Practical work study of plant and animal cells under a microscope, their description

The genus of hares proper, which includes the hare and hare, as well as 28 other species, is quite numerous. The most famous hares in Russia are hare and hare. Belyak 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 hare is also common 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 the Transcaucasus. 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, also brightens greatly by winter, but it never happens to be 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 white hare, and it runs better. At short distances, this hare can reach speeds of up to 50 km / h. The hare's paws are wide, with dense pubescence in order to fall less into loose forest snowdrifts. And the hare has narrower paws, because in open places the snow, as a rule, is hard, caked, “trodden down by the wind.”

The body length of the hare is 45-75 cm, weight is 2.5-5.5 kg. The ears are shorter than those of the hare. The body length of a hare is 50-70 cm, weight is up to 5 (sometimes 7) kg.

Hares usually breed twice, and in the south three or even four times a year. White hares can have two, three five, seven hares in the output, and hare usually have only one or two hares. Rusaks begin to taste grass two weeks after birth, and whites even faster - a week later.

Practical work 7

Identification of adaptations of organisms to the environment

Objective: Find out the mechanisms for the formation of adaptations, concluding that fitness is the result of natural selection

Material for work: textbooks, textbook drawings, herbarium specimens of plants

Exercise:

BUT) read the text of the textbook, look at the drawings, consider the external structure of plant species using herbarium samples:

According to herbarium samples, consider the external structure of the following plant species:

B) not eaten by animals: stinging nettle, prickly hawthorn, Siberian hogweed;

AT) early flowering: spring chistyak, goose onion, May lily of the valley.

Enter the results of work for task A in the table:

Adaptations of organisms to living conditions

1. 
   What structural features of the first group of plants protect them from being eaten by animals, and in the second group they provide early flowering.
2. 
   Determine what environmental factors are associated with the adaptive features of the organization.
3. 
   What advantages did plants receive in connection with the acquisition of characteristic features
4. 
   Try to explain how adaptive traits arose, assuming that ancestral forms did not possess them.
5. 
   Note the characteristics of birds and mammals that are adaptive to the conditions of existence.

Practical work 8

Comparative characteristics of natural and artificial selection

Purpose: to establish signs of similarity and difference between natural and artificial selection

Main paths of evolution:

- aromorphosis (arogenesis)- major evolutionary changes leading to a rise in the level of biological organization, an increase in the intensity of life processes, examples - the emergence of autotrophic nutrition, aerobic respiration, eukaryotic cells, sexual reproduction, etc.;

- idioadaptation (allogenesis)- minor evolutionary changes, adaptations to certain environmental conditions without raising the level of biological organization, examples - the number of petals and color of flowers, the specialization of some plants for certain pollinators, bacteria of hot springs;

Practical work 9

Observation and identification of adaptations in organisms to the influence of various environmental factors

Target. To form knowledge about the identification of adaptations in organisms to the influence of various environmental factors.

Working process.

1. Environmental factors

1) Characteristics of environmental factors:

2) Laws of action of environmental factors

Based on the scheme of the environmental factor, formulate answers to the questions:

1. 
   What is a "limiting factor"? Give your formulation of J. Liebig's law of the minimum.
2. 
   What is the biological optimum? Formulate the law of biological optimum.
3. 
   Are the adaptations of organisms to individual environmental factors independent of each other? Explain your answer with examples.

2. Main abiotic factors and their significance 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

Target: identification of signs of difference between natural ecosystems and agroecosystems

Target: using the example of an artificial ecosystem to trace the changes that occur under the influence of conditions environment.

Working process.

1. 
   What conditions must be observed when creating an aquarium ecosystem.
2. 
   Describe the aquarium as an ecosystem, indicating abiotic, biotic environmental factors, ecosystem components (producers, consumers, decomposers).
3. 
   Make food chains in the aquarium.
4. 
   What changes can occur in the aquarium if:

• 
  falling direct sunlight;
• 
  There are a lot of fish in the aquarium.

Fitness - the correspondence of the characteristics of the organism (internal and external structure, physiological processes, behavior) habitat, allowing to survive and give offspring. For example, aquatic animals have a streamlined body shape; the green color of the back makes the frog invisible against the background of plants; the tiered arrangement of plants in biogeocenosis makes it possible to effectively use solar energy For photosynthesis. Fitness helps organisms to 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. A white partridge on a sunny day gives itself away as a shadow. The white 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 on the basis of pre-existing ones.

Geographic (alopatric) 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 meet new environmental conditions and communities of organisms. In nature, a population is affected by a mutation process, 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 ended up in different conditions, which led to the emergence of Dahurian larch.

Ecological speciation refers to sympatric occurs in cases where populations of one species remain within their range, but their habitat conditions turn out to be different. Under the influence of the driving forces of evolution, their gene composition changes. Through a number of generations, as a result of differences in gene pools, biological isolation occurs. For example, one species of tradescantia was formed on rocky peaks, the other - in shady forests; seasonal races of the large rattle give seeds before mowing, or after it, and, living in the same territory, do not have the opportunity to interbreed; Trout populations in Lake Sevan vary in terms of spawning time.

A feature of ecological speciation is that it leads to the formation of new species that are morphologically close to the original species.

The similarity of speciation: occur under the action of the driving forces of evolution. Differences: the reasons for the divergence of characters in populations are different: geographical speciation is associated with the expansion of the range and the emergence of isolated populations, and ecological with the settlement of individuals of the same species in different ecological niches within the same area.

Evolution as a historical process has two directions; progress and regression.

biological regression- lack of the necessary level of adaptability, leading to a decrease in the number, narrowing of the range, and a decrease in the number of subordinate systematic groups. Biological regression can lead to extinction. For example, the Ussuri tiger and sable are on the verge of extinction. The reason for the regression: the lag in the rate of evolution of the group from the rate of change external environment. Human activity often leads to a reduction in the 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 are always preserved in organisms in the course of 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 that contribute to adaptation to specific environmental conditions and do not increase the overall level of organization of individuals. An example of idioadaptations is protective, masking or warning coloration, behavior during reproduction, marking the territory, joint protection from enemies.

White hare -Lepus timidus L.

The appearance of the hare is so well known that there is no particular need to describe it: long hind legs, long ears, short upturned tail, fluffy hare fur are known to everyone. Let us point out only some of the features of the structure that distinguish our two hares, the hare and the hare, from each other.
The belyak differs from its fellow, the hare, in its smaller size, denser body structure, blunter muzzle and somewhat shorter legs and ears. If the hare's ear is bent forward, it reaches the end of the muzzle, but not further, and in the hare it protrudes significantly. The hare's tail is white on top throughout the year, while the hare's tail is somewhat longer and black on top. The winter coloration of hare and hare differs quite sharply. The hare is completely white in winter, except for black spots on the very tips of the ears. In winter, a hare has quite a lot of dyed hair on its back, which forms a wide dark stripe. In summer, the hare is colored somewhat lighter and yellower than the hare. The hare is reddish-brown in summer. The average body size of a hare is about 55 cm, the maximum is 65 cm. The weight of a hare is about 2.8-3.2 kg and occasionally reaches 4.5-5 kg. The dental formula in both species is the same: 2.0.3.3/1.0.2.3 = 28.

The white hare is distributed 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 Iceland. In the Gorky region, the hare inhabits all the forests of the region.

Belyak in his life is closely connected with the forest and only in the far north of his distribution slightly goes into the tundra zone, and in the south - into the forest-steppe zone. A typical habitat of the white hare is overgrown burnt areas and cutting areas, aspen swamps in the middle of the forest, subbogs and floodplains of forest rivers, rich in willow. Deaf and gloomy areas of the forest, with poor undergrowth and grassy cover, the hare avoids.

The guiding sense of the white hare, as well as hares in general, is hearing, as evidenced by its long mobile ears. He sees relatively poorly, although his large, bulging, set apart eyes cover large space. In general, the hare can be called a very sensitive and cautious animal, able to hide perfectly, and in right moment- run away with the speed of an arrow. The run of a hare is extremely characteristic: making its huge leaps, it throws its long hind legs far forward, so their traces are ahead of the traces of short front legs.
The mental abilities of a hare, of course, are limited, although they are still immeasurably higher than those of a domestic rabbit, which has lost its last mind under the protection of a person.

Summer food hare is significantly different from winter. During the summer it feeds on various herbaceous plants and partly young shoots of shrubs, wild berries, such as strawberries and blueberries, occasionally eats some mushrooms. At the end of summer, during the ripening period of crops, he often visits them and willingly eats ripening cereals, peas, buckwheat, etc. In winter, the white hare has a hard time. At this time, he almost completely switches to feeding on bark and shoots of trees. Very willingly, he eats young shoots and bark of young aspens, willows, and sometimes young fir trees. At this time, white squirrels often come close to human settlements to profit from hay from haystacks, straw on a barn, or a frozen stalk dug up in a garden. In winter, hares often do harm by gnawing at the bark. fruit trees in gardens and destroying young trees of forest plantings.

The white hare has two or three litters a year. The first estrus begins very early and in our places it usually falls at the end of February - the beginning of March. Pregnancy lasts 49-51 days. The number of young in a litter is from three to five.

The hares of the first litter are sometimes born in March, and hunters call them "martoviks" or "nastoviks". Hares will be born fully formed, slightly over 100 g in weight, covered with hair and sighted. Soon after the birth, the mother feeds the hares, and they scatter in different sides hiding in the grass. The first feeding is enough for hares for several days, since a curdled milk clot forms in their stomach, which ensures their existence for these days. Hungry, they begin to run and look for their mother, and having found, they eat for a few more days.

Rabbits develop very quickly, and after 8-10 days they are able to eat grass themselves. Thus, the female feeds the rabbits only a few times; moreover, they suggest that the hare can feed not only her children, but also the first ones that come across.

Shortly after giving birth, and sometimes immediately after them, the female mates again. The last litter is usually in September, and the hare hunters call this litter "leaf-bearers". Sometimes the last litter happens much later - in October - November.

The hare does not show any concern for the offspring, except for a few feedings. Even for childbirth, she does not make a special nest, but gives birth on an ordinary bed, which looks like a simple, unlined hole or depression among bushes, roots. tree or old stump.

The hare sheds twice a year - in spring and autumn. Spring molting takes place in March - April, and in some places (in the north) - in May. At this time, the winter white fluffy coat falls off, crawling out in shreds, and is replaced by a rarer and shorter summer one. Autumn molt occurs in October - November. The assertion of some researchers that in autumn the white hare does not fall out, but only the hair of the summer fur fades, has not been confirmed; in autumn, the hare molts in the full sense of the word, as in spring.

Hares have sharp fluctuations in numbers. There are years when, as a result of a confluence of favorable conditions for reproduction, 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, are affected by nematodes and cestodes. If summer is added to this, which is unfavorable in terms of weather, then this usually leads to outbreaks of mass epizootics, which entail the death of a huge number of hares or, as they say, “mass pestilence”.

Unfavorable climatic conditions also affect the number of hares in themselves, causing direct death, mainly of young animals from dampness and cold. All this leads to a sharp decrease in the number of hares.

Of course, the number of hare is influenced by its many enemies. The hare has many enemies, and there is only one defense - fast legs, and they do not always save. The most fierce enemies of a hare are a lynx, a fox and an owl. But the hare also suffers a lot from the marten, the polecat, and even such a small robber as an ermine. Of the raptors, hares are pursued by large owls, eagles and goshawks.

In relation to a person, a hare is more of a useful than harmful animal. The harm that it causes, sometimes eating crops and nibbling the bark of fruit and forest trees, is entirely covered by the benefits that a person receives by hunting a hare. The hare is hunted mainly by shooting from under the hounds, but, in addition, they beat him from the approach, tracking down the trail. Hares are hunted for their meat and skins. Given the large number of hare skins that remain in the hands of hunters for their needs, it can be assumed that annually in the Nizhny Novgorod region a hare is hunted much more than its skins are harvested.