) in boreal coniferous forests over most of the territory is characterized by:
A) excess precipitation +
B) balance
C) excess evaporation
D) long-term fluctuations
E) cyclic changes
209. The main edificators in phytocenoses of boreal coniferous forests are:
A) small-leaved species
C) lichens
D) conifers +
E) herbaceous layer
210. The monodominant structure of phytocenoses is characteristic of ecosystems:
A) coniferous boreal forests +
B) deciduous forests
C) subtropical forests
D) gallery scaffolding
211. For the vertical structure of phytocenoses of boreal coniferous forests, the most characteristic number of layers is:
212. In the ecosystems of boreal coniferous forests among vertebrates, edificator species include:
A) hibernating
B) migratory
C) coniferous storage seeds +
E) ungulates
213. The animal population of boreal coniferous forests has a vertical structure, the number of tiers in which is equal to:
214. Features of the lotic ecosystem include:
A) Presence of flow, high oxygen content, active exchange between
water and land. +
B) Weak exchange between water and land, the presence of a current.
D) Predominance of detrital food chains.
E) No water flow, high oxygen content.
215. The presence of soil-bedding, ground, shrub and tree layers of the animal population is typical for ecosystems:
A) subtropical forests
B) deciduous forests
C) subtropical forests
D) gallery scaffolding
E) coniferous boreal forests +
216. The least productive ecosystems are located:
A) in the savannas
B) in the tundra;
C) in coniferous forests;
D) in deserts; +
E) in the steppes;
217. The successive change of biocenoses with a gradual directed change in environmental conditions is called:
A) adaptation
B) evolution +
C) succession
D) dynamic
E) trending
218. Biome distributed in the Arctic zone of the Earth:
A) savannah;
D) forest-steppe;
E) tundra. +
219. Relationships between organisms through which the transformation of matter and energy occurs in ecosystems:
A) trophic web;
B) food web;
C) trophic chain; +
D) trophic level;
E) trophic branch.
220. Autotrophic organisms include:
A) consumers;
B) producers; +
C) decomposers;
E) predators.
221. Water bodies with an average level of primary production:
A) oligotrophic;
B) dystrophic
C) polysaprobic;
D) eutrophic;
E) mesotrophic; +
222. Pedobionts that make up most of the biomass of soil fauna:
A) springtails;
B) nematodes;
D) earthworms; +
E) insect larvae
223. Biocenoses on agricultural land:
A) agrocenosis; +
B) agro-wall
C) agrophytocenosis;
D) agrobiogeocenosis
E) agroecosystem.
224. All relationships in the biocenosis are carried out at the level of:
B) communities
C) individuals;
D) families, packs, colonies
E) populations. +
225. The most important factor in the transition from tropical rain forests to semi-evergreen tropical forests is:
A) lowering the temperature
B) seasonal rhythm of precipitation +
C) decrease in the amount of precipitation
D) decrease in air humidity
E) reduction of solar radiation
226. The appearance of seasonal rhythms of life processes in all animal species during the transition from tropical rainforests to semi-evergreen tropical forests is due to:
A) lowering the temperature
B) a decrease in solar radiation
C) a decrease in the amount of precipitation
D) decrease in air humidity
E) seasonal rhythm of precipitation +
227. Communities characterized by the presence of a closed grass cover with a varying share of shrubs and trees, the seasonality of which is associated with the frequency of precipitation:
A) prairies;
B) semi-evergreen forests;
C) mangroves;
D) savannas; +
E) forest-steppe
228. Large phytophages from the orders of artiodactyls, equids and proboscis are the most widespread and most characteristic group of mammals in ecosystems:
A) prairies;
B) semi-evergreen forests;
C) mangroves;
D) savannas; +
E) forest-steppe
229. The largest accumulations of large phytophages, the biomass of which reaches the maximum values for modern ecosystems up to 50 kg per 1 ha, are found:
A) on the prairies;
B) in semi-evergreen forests;
C) in savannas; +
D) in the Asian steppes
E) in the forest-steppe
230. Forest communities of the littoral zone of the tropical belt, characterized among animal organisms by a mixture of terrestrial and marine forms adapted to long-term or temporary life on land:
A) gallery scaffolding;
B) semi-evergreen forests;
C) mangroves; +
D) floodplain forests;
E) tropical rainforests
231. Types of biogeocenoses localized in the temperate, subtropical and tropical zones, the appearance, structure, dynamics and productivity of which are controlled by a sharp predominance of evaporation over precipitation:
A) prairies;
B) deserts; +
D) savannas;
E) forest-steppe
232. Life forms of plants, in which the mass of roots significantly exceeds the mass of shoots, are characteristic of ecosystems:
A) prairies;
B) tundra;
C) steppes;
D) savannas;
E) deserts. +
233. Adaptations, expressed in the presence of a period of rest (hibernation) in seasons of the year unfavorable for active life, the development of underground layers, migrations, specific physiological processes, are characteristic of animals living in ecosystems:
B) tundra;
C) deserts; +
D) savannas;
E) forest-steppe
234. Ecosystems are characterized by the least primary production and biomass reserves:
B) tundra;
C) deserts; +
D) savannas;
E) forest-steppe
235. Hydrothermal regime with non-coincidence of warm and humid periods in time (wet cool winters and dry hot summers) is the most striking feature of ecosystems:
B) deciduous forests;
C) deserts;
D) savannas;
E) subtropical hardwood forests +
236. Forest communities in areas with a large amount of evenly distributed rainfall, moderate temperatures and pronounced seasonal changes:
A) boreal coniferous forests;
B) deciduous forests; +
C) semi-evergreen forests;;
E) forest-steppe
237. An ecosystem in which the seasonality of the cycles of development of plants and animals is determined not by temperature, but by rain:
A) deciduous forests;
C) deserts;
D) savannas; +
C) subtropical hardwood forests
238. Forest communities with the most pronounced vertical structure, consisting of four tiers - tree, shrub, grass (or grass-shrub) and moss (moss-lichen):
A) boreal coniferous forests;
B) deciduous forests; +
C) semi-evergreen forests;;
D) subtropical hardwood forests;
E) gallery forests;
Abstract on the topic:
"Biological Diversity"
INTRODUCTION
Biodiversity is defined by the World Wide Fund for Nature (1989) as “the entire diversity of life forms on earth, the millions of species of plants, animals, micro-organisms with their gene sets, and the complex ecosystems that make up wildlife”. Therefore, biodiversity should be considered at three levels. Biological diversity at the species level covers the entire range of species on Earth from bacteria and protozoa to the kingdom of multicellular plants, animals and fungi. On a smaller scale, biological diversity includes the genetic diversity of species, both from geographically distant populations and from individuals within the same population. Biological diversity also includes the diversity of biological communities, species, ecosystems formed by communities and the interactions between these levels.
For the continuous survival of species and natural communities, all levels of biological diversity are necessary, all of which are also important for humans. Species diversity demonstrates the richness of evolutionary and ecological adaptations of species to different environments. Species diversity serves as a source of diverse natural resources for humans. For example, tropical rainforests, with their richest variety of species, produce a remarkable variety of plant and animal products that can be used for food, construction, and medicine. Genetic diversity is necessary for any species to maintain reproductive viability, resistance to diseases, and the ability to adapt to changing conditions. The genetic diversity of domestic animals and cultivated plants is especially valuable to those working on breeding programs to maintain and improve modern agricultural species.
Community-level diversity is the collective response of species to different environmental conditions. The biological communities found in deserts, steppes, forests and floodlands maintain the continuity of the normal functioning of the ecosystem by providing “maintenance” to it, for example, through flood control, soil erosion protection, air and water filtration.
The purpose of the course work is to identify the main biomes of the world and the protection of their biodiversity.
To achieve the goal, the following tasks were set:
1. Definition of the concept of tundra and forest tundra;
2. Consideration of the concept of broad-leaved forests of the boreal zone;
3. Analysis of steppe ecosystems of the world, deserts of the world;
4. Definition of subtropical deciduous forests;
5. Consideration of the principles of biodiversity protection.
TUNDRA AND FOREST-TUNDRA
The main feature of the tundra is the treelessness of monotonous swampy lowlands in a harsh climate, high relative humidity, strong winds and permafrost. Plants in the tundra are pressed against the surface of the soil, forming densely intertwined shoots in the form of a pillow. A variety of life forms can be seen in plant communities.
There is a moss-lichen tundra, where green and other mosses alternate with lichens (the most important of them is reindeer moss, which feeds on reindeer); shrub tundra, where thickets are widespread, especially dwarf birch (polar willow, bushy alder), and in the Far East - elfin cedar. Tundra landscapes are not without diversity. Large areas are occupied by hummocky and hilly tundra (where turf forms hummocks and mounds among swamps), as well as polygonal tundra (with special forms of microrelief in the form of large polygons broken by frost cracks).
In addition to sparse moss-lichen vegetation, perennial cold-resistant grasses (sedge, cotton grass, dryad, buttercups, dandelions, poppies, etc.) are widespread in the tundra. The view of the tundra blooming in spring makes an indelible impression on the variety of colors and shades that caress the eye to the very horizon.
The rather poor fauna of the tundra developed during the period of glaciation, which determines its relative youth and the presence of endemics, as well as species associated with the sea (birds living in bird colonies; polar bear, pinniped rookeries). Tundra animals have adapted to the harsh conditions of existence. Many of them leave the tundra for the winter; some (such as lemmings) stay awake under the snow, others hibernate. Arctic fox, ermine, weasel are widespread; meet a wolf, a fox; from rodents - voles. The endemics of the tundra include: from ungulates - a musk ox and a long time domesticated reindeer from birds - a white goose, a snow bunting, a peregrine falcon. There are numerous white and tundra partridges, horned larks. Of the fish, salmon predominate. Mosquitoes and other blood-sucking insects are plentiful.
Plots of tundra are found in the forest-tundra.
The issue of the borders of tundra forests has been discussed for a long time. There is no unity of opinion about either the northern or southern borders. It is not possible to clearly separate forests and tundra, forest-tundra and taiga due to the laws of vegetation continuity. On satellite images and topographic maps built on the basis of aerial surveys of different scales, these boundaries "float". Forest tracts in islands and islets, strips and ribbons of different widths along river valleys often go far into the tundra. The situation is aggravated by the high swampiness of the territories. Although swamps are azonal objects, when establishing the ratio of the main components of the landscape, they must also be taken into account along with forest and tundra ecosystems. It is quite obvious that the protective zone allocated by the Decree of the Government cannot reflect the natural boundaries of the tundra forest zone. It is known that this band was established by experts using topographic maps and aerial survey materials. It represents only a special economic part in the general forest fund. In order to reduce the number of unproductive from a utilitarian point of view, but requiring protection, the forest fund included only areas with a clear predominance of forest formations - ecosystems of the forest type itself.
When defining the boundaries of this strip, it is necessary, in my opinion, to use a landscape-biological approach. The main plant formations in the territories under consideration are forest, tundra and swamp. In the zone of contact between forest formations and tundra, each type of ecosystem generally accounts for 33% of the area. But since swamp ecosystems are azonal formations, they can be considered in the landscape, although as an integral, but still a secondary element. They can only complement the properties of the main components of ecosystems: either forest or tundra. That is, if one of these main types of vegetation is more than 33 (for the strength of positions - more than 35%), then the formation corresponding to it should be considered decisive. Based on this, from a biological and ecological point of view, the boundary between the tundra and the belt of near-tundra forests should be drawn along the lines separating territories covered by forest communities by 35 percent or more. In practice, the northern border of the tundra forest belt, formalized in this way, is proposed to be established using satellite images or topographic maps at a scale of 1:1000000. Of course, when it is carried out, simplifications and generalizations cannot be avoided. Apparently, in this case, the “tundroforest” zone will significantly expand to the north against the current one. This will mean expanding the holdings of the Federal Forest Service.
Discussing the issue of the northern border of the tundra forests, one cannot fail to note the proposal of the well-known specialist Chertovsky V.G. to refer to this territory all the spaces of the geobotanical zone of the forest-tundra, where today forest groups are represented in any way. Considering that the northern limits of the distribution of forests change over time, it is possible that someday we will return to this point of view.
No less debatable is the question of the southern boundaries of the tundra forest subzone, i.e. about its border with the northern taiga subzone. This boundary is also very conditional, and does not coincide with the boundaries of the temperate and cold climate zones, or the natural boundaries of landscapes. If we consider it as a boundary of natural complexes, then indicators of productivity and sustainability of ecosystems should be put at the forefront. It seems to us that the main indicator should be the criterion of their guaranteed self-renewal. With the complete uncertainty of this concept in forestry practice, we propose to operate with the concept of "sustainable periodicity of seeding". We are talking about edificatory breeds.
Thus, the forest-tundra-closed boreal coniferous forests near the northern limit of their distribution usually gradually but steadily become more red-hardy. Treeless areas appear; there are more of them to the north. Low, often ugly trees are separated from one another by 10 m or more.
Shrubs, dwarf birches, low willows and other plants grow between them. Finally, only isolated islands of forest remain, but even these are preserved mainly in places protected from the wind, mainly in river valleys. This borderline between the forest and the tundra is the forest-tundra, which in many places extends in the form of a relatively narrow zone, but often in places its diameter (from north to south) reaches hundreds of kilometers. The forest tundra is a typical transition zone between forest and tundra, and it is often very difficult, if not impossible, to draw a clear line between the two zones.
dark coniferous forests
Dark coniferous forests - the tree stand of which is represented by species with dark evergreen needles - numerous species of spruce, fir and Siberian pine (cedar). Due to the large darkening, the undergrowth in dark coniferous forests is almost not developed, hard-leaved evergreen shrubs and ferns dominate in the ground cover. Soils are usually podzolic. Dark coniferous forests are part of the taiga zone (taiga) of North America and Eurasia, and also form an altitudinal zone in many mountains of the temperate and subtropical geographical zones; they do not enter the Subarctic, just as they are almost absent in the extracontinental longitude zone.
Eurasian taiga
The taiga natural zone is located in the north of Eurasia and North America. On the North American continent, it stretches from west to east for more than 5 thousand km, and in Eurasia, originating in the Scandinavian Peninsula, it spread to the shores of the Pacific Ocean. The Eurasian taiga is the largest continuous forest zone on Earth. It occupies more than 60% of the territory of the Russian Federation. The taiga contains huge reserves of wood and supplies a large amount of oxygen to the atmosphere. In the north, the taiga smoothly turns into the forest-tundra, gradually the taiga forests are replaced by light forests, and then by separate groups of trees. The furthest taiga forests enter the forest-tundra along river valleys, which are most protected from strong northern winds. In the south, the taiga also smoothly turns into coniferous-deciduous and broad-leaved forests. For many centuries, humans have interfered with natural landscapes in these areas, so now they are a complex natural-anthropogenic complex.
The climate of the taiga zone within the temperate climatic zone varies from maritime in the west of Eurasia to sharply continental in the east. In the west, relatively warm summers +10 ° C) and mild winters (-10 ° C), more precipitation falls than can evaporate. Under conditions of excessive moisture, the decomposition products of organic and mineral substances are carried out into the “lower soil layers, forming a clarified ‘podzolic horizon’, according to which the prevailing soils of the taiga zone are called podzolic. Permafrost contributes to moisture stagnation, therefore, large areas within this natural zone are occupied by lakes, swamps and swampy woodlands. In dark coniferous forests growing on podzolic and frozen-taiga soils, spruce and pine dominate and, as a rule, there is no undergrowth. Twilight reigns under the closing crowns, mosses, lichens, forbs, dense ferns and berry bushes grow in the lower tier - lingonberries, blueberries, blueberries. In the north-west of the European part of Russia, pine forests predominate, and on the western slope of the Urals, which is characterized by high cloudiness, sufficient precipitation and heavy snow cover, spruce-fir and spruce-fir-cedar forests.
On the eastern slope of the Urals, the humidity is less than on the western one, and therefore the composition of forest vegetation is different here: light coniferous forests predominate - mostly pine, in places with an admixture of larch and cedar (Siberian pine).
The Asian part of the taiga is characterized by light coniferous forests. In the Siberian taiga, summer temperatures in continental climates rise to +20 °C, and in northeastern Siberia in winter they can drop to -50 °C. On the territory of the West Siberian Lowland, mainly larch and spruce forests grow in the northern part, pine forests in the central part, and spruce, cedar and fir in the southern part. Light coniferous forests are less demanding on soil and climatic conditions and can grow even on poor soils. The crowns of these forests are not closed, and through them the sun's rays freely penetrate into the lower tier. The shrub layer of the light coniferous taiga consists of alder, dwarf birches and willows, and berry bushes.
In Central and North-Eastern Siberia, under conditions of a harsh climate and permafrost, larch taiga dominates. The coniferous forests of North America grow in a temperate continental climate with cool summers and excessive moisture. The species composition of plants here is richer than in the European and Asian taiga. For centuries, almost the entire taiga zone has suffered from the negative impact of human economic activity: slash-and-burn agriculture, hunting, haymaking in floodplains, selective logging, atmospheric pollution, etc. Only in hard-to-reach areas of Siberia today you can find corners of virgin nature. The balance between natural processes and traditional economic activity, which has evolved over thousands of years, is being destroyed today, and the taiga as a natural complex is gradually disappearing.
Coniferous forests of America
There are different opinions about the natural presence of coniferous forests on the plains of temperate latitudes. Especially in drier regions, the pine forest may represent the normal vegetation. This is observed in the warm and arid regions of the southwestern United States, in the Iberian Peninsula and in the karst areas of the Balkans. Exclusively coniferous species can overgrown and less favorable individual places on the plain, such as northern slopes or pits with cold air.
Many coniferous forests in relatively densely populated parts of the planet are artificial, since deciduous or mixed forests would be natural there. They have been established in Europe and North America since the end of the 18th century. In Europe, reforestation was carried out after it was almost cut down in many areas, and due to the impoverishment of the soil, only resistant conifers were suitable for this. In North America, more valuable hardwoods have been cut down much more intensively, resulting in coniferous trees predominating in the forests. Later, such forests were abandoned, as conifers grew faster and allowed for faster profits. Nowadays, in many places there has been a rethinking of this traditional policy and many forests are gradually being converted into mixed forests.
In many densely populated areas, the coniferous forest suffers from exhaust gases.
The main territory of the remaining 49 states is divided into several regions according to the nature of the vegetation. West: This includes the vast Cordillera mountain system. These are the slopes of the Coast Range, the Cascade Mountains, the Sierra Nevada and the Rocky Mountains, dressed in coniferous forests. East: elevated plateaus around the Great Lakes region and inland forest-steppe plains, as well as mid-mountain elevated areas that are part of the Appalachian Mountains, where the main massifs of broad-leaved and partially coniferous-broad-leaved temperate forests are located. South: subtropical and partly tropical (in southern Florida) forests are common here.
In the west of the country are the most productive and valuable coniferous forests, which are part of the Pacific Northwest region. Its territory includes the western slopes of the Cascade Mountains in the states of Washington and Oregon and the expanses of the Coast Range and Sierra Nevada located in California. Ancient coniferous virgin forests of evergreen sequoia (Sequoia sempervirens), reaching a height of 80-100 m, have been preserved here. The most productive and complex sequoia forests are located in California on oceanic slopes at an altitude of 900-1000 m above sea level. seas. Together with the sequoia, no less large douglas trees (Pseudotsuga manziesii) grow, the trunks of which reach 100-115 m in height, and large fir: great (Abies grandis) with trunks 50-75 m high, noble (A. nobilis) - 60-90 m; pretty (A. amabilis) - up to 80 m; lowa fir (A. lowiana) - up to 80 m; single color (A. concolor) - 50-60m; Californian, or lovely (A. venusta) - up to 60 m; magnificent (A. magnifica) - up to 70 m. Here there are giant thuja trees (Thuja plicata) 60-75 m high; Sitka spruce - 80-90 m; Lawson's cypress (Chamaecyparis lawsoniana) - 50-60 m; California river cedar, or incense (Calocedrus decurrens) - up to 50 m; western hemlock, etc. Sequoia forests stretch along the coast of the Pacific Ocean for 640 km and do not go deeper into the mainland further than 50-60 km.
In somewhat drier places in Southern California and on the western slopes of the Sierra Nevada, patches of once majestic coniferous spruces from the giant sequoiadendron, or mammoth tree (Sequoiadendron giganteum), have been preserved. Most of these sites are included in the nature reserves and national parks (Yosemite, Sequoia, Kings Canyon, General Grant, etc.). The companions of the giant sequoiadendron are Lambert's pine, or sugar pine (Pinus lambertiana), yellow pine (P. ponderosa), plain and magnificent fir, California river cedar, etc. South of the sequoia forests along the slopes of the Coast Range and the Sierra Nevada at an altitude of 1000 to 2500 m in the state of California, pure pine forests of Sabin pine (P. sabiniana) and Lambert pine are common, reaching a height of 50-60 m, to which low (18-20 m) Pseudo-sugi large-cone trees. At an altitude of 2000-2100 m, this species often forms low-growing clean forests.
On the western slopes of the Sierra Nevada (1800-2700 m), Lambert pine forests give way to forests of Jeffrey pine (P. jeffreyi) and yellow pine (P. ponderosa). The latter breed is also widespread in areas bordering the Great Plains. There, along the slopes of the Rocky Mountains (1400-2600 m), it forms the famous western pine (ponderose) forests, which make up 33% of all US coniferous forests. Most of the yellow pine forests are part of the Intermountain (Idaho, Nevada, Arizona) and Rocky Mountain (Montana, Wyoming, Colorado, New Mexico) forest regions. Pine trees grow in these areas: mountain weymouth, or Idaho white (P. monticola), Murray (P. murrayana), white-stemmed (P. albicaulis), flexible (P. flexilis) and twisted (P. contorta). Together with them, at an altitude of 1500-3000 m, spruce trees grow - prickly (Picea pungens) and Engelmann (P. engelmannii), fir - subalpine (Abies lasiocarpa) and Arizona (A. arizonica), larch - western (Larix occidentalis) and Lyell ( L. lyallii), Mertens' hemlock (Tsuga mertensiana) and false suga - gray-gray (Pseudotsuga glauca) and gray (P. caesia).
In the southern regions of the Rocky Mountains, in the states of Arizona, New Mexico, as well as in southern California, there are communities of evergreen shrubs - chaparral, among which low pines are found on sandy hillocks and along the slopes - spiny (P. aristata), cedar (P. cembroides ), edible (P. edulis), Torreya (P. torreyana), four-coniferous (P. quadrifolia), etc., as well as evergreen oaks - herbaceous (Quercus agrifolia), shrubby (Q. dumosa), etc., adenostoma (Adenostoma fasciculatum), buckthorn (Rhamnus crocea), cherry (Prunus ilicifolia), various heathers, sumac. In total, there are more than a hundred species of shrubs in the chaparral.
To the northeast of Minnesota, through the northern territories of the states surrounding the Great Lakes, and further to the state of Maine, the Northern region of coniferous-deciduous forests is distinguished. It also includes forests along the northern slopes of the Allegan Plateau, the Allegan Mountains and the Appalachian Mountains (New York, Pennsylvania, West Virginia, Kentucky, North Carolina to Tennessee and northern Georgia). In the north of this region, there is a border of distribution of Canadian spruce (Picea canadensis) and black spruce (P. mariana), which is replaced along the slopes of the Appalachians by red spruce (P. rubens). Spruce forests occupy the shores of lakes, river valleys, border swamps and lowlands. Together with spruces, hard pine (Pinus rigida), western thuja (Thuja occidentalis), American larch (Larix americana) and red maples (Acer rubrum) and black maples (A. nigrum) grow. In drained and elevated areas, mixed forests are represented by white pine (Pinus strobus), balsam fir (Abies balsamea), Canadian hemlock (Tsuga canadensis), oaks - white (Q. alba), mountain (Q. montana), velvety (Q. velutina ), northern (Q. borealis), large-fruited (Q. macrocarpa), etc.; maples - sugar (Acer saccharum), silver (A. saccharinum), Pennsylvania (A. pensylvanicum); toothed chestnut (Castanea dentata), large-leaved beech (Fagus grandifolia), American lime (Tilia americana), smooth hazel (Carya glabra), hop hornbeam (Ostrya virginiana), elm (Ulmus americana), yellow birch (Betula lutea), late bird cherry ( Padus serotina) and other hardwoods. On sandy and loamy dry soils, there are pure pine forests formed by the Banks pine (Pinus banksiana). Often they grow together with sony resin (P. resinosa). On the dry slopes of the Appalachian mountains, forests of barbed pine (P. pungens) are common.
To the south of the Northern region of coniferous-deciduous forests, broad-leaved forests of the Central region extend. It includes forest areas in the south of the states of Minnesota, Wisconsin and Michigan, in the east of Iowa, Missouri, Illinois, Indiana, Ohio, Kentucky, Tennessee, Pennsylvania and Virginia, in the northeast of Oklahoma and Texas, in the north of Arkansas, Mississippi, Alabama, Georgia , and South Carolina. Once this area was characterized by an abundance of forests and a variety of tree species, especially hardwoods. The main part of the forests was destroyed during the period of settlement of the country and plowing of lands. They have survived in isolated patches along the river valleys, on the Ozark Plateau, and in the hilly regions bordering the Appalachian Mountains to the south. There are numerous species of oaks here: chestnut (Quercus prinus), pointed (Q. acuminata), marsh (Q. palustris), Michaux (Q. michauxii), large-fruited, velvety, white, bay leaf (Q. laurifolia), red (Q. rubra), Maryland (Q. marilandica), sickle-shaped (Q. falcata), black (Q. nigra), small (Q. minor), etc. Chestnuts grow: notched (Castanea dentata), undersized (C. pumila); several types of hazel (hickory): white (Carya alba), smooth (C. glabra), oval (C. ovata), pecan (C. illinoensis), etc., numerous maples, including sugar, silver, red, ash-leaved (Acer negundo) and others; horse chestnuts: bicolor (Aesculus discolor), small-flowered (A. parviflora), forgotten (A. neglecta), eight-stamen (A. octandra). Along the Allegan Mountains, a narrow strip (through the states of Georgia, South and North Carolina, Virginia) stretches forests of Caroline hemlock (Tsuga caroliniana), along with which there are elms, oaks, maples, and various willows.
In the eastern part of the region, along with beech (Fagus grandifolia), ash (Fraxinus americana), black walnut (Juglans nigra), such remarkable ancient, tertiary species grow as the tulip tree (Liriodendron tulipifera), resinous liquidambre (Liquidambar styraciflua), magnolias (Magnolia acuminata, etc.), white locust (Robonia pseudoacacia) and sticky locust (R. viscosa).
In the southeast of the country, the Southern Subtropical Pine Forest Region stands out, including eastern Texas, southern Oklahoma and Arkansas, Louisiana, Mississippi, Alabama, Georgia and Florida, eastern South and North Carolina, Virginia, Maryland, Delaware and New Jersey. Here, along the coasts of the Gulf of Mexico and the Atlantic, there are significant areas of pine forests (more than 50% of the area of all coniferous forests in the country). Subtropical pine forests of frankincense pine (Pinus taeda), hedgehog or short coniferous (P. echinata), swamp or long coniferous (P. palustris), late or lake (P. serotina) pines are especially common. A smaller area is occupied by forests of Elliot pines, or swampy (P. elliottii), sandy (P. clausa), western Indian (P. occidentalis). In addition to pines, this region is characterized by Florida yew (Taxus floridana), virginian juniper (Juniperus virginiana), as well as broad-leaved species: white, chestnut, laurel, Maryland, sickle-shaped, black, marsh oaks; Florida chestnut (Castanea floridana), large-leaved beech, red maple, silver maple, etc., black ash, tulip tree, liquidambre, forest nissa, magnolias, hickory and other walnut trees.
There is a small area of rainforest in southeast Texas and south Florida. Here among the lowlands and marshes grow marsh cypress (Taxodium distichum), royal (Roystonea regia) and reed (Thrinax spp.) palms, saw palmetto (Serenoa serrulata), Florida yew, cycad (Zamia floridiana), laguncularia (Laguncularia racemosa), and Rhizophora mangle mangroves are also common in places flooded with sea water.
The Hawaiian Islands are dominated by tropical forests formed by a species of the myrtle family (Eugenia malaccensis), called the "Malay apple", white sandalwood (Santalum album), numerous tree ferns, various lianas; coconut palm grows on the coast.
Broadleaf forests of the boreal zone
Deciduous forests of Europe
Deciduous forests, groups of forest formations in which the tree layer is formed by trees with large or small leaf blades. To L. l. include rain and seasonal evergreen and seasonal deciduous forests of the tropical zone, hardwood forests of the subtropical zone and deciduous (summer green) forests of temperate latitudes.
Deciduous forests of the temperate zone of the Northern Hemisphere grow in a temperate cool climate, year-round rainfall and a growing season lasting 4-6 months. Even on Wed. For centuries, deciduous forests were distributed in continuous massifs in Europe (from the Iberian Peninsula to Scandinavia), to the east of the Carpathians their strip narrowed sharply, wedging out to the Dnieper, and continued beyond the Urals as a narrow intermittent strip. In the east of North America and in East Asia, they formed a strip about 2500 km wide from north to south.
The deciduous forests of the temperate zone have long been subjected to strong human impact (in their place are the main industrialized states).
Deciduous forests of the temperate zone, depending on their constituent trees and undergrowth, are characterized by 1-3 tree layers, shrub and grass layers; mosses are prevalent. on stumps and rocks.
The composition of the vegetation cover in temperate deciduous forests depends on local climatic conditions. So, in Zap. and Center. Beech forests are developed in Europe, and oak and hornbeam forests east of the Carpathians. From the Urals to Altai L. l. represented by insular birch forests - pegs. In the deciduous forests of East Asia, areas of forests of the Manchurian type have been preserved, unusually rich in species composition, both in tree and shrub species, and in species of the herbaceous layer; only in the southern part of Kamchatka, on about. Sakhalin and in some districts of Primorye they are formed by sparse park-type plantations of stone birch. In North America, deciduous forests are represented by formations of beech (in the mountains), beech-magnolia and oak-hickory forests; pl. oak forests are secondary.
Despite their small area, deciduous forests play an important role as regulators of the local water regime. They include many valuable breeds of great practical importance.
Deciduous forests of North America
The soil and litter of deciduous forests are inhabited by many insectivorous invertebrates (ground beetles, rove beetles, centipedes), as well as vertebrate animals (shrews, moles). In the forests of America, as in East Asia, moles are very diverse. The appearance of a star-nosed star with soft outgrowths at the end of the muzzle in the form of a star from numerous mobile processes is original. In appearance and way of life, it is similar to the shrews of the mole shrew from the mountain forests of the Western United States. Of the shrews, the shrews are the most widespread, as in Eurasia. More original is the pygmy shrew, typical of Canadian maple and ash forests.
Of the snakes, especially numerous in the south, rattlesnakes and muzzles predominate. Of the former, the most common is the striped or terrifying rattlesnake, and of the latter, the moccasin snake. In the south, in Florida, fish muzzles dominate in damp areas.
The diverse species of American broadleaf forests produce a rich crop of beech, linden, maple, ash, walnut, chestnut, and acorn seeds. Therefore, among the animal population there are many consumers of these feeds. In our country, such consumers (and in the Old World in general) primarily include various mice and rats. In America, these rodents are absent, but their place is occupied by species of the hamster-like group. Peromiscus are called deer, or white-footed mice, and ochrotomis are called golden mice, although they are not really mice, but hamsters. Wood voles feed on both seeds and grass. Of the other rodents in the zone of deciduous forests, gray voles are common, as in the Old World, but they are more characteristic of meadow or field landscapes. The water vole - muskrat - is now acclimatized in Eurasia because of its valuable skin.
As on other continents, deer are characteristic of deciduous forests. Races of the same red deer are common in North America as in Eurasia. The American red deer is called wapiti. Wapiti is most of all similar to deer and wapiti. The most widespread species is a representative of a special subfamily (endemic to the New World), the white-tailed, or virginian, deer. It penetrates as far south as Brazil. In winter, deer feed on branches of trees and shrubs, in the rest of the time they also feed on grass. White-tailed deer, due to their high numbers, are the most important object of sport hunting in the United States. Black-tailed deer live in the mountains of the Pacific coast. It lives not only in broad-leaved forests, but also in coniferous and xerophytic chaparral thickets.
Insectivorous birds predominate among the birds of broad-leaved forests, while during the nesting period small passerines predominate. The types of oatmeal are diverse; on this basis, American forests are moving closer to areas of East Asia. Thrush species are also characteristic. Such typical Eurasian families as flycatchers and warblers are absent. They are replaced respectively by tyranaceae and woody species. Both of these families are widespread in both Americas, and are most characteristic of forest habitats. Mockingbirds should also be included here.
Most predators (both animals and birds) that feed on vertebrates are widely distributed across the continent. Deciduous forests of predatory mammals are characterized by such species as the large marten pecan - the enemy of squirrels and porcupines, skunk, raccoon from the raccoon family. Nosuhi also penetrate into the subtropical deciduous forests of the south. The raccoon is the only species of the family (and the northernmost) that hibernates for the winter. The American baribal is ecologically similar to the black bear of Southern and Eastern Eurasia. In addition to the ubiquitous red fox, the gray fox is very typical of the zone. This is an animal that has a somewhat extravagant habit for foxes and the entire canine family to climb trees and even hunt in crowns. Outwardly, the gray fox is similar to the usual one, differing in color, short ears and muzzle.
In conclusion of the review of the animal world, one animal should be mentioned, which can hardly be compared with any species of Eurasia. This is a climbing (with the help of paws and a tenacious tail) opossum - the only representative of marsupials that penetrates from South America so far to the north. The distribution of the possum, in general, corresponds to the distribution of broad-leaved forests of the subtropical and temperate latitudes of the continent. The animal is the size of a rabbit and is active at night. It feeds on a variety of small animals, fruits, mushrooms, and can harm fields and gardens. Possums are hunted for their meat and skins. The prickly porcupine from a special, also predominantly South American family of tree porcupines, also leads an arboreal lifestyle.
In terms of organic mass reserves, deciduous and coniferous-broad-leaved forests of temperate and subtropical latitudes correspond to similar groups of other continents. It ranges from 400-500 t/ha. In temperate latitudes, productivity is 100-200 c/ha per year, and in subtropical latitudes - up to 300 c/ha. In valleys and wet delta areas, productivity can be even higher (Mississippi Delta and some areas of Florida - 500 c/ha and more dry organic matter per year). In this regard, broad-leaved forests are second only to tropical and equatorial forests. The phytomass of chaparral is much less - about 50 t/ha; productivity - about 100 q/ha per year. This is close to the corresponding figures for other Mediterranean types of biocenoses.
Steppe Ecosystems of the World
An ecosystem can be defined as a collection of different species of plants, animals, and microbes interacting with each other and with their environment in such a way that the whole combination can be preserved indefinitely. This definition is a very concise description of the facts observed in nature.
Eurasian steppes
The Eurasian steppe is a term often used to describe the vast Eurasian steppe ecoregion extending from the western borders of the Hungarian steppes to the eastern border of the Mongolian steppes. Most of the Euro-Asian steppe is included in the Central Asian region, and only a small part of it is included in Eastern Europe. The term Asian steppe usually describes the Euro-Asian steppe, without the westernmost part, i.e. steppes of western Russia, Ukraine and Hungary.
The steppe zone is one of the main land biomes. Under the influence, first of all, of climatic factors, zonal features of biomes were formed. The steppe zone is characterized by a hot and arid climate during most of the year, and in spring there is a sufficient amount of moisture, so the steppes are characterized by the presence of a large number of ephemera and ephemeroids among plant species, and many animals are also confined to a seasonal lifestyle, falling into hibernation in arid and cold season.
The steppe zone is represented in Eurasia by the steppes, in North America by the prairies, in South America by the pampas, and in New Zealand by the Tussok communities. These are spaces of the temperate zone, occupied by more or less xerophilous vegetation. From the point of view of the conditions for the existence of the animal population, the steppes are characterized by the following features: a good view, an abundance of plant food, a relatively dry summer period, the existence of a summer period of rest or, as it is now called, semi-rest. In this respect, steppe communities differ sharply from forest communities. Among the predominant life forms of steppe plants, grasses stand out, the stems of which are crowded into turfs - turf grasses. In the Southern Hemisphere, such turfs are called Tussocks. Tussocks are very tall and their leaves are less rigid than those of the tufts of steppe grasses of the Northern Hemisphere, since the climate of communities close to the steppes of the Southern Hemisphere is milder.
Rhizome grasses that do not form turfs, with single stems on creeping underground rhizomes, are more widely distributed in the northern steppes, in contrast to turf grasses, whose role in the Northern Hemisphere increases towards the south.
Thus, the steppe biogeographical zone is characterized by the originality of representatives of the flora and fauna, adapted to life in this zone.
prairies
Prairie (fr. prairie) is a North American form of steppe, a vegetation zone in the Midwest of the USA and Canada. Makes up the eastern edge of the Great Plains. Limited vegetation, expressed in the rarity of trees and bushes, is due to the inland location and the Rocky Mountains, which shield the prairie from the west from precipitation. Arid climatic conditions are associated with this circumstance.
Significant areas of the steppes are in America. They are especially widespread in North America, where they occupy the entire central region of the mainland. Here they are called prairies. The vegetation of individual sections of the prairies is not the same. Most similar to our steppes are American real prairies, in which the vegetation consists of feather grasses, bearded vultures, keleria, but these plants close to ours are represented there by other species. When the grasses and dicotyledons of the real prairies reach full development, the height of the herbage exceeds half a meter. There is no summer break in the life of plants here.
Grassland prairies are found in wetter areas where forest can grow along with herbaceous vegetation. Oak forests occupy the slopes of shallow valleys, flat and elevated areas of the meadow prairie are covered with grass, consisting of tall grasses. The height of the herbage here is about a meter. In the last century, the height of the grass in some places reached the horse's back.
Most of the North American steppes are occupied by low-cereal prairies. This type of herbaceous vegetation is characteristic of the most arid parts of the steppes. The herbage of the low-grass prairie is dominated by two grasses - buffalo grass and Gram grass. Their leaves and stems form a dense brush on the surface of the soil, and their roots form an equally dense plexus in the soil. It is almost impossible for any other plant to penetrate into these dense thickets, so the low-grass steppes are monotonous. Grass in the low-cereal steppe reaches a height of 5-7 cm and forms very little plant mass.
American researchers have proved in recent years that low-cereal steppes originated from real and even meadow prairies.
At the end of the last and the beginning of the 20th century, pastoralists-industrialists kept so many cattle on the prairies that all natural grasses, well eaten by animals, were completely destroyed and could no longer be restored. In the steppe, low-growing cereals and coarse dicotyledonous plants survived and spread. They formed low-cereal prairies.
Most of the North American prairies are plowed up and used for sowing various crops.
In South America, an area covered with grassy vegetation is called a pampa. The Pampa is an immense, slightly hilly expanse that occupies most of Argentina and Uruguay and reaches in the west to the foot of the Cordillera. In the pampa, several plant groups are replaced during the summer: early grasses give way to late ones, early-flowering dicotyledonous plants - late-flowering. There are many grasses in the herbage of the pampas, and among the dicots, there are especially many species of Compositae. The development of vegetation in the pampas begins in October and ends in March - after all, the pampas are located in the southern hemisphere.
Pampas
Pampas (Pampas) (Spanish Pampa) - a steppe in the southeast of South America, mainly in the subtropical zone, near the mouth of the Rio Plata. In the west, the pampas are bounded by the Andes, in the east by the Atlantic Ocean. To the north is the savannah of the Gran Chaco.
Pampa is a herbaceous cereal vegetation on fertile reddish-black soils formed on volcanic rocks. It consists of South American species of those genera of cereals that are widespread in Europe in the steppes of the temperate zone (feather grass, bearded vulture, fescue). The pampa is connected with the forests of the Brazilian Highlands by a transitional type of vegetation, close to the forest-steppe, where grasses are combined with thickets of evergreen shrubs. The vegetation of the pampas has been the most severely destroyed and is now almost completely replaced by crops of wheat and other cultivated plants. When the grass cover dies off, fertile gray-brown soils are formed. In the open steppe expanses, fast-running animals predominate - the pampas deer, the pampas cat, among the birds - the ostrich rhea. There are many rodents (nutria, viscacha), as well as armadillos.
The pampa becomes more and more arid as it moves away from the Atlantic Ocean. The climate of the pampas is temperate. In the east, temperature differences between summer and winter are less significant, in the west the climate is more continental.
The states whose territory is affected by the pampas are Argentina, Uruguay and Brazil. The Pampa is the main agricultural region of Argentina and is mainly used for cattle breeding.
Savannah
Savannahs (otherwise campos or llanos) are steppe-like places characteristic of more elevated tropical countries with a dry continental climate. Unlike real steppes (as well as North American prairies), savannas, in addition to grasses, also contain shrubs and trees, sometimes growing in a whole forest, as, for example, in the so-called "campos cerrados" of Brazil. The herbaceous vegetation of the savannas consists mainly of high (up to ⅓-1 meters) dry and hard-skinned grasses, usually growing in tufts; grasses are mixed with turfs of other perennial grasses and shrubs, and in damp places flooded in spring, also various representatives of the sedge family (Cyperaceae). Shrubs grow in savannahs, sometimes in large thickets, covering an area of many square meters. Savannah trees are usually stunted; the tallest of them are no taller than our fruit trees, to which they are very similar in their crooked stems and branches. Trees and shrubs are sometimes entwined with vines and overgrown with epiphytes. There are few bulbous, tuberous and fleshy plants in the savannas, especially in South America. Lichens, mosses and algae are extremely rare in savannas, only on rocks and trees.
The general appearance of the savannahs is different, which depends, on the one hand, on the height of the vegetation cover, and on the other hand, on the relative amount of grasses, other perennial grasses, semi-shrubs, shrubs and trees; for example, the Brazilian shrouds ("campos cerrados") are actually light, rare forests, where you can freely walk and drive in any direction; the soil in such forests is covered with a herbaceous (and semi-shrub) cover ½ and even 1 meter high. In the savannahs of other countries, trees do not grow at all or are extremely rare and are very short. The grass cover is also sometimes very low, even pressed to the ground. A special form of savannas is the so-called llanos of Venezuela, where trees are either completely absent or are found in a limited number, with the exception of damp places where palm trees (Mauritia flexuosa, Corypha inermis) and other plants form entire forests (however, these forests do not belong to savannas); in llanos there are sometimes single specimens of Rhopala (trees from the Proteaceae family) and other trees; sometimes the cereals in them form a cover as tall as a man; Compositae, leguminous, labiate, etc. grow between cereals. Many llanos in the rainy season are flooded by the floods of the Orinoco River.
Living conditions in the savannah are very harsh. The soil contains few nutrients, during dry seasons it dries up, and during wet seasons it becomes waterlogged. In addition, fires often occur there at the end of dry seasons. Plants that have adapted to the conditions of the savannas are very cruel. There are thousands of different herbs growing there. But trees, in order to survive, need some specific qualities to protect against drought and fire. For example, the baobab is distinguished by a thick trunk protected from fire, capable of storing water reserves, like a sponge. Its long roots suck up moisture deep underground. Acacia has a wide flat crown, which creates a shadow for the leaves growing below, thereby protecting them from drying out. Many areas of the savannah are now used for pastoralism and the wild forms of life there have completely disappeared. However, in the African savannah there are huge national parks where wild animals still live.
Savannahs are characteristic of South America proper, but in other countries one can point out many places that are very similar in the nature of their vegetation to savannahs. Such, for example, are the so-called Campine in the Congo (in Africa); in South Africa, some places are covered with a vegetation cover consisting mainly of grasses (Danthonia, Panicum, Eragrostis), other perennial grasses, shrubs and trees (Acacia horrida), so that such places resemble both the prairies of North America and the savannas of South America; similar places are found in Angola. ("Campos Cerrado")
In areas located a few degrees north and south of the equator, the climate is usually very dry. However, during certain months it gets very hot and it rains. Such places, located all over the world, are called savanna zones. This name comes from the African savanna, which is the largest region with this type of climate. Savannah zones are located between two tropics - lines where twice a year the sun at noon is exactly at its zenith. At such times, it becomes much hotter there and much more sea water evaporates from this, which leads to heavy rains. In the areas of the savannas closest to the equator, the sun is exactly at its zenith at the intermediate moments of the year (in March and September), so that several months separate one rainy season from another. In the areas of the savannas, the most distant from the equator, both rainy seasons are so close in time to each other that they practically merge into one. The duration of the rainy period is from eight to nine months, and at the equatorial borders - from two to three.
The vegetation of the savannas is adapted to a dry continental climate and to periodic droughts that occur in many savannas for whole months. Cereals and other grasses rarely form creeping shoots, but usually grow in tufts. The leaves of cereals are narrow, dry, hard, hairy or covered with a waxy coating. In grasses and sedges, young leaves remain rolled up into a tube. In trees, the leaves are small, hairy, shiny (“lacquered”) or covered with a waxy coating. The vegetation of the savannas has a pronounced xerophytic character. Many species contain large amounts of essential oils, especially those of the Verbena, Labiaceae, and Myrtle families of South America. The growth of some perennial grasses, semi-shrubs (and shrubs) is especially peculiar, namely, that the main part of them, located in the ground (probably, the stem and roots), grows strongly into an irregular tuberous woody body, from which then numerous, mostly unbranched or weakly branched, offspring. In the dry season, the vegetation of the savannas freezes; savannahs turn yellow, and dried plants are often subjected to fires, due to which the bark of trees is usually scorched. With the onset of rains, the savannahs come to life, covered with fresh greenery and dotted with numerous different flowers. The eucalyptus forests of Australia are quite similar to the "campos cerratos" of the Brazilians; they are also light and so rare (the trees are far apart from each other and do not close in crowns) that it is easy to walk in them and even drive in any direction; the soil in such forests during the rainy season is covered with green thickets, consisting mainly of cereals; in the dry season, the soil is exposed.
Savannah animals have been forced to adapt to survive in drought conditions. Large herbivores such as giraffes, zebras, wildebeests, elephants and rhinoceroses are able to travel great distances and if it gets too dry in some place, they go to where it rains and where there is a lot of vegetation. Predators such as lions, cheetahs and hyenas prey on wandering herds of animals. It is difficult for small animals to start out in search of water, so they prefer to hibernate during the entire dry season.
Deserts of the world
sandy deserts
Depending on the rocks that make up the territory, there are: clay, rocky and sandy deserts. Contrary to the popular idea of deserts as vast expanses of endless undulating rows of sand dunes, only one-fifth of the area of the world's deserts is covered with sand. However, there are many impressive sandy seas. In the Sahara, sandy deserts, ergs, cover many tens of thousands of square kilometers. The sand that is washed away from the neighboring highlands is formed as a result of the weathering of the desert rocks. It is constantly carried by the wind from place to place and eventually accumulates in lowlands and depressions.
Transverse dunes are long ridges of sand at right angles to the prevailing local wind. The dunes have a horseshoe shape, and their "horns" are directed to the wind. Star dunes often reach enormous sizes. They are formed under the influence of winds blowing from different directions. Created by very strong winds, they often stretch for many kilometers and reach 100 m in height. Windswept hollows between rows of spear-shaped dunes with exposed bedrock have traditionally served as the main trade routes of the nomadic peoples of the desert.
The dunes have an almost regular crescent shape, and their pointed tails - horns - are extended in the direction of the wind. They are found mainly in those deserts where there is relatively little sand, so the dunes move along gravel-strewn surfaces or even exposed bedrock. Of all the dunes, dunes are the most mobile.
There are also star-shaped dunes that resemble whole mountains of sand. Sometimes their height reaches 300 m, and from above, such dunes look like a starfish with curved tentacle rays. They form where the winds blow alternately from different directions, and, as a rule, do not move anywhere.
Features of the climate and relief of sandy deserts greatly complicate the conditions for the construction and operation of roads. The relief of sandy deserts is unstable. The higher the wind speed at the earth's surface, the larger particles it moves.
The wind-sand flow around the irregularities of the sandy relief is accompanied by the formation of areas of local increase in flow velocities, eddies, and calm zones. In the swirl zone, sand is dispersed, and in the calm zone it is deposited.
The movement of sand grains in the direction of the wind causes a general movement of the surface layers of sand in the form of ripples. Gradually I climb the slopes of sandy hills, the grains of sand, after being transferred over the top, roll down and are deposited in the calm zone on the leeward side. As a result, sand hills gradually move in the direction of the wind. Such sands are called mobile. The speed of movement of sand mounds decreases with increasing height.
The following characteristic relief forms of sandy deserts, formed under the influence of wind, are distinguished: barchans, dune chains, sandy ridges, hilly sands. The formation of each of their relief forms is associated with certain conditions for the movement of sands, with the strength and direction of the prevailing winds.
Barkhans are called single or grouped sandy hills up to 3-5 m or more high, up to 100 m wide, having the shape of a crescent moon with horns oriented in the direction of the wind. The windward gentle slope, depending on the size of the sand, has a steepness of 1:3-1:5, the leeward slope is 1:1.5-1:2. This form of relief is the most unstable and easily succumbs to the action of the wind. Single dunes are formed on the outskirts of loose sands, on smooth, bare and flat takyr and solonchak
Takyrs are called flat surfaces, covered with hard clay soil, takyrs are located mainly along the outskirts of the sands and represent the dry bottom of temporary lakes formed during the rapid melting of snow or after heavy rains. Clay and silt particles settling from the water form a dense waterproof layer over time. After the rains, the takyrs are covered with water for several days, and then, when the water evaporates, the clay cracks into separate tiles.
rocky desert
Rocky deserts come in several types, depending on the type of surface. It can be formed by stone, crushed stone, pebbles, gypsum. The surface of some deserts is well permeable to water, while others form a dense waterproof crust. In the first case, the water goes to a depth inaccessible to the roots of plants. In the second, it evaporates from the surface, further fixing the crust of the desert.
Where there used to be water, salts form. In some places, their concentration is so great that they create a crust on the surface. There are places that are 15 cm thick with hummocks up to a meter high. If the moisture has not completely evaporated, salt marshes look like a marshy swamp.
One of the most common types of deserts are stony, gravel, gravel-pebble and gypsum deserts. They are united by roughness, hardness and surface density. The permeability of rocky soils is different. The largest pebble and rubble fragments, which lie rather loosely, easily pass water, and atmospheric precipitation quickly seeps to great depths inaccessible to plants. But more often, however, surfaces are common where gravel or crushed stone is cemented with sand or clay particles. In such deserts, stony fragments lie densely, forming the so-called desert pavement.
The relief of rocky deserts is different. There are areas of even and flat plateaus, slightly inclined or flat plains, slopes, gentle hills and ridges among them. On the slopes, ravines and gullies are formed. There are frequent changes in temperature and condensation of moisture at night.
Life in rocky deserts is especially dependent on rainfall and evaporation. In the most severe conditions, it is simply impossible. The rocky deserts of the Sahara (hamadas), occupying up to 70% of its area, are often devoid of higher vegetation. Cushion-like shrubs of freodolia and limonastrum are fixed only on separate screes. In the more humid deserts of Central Asia, although sparsely, they are evenly covered with wormwood and saltworts. On the sandy-pebble plains of Central Asia, undersized thickets of saxaul are common.
In tropical deserts, succulents settle on rocky surfaces. In South Africa, these are cissuses with thick barrel-shaped trunks, spurges, "tree lily"; in the tropical part of America - a variety of cacti, yucca and agave. There are many different lichens in the stony deserts, covering the stones and coloring them in white, black, blood red or lemon yellow.
Scorpions, phalanges, geckos live under stones. Here, more often than in other places, the muzzle is found.
Subtropical deciduous forests
Tropical and subtropical deciduous biomes do not respond to seasonal changes in temperature, but to the amount of precipitation that falls during the season. During the dry season, plants shed their leaves to conserve moisture and avoid desiccation. Leaf fall in such forests does not depend on the season, at different latitudes of different hemispheres, even within a small region, forests can differ in time and duration of leaf fall, different slopes of the same mountain or vegetation on river banks and watersheds can be like a patchwork quilt from bare and leafy trees.
Subtropical evergreen forests
Subtropical evergreen forest - a forest common in subtropical zones.
Dense deciduous forest with evergreen trees and shrubs.
The subtropical climate of the Mediterranean is dry, precipitation in the form of rain falls in winter, even mild frosts are extremely rare, summers are dry and hot. In the subtropical forests of the Mediterranean, thickets of evergreen shrubs and low trees predominate. Trees rarely stand, and various herbs and shrubs grow wildly between them. Here grow junipers, noble laurel, strawberry tree, which sheds its bark every year, wild olives, tender myrtle, roses. Such types of forests are characteristic mainly in the Mediterranean, and in the mountains of the tropics and subtropics.
The subtropics on the eastern outskirts of the continents are characterized by a more humid climate. Atmospheric precipitation falls unevenly, but it rains more in summer, that is, at a time when vegetation is in particular need of moisture. Dense moist forests of evergreen oaks, magnolias, and camphor laurels predominate here. Numerous creepers, thickets of tall bamboos and various shrubs enhance the originality of the humid subtropical forest.
From humid tropical forests, the subtropical forest differs in lower species diversity, a decrease in the number of epiphytes and lianas, as well as the appearance of coniferous, tree-like ferns in the forest stand.
The subtropical belt is characterized by a wide variety of climatic conditions, which is expressed in the peculiarities of humidification of the western, inland and eastern sectors. In the western sector of the mainland, the Mediterranean type of climate, the originality of which lies in the mismatch between humid and warm periods. The average annual precipitation on the plains is 300-400 mm (in the mountains up to 3000 mm), the predominant part of them falls in winter. The winter is warm, the average temperature in January is not lower than 4 C. The summer is hot and dry, the average temperature in July is above 19 C. Under these conditions, Mediterranean hard-leaved plant communities were formed on brown soils. In the mountains, brown soils are replaced by brown forest ones.
The main area of distribution of hard-leaved forests and shrubs in the subtropical zone of Eurasia is the Mediterranean territory, developed by ancient civilizations. Goat and sheep grazing, fires and land exploitation have led to almost complete destruction of the natural vegetation cover and soil erosion. The climax communities here were represented by evergreen hardwood forests dominated by the oak genus. In the western part of the Mediterranean with a sufficient amount of precipitation on various parent species, sclerophyte holm oak up to 20 m high was a common species. The shrub layer included low-growing trees and shrubs: boxwood, strawberry tree, phyllyria, evergreen viburnum, pistachio and many others. The grass and moss cover was sparse. Cork oak forests grew on very poor acidic soils. In eastern Greece and on the Anatolian coast of the Mediterranean Sea, holm oak forests were replaced by kermes oak forests. In the warmer parts of the Mediterranean, oak plantations gave way to plantations of wild olive (wild olive tree), lentiscus pistachio and caratonia. The mountainous regions were characterized by forests of European fir, cedar (Lebanon), and black pine. Pine trees (Italian, Aleppo and Maritime) grew on the sandy soils of the plains. As a result of deforestation, various shrub communities arose in the Mediterranean long ago. The first stage of forest degradation, apparently, is represented by a maquis shrub community with isolated trees that are resistant to fires and felling. Its species composition is formed by a variety of shrubs of the undergrowth of degraded oak forests: various types of erica, rockroses, strawberry tree, myrtle, pistachio, wild olive, carob tree, etc. The abundance of thorny and climbing plants makes maquis impassable. In place of the flattened maquis, a gariga formation of a community of low-growing shrubs, semishrubs, and xerophilous herbaceous plants develops. Undersized (up to 1.5 m) thickets of Kermes oak dominate, which is not eaten by livestock and quickly captures new territories after fires and clearings. The families of labiales, legumes and rosaceae are abundant in garigi, which produce essential oils. Of the characteristic plants, pistachio, juniper, lavender, sage, thyme, rosemary, cistus, etc. should be noted. Gariga has various local names, for example, tomillaria in Spain. The next formation, which is formed on the site of a degraded maquis, is a frigan, the vegetation cover of which is extremely sparse. Often these are rocky wastelands. Gradually, all plants eaten by livestock disappear from the vegetation cover, for this reason, geophytes (asphodelus), poisonous (euphorbia) and thorny (astragalus, Compositae) plants predominate in the freegana. In the lower zone of the mountains of the Mediterranean, including the western Transcaucasia, subtropical evergreen laurel, or laurel-leaved, forests are common, named after the prevailing species of various species of laurel.
Tropical rain forests
Evergreen tropical rainforests are located along the equator, in a zone where 2000-2500 mm/g of precipitation is distributed fairly evenly over the months. Rainforests are located in three main areas: 1) the largest continuous massif in the Amazon and Orinoco basins in South America; 2) in the basins of the Congo, Niger and Zambezi rivers in Africa and on the island of Madagascar; 3) Indo-Malay and the islands of Borneo - New Guinea (Fig. 7.3). The annual course of temperatures in these areas is quite even and in some cases reduces seasonal rhythms in general or evens them out.
In tropical rainforests, trees form three tiers: 1) rare tall trees create an upper tier above the general canopy level; 2) a canopy forming a continuous evergreen cover at a height of 25-35 m; 3) the lower tier, which clearly manifests itself as a dense forest only in places of a gap in the canopy. Herbaceous vegetation and shrubs are practically absent. But a large number of vines and epiphytes. The species diversity of plants is very high - on several hectares you can find as many species as there are not in the flora of the whole of Europe (Yu. Odum, 1986). The number of tree species according to different records is different, but, apparently, it reaches 170 or more, although there are no more than 20 species of herbs. The number of species of interlayer plants (lianas, epiphytes, etc.), together with herbs, is 200-300 or more.
Tropical rainforests are fairly ancient climax ecosystems in which nutrient cycling has been brought to perfection - they are little lost and immediately enter the biological cycle, carried out by mutualistic organisms and shallow, mostly aerial, with powerful mycorrhiza, tree roots. It is because of this that forests grow so luxuriantly on scarce soils.
The fauna of these forests is no less diverse than the vegetation. Most of the animals, including mammals, exist in the upper tiers of vegetation. The diversity of animal species can be illustrated by the following figures: there are 20,000 species of insects per 15 km2 of rainforest in Panama, while there are only a few hundred of them in the same area in western Europe.
Of the large animals of the tropical forests, we will name only a few of the most famous: monkeys, jaguars, anteater, sloth, cougar, great apes, buffalo, Indian elephant, peacock, parrots, condor, royal vulture and many others.
The tropical forest is characterized by a high rate of evolution and speciation. Many species have become part of more northern communities. Therefore, it is very important to conserve these forests as a “resource of genes”.
Tropical rainforests have a large biomass and the highest productivity of terrestrial biocenoses.
In order for the forest to recover to the state of climax, a long succession cycle is required. To speed up the process, it is proposed, for example, to cut it down with narrow clearings, leaving plants that are of no value to industry, without disturbing the supply of nutrients in root pads, and then seeding from unaffected areas will help to quickly restore the forest to its original form.
LEVELS OF BIODIVERSITY
Biodiversity levels
Diversity can be considered as the most important parameter of biosystems, associated with their vital characteristics, which are criteria for efficiency and are extremized in the course of their development (stability, entropy production, etc.). The extreme (maximum or minimum) value of the bnosystem efficiency criterion G* (Fig. 1) is achieved at the optimal level of diversity D*. In other words, the biosystem achieves its goal at the optimal level of diversity. A decrease or increase in diversity compared to its optimal value leads to a decrease in the efficiency, stability, or other vital characteristics of the biosystem.
Critical or acceptable levels of diversity are determined by the same relationship between the criterion of system efficiency and its diversity. It is obvious that there are such values of the efficiency criterion at which the system ceases to exist, for example, the minimum values of stability or energy efficiency of the Go system. These critical values correspond to the levels of system diversity (Do), which are the maximum allowable, or critical, levels.
The possibility of the existence of optimal values of diversity in biosystems of the population and biocenotic levels is shown on empirical data and the results of biodiversity modeling. The idea of critical levels of diversity is today one of the theoretical principles of wildlife conservation (concepts of minimum population size, critical levels of genetic diversity in populations, minimum area of ecosystems, etc.).
Passive and active methods of biodiversity protection
To regulate the impact of any kind of anthropogenic activity on biodiversity, only a few methods are used:
An environmental impact assessment (EIA) is a method for identifying serious problems before they even manifest themselves. The most important stage of such an assessment is the survey of the area. For example, in vulnerable island ecosystems, all tourist accommodation and services should be located at a sufficient distance from the most vulnerable areas and well above the maximum tide level, since many beaches are characterized by natural processes of erosion and sedimentation.
A proposed strategy analysis (SEA) is designed to examine proposed strategies, plans or programs and assess their environmental impact and consequences.
Tolerance Assessment (CCA) is the determination of the maximum load from human activities or the maximum number of users that a natural or man-made resource or system can withstand without seriously endangering them.
Environmental impact assessment is a strategically important legal tool for biodiversity protection, as it aims to eliminate problems before projects start. Such an assessment should be carried out within the framework of individual industries, types of land use, programs and plans: in particular, when planning the construction of roads, changes in the water regime of the river basin, forest management, etc. If the project has already become an integral part of an approved plan or program, it is often too late or impossible to make such an assessment at the stage of its implementation to prevent major damage.
As a result of the transformation of nature by man, many species of animals and plants have been brought to the brink of destruction. Measures to protect such species have become an urgent need. Red Books are compiled, the extraction of rare species is prohibited, international trade is strictly limited, nature reserves, national parks, and other specially protected natural areas are being created. Unfortunately, some animal species are pushed to such a limit that these generally accepted, traditional protection measures are no longer enough for them. To save them, it is necessary to take more active actions, as they say - to use intensive methods of protection. Quite a lot of such methods are known. They can be aimed both at creating optimal conditions for reproduction, and at optimizing the food supply or protective habitat conditions. The creation of devices that prevent the death of animals on power lines or during agricultural work, captive breeding and resettlement of rare species - all these are various methods of intensive wildlife protection, which in foreign literature have received such a name as management of wild animal populations. In our country, the term "biotechnical measures" is more often used. For quite a long time, biotechnical measures were mainly used for purely utilitarian purposes - to increase the number of valuable commercial species. At the same time, feeding, arranging artificial nests, and other assistance to animals were undertaken by man for other, disinterested, reasons, including those for environmental purposes. The oldest traditions have various types of biotechnical work aimed at the protection of birds
CONCLUSION
Biodiversity has been defined as “the variability of living organisms from all sources, including, inter alia (Latin for “among others”), terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part: this includes diversity within species, diversity of species and diversity of ecosystems. This definition has become an official definition in terms of the letter of the law, since it is included in the UN Convention on Biodiversity, which is accepted by all countries of the Earth, with the exception of Andorra, Brunei, Vatican, Iraq, Somalia and the United States. The UN has established the International Day for Biological Diversity. It is rather difficult to determine the need to conserve and maintain biodiversity in any objective way, since it depends on the point of view of the one who evaluates this need. However, there are three main reasons to conserve biodiversity: From a utilitarian point of view, the elements of biodiversity are resources that are of real benefit to humans today or may be useful in the future. Biodiversity as such provides both economic and scientific benefits (for example, in the search for new drugs or treatments). The choice to conserve biodiversity is an ethical choice. Mankind as a whole is a part of the ecological system of the planet, and therefore it must carefully treat the biosphere (in fact, we all depend on its well-being). The significance of biodiversity can also be characterized in aesthetic, substantive and ethical terms. Nature is glorified and sung by artists, poets and musicians all over the world; for man, nature is an eternal and enduring value.
Tundra (from Finnish tunturi - treeless bare upland), a type of biome with characteristic treelessness in the subarctic zone of the Northern Hemisphere. It occupies an area of about 3 million km2, stretching along the northern coast of North America and Eurasia in a continuous strip up to 500 km wide. Tundra is also found on some islands near Antarctica. In the mountains it forms a high-altitude landscape belt (mountain tundra).
Forest-tundra - closed boreal coniferous forests near the northern limit of their distribution usually gradually but steadily become more red-hardy. Treeless areas appear; there are more of them to the north. Low, often ugly trees are separated from one another by 10 m or more.
Dark coniferous forests - the tree stand of which is represented by species with dark evergreen needles - numerous species of spruce, fir and Siberian pine (cedar).
Coniferous forest – A forest consisting almost exclusively of coniferous trees. A significant part of coniferous forests is located in the cold climate of northern latitudes as taiga, but coniferous forests are also found in other parts of the planet. In Central Europe, many mountain ranges are covered with them.
BIBLIOGRAPHY
- Voronov A.G. Biogeography with the basics of ecology. - 2nd ed. - M.: Publishing House of Moscow State University, 2007.
- Vtorov P.P., Drozdov N.N. Biogeography of continents. - 2nd ed. - M.: Education, 2006.
- Kiselev V.N. Fundamentals of ecology. - Minsk, 2000.
- Boxes V.I., Peredelsky L.V. Ecology - Rostov-on-Don: Phoenix, 2001
- Peredelsky L.V., Korobkin V.I. Ecology in questions and answers. - Rostov n / D., 2002.
- Stolberga F.V. City ecology. K.: 2000
- Tolmachev A.I., On the history of the emergence and development of the dark coniferous taiga, M.-L., 2004
- Khachaturova T.S. Environmental economics. M.: Publishing House of Moscow State University, 2001
- Shamileva I.A. Ecology. Textbook for universities. - M., 2004.
- Shilov I.A. Ecology. - M., 2000.
Biocenoses differ in the species diversity of their constituent organisms.
The species structure of a biocenosis is understood as the diversity of species in it and the ratio of their abundance or biomass.
Species structure.
STRUCTURE OF BIOCENOSIS.
A biotope is a place of existence, or a habitat for a biocenosis, and a biocenosis can be considered as a historically established complex of living organisms, characteristic of a particular biotope.
A biotope is a piece of territory with more or less homogeneous conditions, occupied by a particular community of living organisms (biocenosis).
In other words,
The section of ecology that studies the patterns of composition of communities and the coexistence of organisms in them is called synecology (biocenology).
Synecology arose relatively recently - at the beginning of the twentieth century.
The structure of a biocenosis is the ratio of various groups of organisms that differ in their systematic position; according to the place occupied by them in space; according to the role that they play in the community, or according to another sign that is essential for understanding the patterns of functioning of this biocenosis.
Distinguish species, spatial and ecological structure of the biocenosis.
Each specific biocenosis is characterized by a strictly defined species composition (structure).
In those biotopes where environmental conditions are close to optimal for life, extremely species-rich communities arise ( for example, biocenoses of tropical forests or coral reefs).
The biocenoses of the tundra or desert are extremely poor in species. This is due to the fact that only a few of the species can adapt to such unfavorable environmental conditions as a lack of heat or lack of moisture.
The ratio between the conditions of existence and the number of species in the biocenosis is determined by the following principles:
1. The principle of diversity: the more diverse the conditions of existence within the biotope, the more species in a given biocenosis.
2. The principle of rejecting conditions: the more the conditions of existence within the biotope deviate from the norm (optimum), the poorer the biocenosis becomes in species and the more numerous each species.
3. The principle of smooth change of environment: the more smoothly the environmental conditions in the biotope change and the longer it remains unchanged, the richer the biocenosis in species and the more balanced and stable it is.
The practical significance of this principle is that the more and faster the transformation of nature and biotopes occurs, the more difficult it is for species to have time to adapt to this transformation, and therefore the species diversity of biocenoses becomes less
The pattern of change in species diversity is also known (Wallace's rule): species diversity decreases as one moves from south to north ( those. from the tropics to the high latitudes).
For example:
- in humid tropical forests, there are up to 200 species of tree species per 1 hectare;
· pine forest biocenosis in the temperate zone can include a maximum of 10 tree species per 1 ha;
· in the north of the taiga region, there are 2-5 species per 1 ha.
The species diversity of biocenoses also depends on the duration of their existence and the history of each biocenosis.
- young, emerging communities, as a rule, have a smaller set of species than long-established, mature ones;
- biocenoses created by man (gardens, orchards, fields, etc.) are usually poorer in species compared to similar natural biocenoses (forest, meadow, steppe)
In each community, a group of the main, most numerous species can be distinguished.
Species that prevail in the biocenosis in terms of numbers are called dominant or dominant.
Dominant species occupy a leading, dominant position in the biocenosis.
So, for example, the appearance of a forest or steppe biocenosis is represented by one or more dominant plant species:
in an oak forest it is an oak, in a pine forest it is a pine, in a feather-grass-fescue steppe it is a feather grass and a fescue..
Usually terrestrial biocenoses are named according to the dominant species:
* larch forest, coniferous forest (pine, spruce, fir), sphagnum bog (sphagnum moss), feather grass-fescue steppe (feather grass and fescue).
Species living at the expense of dominants are called predominants.
For example, in an oak forest, these are various insects, birds, mouse-like rodents feeding on oak.
Among the dominant species are edificators are those species that, by their vital activity, create the conditions for the life of the entire community to the greatest extent.
Consider the edificatory role of spruce and pine.
Spruce in the taiga zone forms dense, heavily darkened forests. Under its canopy, only plants adapted to conditions of strong shading, high humidity, high acidity of soils, etc. can live. According to these factors, a specific animal population is formed in spruce forests.
Consequently, spruce in this case acts as a powerful edificator, which determines a certain species composition of the biocenosis.
In pine forests, pine is the edificator. But compared to spruce, it is a weaker edificator, since the pine forest is relatively light and sparse. Its species composition of plants and animals is much richer and more diverse than in the spruce forest. In pine forests there are even plants that can live outside the forest.
Edificator species are found in almost any biocenosis:
* on sphagnum bogs - these are sphagnum mosses;
* in steppe biocenoses, feather grass serves as a powerful edificator.
In some cases, animals can also be edificators:
* in the territories occupied by marmot colonies, it is their activity that mainly determines the nature of the landscape, the microclimate and the conditions for the growth of grasses.
However, the role of edificators in certain biocenoses is not absolute and depends on many factors:
* Thus, when a spruce forest is thinned out, spruce may lose the function of a powerful edifier, since this leads to lightening of the forest and other species that reduce the edificatory value of spruce are introduced into it;
* in a pine forest located on sphagnum bogs, pine also loses its edificatory value, as sphagnum mosses acquire it.
In addition to a relatively small number of dominant species, a biocenosis usually includes many small and even rare forms (secondary species), which create its species richness, increase the diversity of biocenotic relationships and serve as a reserve for replenishment and replacement of dominants, i.e. give stability to the biocenosis and ensure its functioning in different conditions.
Based on the relationship of species in populations, biocenoses are divided into complex and simple.
Complex biocenoses are called biocenoses, consisting of a large number of populations of different species of plants, animals and microorganisms, interconnected by various food and spatial relationships.
Complex biocenoses are the most resistant to adverse effects. The disappearance of any species does not significantly affect the organization of such biocenoses, since, if necessary, another species can replace the disappeared one.
In exceptionally complex biocenoses of tropical forests, outbreaks of mass reproduction of individual species are never observed.
For simple tundra or desert biocenoses are characterized by a sharp increase or decrease in the number of animals that have a significant impact on the vegetation cover.
This is explained by the fact that in the simplified biocenosis there are not enough species that, if necessary, could replace the main species and act, for example, as food for predators.
