Target: study the laws and consequences of food relations.
Tasks: emphasize the universality, diversity and extraordinary role of food relations in nature. Show that it is food connections that unite all living organisms into a single system and are also one of the most important factors of natural selection.
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Lesson topic: LAWS AND CONSEQUENCES OF FOOD RELATIONSHIPS
Target : study the laws and consequences of food relations.
Tasks: emphasize the universality, diversity and extraordinary role of food relations in nature. Show that it is food connections that unite all living organisms into a single system and are also one of the most important factors of natural selection.
Equipment: graphs reflecting fluctuations in numbers in the predator-prey relationship; herbarium specimens of insectivorous plants; wet preparations (tapeworms, liver fluke, leeches); insect collections (ladybug, ant, gadfly, horsefly); images of herbivorous rodents, mammals (eagle, tiger, cow, zebra, baleen whales).
I. Organizational moment.
P. Test of knowledge. Test control.
1. Light-loving herbs growing under spruce are typical
representatives of the following type of interactions:
a) neutralism;
b) amensalism;
c) commensalism;
d) proto-cooperation.
2. Type of relationship between the following representatives
of the new world can be classified as “freeloading”:
a) hermit crab and sea anemone; b) crocodile and cowbird;
c) shark and sticky fish;
d) wolf and roe deer.
3. An animal that attacks another animal, but
eats only part of its substance, rarely causing death, relatively
goes to the number:
a) predators;
b) carnivores;
d) omnivores.
4. Coprophagia occurs:
a) in hares;
b) in hippopotamuses;
c) in elephants;
d) in tigers.
5. Allelopathy is an interaction with the help of biologically active substances, characteristic of the following organisms:
a) plants;
b) bacteria;
c) mushrooms;
d) insects.
6. Do not enter into symbiotic relationships:
a) trees and ants;
b) legumes and rhizobium bacteria;
c) trees and mycorrhizal fungi;
d) trees and butterflies.
a) late blight;
b) tobacco mosaic virus;
c) champignon, honey fungus;
d) dodder, broomrape.
a) eat only the outer integument of the victim;
b) occupy a similar economic niche;
c) attack mainly weakened individuals;
d) have similar methods of hunting prey.
9. Wasp wasps are:
b) predators with traits of decomposers;
a) fleas;
b) lice;
c) stem nematodes;
d) rust mushrooms.
a) mushrooms; b) worms;
c) fish;
d) birds.
b) broomrape;
c) white mistletoe;
d) smut.
a) amoeba - opaline - frog;
b) frog -> scorch - amoeba;
c) mushrooms - * frog -> scorch;
d) frog - * amoeba - scorch.
III. Learning new material. 1.Teacher's story.
Life on Earth exists due to solar energy, which is transmitted through plants to all other organisms that create a food, or trophic, chain: from producers to consumers, and so on 4-6 times from one trophic level to another.
The trophic level is the location of each link in the food chain. The first trophic level is producers, all the rest are consumers. The second level is herbivorous consumers; the third - carnivorous consumers feeding on herbivorous forms; the fourth are consumers who consume other carnivores, etc.
Consequently, consumers can be divided into levels: consumers of the first, second, third, etc. orders.
Energy costs are associated primarily with maintaining metabolic processes, which are called respiration costs; a smaller part of the expenditure goes towards growth, and the rest of the food is excreted in the form of excrement. Ultimately, most of the energy is converted into heat and dissipated in the environment, and no more than 10% of the energy from the previous one is transferred to the next, higher trophic level.
However, such a strict picture of the transfer of energy from level to level is not entirely realistic, since the trophic chains of ecosystems are complexly intertwined, forming trophic networks.
For example, sea otters feed on sea urchins, which eat brown algae; The destruction of otters by hunters led to the destruction of algae due to the growth of the hedgehog population. When otter hunting was banned, algae began to return to their habitats.
A significant part of heterotrophs are saprophages and sa-prophytes (fungi), which use the energy of detritus. Therefore, two types of trophic chains are distinguished: grazing chains, or grazing chains, which begin with the consumption of photosynthetic organisms, and detrital decomposition chains, which begin with the decomposition of the remains of dead plants, corpses and animal excrement. So, the flow of radiant energy in an ecosystem is distributed over two types of trophic networks. The end result: dissipation and loss of energy, which must be renewed for life to exist.
2. Work with the textbook in small groups.
Task 2. Indicate the features of the feeding relationships of typical predators. Give examples.
Task 3. Indicate the features of the food relationships of animal-gatherers. Give examples.
Task 4. Indicate the features of food relationships of grazing species. Give examples.
Note: the teacher should draw students' attention to the fact that in foreign language literature the term denoting relationships like
In this regard, it is necessary to keep in mind that the term “predator” is used in the literature on ecology in a narrow and broad sense.
Answer to task 1.
Answer to task 2.
Typical predators spend a lot of energy searching, tracking and capturing prey; They kill the victim almost immediately after the attack. Animals have developed special hunting behavior. Examples - representatives of the order Carnivora, Mustelidae, etc.
Answer to task 3.
Gatherer animals spend energy only searching for and collecting small prey. Foragers include many granivorous rodents, chicken birds, carrion vultures, and ants. Peculiar collectors - filter feeders and ground eaters of water bodies and soils.
Answer to task 4.
Grazing species feed on abundant food, which does not require a long search and is easily accessible. Usually these are herbivorous organisms (aphids, ungulates), as well as some carnivores (ladybugs on aphid colonies).
3. D and s k u s s i .
Question. In what direction is the evolution of species going?
with typical predators? Sample answer.
The progressive evolution of both predators and their prey is aimed at improving the nervous system, including sensory organs, and the muscular system, since selection maintains in prey those properties that help them escape from predators, and in predators those that help in getting food.
Question. In which direction does evolution go in the case of gathering?
Sample answer.
The evolution of species follows the path of specialization: selection in prey maintains characteristics that make them less noticeable and less convenient for collection, namely protective or warning coloration, imitative resemblance, and mimicry.
Question With. In what situations does a person act as a typical predator?
Sample answer.
- When using commercial species (fish, game, fur-bearing and ungulate animals);
- when destroying pests.
Note: the teacher should focus on the fact that in an ideal case, with the competent use of commercial objects (fish in the sea, wild boars and moose in the forest, wood), it is important to be able to foresee the consequences of this activity in order to stay on the fine line between acceptable and excessive use resource. The goal of human activity is to preserve and increase the number of “victims” (resource). IV. Consolidation new material. Textbook, §9, questions 1-3. Answer to question 1.
Not always. The nesting territory can only accommodate a certain number of birds. The dimensions of individual plots determine how many hanging nests will be occupied. The rate of reproduction of the pest may be so high that the available number of birds will not be able to significantly reduce its numbers.
Answer to question 2.
A simplification of the model is as follows: they did not take into account that prey can run and hide from predators, and predators can feed on different prey; in reality, the fertility of predators depends not only on the food supply, etc., that is, the relationships in nature are much more complex.
Answer to question 3.
The food supply for moose has improved and mortality from predators has decreased. Permission for moderate hunting is given if high elk numbers begin to negatively affect forest restoration.
Homework:§ 9, task 1; Additional Information.
1) hare - clover;
2) woodpecker – bark beetle;
3) fox - hare;
4) man – roundworm;
5) bear - elk;
6) bear – bee larvae;
7) blue whale – plankton;
8) cow – timothy;
9) tinder fungus – birch;
10) carp – bloodworm;
11) dragonfly - fly;
12) toothless mollusk – protozoa;
13) aphid – sorrel;
14) Siberian silkworm caterpillar – fir;
15) grasshopper - bluegrass grass;
16) sponge – protozoa;
17) influenza virus – human;
18) koala – eucalyptus;
19) ladybug beetle - aphid.
138. Choose the correct answer. The result of food relations between populations of foxes and hares will be:
a) a decrease in the numbers of both populations;
b) regulation of the numbers of both populations;
c) an increase in the size of both populations.
139. Explain the following facts: a) during the mass shooting of birds of prey (hawks, eagle owls) feeding on partridges and black grouse, the number of the latter first increases and then decreases; b) when wolves are exterminated, the number of deer in the same territories decreases over time.
140. Indicate which of the following groups the organisms belong to.
List of organisms:
3) sundew;
4) ixodid tick;
6) bovine tapeworm;
7) daphnia;
8) rabbit;
11) tinder fungus;
13) boletus;
14) Koch's wand;
16) female mosquito;
17) earthworm;
18) dung fly larva;
19) Colorado potato beetle;
21) nodule bacteria;
22) scarab beetle.
141. Explain why in China, following the destruction of sparrows, the grain harvest sharply decreased.
142. Jays feed primarily on oak acorns in the fall. They bury a lot of acorns in the ground as a reserve for the winter and early spring. Describe how these types of relationships are mutually beneficial.
143. Indicate the type of biotic relationships that corresponds to a pair of interacting species in the forest (Fig.).
144. In mid-summer, after the fire, a breeding ground for bark beetles appeared in the burnt area: all living trees touched by the fire were damaged by pests. Explain why.
145. How can the phenomenon of predation and parasitism be used in agriculture? Give specific examples.
146. It is known that many insects feed on pines: sawflies, weevils, bark beetles, longhorned beetles, etc. Why do pests mainly live on diseased trees and avoid healthy, young pines?
147. One and the same organism can be either a predator or a prey in relation to individuals of different ages of another species. Give examples.
148. The feeding relationships between individuals within a species are of utmost importance. Eating their own kind - cannibalism - is a fairly common phenomenon among fish. Give examples.
149. Creating a mathematical model of changes in the number of predators and prey, A. Lotka and V. Voltera assumed that the number of predators depends only on two reasons: the number of prey (the larger the food supply, the more intense the reproduction) and the rate of natural decline of predators. At the same time, they understood that they had greatly simplified the relationships existing in nature. What is this simplification?
150. Relationships in a biocenosis, consisting in the creation of a habitat by one species for another, are called:
a) trophic; b) topical; c) phoric; d) factory.
151. A pollinator and pollinated plant are an example of a relationship:
a) trophic; b) topical; c) phoric; d) factory.
153. Competition for food is an example of relationships: a) trophic; b) topical; c) phoric; d) factory.
154. Interspecific relationships in a biocenosis, based on the participation of one species in the distribution of another, are called: a) topical; b) phoric; c) factory; d) trophic.
155. The construction of nests by birds from various natural materials is an example of relationships: a) trophic; b) topical; c) phoric; d) factory.
156. Interspecific relationships in a biocenosis based on food relationships are called: a) topical; b) phoric; c) factory; d) trophic.
In nature, they have another important role - they keep species in communities, regulate their numbers and influence the course of evolution. Food connections are extremely diverse.
Typical predators spend a lot of energy tracking down prey, catching it and catching it (Fig. 40). They have developed special hunting behavior.
Rice. 40. Cheetah in pursuit of prey
They need many sacrifices throughout their lives. These are usually strong and active animals.
Animal Gatherers spend energy searching for seeds or insects, i.e. small prey. Mastering the food they find is not difficult for them. They have developed search activity, but no hunting behavior.
grazing species do not spend much effort searching for food; there is usually quite a lot of it around, and most of their time is spent absorbing and digesting food.
In the aquatic environment, this method of acquiring food is widespread: filtering I, at the bottom - ingestion and passage of soil along with food particles through the intestines.
The effects of food connections are most pronounced in relationships. predator - prey(Fig. 41).
If a predator feeds on large, active prey that can run away, resist, and hide, then those who do it better than others, that is, have sharper eyes, sensitive ears, a developed nervous system, and muscular strength, survive. Thus, the predator selects for the improvement of victims, destroying the sick and weak. In turn, among predators there is also selection for strength, agility and endurance. The evolutionary consequence of these relationships is the progressive development of both interacting species: predator and prey.
If predators feed on inactive or small species that are not able to resist them, this leads to a different evolutionary result. Those individuals that the predator manages to notice die. Victims who are less noticeable or somehow inconvenient to capture win. This is how natural selection is carried out for protective coloring, hard shells, protective spines and needles and other weapons of salvation from enemies. The evolution of species moves towards specialization for these characteristics.
The most significant result of trophic relationships is the containment growth number of species. The existence of food relations in nature is opposed to the geometric progression of reproduction.
For each pair of predator and prey species, the result of their interaction depends primarily on their quantitative relationships. If predators catch and destroy their prey at approximately the same rate at which their prey reproduces, then they can restrain the growth of their population. These are the results of these relationships that are most often characteristic of stable natural communities. If the rate of reproduction of prey is higher than the rate of their consumption by predators, an outbreak of the species occurs. Predators can no longer contain him number. This also sometimes occurs in nature. The opposite result - the complete destruction of the prey by a predator - is very rare in nature, but in experiments and in human-disturbed conditions it occurs more often. This is due to the fact that with a decrease in the number of any type of prey in nature, predators switch to other, more accessible prey. Hunting only for a rare species takes up too much energy and becomes unprofitable.
In the first third of this century, it was discovered that predator-prey relationships could be the cause of regular periodic fluctuations in the numbers of each of the interacting species. This opinion was especially strengthened after the results of the research of the Russian scientist G. F. Gause. In his experiments, G. F. Gause studied how the number of two types of ciliates, connected by a predator-prey relationship, changes in test tubes (Fig. 42). The victim was one of the species of slipper ciliates that feeds on bacteria, and the predator was a didinium ciliate that eats slippers.
At first, the number of the slipper grew faster than the number of the predator, which soon received a good food supply and also began to multiply quickly. When the rate of eating shoes became equal to the rate of their reproduction, the growth of the species stopped. And since didiniums continued to catch slippers and reproduce, soon the consumption of victims far exceeded their replenishment, and the number of slippers in the test tubes began to decline sharply. After some time, having undermined their food supply, they stopped dividing and the didiniums began to die. With some modifications of the experiment, the cycle repeated itself from the beginning. The unhindered reproduction of the surviving slippers again increased their abundance, and after them the didinium population curve went up. In the graph, the predator abundance curve follows the prey curve with a shift to the right, so that changes in their abundance are asynchronous.
Thus, it was proven that interactions between predator and prey can, under certain conditions, lead to regular cyclic fluctuations in the numbers of both species. The course of these cycles can be calculated and predicted, knowing some of the initial quantitative characteristics of the species. Quantitative laws of interaction between species in their food relationships are very important for practice. In fishing, the extraction of marine invertebrates, fur fishing, sport hunting, the collection of ornamental and medicinal plants - wherever a person reduces the number of species he needs in nature, from an ecological point of view he acts in relation to these species as a predator. Therefore, it is important to be able to foresee the consequences of your activities and organize them so as not to undermine natural reserves.
G.F. Gause (1910 -1986) " Russian scientist
In fishing and fishing, it is necessary that when the number of species decreases, fishing rates also decrease, as happens in nature when predators switch to more easily accessible prey (Fig. 43).
If, on the contrary, we strive with all our might to obtain a declining species, it may not restore its numbers and cease to exist. Thus, as a result of overhunting, due to the fault of people, a number of species that were once very numerous have already disappeared from the face of the Earth: American bison, European aurochs, passenger pigeons and others.
When a predator of any species is accidentally or intentionally destroyed, outbreaks in the number of its victims first occur. This also leads to an environmental disaster, either as a result of the species undermining its own food supply, or the spread of infectious diseases, which are often much more destructive than the activities of predators. The phenomenon of an ecological boomerang occurs when the results turn out to be directly opposite to the initial direction of impact. Therefore, the competent use of natural environmental laws is the main way of human interaction with nature.
Examples and additional information
1. For the first time, regular fluctuations in the predator-prey system were noticed and described in the 20s. of our century, the famous English ecologist Charles Elton. He processed many years of data from a fur company on hare and lynx production in Northern Canada. It turned out that the years that were “fruitful” for hares were followed by increases in the number of lynx, and these fluctuations were clearly of a natural nature, repeating after certain periods. At the same time, independently of each other, two mathematicians, A. Lotka and V. Volterra, calculated that based on the interactions of predator and prey, oscillatory cycles in the numbers of both species could arise. These calculated data required experimental verification, which G.F. Gause undertook, proving the occurrence of the corresponding cycles using the example of the predatory ciliate Didinium and its victim, the slipper. So, as a result of research by scientists from different countries, one of the important environmental patterns was discovered.
2. The global cod fishery occurred largely spontaneously and was not justified by biological characteristics. Total production reached 1.4 million tons per year. This turned out to be significantly more than could be reproduced, so both the number of cod and its production fell by 7-10 times. When the cod stock in the Barents Sea fell into decline (70-80s), the number of capelin, the main victim of cod, increased sharply. Fishermen switched to this fish, catching about two-thirds of its total weight. As a result of overfishing, the number of capelin also fell. Cod, like all predatory fish, feeds on all small fish, including its own fry. With the small number of capelin, it began to eat its young, so the herd lost the opportunity to recover.
3. During evolution, prey develop a variety of adaptations to protect themselves from predators. For example, the smallest aquatic rotifers grow long shell spines in the presence of other, predatory rotifers.
These spines greatly prevent predators from swallowing their prey, as they literally stand across their throats. The same defense occurs in peaceful Daphnia crustaceans - against other predatory crustaceans. The predator, having captured the daphnia, picks it up with its legs and turns it over to eat it from the soft ventral side. The thorns get in the way and the prey is often lost. It turned out that the victims grow spines in response to the presence of metabolic products of predators in the water. If there are no enemies in the pond, thorns do not appear on the victims.
4. One of the first examples of the successful use of a predator to suppress the population of a pest is the use of the rhodolia ladybug in the fight against the Australian grooved bug (Fig. 44, 45).
This mealybug, a sedentary insect that sucks citrus fruits, was accidentally introduced to California in 1872, where it had no natural enemies. It quickly multiplied and became a dangerous pest, causing gardeners to suffer huge losses. To combat the scale insect, its natural enemy, the small rhodolia ladybug, was imported from Australia. In 1889, about 10 thousand beetles were dispersed into hundreds of gardens in southern California. After just a few months, the infestation of trees with scale insects dropped sharply. The ladybug took root in California, and mass reproduction of scale insects was no longer observed. This success was repeated in fifty countries around the world, in Azda, where rhodolia was released against the grooved scale insect. Rhodolia is more sensitive to pesticides than scale insects! Therefore, where citrus fruits were treated with poisons against other pests, the number of scale insects soon reached gigantic proportions.
5. Red forest ants feed on many species of invertebrate animals, but the basis of their prey is always the most abundant species. During an outbreak of forest pests, ants feed primarily on them. It is estimated that in Siberian forests the inhabitants of one large anthill destroy up to 100 thousand larvae of the small spruce sawfly and 10-12 thousand butterflies of the gray larch leaf roller. This means that if there are 5-8 large anthills per hectare, you don’t have to worry about the trees being damaged by these pests; the ants will restrain the growth of their numbers.
Questions.
1. Are birds attracted to tree stands by artificial nest boxes always able to reduce the number of harmful insects?
2. Creating a mathematical model of changes in the number of predators and prey, A. Lotka and V. Volterra assumed that the number of predators depends on only two reasons: the number of victims (the larger the food supply, the more intense the reproduction) and the rate of natural death of predators. At the same time, they understood that they had greatly simplified the relationships existing in nature. State what this simplification is.
3. Elk is the largest modern deer. Lives in forest areas, feeds on the growth of deciduous trees and tall grasses. At the beginning of the 20th century, its numbers in Europe greatly decreased. However, starting from the 20s. and especially in the 40s. it has begun to recover as a result of elk conservation, forest rejuvenation, and a decline in wolf numbers. Indicate which food connections played a role in the restoration of the species. Why is moderate elk hunting currently allowed?
Tasks.
Topics for discussion.
1. Although calculations and experiments indicate that in nature oscillatory cycles can occur between each pair of predator-prey species, such cycles are rarely observed in nature. Why?
2. In the Far Eastern forests, intensive fishing is carried out for a valuable medicinal plant - ginseng. The species is on the verge of extinction. What measures would you take to preserve it? What does understanding the predator-prey relationship have to do with these events?
3. For a long time, wolf hunting was encouraged in our country and a bonus was given for each killed animal. Then wolf hunting was completely banned. Currently, in a number of areas this ban has been lifted again and some wolves are allowed to be shot. How do you think we can explain such inconsistency in the orders of environmental authorities?
4. In nature, predator-prey relationships between specific species have existed for millions of years. Modern man, entering into the same relationships with species of wild nature (hunting, fishing, collecting medicinal and food plants, flowers, etc.), quickly undermines their numbers. Why is this happening? Can knowledge and application of environmental regulations change these results?
5. Suppose you have to set a catch rate for a valuable fish species. What information about this species do you need to have to calculate this rate? What happens if the catch rate is overestimated? its understatement?
Chernova N. M., Fundamentals of Ecology: Textbook. days 10 (11) grade. general education textbook institutions/ N. M. Chernova, V. M. Galushin, V. M. Konstantinov; Ed. N. M. Chernova. - 6th ed., stereotype. - M.: Bustard, 2002. - 304 p.
Textbooks and books on all subjects, homework, online book libraries, lesson plans on ecology, essays and lesson notes on ecology for grade 10
Nutritional relationships not only provide the energy needs of organisms. They play another important role in nature - they hold species in communities, regulate their numbers and influence the course of evolution. Food connections are extremely diverse.
Typical predators spend a lot of energy tracking down their prey, catching it and catching it. They have developed special hunting behavior.
Lion hunt
They need many sacrifices throughout their lives. These are usually strong and active animals.
Life cycle of the bovine tapeworm
Gatherer animals spend energy searching for seeds or insects, i.e., small prey. Mastering the food they find is not difficult for them. They have developed search activity, but do not have hunting behavior.
Field mouse
Grazing species do not spend much effort searching for food; there is usually quite a lot of it around, and most of their time is spent absorbing and digesting food.
African elephant
In the aquatic environment, a widespread method of acquiring food is filtration, and at the bottom - ingestion and passage of soil along with food particles through the intestines.
Edible mussel (an example of a filter-feeding organism)
The consequences of food connections are most clearly manifested in predator-prey relationships.
If a predator feeds on large, active prey that can run away, resist, and hide, then those who do it better than others, that is, have sharper eyes, sensitive ears, a developed nervous system, and muscular strength, survive. Thus, the predator selects for the improvement of victims, destroying the sick and weak. In turn, among predators there is also selection for strength, dexterity and endurance. The evolutionary consequence of these relationships is the progressive development of both interacting species: predator and prey.
If predators feed on inactive or small species that are not able to resist them, this leads to a different evolutionary result. Those individuals that the predator manages to notice die. Victims who are less noticeable or somehow inconvenient to capture win. This is how natural selection is carried out for protective coloring, hard shells, protective spines and needles and other means of salvation from enemies. The evolution of species moves towards specialization for these characteristics.
The most significant result of trophic relationships is the inhibition of species population growth. The existence of food relations in nature is opposed to the geometric progression of reproduction.
For each pair of predator and prey species, the result of their interaction depends primarily on their quantitative relationships. If predators catch and destroy their victims at approximately the same rate at which these victims reproduce, then they can restrain the growth of their numbers. These are the results of these relationships that are most often characteristic of stable natural communities. If the rate of reproduction of prey is higher than the rate of their consumption by predators, an outbreak of the species occurs. Predators can no longer contain its numbers. This also sometimes occurs in nature. The opposite result—the complete destruction of the prey by a predator—is very rare in nature, but in experiments and in human-disturbed conditions it occurs more often. This is due to the fact that with a decrease in the number of any type of prey in nature, predators switch to other, more accessible prey. Hunting only for a rare species takes up too much energy and becomes unprofitable.
G. F. Gause (1910-1986)
In the first third of our century, it was discovered that predator-prey relationships can be the cause of regular periodic fluctuations in the numbers of each of the interacting species. This opinion was especially strengthened after the results of the research of the Russian scientist G. F. Gause. In his experiments, G.F. Gause studied how the numbers of two types of ciliates, connected by a predator-prey relationship, changed in test tubes. The victim was one of the species of slipper ciliates that feeds on bacteria, and the predator was a didinium ciliate that eats slippers.
At first, the number of the slipper grew faster than the number of the predator, which soon received a good food supply and also began to multiply quickly. When the rate of eating shoes became equal to the rate of their reproduction, the growth of the species stopped. And since didiniums continued to catch slippers and reproduce, soon the consumption of victims far exceeded their replenishment, and the number of slippers in the test tubes began to decline sharply. After some time, having undermined their food supply, they stopped dividing and the didiniums began to die. With some modifications of the experiment, the cycle repeated itself from the beginning. The unhindered reproduction of the surviving slippers again increased their abundance, and after them the didinium population curve went up. On the graph, the predator abundance curve follows the prey curve with a shift to the right, so that changes in their abundance are asynchronous.
Thus, it was proven that interactions between predator and prey can, under certain conditions, lead to regular cyclical fluctuations in the numbers of both species. The course of these cycles can be calculated and predicted, knowing some of the initial quantitative characteristics of the species. Quantitative laws of interaction between species in their food relationships are very important for practice. In fishing, harvesting marine invertebrates, fur fishing, sport hunting, collecting ornamental and medicinal plants - wherever a person reduces the number of species he needs in nature, from an ecological point of view he acts in relation to these species as a predator. ka. Therefore, it is important to be able to foresee the consequences of your activities and organize them so as not to undermine natural reserves.
In fishing and hunting, it is necessary that when the number of species decreases, fishing standards also decrease, as happens in nature when predators switch to more easily accessible prey. If, on the contrary, one strives with all one’s might to catch a declining species, it may not restore its numbers and cease to exist. Thus, as a result of overhunting, due to the fault of people, a number of species that were once very numerous have already disappeared from the face of the Earth: American bison, European aurochs, passenger pigeons and others.
When a predator of any species is accidentally or intentionally destroyed, outbreaks in the number of its victims first occur. This also leads to an environmental disaster, either as a result of the species undermining its own food supply, or the spread of infectious diseases, which are often much more destructive than the activities of predators. The phenomenon of an ecological boomerang occurs when the results turn out to be directly opposite to the initial direction of impact. Therefore, the competent use of natural environmental laws is the main way of human interaction with nature.
Lesson plan. Lesson plan. Repetition of the material covered Repetition of the material covered (checking homework) (checking homework) 1. testing; 1. testing; 2. work with charts; 2. work with charts; 3. work with diagrams; 3. work with diagrams; 4. work in small groups. 4. work in small groups. Learning new material. Learning new material. Teacher's story with elements of conversation. Teacher's story with elements of conversation. Student reports. Student reports. Reinforcing the studied material Reinforcing the studied material textbook §10, questions 2,3,4,6. textbook §10, questions 2,3,4,6. Summing up Summing up
Learning new material. Learning new material. Habitat is a territory or water area occupied by a population with a complex of environmental factors inherent to it. Habitat is a territory or water area occupied by a population with a complex of environmental factors inherent to it. Stations are habitats for terrestrial animals. Stations are habitats for terrestrial animals. An ecological niche is the totality of all environmental factors within which the existence of a species is possible. An ecological niche is the totality of all environmental factors within which the existence of a species is possible. A fundamental ecological niche is a niche determined only by the physiological characteristics of an organism. A fundamental ecological niche is a niche determined only by the physiological characteristics of an organism. A realized niche is a niche within which a species actually occurs in nature. A realized niche is a niche within which a species actually occurs in nature. A realized niche is that part of the fundamental niche that a given species or population is able to “defend” in competition. A realized niche is that part of the fundamental niche that a given species or population is able to “defend” in competition.
Learning new material Interspecific competition is an interaction between populations that has a detrimental effect on their growth and survival. Interspecific competition is an interaction between populations that has a detrimental effect on their growth and survival. The process by which populations separate species of space and resources is called differentiation of ecological niches. Result The process of separating species of space and resources by populations is called differentiation of ecological niches. The result of niche differentiation reduces competition. niche differentiation reduces competition. Interspecific Competition for ecological niches Competition for resources.
Learning new material. Question: What is the consequence of interspecific competition? Question: What is the consequence of interspecific competition? Answer: In individuals of one species, fertility, survival and growth rate decrease in the presence of another. Answer: In individuals of one species, fertility, survival and growth rate decrease in the presence of another. Work according to the table. Work according to the table. Results of competition between flour beetle species in cups of flour. Conclusion: The result of competition between two species of beetles - flour beetles - depends on environmental conditions. Maintenance regime (t*C, humidity) Survival results First species Second species 34 *С, 70% 34 *С, 70% *С, 30% 34 *С, 30% *С, 70% 29 *С, 70% * С, 30% 29*С, 30% *С, 70% 24*С, 70% *С, 30% 24*С, 30%
Learning new material. Question. What are the ways out of interspecific competition? Question. What are the ways out of interspecific competition? (in birds) (in birds) Conclusion. The listed ways out of interspecific competition make it possible for ecologically similar populations to coexist in the same community. Exit routes Differences in methods of obtaining food Differences in the size of organisms Differences in activity time Spatial separation of food “spheres of influence” Separation of nesting sites
Studying new material Question: What is the danger of intraspecific competition? Question: What is the danger of intraspecific competition? Answer: The need for resources per individual decreases; as a result, the rate of individual growth and the development of the amount of stored substances decreases, which ultimately reduces survival and reduces fertility. Answer: The need for resources per individual decreases; as a result, the rate of individual growth and the development of the amount of stored substances decreases, which ultimately reduces survival and reduces fertility.
Studying new material Mechanisms of exit from intrapopulation Mechanisms of exit from intrapopulation competition in animals competition in animals Paths of exit Differences in ecological connections at different stages of development of organisms Differences in the ecological characteristics of the sexes in organisms of different sexes Territoriality and hierarchy as behavioral mechanisms of exit Settlement of new territories.
Consolidation of the studied material. Textbook, § 10, questions 2,3,4,6. Textbook, § 10, questions 2,3,4,6. Conclusions: Competition leads to natural selection in the direction of increasing environmental differences between competing species and the formation of different ecological niches by them. Conclusions: Competition leads to natural selection in the direction of increasing environmental differences between competing species and the formation of different ecological niches by them.
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