Practical work studying the cells of plants, animals under a microscope, their description
Option 2. White hare and a brown hare
The genus of hares proper, which includes hare and white hare, as well as 28 more species, is quite numerous. The best known hares in Russia are the hare and hare. The white hare can be found on the territory from the coast of the Arctic Ocean to the southern border of the forest zone, in Siberia - to the borders with Kazakhstan, China and Mongolia, and in the Far East - from Chukotka to North Korea. The white hare is widespread in the forests of Europe, as well as in the east of North America. Rusak lives on the territory of European Russia from Karelia in the south of the Arkhangelsk region to the southern borders of the country, in Ukraine and in Transcaucasia. But in Siberia, this hare lives only in the south and west of Lake Baikal.
Belyak got its name due to snow-white winter fur. Only the tips of his ears remain black all year round. Rusak in some northern areas is also much brighter by the winter, but it is never snow-white. And in the south, it does not change color at all.
The hare is more adapted to life in open landscapes, since it is larger than the hare, and it runs better. At short distances, this hare can reach speeds of up to 50 km / h. In white haws, the paws are wide, with thick pubescence to fall less into loose forest drifts. And the hare has paws already, because in open places the snow is, as a rule, hard, packed, "trampled by the wind."
The length of the white hare body is 45-75 cm, the mass is 2.5-5.5 kg. Ears shorter than the hare. Body length hare - 50-70 cm, weight up to 5 (sometimes 7) kg.
Hares usually breed two times, and in the south three or even four times a year. The white hares in the conclusion can have two, three five, seven hare, and the hares usually have only one or two hares. Rusaki begin to try the grass in two weeks after birth, and the whites and even faster - in a week.
Practical work 7
Identification of adaptations of organisms to the environment
Objective: Determine the mechanisms of the formation of devices, concluding that fitness is the result of natural selection
Material for work: textbooks, textbooks, herbarium specimens of plants
The task:
BUT)read the text of the textbook, look at the drawings, on the herbarium specimens look at the external structure of the plant species:
For herbarium specimens, consider the external structure of the following plant species:
B) not eaten by animals: stinging nettle, prickly hawthorn, Siberian hogweed;
AT) early flowering: spring purge, goose onions, lily of the valley in May.
The results of the work for the task A enter in the table:
Adaptation of organisms to habitat conditions
| Adaptations | a brief description of | Examples |
| Morphological | ||
| Protective coloration | ||
| Cautionary coloring | ||
| Mimicry | ||
| Biochemical adaptations | ||
| Physiological adaptations | ||
| Behavioral responses |
The results of the work for task B, C are listed in the table:
When performing tasks, determine:
What features of the structure of the first group of plants protect them from being eaten by animals, while in the second they provide early flowering.
Determine what environmental factors are associated adaptive features of the organization.
What are the benefits of plants in connection with the acquisition of characteristic features
Try to explain how the adaptive symptoms arose, assuming that the ancestral forms did not have them.
Note the adaptive to the conditions of existence of signs in birds and mammals.
Practical work 8
Comparative characteristics of natural and artificial selection
Objective: to establish signs of similarities and differences between natural and artificial selection
| Sign of | Natural selection | Artificial selection |
| Source material for selection | ||
| Selection factor | ||
| The path of favorable change | ||
| Path adverse changes | ||
| Focus of action | ||
| Result of selection | ||
| Forms of selection |
Main directions of evolution: biological progress and biological regression
The main ways of evolution:
- aromorphoses (arogenesis) - major evolutionary changes leading to a rise in the level of biological organization, an increase in the intensity of life processes, examples are the appearance of autotrophic nutrition, aerobic respiration, eukaryotic cells, sexual reproduction, and so on;
- idioadaptation (allogenesis) - small evolutionary changes, adaptations to certain environmental conditions without raising the level of biological organization, examples are the number of petals and flower color, the specialization of some plants to certain pollinators, bacteria from hot springs;
Practical work 9
Observation and identification of adaptations in organisms to the influence of various environmental factors
Purpose. Generate knowledge about the identification of adaptations in organisms to the influence of various environmental factors.
Working process.
1. Ecological factors
1) Characteristics of environmental factors:
2) Regularities of environmental factors
Based on the scheme of the environmental factor, formulate the answers to the questions:
What is a "limiting factor"? Give your formulation of the law of minimum J.Libiha.
What is a biological optimum? Formulate the law of biological optimum.
Are the adaptations of organisms to individual environmental factors independent of each other? The answer is explained by examples.
2. The main abiotic factors and their importance for organisms
Fill the table:
3. Biotic factors and their significance for organisms
2) Fill in the table:
Practical work 10
Comparative characteristics of ecosystems and agroecosystems
Purpose:identification of signs of difference between natural ecosystems and agroecosystems
| Signs of Difference | Natural ecosystems | Agroecosystems |
| Ecosystem examples | ||
| Species diversity of plants | ||
| Species diversity of animals | ||
| Process regulation | ||
| Human attitude |
Study of changes in ecosystems on biological models (aquarium)
Purpose:using the example of an artificial ecosystem to trace changes occurring under the influence of environmental conditions.
Working process.
What conditions must be observed when creating an aquarium ecosystem.
Describe the aquarium as an ecosystem, indicating abiotic, biotic environmental factors, ecosystem components (producers, consumers, decomposers).
Make food chains in the aquarium.
What changes can occur in the aquarium if:
direct sunlight is falling;
a large number of fish inhabit the aquarium.
Fitness - compliance with the characteristics of the body (internal and external structure, physiological processes, behavior) habitat, allowing it to survive and give offspring. For example, aquatic animals have a streamlined body shape; frog makes invisible against the background of plants green color of the back; The layered arrangement of plants in the biogeocenosis makes it possible to effectively use solar energy for photosynthesis. Fitness helps organisms survive in the conditions in which it was formed under the influence of the driving forces of evolution. But even in these conditions it is relative. The white partridge and a sunny day gives himself a shadow. The hare, imperceptible in the snow, is clearly visible against the background of dark trunks.
Speciation, their microevolution is the initial stage of the evolution of the organic world, which consists in the emergence of new species based on previously existing ones.
Geographical (allopatric) speciation occurs as a result of the expansion of the range of the original species or the division of its range into isolated parts by natural barriers (mountains, rivers, etc.). In this case, populations are found with new environmental conditions and communities of organisms. The mutation process acts on the population in nature, fluctuations in the number of individuals occur, and natural selection acts. Over time, the gene composition of the population changes, it acquires differences from other populations of the same species. For example, Siberian larch settled from the Urals to Baikal and was in different conditions, which led to the emergence of Dahurian larch.
Ecological speciation refers to the sympatric occurs in cases where populations of the same species remain within their range, but their living conditions are different. Under the influence of the driving forces of evolution, their gene composition changes. Through a series of generations as a result of differences in gene pools, biological isolation occurs. For example, one type of tradescantia formed on rocky peaks, another - in shady forests; the seasonal races of a large rattle give seeds before mowing, or after it, and, dwelling in the same territory, are not able to interbreed; Trout populations in Lake Sevan differ in terms of spawning periods.
The peculiarity of ecological speciation is that it leads to the formation of new species, morphologically close to the original species.
The similarity of speciation: occur under the action of the driving forces of evolution. Differences: the causes of differences in the characteristics of populations are different: geographical speciation is associated with the expansion of the range and the emergence of isolated populations, and the ecological with the settlement of individuals of one species of different ecological niches within the same range.
Evolution as a historical process has two directions; progress and regress.
Biological regression - the lack of the necessary level of fitness, leading to a decrease in the number, narrowing of the area, a decrease in the number of subordinated systematic groups. Biological regression can lead to extinction. For example, the Ussuri tiger, sable are on the verge of extinction. The reason for the regression: the lag in the pace of evolution of the group from the rate of change of the external environment. Human activity often leads to a reduction in the number of populations of many species.
Aromorphosis - These are changes in the body that increase the overall level of organization and vital activity of individuals, contributing to the transition to a new habitat. Aromorphosis is the main direction of evolution, which leads to the formation of new systematic groups - classes, types, orders. Acquired aromorphoses always remain in organisms during evolution and lead to a gradual complication of the structure of organisms.
Idioadaptation - the direction of evolution, which is based on changes in the body, contributing to the adaptation to specific environmental conditions and not increasing the overall level of organization of individuals. An example of idioadaptatsii can serve as a protective, masking or warning coloring, behavior during reproduction, marking of the territory, joint protection against enemies.
White hare -Lepus timid us L.
The appearance of a hare is so well known that there is no particular need to describe it: long hind legs, long ears, a short upturned tail, and fluffy fur of a hare are known to all. We indicate only some of the structural features that distinguish our two white hares and the hare from each other.
The white dog differs from its fellow, the hare, with its smaller size, denser body fit, a more obtuse muzzle and somewhat shorter legs and ears. If the white hare ear is bent forward, it reaches the end of the muzzle, but not further, and with the hare it is given out considerably. The tail of a white hare is white from above throughout the year, with the hare it is somewhat longer and black on top. Winter color of the hare and the hare varies quite sharply. The white hare is completely white in winter, except for black specks on the tips of the ears. In the same winter, quite a lot of dyed hair is preserved on the back, which forms a wide dark band. In the summer the hare is colored somewhat lighter and more yellow than a white hare. The white hare is painted a reddish-brown color in summer. The average body size of a white hare is about 55 cm, the maximum is 65 cm. The white hare weight is about 2.8-3.2 kg and occasionally reaches 4.5-5 kg. The dental formula in both types is the same: 2.0.3.3/1.0.2.3 = 28.
The white hare is spread throughout the forest region of Europe, in Ireland, Scotland, the Pyrenees, the Alps, Scandinavia, in the northern half of eastern Europe, throughout Siberia, including Kamchatka and Sakhalin, in northern North America and in Iceland. In the Gorky region, the white hair inhabits all the forests of the region.
In its life, the Belyak is closely connected with the forest and only in the extreme north of its distribution does it slightly go to the tundra zone, and in the south to the forest-steppe zone. The typical habitat of the hare are overgrown ashes and logging sites, aspen marshes among the forest, suboloti and floodplains of forest streams, rich in willow. Deer and gloomy parts of the forest, with poor undergrowth and grass cover, the white hare avoids.
The white hare’s guiding sense of hare is hearing, as evidenced by its long, moving ears. He sees relatively poorly, although his large bulging, spaced eyes cover a large space. In general, the white hare can be called a very sensitive and cautious beast that knows how to hide perfectly, and at the right moment to run away with the speed of an arrow. Running a hare is extremely characteristic: making its huge jumps, it throws long back legs far forward, therefore their tracks appear ahead of the tracks of short front paws.
The hare's mental abilities are, of course, limited, although they are still immeasurably higher than those of the domestic rabbit, which has lost its last little bit under the protection of the person.
Summer hawk food is significantly different from winter. In summer, it feeds on various herbaceous plants and partly on young shoots of bushes, wild berries, such as strawberries and blueberries, occasionally eat some mushrooms. At the end of the summer, during the ripening of crops, he often visits them and willingly eats ripening cereals, peas, buckwheat, etc. In winter, the white hare falls tight. At this time, he almost entirely goes to food bark and shoots of trees. Very willingly he eats young shoots and bark of young aspens, willows, and sometimes young trees. At this time, white hares often come close to human settlements in order to profit from haystacks, straws in a barn, or a frozen stalk dug up in the garden. In winter, hares often cause harm by gnawing on the bark of fruit trees in gardens and destroying young trees of forest plantings.
The hare has two or three litters a year. The first estrus begins very early and in our places usually falls at the end of February - the beginning of March. Pregnancy lasts 49-51 days. The number of young in the litter is from three to five.
Hares of the first litter are sometimes born in March, and hunters call them 
"Martovikov" or "nastovikami." Zaychata are born fully formed, a little more than 100 g in weight, covered with wool and sighted. Shortly after giving birth, the mother feeds the hare, and they scatter in different directions, hiding in the grass. The first feeding hare lasts for several days, as a chewy milk clot forms in their stomach, which ensures their existence for these days. When they get hungry, they start to run and look for their mother, and, having found them, they are full for a few more days.
The hares develop very quickly, and after 8-10 days they are able to eat grass themselves. Thus, the female feeds the hare only a few times; moreover, it is suggested that the hare can feed not only his children, but also the first to fall.
Shortly after birth, and sometimes immediately after, the female mates again. The last litter is usually in September, and the hunters of the hare of this litter are called “leaf-dropping”. Sometimes the last litter happens much later - in October - November.
Care for the offspring hare does not show any, except for a few feedings. Even for childbirth, it does not make a special nest, but will give birth in a regular bed, which has the appearance of a simple, lined fossa or hollow, among bushes and roots. tree or old stump.
The white hare casts twice a year - in spring and autumn. Spring moult occurs in March - April, and in some places (in the north) - in May. At this time, the winter white fluffy wool subsides, getting out in shreds, and is replaced by a rarer and shorter summer. Autumn moult occurs in October - November. The statement of some researchers that the white hair does not fall out in the fall, but only the fading of the hair of the summer fur, was not confirmed; in autumn, a white hare sheds in the full sense of the word, just like in spring.
In rabbits there are sharp fluctuations in numbers. There are years when, as a result of a confluence of favorable conditions for breeding, the number of hares in a certain area increases greatly. The increased density contributes to the transmission of epizootic diseases to which hares are highly susceptible. Hares suffer from tularemia, coccidiosis, and are affected by nematodes and cestodes. If summer is unfavorable with respect to the weather, this usually leads to outbreaks of mass epizootics, which entail the death of a huge number of hares or, as they say, a “mass sea”.
Adverse climatic conditions also affect the number of hares themselves, causing the immediate death of mainly young stock from damp and cold. All this leads to a sharp decrease in the number of hares.
Of course, his numerous enemies have influence on the number of the hare. There are many enemies of the hare, and the protection is only one - fast legs, and they do not always save. The most fierce enemies of the hare are the lynx, the fox and the owl. But the hare also suffers a lot from the marten, polecat, and even such a small robber like an ermine. Among the feathered predators of hares, large owls, eagles and goshawk pursue.
In relation to man, the hare is more useful than harmful, animal. The harm that he inflicts, eating sometimes crops and gnawing on the bark of fruit and forest trees, is entirely covered by the benefits that a person receives by hunting a hare. The white hare is hunted mainly by shooting from under the hounds, but, in addition, they beat it from the approach, tracking down the trail. Mining hare for meat and skins. Given the large number of white skins, which remain in the hands of hunters for their own needs, we can assume that every year in the Nizhny Novgorod region a white hare is harvested significantly more than its skins are harvested.
