Types of forest ecosystems, their characteristics. forest ecosystem

Help please. Biology. and got the best answer

Answer from Daria Gubina[newbie]
1. Birds that eat insects nest in hollow trees. If they are cut down, insect pests will damage young trees and plants, which will lead to the gradual death of the forest.
2. Herbaceous, light-loving plants develop first, then sprouts of birch, aspen, and pine appear, the seeds of which fell with the help of wind, birds, insects, and a small-leaved or pine forest is formed; under the canopy of light-loving species, shade-tolerant spruce trees develop, which will subsequently completely displace other trees.
3. Grass emits less oxygen per m^2 of land than a tree! The grass is covered with snow in winter, but the tree still continues to fulfill its mission of releasing oxygen.
5The food network is formed from a variety of interconnected food chains, which means that its diversity is based on the diversity of species, the presence among them of producers, consumers, decomposers and the variety of their food (broad food specialization).

PRACTICAL WORK

evolution.

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. Using the picture, determine what form of selection it illustrates and justify it. Will the size of the ears of hares change during the process of evolution under the influence of this form of natural selection and under what living conditions will this selection manifest itself?

Number of individuals

Significance value

PRACTICAL WORK

SOLVING ENVIRONMENTAL PROBLEMS 11 CL

1. What types of environmental factors contribute to the regulation of wolf numbers in an ecosystem? Explain your answer.

1. Explain why not all the energy supplied by food is spent on the growth of the animal. Give at least three reasons.

1. Brook trout lives in water with an oxygen concentration of at least 2 mg/l. When its content drops to 1.6-2 mg/l or less, the trout dies. Explain the reason for the death of trout, using knowledge about the reaction norm of the trait.

1. What characterizes the geographic mode of speciation? Please provide at least three items.

1. How is the population of insects, insectivores and insects regulated? birds of prey in the ecosystem mixed forest, if the number of insects increases?

1. Blood-sucking insects are common inhabitants of many biocenoses. Explain in what cases they occupy the position of consumers of II, III and even orders in food chains.

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. A type criterion is a set of characteristics that distinguish this type from another. 2. The basis of the physiological criterion is a combination of factors external environment, in which the species exists. 3. The genetic criterion is characterized by a certain karyotype. 4. Ecological criterion is a certain area occupied by a species in nature. 5. Other criteria for a species include: morphological, biochemical, geographical, etc. 6. To establish species identity, it is enough to use one criterion.

1. In the forest biogeocenosis, trees were treated with pesticides to kill mosquitoes and midges. Specify at least four consequences the impact of this event on the forest biogeocenosis.

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. Charles Darwin identified the driving forces of evolution of the organic world.

2. He included the diversity of species, the struggle for existence and natural
nal selection. 3. Charles Darwin believed that the material for evolution is not
hereditary variability. 4. He also called it a modification of
changeability. 5. Natural selection, according to Darwin, plays a creative role
role. 6. He considered natural selection as the main driving force)
evolution.

1. Treatment with antibiotics of human diseases caused by microorganisms becomes ineffective over time. It is necessary to search for new drugs. In terms of the evolutionary process, explain how antibiotic resistance develops.

1. Rodents are the largest order of mammals in terms of the number of species in their distribution. What makes rodents thrive in nature? Give at least three reasons.

1. Why a decline in the number of a species can cause its extinction. Give at least three reasons. Explain your answer

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. Visible rays account for most of the energy of solar radiation reaching earth's surface. 2. Life on Earth is possible only because long-wave rays are blocked by the ozone screen. 3. In small doses, infrared rays prevent the occurrence of rickets in humans. 4. Infrared rays are an important source of internal energy. 5. The influence of three areas of solar radiation on organisms is classified as biotic environmental factors of influence.

1. Why is a broadleaf forest considered a more resilient ecosystem than a forb meadow? Provide at least three pieces of evidence.

1. The rate of photosynthesis depends on factors, including light, carbon dioxide concentration, water, and temperature. Why are these factors limiting the photosynthesis reaction?

1. Explain why the reduction in the number of wolves due to shooting in tundra biocenoses leads to a decrease in the supply of moss - food for reindeer.

1. In nature, the oxygen cycle occurs. What role do living organisms play in this process?

1. Carp were released into an artificial reservoir. Explain how this can affect the number of insect larvae, crucian carp and pike living in it.

1. Why is a mixed forest ecosystem considered a more sustainable ecosystem than a spruce forest ecosystem?

1. In a small reservoir formed after a river flood, the following organisms were found: slipper ciliates, daphnia, white planaria, big pond snail, Cyclops, Hydra. Explain. Can this body of water be considered an ecosystem? Provide at least three pieces of evidence.

1. What environmental factors contribute to the regulation of the number of wolves in the ecosystem?

1. How does a natural ecosystem differ from an agroecosystem?

1. What is the role of bacteria in the cycle of substances?

1. Squirrels, as a rule, live in coniferous forests and feed mainly on spruce seeds. What biotic factors can lead to a decline in the squirrel population?

1. Clover grows in meadows and is pollinated by bumblebees. What biotic factors can lead to a decline in clover populations?

1. What changes in biotic factors can lead to an increase in the population of a naked slug that lives in a forest and feeds mainly on plants?

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. A population is a collection of freely interbreeding individuals of different species, long time inhabiting a common territory.2. The main group characteristics of a population are size, density, age, sex and spatial structure. 3. The totality of all genes in a population is called the gene pool. 4. The population is structural unit wildlife. 5. The population size is always stable.

1. Why are plants (producers) considered the initial link in the cycle of substances and energy conversion in the ecosystem?

1. As a result of volcanic activity, an island was formed in the ocean. Describe the sequences of ecosystem formation on a newly formed landmass. Please provide at least three items.

1. As a result of a forest fire, part of the spruce forest burned out. Explain how its self-healing will occur. Specify at least three stages.

1. In some forest biocenoses, to protect chicken birds, mass shooting of daytime birds of prey was carried out. Explain how this event affected the number of chickens.

1. The color of the white hare's coat changes throughout the year: in winter the hare is white, and in summer it is gray. Explain what type of variability is observed in the animal and what determines the manifestation of this trait.

1. How does the land-air environment differ from the water environment?

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. Explain how plants are harmed acid rain. Give at least three reasons.

1. What are the manifestations of morphological, physiological and behavioral adaptations to environmental temperature in warm-blooded animals?

1. What role do birds play in the forest biocenosis? Provide at least three parameters.

1. Using the picture, determine what form of selection it illustrates. Justify your answer. Will the size of the ears of hares change during the process of evolution under the influence of this form of natural selection and under what living conditions will this selection manifest itself?

Number of individuals

Significance value

1. Birds and mammals have achieved great success in evolution in mastering? terrestrial-air environment compared to other vertebrates. Explain what common features of their organization contributed to this. Give less than three signs.

1. Find errors in the given text. Indicate the numbers of the sentences in which they are made, correct them.

1. A population is a collection of freely interbreeding individuals of the same species that inhabit a common territory for a long time. 2. Different populations of the same species are relatively isolated from each other, and their individuals do not interbreed. 3. The gene pool in populations of the same species is the same. 4. The population is the elementary unit of evolution. 5. A group of frogs of the same species living in the deep during one summer constitutes a population.

1. What characteristics do plants living in arid zones have?

1. The body shape of the callima butterfly resembles a leaf. How was this butterfly body shape formed?

Forests occupy a huge part of the land on our planet - more than 4 billion hectares of land. Forest ecosystems (FE) are unique communities of animals and plants connected by many types of connections to exchange energy. Plants play the main role in any forest ecosystem. According to their dominant species of flora representatives, it is customary to distinguish the following species:

1. Mixed forest ecosystem
2. Ecosystem coniferous forests
3. Rainforest ecosystem
4. Broadleaf forest ecosystem

Forest ecosystems are characterized by tiers: the top tier contains trees, the middle tier consists of shrubs, and the lower tier contains grasses. The uniqueness of LE can be explained by three factors:

• Firstly, this is practically the only type of ecosystem that has been preserved in its original form and practically unchanged by man.
• Secondly, LEs are among the largest on the planet.
• Thirdly, LEs are considered one of the most productive for humanity.

Let's take a closer look at each type of forest ecosystem.

Mixed forest ecosystem

Mixed forests are a symbiosis of coniferous and deciduous forest ecosystems. They complement each other and strengthen each other, which is why this ecosystem is considered the most stable of all forest ecosystems.

Forests are considered mixed if other species are added to the main type of trees, but in a numerical ratio - no more than 5%. Therefore, such forests are located between conifers in the north and broad-leaved ones in the south - in a strip where the territories of southern Scandinavia, the East European and West Siberian plains, the Carpathians, the Caucasus, the Far East and Southeast Asia are located. On the American continent this is the territory of the Great Lakes and California. In the southern hemisphere, the mixed forest ecosystem is located in most of the South America and in New Zealand.

The dominant trees in this ecosystem are oak, maple, spruce, pine, linden, and elm. In America - sequoia, in the mountains - larch, in the Caucasus and the Far East - beech and fir.

Consumers or consumers in the ecosystem of mixed forests are animals, birds, fish, amphibians, insects, and fungi. Gravediggers close the food chain: worms, larvae, microorganisms.

The main feature of a mixed forest ecosystem is sustainability, which is determined by the ability to completely replace the species. That is, if a population of a species disappears, its place is quietly replaced by an increased number of individuals of another species.

The weak point of such an ecosystem is insects. If they disappear, the mixed forest ecosystem will decline and die.

Coniferous forest ecosystem

A cold climate is necessary for the formation of a coniferous forest ecosystem. Therefore, they form mainly in the north, where average air temperature fluctuations range from -5°C to +5°C. There is little precipitation - up to 200 mm per year, and most often it falls in the form of snow. Summer in these parts is cold and short, and winter is long and frosty.

These climatic conditions are excellent for the growth of coniferous trees: pines, spruces, fir, cedars, larches. They occupy a dominant position in this ecosystem and are located on the upper tier.

Coniferous forests united in massifs are called taiga. This ecosystem is distributed in the northern hemisphere, mainly in Siberia and Canada. In the southern hemisphere, coniferous forests do not create such massifs and are found in separate areas. And in Australia and South America, coniferous forests grow in the mountains.

Coniferous trees have needles instead of leaves, which... Due to their small area, they perfectly retain heat and moisture. And the resin that wraps coniferous trees allows you to easily endure prolonged frosts. Photosynthesis in these trees does not stop even at 0°C.

In the ecosystem of coniferous forests there is practically no middle layer. And the lower one is inhabited by mosses and lichens. Together with trees, these types of vegetation are producers - they actively participate in photosynthesis, processing solar energy. In addition, they provide food for the next link in the ecosystem - animals.

The top of the food chain in such forests are predators: lynxes, tigers, bears, wolves, foxes. Of the herbivorous mammals, artiodactyls are especially common: deer, elk, wapiti. Many animals with valuable fur: sables, martens, squirrels, weasels. These are consumer organisms.

Destructive organisms include fungi, bacteria and worms.

Food chains in coniferous forest ecosystems are often short. For example, a tree is a herbivore (squirrel) - a predator (fox).

If a person does not interfere in the ecosystem of a coniferous forest, then a process of self-regulation occurs here: one species of animal never completely destroys individuals of another species. What makes this type of ecosystem very resilient.

Broadleaf forest ecosystem

Broadleaf forests are found throughout much of Europe and East Asia, North America and south of Chile.

The dominant role is played by deciduous trees - those that shed their leaves with the onset of cold weather. These are linden, oak, ash, elm, maple, chestnut. Bird cherry and birch trees grow on the middle tier. The lower one is completely occupied by herbs and berries: forest grass, lungwort, strawberries, etc.

The consumer class in this ecosystem is represented by mammals (foxes, wolves, tigers, bears, hedgehogs, raccoons, wild boars, hares, squirrels), birds (nightingales, bullfinches, siskins, wood grouse, cuckoos, storks), reptiles, amphibians and fish.

The decomposers are the same gravediggers, worms and microorganisms.

The broadleaf forest ecosystem is very resilient. It becomes vulnerable during cold weather, when trees shed their leaves and the process of photosynthesis stops. During this period, a special role is given to decomposers, which convert organic matter into inorganic substances.

Rainforest ecosystem

Tropical forests encircle our planet along the equator and cover the subtropical, tropical and equatorial climate zones. In this case, air humidity plays a huge role. In a humid climate, tropical forests are evergreen; in a dry climate (far from oceans and seas), forests are green only in the warm season.

Ecosystem tropical forest the richest of all forest ES in terms of species diversity. Palm trees, myrtaceae, and legumes dominate here; in the dry tropics - bamboo, laurel, and albizia.

One of the features of the tropical forest ecosystem is the blurring of the boundaries of the layers. Thus, herbs can grow up to 6 m in height, climbing to the middle tier. Ferns can generally occupy all three tiers at once. Adds blurriness and an abundance of vines and epiphytes, which envelop all plants in a dense network.

Another feature of the tropical forest ecosystem is that most species of consumers live directly in the trees. These include numerous animals (monkeys, sloths, flying squirrels), birds (parrots, hummingbirds, woodpeckers, toucans), and reptiles (snakes, lizards, geckos, chameleons). Even frogs try to climb higher. There are few land animals in this ecosystem, but they are all very large: elephants, giraffes, rhinoceroses, hippos, buffalos.

The decomposers are mainly fungi and termites.

Sustainability of forest ecosystems

(Russian Ecosystem Sustainability Scheme)

Among all forest ecosystems, the most stable is the mixed forest ecosystem. Next, in descending order, are deciduous, coniferous and tropical forests.

This is explained by the density of trees and the degree of penetration of sunlight into the lowest tiers of the forest. For example, in mixed forests, trees do not grow densely, leaving free space for sunlight. The rays penetrate right to the ground, having a significant impact on the activity of decomposers, which, in turn, produce useful material for the growth of the trees themselves.

In coniferous forests, the tops of trees often close together, blocking sunlight. The same thing happens in the tropics, where, due to the abundance of plants, decomposers are simply not able to process such a huge amount of organic matter. Therefore, in the tropics, despite the fact that the plants here produce the most a large number of oxygen, and carbon dioxide is preserved in huge quantities.

A forest ecosystem is a collection of living organisms, the main life form of which is trees. Forests occupy a third of the Earth's land area, which is 38 million km 2. Half of this area is occupied by tropical, the rest by coniferous, mixed, deciduous and broad-leaved forests.

According to its structure, the forest ecosystem is divided into tiers. The height of each tier and the composition of living organisms in it depend on the species diversity of the plants that form it.

The main ones in the ecosystem as a whole and in its food chain are obviously the producing plants. Other links trophic chain- consumers and destroyers of the forest ecosystem, play a dependent but important role in it. And if the “activity” of consumers in all types of ecosystems is approximately the same, then the “existence and work” of destroyers is different in each type.

The coniferous forest ecosystem is formed in cold climatic conditions. Average annual temperature this natural area from +5 0 C to – 5 0 C. Low level of precipitation – up to 200 mm. They mostly fall in the form of snow. Winter is long. Summer is short. But the daylight hours are long. This temperature and light regime prevents moisture from quickly evaporating from the soil surface, and these are excellent conditions for the growth of coniferous trees.

They are widespread in North America and Eurasia. In the southern hemisphere, such forests do not form a single tract. In South America and Australia they are found mainly in the mountains.

Another name for coniferous forest is taiga. There are many plant species, but coniferous trees dominate and occupy the upper tier of the ecosystem. The needle, which replaces the leaf in these rocks, does not fall off depending on the time of year. Snow slides down easily. It is “sheltered” from frost by a layer of resin, and its small surface allows it to withstand cold well and release less moisture during evaporation. These trees do not stop photosynthesis even at a temperature of 0 0 C.

In the tropics, pine forests can grow on certain types of soil. They have their own species composition.

The main types are: fir, pine, spruce, hemlock and larch. Another one of them distinctive feature except for needles instead of leaves, there are cones. The presence of needles instead of leaves does not mean that all conifers are evergreen. There are tree species that shed their needles seasonally.

Coniferous forest ecosystems are inhabited by mosses and lichens, which, together with trees, are also producers. They not only participate in the process of photosynthesis, but also provide a nutritional base for the next link in the food chain - consumers - animals.

The main and top of the trophic chain of this type of forest are predators, in particular felines - the tiger and the lynx. There are wolves, bears, foxes and other predators. Herbivorous mammals are mainly from the deer family. There are hare, squirrel, marten, sable, hedgehog and tree porcupine, different types birds.

The “work” of decomposers or destroyers in them depends on the density of the crowns or canopy. There are dark coniferous and light coniferous forests. The former consist of varieties of shade-tolerant trees that are closely planted, resulting in a high canopy density. This slows down the processes of processing organic matter and the formation of humus. The soils are therefore less fertile. In light-coniferous trees, sunlight penetrates the soil more easily and processes in it proceed faster.

To the south of the coniferous there is a mixed one.

Mixed

A mixed forest ecosystem is a mixture of two ecosystems due to the presence of deciduous and coniferous species. Thus, ecosystems complement and strengthen each other, and the resulting overall ecosystem becomes more stable. It is considered mixed when one type of tree is mixed with another in a volume of at least 5%. Therefore, it is no coincidence that such forests are located between coniferous forests in the north and broad-leaved forests in the south. They are mainly found in climatic zones With warm summer And cold winter. With an average annual precipitation of up to 700 mm. The soils they grow in are soddy-podzolic or brown with big amount humus.

The natural zone of these forests is temperate zone: South part Scandinavia, East European and West Siberian plains, Carpathians, Caucasus, Far East, Southeast Asia. On the American continent - Appalachia, the Great Lakes region and California in North America, most of South America and New Zealand.

The main tree species are: spruce, pine, oak, maple, linden, ash and elm. In the Caucasus and Far East beech and fir are added. In mountainous regions - larch, and in America - sequoia. Plants representing the lower tiers also have a wide variety of species.

The rich flora of mixed forests are producers and autotrophs, that is, organisms that synthesize oxygen and organic substances from inorganic ones using solar energy. They are the basis of any ecosystem, and mixed forests are no exception.

The next stage in the food chain belongs to consumers or consumers, heterotrophic organisms. Their total mass is an order of magnitude less than the plant mass - green, which is the basic rule of the viability of the ecosystem. These include: animals, birds, fish, amphibians, reptiles, insects, fungi and bacteria. It is less diverse. These are: rodents - hares, squirrels, mice; mammals - deer, elk, wolves, foxes; birds - owl, woodpecker; insects – ticks, mosquitoes, spiders; protozoa - bacteria.

Closing the food chain are gravediggers—destroyers or decomposers: insect larvae, worms, microorganisms.

A feature of the mixed forest food chain is sustainability due to species complementarity and, if necessary, replacement. When the population decreases or disappears, a species of producer is replaced by the number of individuals of another. This rule does not apply to insects. They are plant pollinators, and their larvae are decomposers. Their disappearance will lead to the extinction of the ecosystem.

Mixed forest ecosystems are replaced by broad-leaved ones.

In a broad-leaved forest, the ecosystem is characterized by a species diversity of deciduous or summer-green plants, that is, shedding their leaves in the autumn-winter period. Their leaves have wide leaf blades. Such forests grow in humid and moderately humid climates with high temperature. Summer is long. Winter is mild. They prefer soils that are gray, podzolic, brown, or even black soil. Distribution areas - Europe, North America, East Asia, New Zealand and southern Chile.

The base of the forest and its upper tiers are represented by: hornbeam, linden, ash, elm, maple, beech, oak and chestnut. Below are hazel, bird cherry and euonymus. The “ground floor” of the forester, snyty, zelenchuk, lungwort, and so on. These are all producers.

Consumers are mammals such as: wild boar, deer, elk, bison, beaver, squirrel, hedgehog, fox, lynx, wolf, tiger, skunk, raccoon and Brown bear. Birds: siskin, hazel grouse, nightingale, tit, bullfinch, wood grouse, black grouse, owl, eagle owl, stork, duck and others. Reptiles, amphibians and fish are also consumers. These are viper, copperhead, frog, toad, salamander, catfish, pike, carp and salmon.

The decomposers or gravediggers of a broad-leaved forest are almost the same as in other ecosystems - worms, insect larvae, microorganisms.

The broadleaf forest ecosystem is also resilient and well-regulated. A special feature is the period when trees are without leaves. The process of photosynthesis stops. The “main” role passes to decomposers, who must transform as much as possible organic compounds to inorganic.

At the equator, deciduous trees are replacing tropical forest ecosystems.

The tropical forest ecosystem has developed based on warm tropical, subtropical and equatorial climates. They encircle the Earth at the equator. The diversity of flora and fauna is dictated solely by the amount and distribution of precipitation over the seasons. There are humid forests equatorial belt and dry tropical. If the humidity is approximately the same throughout the year, then they are evergreen. If not, then green only in winter.

Tropical rainforests have a very diverse flora. It is dominated by trees, of which there can be up to 100 species per hectare. The main types of trees are: dipterocarps, legumes, myrtle and palms. Among other types of vegetation, it is necessary to highlight ferns, which exist on different tiers of the tropical forest. There are three such tiers in total. The top reaches 55 meters in height, the next up to 30 and the bottom up to 20. The grass here can reach a height of 6 meters. For example: banana. Plants such as vines, epiphytes, bamboo, ferns, and so on blur the boundaries of the tiers.

Seasonal deciduous forests contain terminalia, dalbergia, albizia, bamboo, teak and ebony, palms, laurel and sugar cane. The main herbs are cereals. Sometimes, to retain moisture, plants are covered with thorns.

The species diversity of tropical consumers exceeds any other forests. Many animal species spend most of their time in trees. The most famous are monkeys, flying squirrels, and sloths. Birds also live there - parrots, woodpeckers, toucans, hummingbirds and many others. Reptiles also live in places of maximum “accumulation” of food, that is, in trees. These are chameleons, snakes, geckos, jaguanas, agamas and even amphibious frogs, trying to climb higher. There are not many exclusively terrestrial animal species, but they are very large. Their main types are: elephant, rhinoceros, hippopotamus, buffalo, giraffe. Diverse in appearance invertebrates - ants, termites, centipedes and butterflies.

Plants of the second tier usually close the canopy so tightly that they do not let in sunlight. This negatively affects the “activities” of destroyers. In deciduous forests there are decomposers, and these are mainly mushrooms and termites, which also cannot process such a huge volume of organic matter. Therefore, tropical, with such an intensive “production” of oxygen - about 55.5 Gt per year, “preserve” in their organic matter up to 4.6 Gt of carbon dioxide.

Conclusion

A common characteristic of a forest ecosystem may be as follows. They are all built on the basis of dominance flora over the animal. Among plants, one or more tree species play a major role. Depending on this, systems are classified as single-species or mixed. An ecosystem of any kind has tiers. The density of the closure of tree crowns determines the amount of sunlight and oxygen penetrating into its lower tiers. Especially in layers inhabited by decomposers - destroyers. And this, in turn, affects the amount of inorganic “food” they synthesize for the trees themselves. Ecosystems in which there is an imbalance in favor of any living organisms are not stable enough and can be damaged and destroyed. The most stable are forest ecosystems with a mixture of species and their interchangeability.

Video - Forest ecosystems