Forest ecosystem. Why broadleaf forest is considered a more sustainable ecosystem Video - Forest Ecosystems

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

Ecosystem mixed forests
coniferous forest ecosystem
Ecosystem rainforest
Ecosystem widely deciduous forests

Layered ecosystems are typical for forest ecosystems: trees are located on the upper layer, shrubs make up the middle layer, and grasses make up the lower layer. The uniqueness of LE can be explained by three factors:

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

Let's consider each of the types of forest ecosystems in more detail.

mixed forest ecosystem

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

Mixed forests are considered if other species are added to the main type of trees, but in a numerical coefficient - no more than 5%. Therefore, such forests are located between coniferous in the north and broad-leaved in the south - in the strip where the territories of the south of 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 South America and in New Zealand.

The dominant trees in this ecosystem are oak, maple, spruce, pine, linden, 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, fungi. Gravediggers close the food chain: worms, larvae, microorganisms.

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

The vulnerability of such an ecosystem is insects. If they disappear, the mixed forest ecosystem will begin to fade and die.

coniferous forest ecosystem

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

These climatic conditions are excellent for growing conifers trees: pines, firs, firs, cedars, larches. It is they who occupy a dominant position in this ecosystem and are located on the upper tier.

Coniferous forests, combined into arrays, 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. Due to their small area, they perfectly retain heat and moisture. And the resin that wraps coniferous trees allows you to freely 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 tier. And the lower one is inhabited by mosses and lichens. Together with trees, these types of vegetation are producers - they are actively involved in photosynthesis, processing solar energy. In addition, they are 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, deer. There are many animals with valuable fur: sables, martens, squirrels, weasels. These are consumer organisms.

Destructive organisms include fungi, bacteria and worms.

Food chains in the coniferous forest ecosystem 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 takes place here: one species of animals never completely destroys individuals of another species. What makes this kind 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 drop their leaves with the onset of cold weather. These are lindens, oaks, ash-trees, elms, maples, chestnuts. On the middle tier, bird cherry and bereskets grow. The lower one is completely occupied by herbs and berries: blueberry, lungwort, strawberries, etc.

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

The decomposers are all the same gravediggers, worms and microorganisms.

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

rainforest ecosystem

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

Ecosystem rainforest the richest of all forest ES in terms of species diversity. Palms, myrtle, legumes dominate here, in the dry tropics - bamboo, laurel, albizia.

One of the features of the rainforest ecosystem is the blurring of layer boundaries. So, grasses can grow up to 6 m in height, climbing to the middle tier. Ferns in general can occupy all three tiers at once. Adds blur and an abundance of vines, epiphytes, which envelop all plants in a dense network.

Another feature of the rainforest ecosystem is that most types of consumers live directly on the trees. These are numerous animals (monkeys, sloths, flying squirrels), birds (parrots, hummingbirds, woodpeckers, toucans), reptiles (snakes, lizards, geckos, chameleons). Even frogs - and they tend to climb higher. There are few land animals in this ecosystem, but they are all very large: elephants, giraffes, rhinos, hippos, buffaloes.

Decomposers are mainly fungi and termites.

Resilience of forest ecosystems

(scheme of sustainability of ecosystems in Russia)

Among all forest ecosystems, the mixed forest ecosystem is the most stable. Further, in descending order, are broad-leaved, coniferous and tropical forests.

This is due to the density of tree growth and the degree of penetration of sunlight into the lowest tiers of the forest. So, for example, in mixed forests, trees do not grow densely, leaving free space for the sun's rays. The rays penetrate to the very ground, exerting a significant influence 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 great amount organics. Therefore, in the tropics, despite the fact that plants here produce the most a large number of oxygen, and carbon dioxide is preserved in huge quantities.

The forest ecosystem is a collection of living organisms, the main life form of which are trees. Forests occupy one third of the Earth's land area, which is 38 million km2. 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 thing in the ecosystem as a whole and in its food chain, obviously, are the plants - producers. The remaining links of the trophic chain are consumers and destroyers of the forest ecosystem, although they 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. Small amount of precipitation - up to 200 mm. They mostly fall in the form of snow. Winter is long. Summer is short. But daylight hours are long. Such a temperature and light regime does not allow moisture to quickly evaporate from the soil surface, and these are excellent conditions for the growth of coniferous trees.

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

Another name for coniferous forest is taiga. It has many plant species, but coniferous trees dominate and occupy the top layer of the ecosystem. The needle, which in these rocks replaces the leaf, does not fall off depending on the season. Snow slides easily over it. It is “covered” from frost with a layer of resin, and a small surface allows it to tolerate cold well and give less moisture during evaporation. These trees do not stop photosynthesis even at a temperature of 0 0 C.

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

The main species are: fir, pine, spruce, hemlock and larch. Another one of them hallmark besides needles instead of leaves, 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 serve as a nutrient 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, cats - tiger and lynx. There are wolves, bears, foxes and other predators. Herbivorous mammals are mainly from the deer family. There is a hare, a squirrel, a marten, a sable, a hedgehog and a tree porcupine, different types of birds.

The “work” of decomposers or destroyers in them depends on the density of crown or canopy density. There are dark coniferous and light coniferous forests. The first consist of varieties of shade-tolerant trees, which are closely closed, which is why the density of the canopy is high. This slows down the processes of processing organic substances and the formation of humus. Soils are therefore less fertile. In light conifers, sunlight penetrates the soil more easily and the processes in it go faster.

South of coniferous is mixed.

Mixed

The ecosystem of a mixed forest is a mixture of two ecosystems, due to the presence of deciduous and coniferous species in it. Thus, ecosystems complement and strengthen each other, and the resulting common 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 from the north and broad-leaved from the south. They are mainly found in climatic zones With warm summer and cold winter. With an average annual rainfall of up to 700 mm. The soils of their growth are sod-podzolic or brown with a large amount of humus.

The natural zone of these forests is temperate zone: the southern part of Scandinavia, the East European and West Siberian plains, the Carpathians, the Caucasus, the Far East, Southeast Asia. On the American continent - the Appalachians, 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 species diversity.

The rich flora of mixed forests are producers and autotrophs, that is, organisms that synthesize with the help of solar energy oxygen and organic substances from inorganic. They are the backbone 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 main rule for the viability of the ecosystem. These include: animals, birds, fish, amphibians, reptiles, insects, fungi and bacteria. It is less varied. These are: rodents - hares, squirrels, mice; mammals - deer, moose, wolves, foxes; birds - owl, woodpecker; insects - ticks, mosquitoes, spiders; protozoa - bacteria.

Close the food chain - gravediggers - destroyers or decomposers: insect larvae, worms, microorganisms.

A feature of the mixed forest food chain is sustainability, due to species mutual complementation and, if necessary, replacement. With a decrease in the population or the disappearance of any type of producer, it is replaced by the number of individuals of another. This rule does not apply to insects. They are pollinators of plants, 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 the species diversity of deciduous or summer-green plants, that is, shedding leaves in the autumn-winter period. Their leaves have wide leaf blades. These forests grow in humid and moderately humid climates with high temperature. Summer is long. Winter is mild. They prefer gray, podzolic, brown or even chernozem soils. Distribution areas - Europe, North America, East Asia, New Zealand and southern Chile.

The basis of the forest and its upper tiers are: hornbeam, linden, ash, elm, maple, beech, oak and chestnut. Below are hazel, bird cherry and euonymus. "First floor" at the forest tree, gout, zelenchuk, lungwort and so on. All of these are producers.

Consumers are consumers, these 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, titmouse, bullfinch, capercaillie, black grouse, owl, eagle owl, stork, duck and others. Reptiles, amphibians and fish are also consumers. This is a viper, copperhead, frog, toad, salamander, catfish, pike, carp and salmon.

The decomposers or gravediggers of the broad-leaved forest are practically 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 the trees are without leaves. The process of photosynthesis stops. The “main” role passes to the decomposers, who must transform as much as possible organic compounds into inorganic.

At the equator, deciduous change tropical forest ecosystems.

In the rainforest, the ecosystem was formed on the basis of warm tropical, subtropical and equatorial climate. 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 wet forests equatorial belt and dry tropical. If the humidity is about 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, which can be up to 100 species per hectare. The main types of trees are: dipterocarps, legumes, myrtle and palms. Of the other types of vegetation, it is necessary to distinguish ferns that exist on different tiers of the rainforest. There are three such tiers in total. The upper one reaches 55 meters in height, the next one up to 30 and the lower one up to 20. The grasses here can reach a height of 6 meters. For example: banana. The boundaries of the tiers are blurred by plants such as creepers, epiphytes, bamboo, fern, and so on.

In seasonal deciduous forests, terminalia, dalbergia, albizia, bamboo, teak and ebony, palm trees, laurel and sugarcane. The main herbs are cereals. Sometimes, to retain moisture, plants are covered with thorns.

The species diversity of tropical consumers surpasses any other forests. Many animal species spend most of their time in trees. The most famous are monkeys, flying squirrels, 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 amphibian frogs, trying to climb higher. Exclusively terrestrial species there are not many animals, but they are very large. Their main species 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 through sunlight. This negatively affects the "activity" of the destroyers. In deciduous forests, there are decomposers, and these are mainly fungi and termites, which also cannot process such a huge amount of organic matter. Because tropical, with such an intensive "production" of oxygen - about 55.5 Gt per year, "preserve" in their organic matter up to 4.6 Gt carbon dioxide.

Conclusion

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

Video - Forest Ecosystems

PRACTICAL WORK

evolution.

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

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

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

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

Number of individuals

Sign value

PRACTICAL WORK

SOLVING ENVIRONMENTAL TASKS 11 CL

What types of environmental factors contribute to the regulation of the number of wolves in the ecosystem? Explain the answer.

Explain why not all the energy received from food is spent on the growth of the animal. Give at least three reasons.

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 a trout using knowledge of the reaction rate of the trait.

What characterizes the geographic mode of speciation? List at least three items.

How is the regulation of the number of insects, insectivorous and birds of prey in a mixed forest ecosystem, if the number of insects increases?

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.

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

1. The criterion of the species is a set of features that distinguish this species from another. 2. The basis of the physiological criterion is a combination of factors external environment, in which the view exists. 3. The genetic criterion is characterized by a certain karyotype. four. Environmental criterion is a specific area occupied by a species in nature. 5. Other species criteria include: morphological, biochemical, geographic, etc. 6. To establish species, it is enough to use any one criterion.

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

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

1. Ch. Darwin defined driving forces evolution organic world.

2. To them he attributed the diversity of species, the struggle for existence and natural
ny selection. 3. C. Darwin believed that the material for evolution is not
hereditary variation. 4. He also called it a modification of
variability. 5. Natural selection, according to Darwin, plays creative boredom
role. 6. He considered natural selection as the main driving force)
evolution.

Antibiotic treatment of human diseases caused by microorganisms over time becomes ineffective. It is necessary to search for new drugs. Explain in evolutionary terms how antibiotic resistance develops.

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

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

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

1. Visible rays account for most of the energy solar radiation reaching earth's surface. 2. Life on Earth is possible only because long-wave rays are delayed 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 impact.

Why is a broad-leaved forest considered a more sustainable ecosystem than a forb meadow? Provide at least three pieces of evidence.

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

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

The oxygen cycle takes place in nature. What role do living organisms play in this process?

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

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

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

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

How is a natural ecosystem different from an agroecosystem?

What is the role of bacteria in the nutrient cycle?

Squirrels usually live in coniferous forest and feed mainly on spruce seeds. What biotic factors can lead to a reduction in the squirrel population.?

Clover grows in the meadow, pollinated by bumblebees. What biotic factors can lead to a decline in the clover population?

What changes in biotic factors can lead to an increase in the population naked slug living in the forest and feeding mainly on plants?

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

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

Why are plants (producers) considered the initial link in the circulation of substances and the transformation of energy in an ecosystem?

As a result of volcanic activity in the ocean, an island was formed. Describe the sequences of ecosystem formation on a newly formed piece of land. List at least three items.

As a result forest fire burned part of the spruce forest. Explain how it will self-heal. List at least three steps.

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

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

What is the difference between land-air environment and water environment?

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

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

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

What role do birds play in the biocenosis of the forest? Give at least three options.

Using the picture, determine which form of selection it illustrates. Justify the answer. Will the size of the ears of hares change in the course of evolution under the action of this form of natural selection, and under what conditions of life will this selection manifest itself?

Number of individuals

Sign value

Birds and mammals have achieved great success in the evolution of mastered? ground-air environment compared to other vertebrates. Explain what common features their organizations contributed to this. Give at least three signs.

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

1. A population is a collection of freely interbreeding individuals of the same species, inhabiting 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 for one summer is a population.

What are the characteristics of plants that live in arid zones?

The body shape of the callima butterfly resembles a leaf. How did this shape of the butterfly's body form?

Exercise 1.

Consider the proposed scheme. Write in the answer the missing term, indicated in the diagram with a question mark.

Explanation: Reproduction of organisms is sexual and asexual (without the participation of germ cells).

The correct answer is asexual.

Task 2.

Choose two correct answers from five and write down the numbers under which they are indicated.

The hybridological research method is used

1. Embryologists

2. Breeders

3. Genetics

4. Ecologists

5. Biochemists

Explanation: hybridological method - a method of obtaining hybrids. They are used in genetics to determine the characteristics and inheritance of a trait and in breeding to develop new breeds, varieties, strains.

The correct answer is 23.

Task 3.

An mRNA molecule takes part in protein synthesis, the fragment of which contains 96 nucleotide residues. Determine the number of nucleotide residues in the region of the DNA template chain that carry information about the primary structure of the protein.

Explanation: during transcription (copying a section of DNA - a gene - onto mRNA) on DNA and mRNA, the same number of nucleotides is obtained as a result, since the gene encodes a protein and the mRNA must transmit this encoded information unchanged.

In this task, non-coding regions of DNA are neglected - introns, which are excised from DNA, so that mRNA is smaller than DNA.

The correct answer is 96.

Task 4.

The signs listed below, except for two, are used to describe the structure and functions of the depicted cell organoid. Identify two signs that "fall out" from the general list, and write down in the table the numbers under which they are indicated.

1. Packs and carries synthesized substances out of the cell

2. Participates in the formation of lysosomes

3. Provides oxidative phosphorylation

4. Consists of a single membrane

5. Contains interconnected grains

Explanation: The figure shows the Golgi apparatus. It packs and takes synthesized substances out of the cell (for example, proteins from ribosomes enter the Golgi apparatus and then are distributed throughout the cell), participate in the formation of lysosomes, and are single-membrane. They do not carry out oxidative phosphorylation (like mitochondria) and do not contain gran (like chloroplasts).

The correct answer is 35.

Task 5.

Establish a correspondence between the characteristics and phases of photosynthesis.

Characteristics

A. Photolysis of water

B. Carbon dioxide fixation

B. Breakdown of ATP molecules

D. Excitation of chlorophyll by light quanta

D. Glucose synthesis

Phases of photosynthesis

1. Luminous

2. Dark

Explanation: Light is required for the light phase of photosynthesis. It includes: photolysis of water, splitting of ATP molecules, excitation of chlorophyll by light quanta. All processes take place on the membrane. The dark phase of photosynthesis does not require light. It includes the Calvin cycle, during which CO2 fixation and glucose synthesis occur.

Correct answer: 12112.

Task 6.

Determine the ratio of females and males in the offspring formed by crossing two heterozygotes. Write down the answer in the form of a sequence of numbers showing the ratio of phenotypes, in descending order.

Explanation: the question is posed incorrectly, since the offspring does not depend on the genotype. The ratio of females and males will always be 50:50 (i.e. 1:1).

The correct answer is 11.

Task 7.

The following characteristics, except for two, are used to describe the causes of combinative variability.

1. Chance meeting of gametes during fertilization

2. Spiralization of chromosomes

3. DNA replication in interphase

4. Gene recombination during crossing over

5. Independent segregation of chromosomes in meiosis

Explanation: combinative variability is determined by: random meeting of gametes during (different combinations) fertilization, gene recombination during crossing over, or independent chromosome segregation in meiosis. Chromosome spiralization and DNA replication in interphase are not characteristics of combinative variability.

The correct answer is 23.

Task 8.

Establish a correspondence between the characteristics and stages of formation of lancelet embryos.

Characteristics

A. Invagination of a group of cells into the blastula

B. Mitosis of the zygote

B. Formation of the walls of the primary intestine

D. Formation of the blastocoel

D. Formation of blastomeres

Stages of embryogenesis

1. Single layer embryo

2. Bilayer embryo

Explanation: blastula is a single-layer stage, which means that everything that enters it belongs to the single-layer period of embryo development (zygote mitosis, blastomere formation, blastocoel formation). During gastrulation, protrusion occurs and the protruding cells represent the second layer, that is, the characteristics of a two-layer embryo include: The protrusion of a group of cells inside the blastula and the formation of the walls of the primary intestine.

The correct answer is 21211.

Task 9.

1. Are perennials

2. Contain chloroplasts with chlorophyll

3. Have flowers and inflorescences

4. Form fruits with seeds

5. Represented by a variety of life forms

6. Propagated by seeds

Explanation: angiosperms - the most progressive group of plants. They differ from all others in the presence of a flower and a fruit. Also, unlike gymnosperms, they are represented by a variety of life forms: grasses, shrubs, trees (gymnosperms are only tree forms). Common features: perennial plants, the presence of chloroplasts with chlorophyll, reproduction by seeds.

The correct answer is 126.

Task 10.

Establish a correspondence between animals and the characteristics of body temperature.

Animals

A. house sparrow

B. quick lizard

B. common dolphin

G. Nile crocodile

D. common newt

E. Common mole

Features of body temperature

1. Constant

2. Fickle

Explanation: in birds (house sparrow) and mammals ( common dolphin, common mole) - constant body temperature (they are warm-blooded). In amphibians (common newt) and reptiles (swift lizard, nile crocodile) unstable body temperature (they are cold-blooded).

Correct answer: 121221.

Task 11.

Establish the sequence of arrangement of systematic groups of plants, starting with the smallest taxon. Write down the corresponding sequence of numbers in the table.

1. Common radish

2. Angiosperms

3. Cruciferous

4. Dicotyledons

5. Radish

6. Eukaryotes

Explanation: arrange the systematic groups, starting with the smallest.

View Common radish

Rod Radish

Cruciferous family

Class Dicotyledonous

Department Angiosperms

Superkingdom of Eukaryotes

The correct answer is 153426.

Task 12.

Choose three correct answers out of six.

Leukocytes are blood cells that

1. Formed in the red bone marrow

2. Able to change their shape

3. Contain kernels

4. Synthesize hemoglobin

5. They secrete substances for the formation of a blood clot

6. Ripe in the nerve nodes

Explanation: leukocytes - white blood cells, they are responsible for immunity, can absorb foreign particles by changing the shape of the cell (phagocytosis), have nuclei, are formed in the red bone marrow. They do not synthesize hemoglobin, do not participate in the formation of a blood clot, do not mature in the nerve nodes.

The correct answer is 123.

Task 13.

Match characteristics and departments nervous system.

Characteristics

A. Coordinates the work internal organs

B. Regulates metabolic processes

B. Acts autonomously, regardless of the desire of a person

G. Provides voluntary movements of the limbs

D. Regulates the activity of smooth muscles

E. Regulates skeletal muscle contraction

Departments of the nervous system

1. Vegetative

2. Somatic

Explanation: the somatic nervous system controls the work of the muscles. Autonomic (autonomous) nervous system - controls the work of internal organs, that is, the autonomic nervous system coordinates the work of internal organs, metabolic processes, and the activity of smooth muscles. The somatic nervous system regulates voluntary movements of the limbs, that is, the contraction of skeletal muscles.

The correct answer is 111212.

Task 14.

Establish the sequence of location of the structures of the eyeball, starting with the cornea. Write down the corresponding sequence of numbers in the table.

1. Retinal neurons

2. Vitreous body

3. The pupil in the pigment shell

4. Light-Sensitive Rods and Cones

5. Convex transparent part of the albuginea

Explanation: Consider the structure of the eyeball.

The most external structure is the convex transparent part of the membrane, then the pupil in the pigment membrane, then the vitreous body, then the neurons of the retina, and finally the light-sensitive cells - rods and cones.

The correct answer is 53214.

Task 15.

Choose from the text three sentences that describe the paths of macroevolution of the organic world. Write down the numbers under which they are indicated in the table.

Explanation: the ways of macroevolution of the organic world are described in sentences 1, 4 and 5.

Macroevolution is the process of formation of large systematic units. We pay attention to the phrases: "aromorphosis", "general degeneration", "increase in the level of organization", "morphophysiological regression".

The correct answer is 145.

Task 16.

Establish a correspondence between the characteristics and criteria of the species Honey bee.

Characteristics

A. Public lifestyle

B. Size difference between males and females

B. Development of larvae in combs

D. Presence of body hairs

D. Feeding on nectar and pollen of flowers

E. Compound eyes

View criteria

1. Morphological

2. Environmental

Explanation: morphological criterion describes external structure organisms, that is, the difference in the size of males and females, the presence of hairs on the body, compound eyes. The ecological criterion describes the interaction of a species with the environment and with other organisms: a social way of life, the development of larvae in combs.

The correct answer is 212121.

Task 17.

Choose three correct answers from six.

In the biogeocenosis, heterotrophs, unlike autotrophs,

1. Are producers

2. Provide a change of ecosystems

3. Increase the supply of molecular oxygen in the atmosphere

4. Extract organic matter from food

5. Turn organic residues into mineral compounds

6. Act as consumers or decomposers

Explanation: heterotrophs - living organisms that consume organic substances and turn them into mineral compounds. In the food chain, heterotrophs act as consumers or decomposers. Producers are autotrophs, green plants release oxygen during photosynthesis, increasing its supply in the atmosphere.

The correct answer is 456.

Task 18.

Establish a correspondence between the characteristics and types of ecosystems.

Characteristics

A. A variety of circuits and power networks

B. Great variety of species

B. Presence of monocultures

D. Closed circulation of substances

E. Instability over time

E. The need for additional energy

Ecosystem types

1. Agrobiocenosis

2. Biogeocenosis

Explanation: agrobiocenosis - an artificial community, is unstable, as it has a number of disadvantages: the presence of a monoculture, instability over time, the need for additional energy.

Biogeocenosis is a natural community, quite stable, as there are a variety of food chains and networks, a wide variety of species, a closed cycle of substances.

The correct answer is 221211.

Task 19.

Establish the sequence of formation of aromorphoses in animals in the process of evolution. Write down the corresponding sequence of numbers in the table.

1. Appearance of internal fertilization

2. The emergence of the sexual process

3. Chord formation

4. Formation of five-fingered limbs

Explanation: among the listed signs, the earliest is the appearance of the sexual process (still in the Coelenterates), then internal fertilization, the appearance of the notochord and the formation of five-fingered limbs.

The correct answer is 2134.

Task 20.

Consider the picture depicting cell division and determine its phases, the set of chromosomes in daughter cells, and what specific cells are formed as a result of such division in plants.

Fill in the blank cells of the table using the terms given in the list. For each lettered cell, select the appropriate term from the list provided.

List of terms

1. Prophase, metaphase, telophase

2. Somatic

3. Diploid

4. Prophase 2, metaphase 2, anaphase 2, telophase 2

5. Prophase 1, metaphase 1, anaphase 1, telophase 1

6. Haploid

7. Dispute

8. First meiotic division

Explanation: The figure shows the second division of meiosis, as haploid cells are formed. In plants, spores are formed during meiosis, and gametes are formed during mitosis (in animals, the opposite is true).

Correct answer - A - cell division phases - prophase 2, metaphase 2, anaphase 2, telophase 2

B - a set of chromosomes in daughter cells - haploid

B - what specific cells are formed in plants - spores

The answer is 467.

Task 21.

Analyze the "Survival of the mouflon at the London Zoo" graph. Select statements that can be formulated based on the analysis of the data presented.

Statements:

1. A group of animals was studied, consisting of 79 individuals

2. 3-4 individuals approximately live up to 9.5 years

3. Born individuals often die in the third year of life

4. Most individuals live up to eight years

5. In the original population average age individuals is one year

Explanation: as you can see from the chart, the largest number individuals are 1-4 years old (12-48 months). A total of 79 individuals were studied, but only 3-4 of them live up to 9.5 years (114 months).

The correct answer is 12.

Task 22.

Several whiskers were taken from one strawberry plant, rooted and mature plants were obtained, which were transplanted to another part of the plantation. However, the fruits of some daughter plants were smaller than those of the parent plant. Name the method used to propagate strawberries. Explain the reason for the appearance of small fruits.

Explanation: the task shows the vegetative method of reproduction. The size of the fruit may vary within the normal range of reaction, depending on environmental conditions. This type of variability is called modification or phenotypic.

Task 23.

What plant organs are indicated in the figure by numbers - 1, 2, 3? What is their role in plant life? What organ are they a modification of?

Explanation: 1 - tuber, 2 - bulb, 2 - rhizome. These organs are modified shoots. With the help of modified shoots, the plant can reproduce vegetatively.

Task 24.

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

1. The endocrine glands have ducts through which the secret enters the blood. 2. These glands secrete biologically active regulatory substances - hormones. 3. All hormones are chemically proteins. 4. Pancreatic hormone - insulin. 5. It regulates blood glucose. 6. With its deficiency, the concentration of glucose in the blood decreases.

Explanation: mistakes were made in sentences 1, 3, 6.

Proposal 1 - the endocrine glands secrete the hormone into the blood and do not have ducts, the external secretion glands secrete the secret into the duct.

Proposition 3 - not all hormones are proteins (for example, adrenaline is not a protein).

Proposition 6 - insulin helps glucose enter the cells, so when it is lacking, the concentration of glucose in the blood does not decrease, but increases (this disease is called diabetes mellitus).

Task 25.

Mammals are a thriving group of vertebrates. Explain what aromorphoses allowed them to achieve biological progress. List at least four features.

Explanation: mammalian aromorphoses:

1. Warm-bloodedness - independence from temperature environment (high level metabolism).

2. The appearance of wool - keeping warm.

3. Differentiation of teeth - they can eat different foods.

4. Four-chamber heart - complete separation of venous and arterial blood.

5. Strongly developed cerebral cortex (characteristically complex behavior).

6. Outer ear - sound collects and passes into the auditory tube.

7. The ability to feed babies with milk and care for offspring.

Task 26.

Why is a broadleaf forest considered a more sustainable ecosystem than a forb meadow? Give at least three pieces of evidence.

Explanation:

1. A forb meadow is represented by plants with only one life form - herbaceous plants, and in the broad-leaved forest there are grasses, shrubs, and trees (there is layering).

2. There are more branched chains in the broad-leaved forest.

3. Broad-leaved forest has more variety of species.

Task 27.

The chromosome set of wheat somatic cells is 28. Determine the chromosome set and the number of DNA molecules in the root tip cells in prophase at the end of the telophase of mitosis. Explain the results obtained in each phase.

Explanation: somatic cells contain a diploid set of chromosomes. In the cells of the root tip in prophase, the set of chromosomes and the number of DNA molecules are 2n4c - 56 molecules (since replication occurred), at the end of the telophase of mitosis - 2n2c - 28 molecules (sister single chromatid chromosomes are in the daughter cells).

Task 28.

Blood type and Rh factor are autosomal recessive traits.

The blood group is controlled by three alleles of one gene: I0, IA, IB. The IA and IB alleles are dominant over the I0 allele. The first group (0) is determined by the recessive I0 genes, the second group (A) is determined by the dominant allele IA, the third group (B) is determined by the dominant allele IB, and the fourth (AB) is determined by two dominant alleles - IAIB. Positive Rh factor (R) dominates over negative (r).

The mother has the second group and Rh positive (heterozygous for the Rh factor), the father has the third blood group and positive for Rh (homozygous for the Rh factor). My son has type I blood and is Rh positive. Make a scheme for solving the problem. Determine the genotypes of the parents and son. Determine what blood types and Rh factor children in this family can have, their possible genotypes and the ratio of phenotypes. What law of heredity is manifested in this case?

Explanation: mother's genotype - IAI0Rr

father's genotype - IBI0RR

son's genotype - I0I0R_

P: IAI0RR x IBI0RR

Gametes: IAR, I0r, IAr, I0R x IBR, I0R

We have the following splitting by 4 phenotypes and 8 genotypes.

F1: IAIBRR, IAIBRr - fourth blood type, Rh positive

IAI0RR, IAI0Rr - second blood type, Rh positive

IBI0Rr, IBI0RR - third blood type, Rh positive

I0I0Rr, I0I0RR - first blood type, Rh positive

The phenotype ratio is 1:1:1:1.

The law of independent inheritance appears.

Option 7. Biology. A set of materials for preparing students for the Unified State Examination 2018. G.S. Kalinova, L. G. Prilezhaeva.

The answers to tasks 1–21 are a sequence of numbers, a number or a word (phrase).

Consider the proposed scheme. Write in the answer the missing term, indicated in the diagram with a question mark.

Choose two correct answers from five and write down the numbers under which they are indicated.

The hybridological research method is used

1. embryologists

2. breeders

3. genetics

4. environmentalists

5. biochemists

An mRNA molecule takes part in protein synthesis, the fragment of which contains 33 nucleotide residues. Determine the number of nucleotide residues in the region of the DNA template chain.

The signs listed below, except for two, are used to describe the structure and functions of the depicted cell organoid. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table.

1. packs and carries synthesized substances out of the cell

2. participates in the formation of lysosomes

3. provides oxidative phosphorylation

4.consists of one membrane

5. contains interconnected grains

Establish a correspondence between the characteristic and the phase of photosynthesis: for each position given in the first column, select the corresponding position from the second column.

CHARACTERISTIC

A. photolysis of water

B. carbon dioxide fixation

B. splitting of ATP molecules

D. excitation of chlorophyll by light quanta

D. glucose synthesis

PHOTOSYNTHESIS PHASE

1. light

2. dark

Determine the ratio of phenotypes in the offspring formed by crossing two heterozygous pumpkin plants with yellow fruits with complete dominance. Write down the answer in the form of a sequence of numbers showing the ratio of phenotypes, in descending order.

Below is a list of terms. All of them, except for two, are used to describe genetic processes and phenomena. Find two terms that fall out of the general row, and write down the numbers under which they are indicated.

1. X chromosome

2. monophyly

3. atavism

5. karyotype

Establish a correspondence between the characteristics and the stage of formation of the lancelet embryo: for each position given in the first column, select the corresponding position from the second column.

CHARACTERISTIC

A. invagination of a group of cells inside the blastula

B. mitosis of the zygote

B. formation of the walls of the primary intestine

D. blastocoel formation

D. formation of blastomeres

STAGE OF EMBRYOGENESIS

1. single layer germ

2. bilayer embryo

Choose three correct answers from six and write down the numbers under which they are indicated. Angiosperms, as opposed to gymnosperms

1. are perennials

3. have flowers and inflorescences

4. form fruits with seeds

5. represented by a variety of life forms

6. reproduce by seeds

Establish a correspondence between a vertebrate animal and a feature of its body temperature: for each position given in the first column, select the corresponding position from the second column.

ANIMAL

A. house sparrow

B. quick lizard

B. common dolphin

G. Nile crocodile

D. common newt

E. common mole

FEATURE OF BODY TEMPERATURE

1. constant

2. fickle

Establish the sequence of arrangement of the systematic groups of the plant, starting with the smallest taxon. Write down the corresponding sequence of numbers.

1. Common radish

2. Angiosperms

3. Cruciferous

4. Dicotyledons

Choose three correct answers from six and write down the numbers under which they are indicated. Leukocytes are blood cells that

1. are formed in the red bone marrow

2. able to change their shape

4. synthesize hemoglobin

5. secrete substances for the formation of a blood clot

6. ripen in nerve nodes

Establish a correspondence between an example of the regulation of vital processes and the department of the nervous system to which it belongs: for each position given in the first column, select the appropriate position from the second column.

REGULATION EXAMPLE

A. coordinates the work of internal organs

B. regulates metabolic processes

V. acts autonomously, regardless of the desire of a person

G. provides arbitrary movements of the limbs

D. regulates the activity of smooth muscles

E. regulates skeletal muscle contraction

DEPARTMENT OF THE NERVOUS SYSTEM

1. vegetative

2. somatic

Establish the sequence of location of the structures of the eyeball, starting with the cornea. Write down the corresponding sequence of numbers.

1. retinal neurons

2. vitreous body

3. pupil in the pigment shell

4. light-sensitive rod and cone cells

5. convex transparent part of the albuginea

Choose three correct answers from six and write down the numbers under which they are indicated in the table. Which of the following examples are classified as aromorphoses?

1. functioning of self-sharpening incisors in rodents

2. leaf-shaped body of the liver fluke

3. development of stinging cells in hydra

4. the emergence of jointed limbs in insects

5. the appearance of internal fertilization in reptiles

6. the emergence of the nodal nervous system in annelids

Establish a correspondence between the trait of a honey bee and the criterion of the species to which it belongs; for each position given in the first column, select the corresponding position from the second column.

HONEY BEE SIGN

A. social lifestyle

B. size difference between males and females

B. development of larvae in combs

D. the presence of hairs on the body

D. feeding on nectar and pollen of flowers

E. compound eyes

TYPE CRITERION

1. morphological

2. ecological

Choose three correct answers from six and write down the numbers under which they are indicated. In the biogeocenosis, heterotrophs, unlike autotrophs,

1. are producers

2. provide a change in ecosystems

3. increase the supply of molecular oxygen in the atmosphere

4. extract organic matter from food

5. convert organic residues into mineral compounds

6. act as consumers or decomposers

Establish a correspondence between the characteristic of an ecosystem and its type: for each position given in the first column, select the corresponding position from the second column.

CHARACTERISTIC

A. A variety of circuits and power networks

B. great variety of species

B. the presence of a monoculture

G. closed circulation of substances

D. instability over time

E. the need for additional energy

TYPE OF ECOSYSTEM

1. agrobiocenosis

2. biogeocenosis

Establish the sequence of formation of aromorphoses in animals in the process of evolution. Write down the corresponding sequence of numbers.

1. the appearance of internal fertilization

2. the occurrence of the sexual process

3. formation of a chord

4. formation of five-fingered limbs

Consider the picture depicting cell division and determine its phases, the set of chromosomes in daughter cells, and what specific cells are formed as a result of such division in plants.

Fill in the blank cells of the table using the terms given in the list. For each lettered cell, select the appropriate term from the list provided.

List of terms:

1. prophase, metaphase, telophase

2. somatic

3. diploid

4. prophase 2, metaphase 2, anaphase 2, telophase 2

5. prophase 1, metaphase 1, anaphase 1, telophase 1

6. haploid

8. first meiotic division

Analyze the graph "Survival of the mouflon at the London Zoo". Select statements that can be formulated based on the analysis of the data presented.

Statements:

1. a group of animals was studied, consisting of 79 individuals

2. three to four individuals live 118 months

3. born individuals often die in the third year of life

4. most individuals live up to eight years

5. in the initial population, the average age of individuals is one year

Part 2.

First write down the task number (22, 23, etc.), then detailed solution. Write your answers clearly and legibly.

Several whiskers were taken from one strawberry plant, rooted and mature plants were obtained, which were transplanted to another part of the plantation. However, the fruits of some daughter plants turned out to be smaller than on the mother plant. Name the method used to propagate strawberries. Explain the reason for the appearance of small fruits.

Show answer

Response elements:

1) the plants were obtained as a result of asexual vegetative propagation;

2) plant differences are due to modification variability associated with the difference in environmental conditions in which the daughter and mother plants were grown

What organs of the plant are indicated in the figure by the letters A, B, C? What is their role in plant life? What organ are they a modification of?

Show answer

Response elements:

1) A - tuber; B - bulb; B - rhizome;

2) in these organs are stored nutrients, which are used in vegetative reproduction;

3) the depicted organs are modified shoots

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