The life environment of a plant is composed of many different elements that affect the body. Individual elements external environment bear the name environmental factors.

Environmental factors acting on the body can be divided into two main groups:

1. Factors of living, nature, or biotic, associated with the influence of other living organisms (plants, animals, humans).

2. Factors of inanimate nature, or abiotic. These include light, temperature, humidity, the composition of the water, air, soil environment, etc.

Certain conditions are necessary for the life of organisms that make up natural communities. Living conditions depend on the influence of various environmental factors. You already know that the sun serves as a source of energy for almost all life on Earth.

The energy of sunlight enters natural communities as a result of the photosynthesis of green plants. Organic matter formed in the process of photosynthesis serves as a source of energy for the plants themselves and for their consumers.

Thus, plants play the most important role in the natural community; therefore, we will consider the features of natural communities by their example.

All environmental factors affect the plant and are necessary for their life. But especially sharp changes in the external appearance and in the internal structure of a plant are caused by such factors of inanimate nature as light, temperature, humidity.

The effect of light on plants. Light is one of the most important factors in the life of a green plant, since it is

is a source of energy in the process of photosynthesis. It also affects other functions of the plant organism - its growth, flowering, fruiting, and in such plants as timothy, strawberries, hoofs and others, and the germination of seeds.

The attitude of plants to light is different, according to this feature, three groups are distinguished: light-loving, shade-loving and shade-tolerant.

Light-loving plants live only in the sunlit open spaces Oh. Light-loving ones include steppe and meadow grasses, cultivated plants of open ground, from tree species - pine, birch, larch, white acacia, from indoor plants- coleus .

Shade-loving plants do not tolerate strong light and grow well only in shaded places. These are herbaceous plants of spruce forests and oak forests, for example, raven's eye, double-leaved mine, anemone, many forest ferns. Aspidistra and some types of ferns can be classified as shade-loving indoor plants.

Shade-tolerant plants grow well in light, but can tolerate shading as well. This group of plants includes many tree species with dense crowns, in which some of the leaves are heavily shaded (linden, oak, beech, ash, etc.), many herbaceous plants of forests, forest edges and meadows, from indoor plants - monstera, sansevier, uzambara violet and many others .

The effect of temperature on plants. Each plant species has adapted to a specific temperature regime. But for all plants, both overheating and excessive cooling are dangerous.

Acting overly high temperatures can cause drying out, burns, destruction of chlorophyll in plants, disruption of vital processes and lead to death.

Light-loving plants are often exposed to high temperatures, often combined with a lack of moisture. These plants have developed a variety of adaptations to avoid the harmful effects of overheating: the vertical position of the leaves, the folding of leaf blades (cereals), a decrease in the leaf surface, the development of thorns (cacti), the ability to store a large number water, developed root system, dense pubescence, which gives the leaves a light color and enhances the reflection of the incident light, etc.

Cold can also adversely affect plants. When water freezes in the intercellular spaces and inside the cell, ice crystals are formed, causing cell damage and death. Plants in cold habitats that have to endure cold winters develop protective changes.

Perennial herbs and shrubs of polar and high-mountain areas have very small leaves and small sizes (dwarf birch, dwarf willow). Their height corresponds to the depth of the snow cover, since all parts protruding above the snow perish.

In some shrubs and trees, growth begins to prevail in the horizontal direction, for example, in elfin cedar, juniper, mountain ash, etc. Their branches spread along the ground and do not rise above the usual depth of snow cover.

In the cold season, all life processes in plants slow down. Preparation for the state of winter dormancy begins well in advance. Plants shed their foliage. They have lignification of the shoots and thickening of the cork layer. In many herbaceous plants, aerial organs die off. Some aquatic plants sink to the bottom of reservoirs or form wintering buds.

The effect of moisture on plants. Water is the most important component of the plant cell, therefore its amount in a particular place largely determines the nature of the vegetation. In plants of deserts, dry steppes, water makes up 30-65% of the total mass, in forest steppe plants- up to 70-80%, in moisture-loving it reaches 90%.

Plants can be divided into three groups in relation to moisture content.

1. Plants are aquatic and excessively hydrated habitats.

2. Plants in dry habitats, with great drought resistance.

3. Plants living in medium (sufficient) moisture conditions.

Plants included in these environmental groups, have their characteristic features of external and internal structure... They have similar vital processes.

The influence of minerals on plants. You know that on different soils various plants grow and develop differently. This is due to the peculiarities of the mineral nutrition of various plants.

Plants receive various minerals from the soil, but most of all they need nitrogen, phosphorus and potassium, as well as not large quantities ah boron, manganese, iron, etc.

The influence of living organisms on plants. Animals feed on plants, pollinate them, carry fruits and seeds. Large plants can shade young, small ones. Some plants use others as a support. Microorganisms that decompose plant residues enrich the soil with humus and minerals.

In turn, plants affect environment... They change the composition of the air: they humidify it, absorb carbon dioxide and release oxygen. Plants change the composition of the soil. They absorb some substances from it and release others into it. Root systems plants fix the slopes of ravines, hills, river valleys, protecting the soil from destruction. Forest rainfall protects the fields from dry winds. Plants that evaporate a lot of moisture, such as eucalyptus trees, can be used to drain wetlands.

Influence of human activities. Man drains swamps and irrigates dry lands, creating favorable conditions for growing crops. He develops new highly productive and disease-resistant plant varieties. Man fights weeds and promotes the spread of valuable plants.

But human activity can harm nature. So, improper irrigation causes waterlogging and salinization of soils and often leads to the death of plants. Deforestation destroys the fertile soil layer and even deserts can form. There are many such examples, and they all testify to the fact that man has a huge impact on the flora and nature in general.

21. Ecology of coniferous forest plants. \

The coniferous forest is one of the most interesting objects of wildlife on our planet. A lot of effort has been spent on its study, and not in vain - after all, the forest for a person has always been a source of untold wealth.
Coniferous forests grow, mainly in areas with a cold climate. If we imagine their location on the globe, we will see a wide belt covering the northern part of Russia, Scandinavia, Canada and America. At the same time, there are few relict forests left, they are gradually being replaced by artificially planted ones.
The main trees of the coniferous forest are cedar, pine, fir, larch. The requirements for moisture and soil fertility for these species are different, therefore, forests are divided into two types - dark coniferous (spruce, fir, cedar) and light coniferous (pine, larch). A mixture of these two types is often found in Russia.
Like any other forest, conifers have several floors (tiers). Coniferous forest tiers are usually well defined. Upper (arboreal), undergrowth (or shrub), herbaceous-shrub layer and moss-lichen cover. However, due to insufficient light in dark coniferous forests, undergrowth and herbaceous-shrub layer may be absent.
The species composition of plants depends on the degree of illumination, soil composition and many other factors. But there are plants of the coniferous forest, which are recognized as its characteristic and integral part. Shrubs include juniper, currant, buckthorn, willow. Shrubs - blueberries, lingonberries, cranberries, heather. Herbs - Ivan tea, angelica, cow parsnip, oxalis, wintergreen and many others. Ferns and mosses (lichen, sphagnum) are most typical for coniferous forests.
As already noted, the diversity of species depends largely on the quality of the soil. The soil of a coniferous forest can be not only clayey, but also loamy and sandy. Coniferous forests rise both on rock outcrops and in swampy areas.

An array dominated by spruces and cedars may seem gloomy and unsociable. Their branches close tightly with each other, creating an insurmountable barrier to the sun's rays. Who wants to live in a place like this? There are those who wish, and there are many of them. Here you can hear the clatter of woodpeckers, the hooting of a tawny owl and a sparrow owl, the sharp cries of a kyksha and the trills of a nutcracker. Capercaillies, wild grouses, crossbills, tits, chicks, korolki - all of them are birds of the coniferous forest. Without some of them (nutcrackers, crossbills), its very existence would be difficult.
It is good to go to a pine or spruce forest to pick mushrooms. The dry earth, covered with a thick layer of pine needles, seems to spring underfoot, to urge on. In the spruce forest there are boletus, chanterelles, russula, mushrooms, raincoats, champignons. The pine forest will delight you with butter mushrooms, honey agarics, pigs, greenfinches. Milk mushrooms and ryadovki are autumn mushrooms of a coniferous forest.
What else will the forest give its guests, where giant cedars and slender pines reign? Pine nuts, essential oils, berries, medicinal herbs - these are just a few of all his treasures. And let's not forget about hunting and fishing.
The trees themselves are actively used in construction and production. various materials... Forests also play a huge role in creating an atmosphere suitable for breathing.

Man and nature are inextricably linked. In the course of his life, a person uses what is part of the plant world. Every day we eat fruits, vegetables, meat. Do not forget about industrial production, which uses trees as resources (construction, furniture industry).

You can also assess how animals affect plants. The fauna is diverse, its representatives have different effects on the flora. Some insects, such as caterpillars, ants, can cause damage to an entire forest. Caterpillars are able to leave a tree with absolutely no leaves. May beetle larvae feed on plant roots, thereby destroying them. But on the other hand, you can see the positive effect of insects on vegetation. For example, the process of pollination or seed transfer is the merit of butterflies, bumblebees, bees. Although the wind is involved, insects definitely do their part. Ants, when building their homes, unwittingly become carriers of seeds. Birds are able to carry seeds over long distances, do not be surprised if the tree grows in an unusual area for it.

How do plants adapt to external conditions in different latitudes of our vast Motherland? In the process of evolution, plants "learned" to adapt to different weather conditions, climatic conditions... This was reflected in their appearance. For example, in places with hot climates, plants have small leaves. How did thorny plants come about? This all happened through the process of evolution. The leaf has transformed into a thorn due to lack of moisture. Shedding leaves is one of the plant's survival options. No leaves - no life, all processes freeze, the tree goes into hibernation. In hot areas, stunted plants are preferable, because a large, developed stem requires a lot of moisture. Frost-hardy plants have adapted to the cold by increasing the content of sugars and other substances that prevent dehydration.

How does a person use plants in their life? Reading books, buying leather goods, some do not even realize that all these are products of the plant world. Russia is the richest country not only in natural resources, but also in the diversity of vegetation. Mosses, lichens, almost all types of deciduous trees - all this property can be seen in the vast country. All plants can be conditionally subdivided into types, depending on the areas of application. Some plants are used for the preparation of firewood and for the production of building materials, others are food products (vegetables, fruits), others are used in the pharmaceutical and chemical industries (resin, tar), the fourth subspecies belongs to animal feed. Do not forget about the plants that flaunt on our windowsills. A person uses them for decorative purposes to please the eye.

The most direct and tangible form of the influence of animals on plants is the consumption of plant matter for food. At the beginning of any trophic chain (With very rare exceptions ") there is a green autotrophic plant, the creator of organic matter. Green plants represent the first trophic level - the primary producers of organic matter, due to which organisms of the second trophic level live - phytophages (animals, microorganisms, and in some cases plants). concrete examples trophic chains (in more complex cases - trophic webs) are shown in Fig. 175.
Herbivorous animals usually feed on certain plants: either one species (monophages), or a group of closely related species (oligophages). Polyphagous phytophages (polyphages) are less common. Among phytophages, there are large animals that consume large amounts of plant matter. In summer, an adult moose eats up to 30-40 kg of various plant foods per day, in winter - about 10 kg of shoots and bark, daily eating about 300-400 trees and shrubs. In the list of its forage plants -
1 An example is trophic chains in ecosystems in the ocean, where some bacteria play the role of an autotrophic link.

sunlight

Seaweed
) f
Animals that feed on algae and bacteria
L
Animals that eat other animals
L
Detritus feeding animals I I I
Nutrient Salts
t
- bacteria
4 Corpses ¦¦ and excreta
1

Bottom sediments
Rice. 175. Examples of food chains in ecosystems (simplified diagrams). A - in an oak forest (according to P. M. Rafes, 1968); B - in the pond (according to L.A. Zenkevich, 1956)

niy - aspen, mountain ash, birch, different kinds willows, gray alder, juniper, etc. In the Leningrad region, of the types of ground vegetation cover (grasses, shrubs, mosses, mushrooms), the diet of moose includes more than 100 species, roe deer - more than 130, red deer - 170. Elk not only eats up phytomass, but causes other damage to plants: eaten and damaged branches and trunks dry out; trees broken and bent by a moose in winter become available to other phytophagous animals (hares, voles). Vegetable food is also consumed by other large animals - deer, bears, wild boars, hares, etc. They prefer young branches of trees and shrubs ("branch fodder") as the most accessible and most nutritious. For plants, this damage means the loss of the most important growing parts, a decrease in growth, a change in the direction of growth and branching; in other words, animals act on plants as a form-forming factor (Fig. 176).
Many birds also consume phytomass. In our country, birds eat the seeds of more than 270 species of trees and shrubs. Particularly intensive destroyers of seeds are crossbills, nutcrackers, great spotted woodpecker, jay, blackbirds, etc. According to zoologists, in some types of southern taiga (Kalinin region) by the time of seed shedding (late winter - early spring), no more than one a third of the original harvest, the rest is destroyed, knocked down or pulled apart by crossbills and woodpeckers (partly squirrels). Birds also eat green parts of plants: for example, the common wood grouse, which feeds on pine (or cedar) needles in winter, eats more than 6 kg of it per month. The buds of deciduous trees and shrubs are eaten in large quantities in winter by black grouse, hazel grouses, and ptarmigan. In some cases, this affects the nature of branching and forms a kind of architectonics of the crown (Fig. 177).
Small phytophagous animals, for example, murine rodents, eat relatively small amounts of phytomass per individual, but due to the large number of populations, their activity is generally quite noticeable for the vegetation cover. According to experimental data, a mouse (or forest vole) is capable of eating from 470 to 1400 spruce seeds per day. Given the high number of murine rodents, one can imagine how many seeds they destroy during the year. This activity of theirs has a significant effect on the regeneration of plants. No wonder it was noted that in the taiga, young spruce undergrowth usually appears only in the years bountiful harvest ate seeds, which rodents and other seed consumers cannot completely destroy. The vegetative parts of plants are also eaten in bulk by mouse-like rodents: for example, in the Tula region, the common vole destroys in some years in clearings up to 70% of young undergrowth of elm, maple, oak and other tree species.
Very numerous, widespread and diverse consumers of plants are insects. So, tree species are damaged

I 1 1 I 1-І L_l I I I ¦ I I L_l I L-
O
b-L.i
35 years
5 10 15 20 25 30

Rice. 176. Influence of damage caused to birch and larch by white hare on the growth of young trees in height (according to LG Dinesman, 1959). Birches: / - intact, 2, 3, and 4 - with a single, three and four times bitten apical shoot. Lnstvei: 5 - intact, b and 7 - with a single and double bitten apical shoot

Rice. 177. The influence of the stone capercaillie on the architectonics of the larch crown (according to AA Mezhenny, 1957).
A - untouched crown; B I C - crowns, "trimmed" by wood grouse
are given by various specialized groups of insects: leaf-eating, tree-eating (xylophages), sucking sap, etc. A special group is made up of insects and mites - gall-forming mites: along with nutrition, their effect on the plant is that they cause the growth of plant tissues in the form of galls and other teratological formations (Fig. 178), i.e.


Rice. 178. Galls on leaves (after Strasburger E. et al., 1962). A - rose hip - Rosa sapipa; B - beech - Fagus sylvatica
direct part of the production of photosynthesis (sometimes quite significant) along a different path, unproductive for the plant itself.
Other invertebrate phytophages (mites, nematodes, protozoa, etc.) also take a large part in the consumption of plant mass.
The role of aquatic animals (from zooplankton to large marine mammals) in the consumption of vegetation of rivers, freshwater bodies of water, seas and oceans is great. Huge quantities of phytoplankton are known to be eaten by whales.
Plant species, which are often damaged by phytophagous animals, have certain protective adaptations and reactions. Strong integumentary and mechanical tissues, various outgrowths, thorns, pubescence, etc. are used as protection against eating. The growth of thistles and other thorny, inedible species on pastures is evidence of the effectiveness of such protection. As shown by special studies on the pastures of Central Asia, protective formations that protect fruits and seeds from eating (thorny outgrowths, thorns, etc.) are especially developed in annuals. This is understandable, since for annuals reliable protection seed serves as a guarantee of the continuation of the existence of the species.
Plant defense reactions include their ability to quickly recover losses. So, in the forest-steppe oak forests, during the years of massive outbreaks of reproduction of the oak leafworm, which almost completely eats the foliage, in the middle of summer, buds laid down for the next year start growing in many trees, and new foliage develops (sometimes this process is repeated again at the end of summer) ... In herbaceous species, the regrowth of vegetative organs after they have been grazed is widespread. In general, the formation of excess phytomass is one of the main ways of protecting a plant from leaf-eating insects, seed-eaters and other phytophages. Another defense reaction is an increase in the photosynthetic activity of leaves that have remained uneaten, which allows plants to maintain the overall productivity of photosynthesis.
More local ways to eliminate damage - the formation of protective tissues (calluses), the release of resins and gums; it is both a "dressing" of a wound, and a way of protecting against further penetration of pests: for example, many insects get stuck in resins, for others they turn out to be toxic. There are also very specific plant defenses directed against phytophagous animals: for example, in seaweed - lime deposition, the presence of microscopic and endolytic (living inside a solid substrate) stages in the development cycle; however, these same features help to transfer other adverse effects of the marine environment (storms, surf, etc.).
The biochemical unsuitability of plant tissues for a phytophage can serve as a protective property. Some plant-produced "secondary" chemical compounds, which are not directly involved in its metabolism, are poisonous or deterrent (repellents). A number of alkaloids, glucosides and other toxic substances give plants a bitter or unpleasant taste. Cases of a kind of mimicry are based on this: some edible plants, in the process of natural selection, acquired the appearance, smell and taste of poisonous species as a means of protection from eating. Sometimes poisonous properties appear only during the most important part of the year for plants; for example, on Central Asian pastures, sheep almost do not eat annual saltwort and wormwood at the beginning of the growing season (before the formation of seeds), since at this time the plants contain many alkaloids; after fruiting, these same species become quite edible.
The listed traits provide plants with relative resistance to being eaten by animals. The protective properties and reactions in plants indicate not the one-sided influence of animals, but the interaction of phytophagous animals and plants as one of the forms of biotic connections in ecosystems. Plant populations usually have an adequate supply of resistance to animal feed; As a result of the joint evolution of phytophagous animals and plants, their relationships are balanced in such a way that the phytophage does not completely destroy the plant species that serves as its source of existence.
However, there are cases of imbalance, when a massive outbreak of phytophage reproduction leads to the death of the population of the host plant and, as a rule, to a change in the plant community. So in 1965-1966 in Northern Finland (Lapland) caterpillars of Oporitiia autumnata completely devastated birch forests of meandering birch - Betula tortuosa over a large area (about 1350 km2); subsequently, a "secondary tundra" developed in their place.
It is pertinent to ask the question: does eating by phytophages represent unfavorable factor in the life of plants and is it possible to identify it with "damage", "harm", "harmful influences" (these terms are often used to describe the effect on plants of certain groups of phytophages - some animals, birds, and especially insects). These terms are quite legitimate in the economic aspect when it comes to plants that are economically valuable for humans (for example, forest tree species). They are also justified from an autoecological point of view (if we consider the violation of the integrity of a plant individual or, even more so, its death as going beyond the optimal conditions) and, in part, from the population-ecological point of view (if we bear in mind the unfavorable consequences of a decrease in the population size). However, at the ecosystem level, assessments of "harmfulness" largely lose their meaning: each component of the ecosystem takes its place and does its job, and phytophagous animals are one of the natural links in the flow of energy and the cycle of substances. Therefore, the consumption of plants for food by phytophages should hardly be considered only as an unfavorable factor in the life of plants. Moreover, the phenomena that are habitually assessed as undesirable at the ecosystem level may be conducive to the intensification of the general biological cycle. So, with massive outbreaks of the reproduction of insect pests in forests and eating large amounts of foliage by them, the mineralization (and hence the return to the biological cycle) of organic matter entering the soil is sharply accelerated: organic residues that have passed through the digestive tract of insects decompose incomparably faster than leaves in the litter.
An important aspect of the activity of animals also consists in the redistribution of organic residues over the territory; without their participation, they would be distributed much less evenly.
The destruction and damage of plant matter by animals occurs not only when it is directly used for food, but also in other cases. One of them is the use of plants in the construction of dwellings. It is known how great is the use of plant material by beavers in the construction of dams: they cut down large trees and cut off bushes (in addition, they gnaw some of the trees and leave them standing on the root, dooming them to dry out). Forest mouse rodents use herbaceous plants for soft lining of burrows. Leaf-cutting bees of the genus Megachile and others cut circles and ellipses from leaf blades to build a refuge for larvae, tube-twid insects

Rice. 179. Damage to leaves during the construction of dwellings by insects (according to Fabre Zh-A, 1963) A - by a bee leaf cutter; B - pipe-runner beetle
roll the leaves into a tube in which the larva develops (Fig. 179). These examples can be continued many times.
Eating and other consumption of plant mass by animals is usually accompanied by mechanical effects - injury to plants (trampling, breakage, etc.). Not all broken or plucked plant parts are eaten. An example of a very uneconomical use of phytomass is the muskrat, which feeds on coastal aquatic plants: for example, in cut plants (reeds, reeds, sedges) it eats a negligible part, the rest of the plant dies. The damage inflicted to plants by murine rodents is not limited to the consumption of phytomass: bitten or gnawed leaves and stems die, plants are used to set up “feeding tables” on which not all plants are eaten. Leaf-eating insects leave stubs from the leaves, which then dry out.
Plants are greatly influenced by the burrowing activity of animals (wild boars, diggers, murine rodents, soil invertebrates). In forests, the number of holes of only mouse-like rodents can reach several hundred per hectare. The influence of diggers on. Plants are the burial of aboveground parts under soil emissions, and direct destruction of underground storage organs, and damage to root systems, often leading to plant drying, and changes in the structure of the soil and its ecological regimes.
Such forms of the influence of animals on the soil as compaction of the surface layers, destruction of the litter and breaking up the sod, enrichment with organic residues, etc. are also essential for plant life. At the same time, the disturbance of the integrity of the forest litter partly contributes to seed renewal of plants; in the places of boar holes, self-seeding appears in the mass and root growth trees and shrubs.
An example of a variety of direct and indirect influences of animals on plants is such a complex form of influence as grazing (which can partly be considered as an anthropogenic influence, since it is organized and directed by humans). Eating plants by livestock leads not only to the destruction of the plant mass; as a result of selective eating of the most preferred species, the species composition and structure of pasture herbage significantly changes. So, under a strong pasture load, many valuable grasses fall out and, on the contrary, non-eating ones grow - poisonous, thorny, etc. Plants that can easily endure trampling gain an advantage on pastures - with creeping growth, the ability to root broken parts, rosette forms (for example , overgrowing of pastures with knotweed, or bird buckwheat, - Polygonum aviculare - the formation of the so-called "cleanup"). Certain species in the process of adaptation are able to form special pasture forms (undersized, rosette or spread over the ground). Examples are plantains, dandelions, etc.
Other effects of grazing are fertilization and sod breaking, which promotes normal plant regeneration.
The influence of grazing is associated not only with human economic activities. Long before the development of the southern Russian steppes by man, huge herds of wild ungulates grazed there - antelopes, tarpans. It is believed that this factor played a significant role in the formation of steppe vegetation, as well as huge herds of bison in the formation of the vegetation cover of the North American prairies. This is evidenced by many years of experience conducted in the steppe reserve "Askania Nova". Steppe felt accumulated on fenced and non-grazing areas, the water regime and soil aeration worsened, which led to difficult regeneration and loss of feather grass first, and then other characteristic and valuable steppe plants, and, finally, to the degradation of steppe herbage. Obviously, grazing in small doses is a natural and necessary factor that supports the very existence of steppe vegetation.
But even when the pastures are overloaded, there is a gradual degradation of vegetation. Its different stages are well traced in space in the form of ring zones around steppe wells and watering holes.
In this case, vegetation can also play an indicator role, indicating a different degree of pasture load. For example, with overgrazing (“failure”), “pasture” plants - knotweed, meadow bluegrass - Poa pratense begin to prevail in the herbage of meadows. In the steppes, such plants are bulbous bluegrass - P. bulbosa, tartar quinoa - Atriplex tatarica, hornhead. In the tundra, with excessive use of the lichen cover, deer fall out slowly growing lichens, and the tundra becomes mossy.
Excessive grazing in steppe zone contributes to the degradation of the steppe herbage and the advancement of southern steppe and semi-desert plants to the north. So, over 150-180 years of the existence of the Derkul stud farm (Luhansk region) in areas subjected to intensive grazing and running horses, the motley grass steppe was replaced by semi-desert groups, where annuals appeared in the mass (for example, ebelek - Ceratocarpus arenarius, the range of which, as a result moved significantly to the north).
The role of animals in pollination of plants is widely known. Pollination by insects - entomophilia - promoted the development of a number of delicate adaptations in plants and insects, which have been repeatedly described in special and popular literature. Let us mention here such interesting adaptations of entomophilous flowers as patterns that form "paths" to nectaries and stamens (often visible only in ultraviolet rays visible insects); the difference in the color of flowers before and after pollination (for example, in the lungwort, newly blossoming pink flowers containing a lot of nectar are especially attractive to insects, and already pollinated or wilting flowers acquire a lilac and blue color); synchronization of circadian rhythms of corolla opening and nectar secretion with the rhythms of pollinator activity; structural features of the corolla and stamens, ensuring the unmistakable ingress of pollen on the body of the insect, and from it on the stigma of another flower; etc. There are numerous examples of flowers "calculated" for the mode of action of a particular pollinator. One of them is represented by the flowers of the clefthoof - Asarum eigoraeite, pollinated by ants and, accordingly, do not rise from under the forest floor.
At the same time, under conditions unfavorable for insects, a secondary loss of entomophilia sometimes occurs. So, under the canopy of the dark coniferous taiga, many plants with flowers entomophilous in structure, due to the lack of pollinators, go to cleistogamy, autogamy, or vegetative propagation.


Rice. 180. Fruits of an epizochoric plant equipped with hooks and hooks (after Herschel K-, Grunert Ch., 1958): A-Caucalis
lappula;

- Harpagophijton procumbens

Birds also take part in the pollination of plants (yav-lt; laziness of ornithophilia). In the tropical and subtropical regions of the southern hemisphere, about 2,000 bird species pollinate flowers when searching for nectar or catching insects hiding in corollas. The most famous pollinators are sunbirds

Rice. 181. Plants with endozoic fruits distributed by birds.
A - Rhamnus franguta; B - Euonymus europaea; B - E. verrucosa
(Africa, South Asia, Australia) and hummingbirds (South America). In the latter case, birds constitute significant competition for insects: in areas of high distribution of hummingbirds, the insect world is much poorer, and some butterflies, instead of feeding on nectar and pollen, have switched to feeding on rotting waste.
The flowers of ornithophilous plants are large, brightly colored. The predominantly bright red color is most attractive to hummingbirds and other birds. Should
notice that it is generally quite rare in flora for a number of physical and chemical reasons. It is very rare in temperate and northern latitudes, where insects, poorly distinguishing red shades, are pollinators, and where, therefore, such a color could not be fixed by selection. Ornithophilous flowers contain a lot of nectar. For example, Australian plants from the genus Dorianthe contain several milliliters of nectar in each flower. In some ornithophilous flowers, there are special protective devices that prevent the nectar from spilling out when the flower moves.
A much rarer case of zoogamy (animal pollination) is the pollination of flowers by mammals. Australian shrubs of the genus Driandra are pollinated by kangaroos, which willingly drink their abundant nectar, moving from flower to flower. Other pollinators of Australian plants are flying squirrels that suck nectar from eucalyptus flowers, marsupial dormouse, narrow-winged heel walker (or "honey mouse"), "flying dogs" that hunt for insects that sleep in the corolla of flowers. In the forests of Africa and South America, in the role of woody pollinators



Rice. 181. Continuation
breeds are small bats-sunbirds. As an adaptation to such unusual pollinators, plants have developed such peculiar features as flowering before the leaves bloom, flowers with a wide bell-shaped corolla (when pollinated by nocturnal animals, it opens at night), a musty smell, slimy nectar.
Animals play important role in the distribution of plant rudiments - fruits, seeds, spores. The zoochory phenomenon has certain ecological patterns and is expressed differently, depending on the habitat of the plant and the nature of its contacts with the carrier animal. Plants of open places more often form epizochoric seeds and fruits that are carried on the surface of the animal's body, and in accordance with this, fruits and seeds have various devices for fixing and holding (hooks, outgrowths, attachments, etc.), for example, burdock and cobweb - Arctium lappa, A. tomentosum, common Velcro - Lappula myosotis and others (Fig. 180). In some species (for example, in terrestrial tribulus - Tribulus terrestris or the South African plant - Harpagophyton procumbens), sharp thorns are developed on the fruits, which pierce the legs of animals (Fig. 180, B).
In the shrub layer of forests, where many birds live, endozoic species prevail, whose fruits and seeds are brightly colored, attracting birds to a juicy pericarp (Fig. 181) and therefore willingly eaten and spread by birds. Such are the fruits of forest bushes - euonymus, hawthorns, rose hips. The dense mechanical tissue protects the seeds from damage as they pass the animals' digestive tract. Often, the digestive juices of birds or animals digest the endosperm of endozoic seeds, but do not affect their embryos. Moreover, there are plants (for example, among the Araliaceae family Of the Far East), in which the embryo of falling seeds is underdeveloped and matures at a temperature of about 40 "° C, which corresponds to the temperature of the stomach of birds.
Eating berries and fruits, they spread the rudiments and herbivorous animals, and even predators (albeit at a relatively short distance). One of the ways of spreading fruits and seeds is their transfer by animals and birds when arranging "storerooms" for the winter (usually these reserves are not completely exterminated). So, jays not only feed on acorns, but also arrange supplies, carrying fruits quite far in the esophagus. For example, in the Lisinsky forestry enterprise (Leningrad region), in a spruce forest 1-3 km from old oaks, there is a young growth of oak trees - obviously from acorns brought into the spruce forest by jays constantly flying there. An inhabitant of the Siberian taiga - a nutcracker bird - hides "pine nuts" in its storerooms in moss and under the bedding, sometimes at a distance of hundreds of meters and even several kilometers from the gathering place. Small animals - squirrels, mice and others - also make supplies. Up to 5 kg of "pine nuts" were found in the burrows of the chipmunk. The size of the storage activity of mouse-like rodents was estimated in laboratory conditions, for example, in one of the experiments, a pair of mice accumulated 45 thousand beech nuts with a total weight of about 9 kg per month. Interestingly, rodents store undamaged, selected (that is, the most viable) seeds.

Rice. 182. Haller's corydalis seeds - Corydalis halleri with eliosomes

There are many plants in the forest cover, whose seeds are carried by ants and have appropriate adaptations. Such species are called myrmecochory, and the phenomenon itself is myrmecochory. Many forest herbs(clefthoof - Asarum eigoraeite, corydalis - Corydalis halieri, scrub - Scilia sibirica, goose onions - Gagea lutea. various types of violets, etc.) have oil-rich outgrowths on the seeds - seedlings, or "ant bodies" (elaiosomes), which serve for ants with bait (fig. 182). In the oak tree plant - Melampyrum petnorosum, white oblong seeds resemble ant cocoons in shape, and the ants drag them into the anthill, and then these same seeds, but already darkened and ripe, are thrown away during harvesting. Seeds with eaten seedlings are also thrown away. The seeds of some species (dandelion, rattles, larch) are used by ants as material for the construction of anthills (but some of them are dropped along the way).
As a result, ants can remove seeds from the mother plant at a distance of several tens of meters. Another form of myrmecochory is the dispersal of fungus spores by leaf-cutting ants, which they breed in their nests.

Being a part of various plant communities, often very complexly organized, plants experience a variety of influences from neighboring plants and themselves have an impact on co-inhabitants. The forms of mutual influences are very diverse and depend on the method and degree of contacts between plants, conductors of influences, etc. Of the various classifications of forms of relationships in Soviet literature, the most common classification is VN Sukachev's (given in a generalized form).
The main forms of relationships between plants (according to Sukachev V.N., Dylis N.V. et al., 1964)

C02, H20, light

Rice. 187. Scheme of the participation of fungi in the carbon cycle in the ecosystem (after Herley J., 1971). The left part is a symbiotic cycle with the direct use of photosynthetic products, the right part is a decomposition cycle

CM


28g
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The fauna is one of the most important components of the natural environment. The existence of our planet is impossible without it.

Type of training session : study and primary consolidation of new knowledge

Didactic goal : create conditions for awareness and comprehension of the block of new educational information

Basic concepts -

Rough plant foods. Trampling.

Main questions

1. What herbivorous animals do you know? How fit them

the digestive system to feed various plant organs?

2. How are pasture plants and ungulates grazing on it interrelated?

Draw a diagram of their interaction.

3.How do animals influence their environment in places

watering hole and rest?

4. What damage do insects do to plants?

Animals live among plants and have a great influence. life. First of all, they use plants for food and in this way the necessary substances and energy for themselves. Food sources for: are both herbs and woody plants, and lichens. Food composition; Getative parts of plants - roots, stems, leaves, and flowers. Vegetative parts of plants are coarse plant foods.

By eating the vegetative organs of plants, animals will naturally change the state of the plants themselves and the environment in which they grow. In response to damage by animals, plants have developed their own adaptations allowing them to regenerate (restore) vegetative organs disturbed by animals. Therefore, damage to plants does not lead to their death and they preserve their ability for further growth and the integrity of the organism.

Moving in search of food on the surface of the soil, animals inflict mechanical damage on plants primarily - they break off the stems of the stems, pull out the grasses. Plants are especially severely damaged by ungulates during grazing, when animals trample them with their feet. However, long-term observations have shown that grazing animals does not destroy pastures. When trampled, the grass seeds are pressed deeply into the soil, as a result of which their germination is improved. In addition, trampling improves the conditions for decaying dead plant parts and the supply of nutrients to the soil.

It turned out that moderate trampling together with grazing favors the development of stable grass cover in the steppes. If the grazing of livestock stops, a change in the vegetation cover occurs in the steppe, which is accompanied by a strong growth of weeds.

Trampling and the rainforest are not avoided. The vegetation of tropical forests in places of constant movement or congestion of elephants and ungulates is exposed to especially strong trampling. For example, African elephants, moving by constant paths to places of watering, significantly widen the clearings in the rainforest, and where they come with their ungulates, trample the grass cover, break bushes, roll in the mud. Such actions of animals noticeably change the appearance of the territories in which they live.

There are known cases of a sharp impact of animals on vegetation, in which the appearance of the terrain has irreversibly changed. So, the island of St. Helena in the Atlantic Ocean in the past was covered with forest. People who were exploring the island brought goats with them. Having run wild and multiplying, the goats destroyed all undergrowth, old trees and grasses. The island's territory became treeless, open to winds, fertile soil was washed away by tropical downpours.

Rice. 1: 1 - types of damage to plants by insects (a - "mining", b - coagulation, c - galls); 2 - clutch and larvae of cabbage moths on leaves; 3 - larvae of May beetle (in the soil near the roots).

Insects lay eggs on the leaves of many plants. The caterpillars that subsequently appeared from them feed on these leaves. Plant roots are also often damaged by the larvae of animal pests (Fig. 1).

There is also the opposite variant of the food interaction of animals with plants: animals serve as food objects for plants. In Russia, more than a dozen species of predatory plants are known - these are various sundews living on sphagnum bogs, and pemphigus inhabitants of water. The need for insect nutrition arises in them when there is a lack of mineral substances in the environment, in particular those containing nitrogen.

Sources of information: Animal ecology. Grade 7 student manual comprehensive school V.G. Babenko; D.V. Bogomolov; et al. 2002.-128p. .

Nature is harmonious, and its representatives are in constant interaction with each other. The climate and landscape features have great importance for representatives of flora and fauna. Animals and plants also have a great influence on each other in the course of evolution.

Instructions

The diversity of the animal kingdom has different effects on plants. For example, for many herbivorous representatives of various orders of animals, green parts of plants are food. Grasses, trees and shrubs could not remain defenseless for a long time, and developed various mechanisms to resist such treatment. Some plants eventually acquired a specific taste that is unpleasant for animals (for example, those herbs that humans use today as spices). Others have become simply poisonous. Still others preferred to acquire means of protection - thorns, which make it difficult for the animals to access their green parts.

For some plants, representatives of the fauna have become faithful helpers in the reproduction and dispersal of their seeds. Plants had to acquire bright colors with sweet nectar to attract pollinating insects (and in some cases, birds). Birds and animals eat the berries of plants (they also had to be made attractive to taste in the course of evolution), after which the seeds contained in them are carried over long distances, leaving with excrement. Therefore, the berries of plants are usually bright - red, black, blue. Green color would be simply invisible against the background of foliage. Some plants have acquired special devices - thorns, or made their seeds sticky, so that, clinging to animal hair, they also spread around the world.

Animals are able to create a favorable environment for plants. Ants, earthworms and small animals regularly enrich the soil with organic matter, loosen it and make it more comfortable for grasses, bushes and trees to grow in this place. And through the holes left by insects and rodents in the soil, water freely gets to the roots of plants, feeding them. Therefore, plant and animal organisms are in close cooperation with each other.