Who eats what

Compose power circuit telling about the heroes of the song "A grasshopper sat in the grass"

Animals that eat plant foods are called herbivores. Those animals that eat insects are called insectivores. Larger prey is hunted by predatory animals, or predators. Insects that eat other insects are also considered predators. Finally, there are omnivorous animals (they eat both plant and animal food).

Into what groups can animals be divided according to the way they feed? Complete the chart.

Food chains

Living things are interconnected in the food chain. For example: Aspens grow in the forest. Hares feed on their bark. A hare can be caught and eaten by a wolf. It turns out such a food chain: aspen - hare - wolf.

Make and write food chains.
a) spider, starling, fly
Answer: fly - spider - starling
b) stork, fly, frog
Answer: fly - frog - stork
c) mouse, grain, owl
Answer: grain - mouse - owl
d) slug, mushroom, frog
Answer: mushroom - slug - frog
e) hawk, chipmunk, bump
Answer: bump - chipmunk - hawk

Read short texts about animals from the book With Love to Nature. Identify and write down the type of animal food.

In autumn, the badger begins to prepare for winter. He eats and gets very fat. Everything that comes across serves as food for him: beetles, slugs, lizards, frogs, mice, and sometimes even small hares. He eats both forest berries and fruits.
Answer: omnivorous badger

In winter, the fox catches mice under the snow, sometimes partridges. Sometimes she hunts hares. But hares run faster than a fox and can run away from it. In winter, foxes come close to human settlements and attack poultry.
Answer: carnivorous fox

In late summer and autumn, the squirrel collects mushrooms. She pricks them on tree branches to dry the mushrooms. And the squirrel stuffs nuts and acorns into hollows and crevices. All this will come in handy for her in the winter starvation.
Answer: herbivorous squirrel

The wolf is a dangerous animal. In summer, he attacks various animals. It also eats mice, frogs, lizards. It destroys bird nests on the ground, eats eggs, chicks, birds.
Answer: carnivorous wolf

The bear breaks open rotten stumps and looks for fat larvae of lumberjack beetles and other insects that feed on wood. He eats everything: he catches frogs, lizards, in a word, whatever he comes across. Digs bulbs and tubers of plants from the ground. You can often meet a bear in the berry fields, where he greedily eats berries. Sometimes a hungry bear attacks moose, deer.
Answer: omnivorous bear

According to the texts from the previous task, compose and write down several food chains.

1. strawberry - slug - badger
2. tree bark - hare - fox
3. grain - bird - wolf
4. wood - beetle larvae - lumberjack - bear
5. young shoots of trees - deer - bear

Make a food chain using the pictures.

Lesson topic:“Who eats what? Food chains.

Lesson type:learning new material.

Textbook: “The world around us, grade 3, part 1” (author A.A. Pleshakov)

Goals and objectives of the lesson

Target:to summarize students' knowledge about the diversity of the animal world, about groups of animals by type of food, about food chains, about reproduction and stages of development, adaptation to protection from enemies and protection of animals.

Tasks:

1. Contribute to the enrichment and development of subjective ideas about the life of animals.

2. Contribute to the formation of children's ability to compose, "read", schemes, and model environmental ties.

3. To promote the development of skills and abilities of independent and group work.

4. Create conditions for the development of logical thinking;

5. Cultivate a sense of responsibility for all living things that surrounds us, a sense of love for nature.

Lesson equipment

Computer.

Sheets with tasks. Cards with puzzles.

Multimedia projector.

Textbook: Pleshakov A.A. The world around us. - M., Enlightenment, 2007.

Board

During the classes.

1 .Organizing time.

2. Reporting the topic of the lesson and posing the problem.

(Appendix slide 1)

Guys, look carefully at the slide. Think about how these representatives of wildlife are connected. Who will determine the topic of our lesson on this slide?

(We will talk about who eats how.)

Right! If you carefully look at the slide, you can see that all the items are connected by arrows in a chain according to the method of nutrition. In ecology, such chains are called ecological chains, or food chains. Hence the theme of our lesson “Who eats what? Food chains”.

3. Actualization of knowledge.

In order to trace different food chains, try to compose them ourselves, we need to remember who eats how. Let's start with plants. What is the nature of their diet? Tell based on the table.

(Appendix slide 3)

(Plants get carbon dioxide from the air. They absorb water and salts dissolved in it from the soil with their roots. Under the influence of sunlight, plants turn carbon dioxide, water and salts into sugar and starch. Their peculiarity lies in the fact that they themselves prepare food.)

And now let's remember which groups animals are divided into according to the way they eat and how they differ from each other.

(Herbivorous animals eat plant foods. Insectivores eat insects. Predatory animals eat the flesh of other animals, which is why they are also called carnivores. Omnivores eat plant and animal food.)

(Appendix slide 4)

4. Discovery of new knowledge .

Food chains are the nutritional links of all living things. There are many food chains in nature. In the forest they are alone, completely different in the meadow and in the reservoir, the third in the field and in the garden. I invite you to play the role of environmental scientists and engage in search activities. All groups will go to different places. Here are the routes of environmental scientists.

(Appendix slide 5)

Where you have to work, the draw will decide.

I invite one person from each group, and they pull out a card with the name of the place. The same children receive sheets with arrows and 4 cards each with the image of plants and animals.

Now listen to the assignment. Each group, using cards, must make a food chain. Cards are attached to the sheet with arrows with paper clips. Immediately agree on who will represent your chain to the class. Think about all the cards you will need.

On a signal, the guys begin to work in groups. For those who finished early, riddles are offered.

(Appendix slide 6)

All finished chains are hung on the board.

Pine grows in the forest. A bark beetle lives under the bark of a pine tree and feeds on it. In turn, the bark beetle is food for woodpeckers. We had an extra picture - a goat. This is a pet and is not part of this food chain.

Let's check out the guys.

(Appendix slide 7)

Other groups explain their chains in the same way.

2) Field: rye - mouse - snake (extra - fish).

(Appendix slide 8)

3) Garden: cabbage - slugs - toad (extra - bear).

(Appendix slide 9)

4) Garden: apple tree - apple aphid - ladybug (extra - fox).

(Appendix slide 10)

5) Pond: algae - crucian carp - pike (extra - hare).

(Appendix slide 11)

All circuits are on the board. Let's see what links they consist of. What is on each table? What comes first? On the second ? On the third ?

(Plant. Animal herbivore. Animal carnivorous, insectivorous or omnivorous.)

5. Primary consolidation of knowledge.

1. Work according to the textbook. pp. 96-97.

And now, guys, let's get acquainted with the tutorial article and test ourselves. Children open the textbook with. 96-97 and silently read the article “Food Chains”.

- What food chains are given in the textbook?

Aspen - hare - wolf.

Oaks - forest mice - owls.

What is the order of the links in the food chain?

I link - plants;

II link - herbivorous animals;

III link - the rest of the animals.

(Appendix slide 12)

2) Repetition of the rules of behavior in the forest.

Here we are in the forest. Listen to the sounds of the forest, look at the diversity of its inhabitants. Do you know how to behave in the forest?

1. Do not break branches of trees and shrubs.

2. Do not pick and trample flowers and medicinal plants.

3. Do not catch butterflies, dragonflies and other insects.

4. Do not destroy frogs, toads.

5. Do not touch bird nests.

6. Do not bring animals home from the forest.

Slide 6 (annex) opens with images of an owl, mice and acorns. Students create a food chain by moving pictures.

Who is bigger in this food chain?

The largest of all is the owl, and the mouse is larger than the acorn.

If we had a magic scale and weighed all the owls, mice and acorns, it would turn out that acorns are heavier than mice, and mice are heavier than owls. Why do you think?

Because there are a lot of acorns in the forest, a lot of mice, and few owls.

And this is no coincidence. After all, one owl needs many mice to feed, and one mouse needs many acorns. It turns out an ecological pyramid.

General conclusion :

Everything in nature is interconnected. Food webs intertwine and form a food web. Plants and animals form ecological pyramids. At the base are plants, and at the top are predatory animals.

6 .Introduction to the concept of “power network”

Food chains in nature are not as simple as in our example. Rabbits can also be eaten by other animals. Which? (fox, lynx, wolf)

A mouse can become a prey for a fox, an owl, a lynx, a wild boar, a hedgehog.

Many herbivorous animals serve as food for various predators.

Therefore, food chains are branched, they can intertwine with each other, forming a complex food network.

7. Problem situation .

Guys, what will happen if all the trees that the hare eats disappear from the forest? (The hare will have nothing to eat)

- And if there are no hares? (Then there will be no food for both the fox and the wolf)

What will happen to the chain? (She will collapse)

What conclusion can be drawn? (If you destroy at least one link in the chain, then the whole chain will collapse.)

8. Make several possible food chains

9. The result of the lesson. Generalization on the topic.

Reflection.

"Speak the sentence."

Animals and plants are interconnected in ……………………

At the heart of the food chain are ………………………………..

And they finish the chain - ……………………………………… ..

In nature, food chains are intertwined, forming

…………………………………………

homemadeexercise.

1. Prepare a message about one of Birch's friends;

2. Complete tasks No. 4 from the manual "The World Around" (the figure shows a plot of the garden. Make up several possible food chains).

The transfer of energy by eating living organisms of each other is called the food chain. These are the specific relationships of plants, fungi, animals, microorganisms that ensure the circulation of substances in nature. Also called a trophic chain.

Structure

All organisms feed, i.e. receive energy that provides life processes. The system of the trophic chain is formed by links. A link in the food chain is a group of living organisms connected with the neighboring group by the relationship "food - consumer". Some organisms are food for other organisms, which in turn are also food for a third group of organisms.
There are three types of links:

• producers - autotrophs;
• consumers - heterotrophs;
• decomposers (destructors) - saprotrophs.

Rice. 1. Links of the food chain.

One chain includes all three links. There can be several consumers (consumers of the first, second order, etc.). The basis of the chain can be producers or decomposers.

Producers include plants that convert organic substances with the help of light into organic substances that, when eaten by plants, enter the body of a first-order consumer. The main feature of the consumer is heterotrophy. At the same time, consumers can consume both living organisms and dead ones (carrion).
Examples of consumers:

• herbivores - hare, cow, mouse;
• predatory - leopard, owl, walrus;
• scavengers - vulture, Tasmanian devil, jackal.

Some consumers, including humans, occupy an intermediate position, being omnivores. Such animals can act as consumers of the first, second and even third order. For example, a bear feeds on berries and small rodents; at the same time it is a consumer of the first and second orders.

Reducers include:

• mushrooms;
• bacteria;
• protozoa;
• worms;
• insect larvae.

Rice. 2. Reducers.

Decomposers feed on the remains of living organisms and their metabolic products, returning to the soil inorganic substances that are consumed by producers.

Kinds

Food chains can be of two types:

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• grazing (chain of grazing);
• detrital (decomposition chain).

Pasture chains are characteristic of meadows, fields, seas, and reservoirs. The beginning of the chain of grazing are autotrophic organisms - photosynthetic plants.
Further, the links of the chain are arranged as follows:

• consumers of the first order - herbivorous animals;
• consumers of the second order - predators;
• consumers of the third order - larger predators;
• decomposers.

In marine and oceanic ecosystems, grazing chains are longer than on land. They can include up to five orders of consumers. The basis of marine chains is photosynthetic phytoplankton.
The following links form several consumers:

• zooplankton (crustaceans);
• small fish (sprats);
• large predatory fish (herring);
• large predatory mammals (seals);
• top predators (killer whales);
• decomposers.

Detrital chains are typical for forests and savannahs. The chain begins with decomposers that feed on organic remains (detritus) and are called detriophages. These include microorganisms, insects, worms. All these living organisms become food for predators of a higher order, for example, birds, hedgehogs, lizards.

Examples of food chains of two types:

• pasture : clover - hare - fox - microorganisms;
• detritus : detritus - fly larvae - frog - snake - hawk - microorganisms.

Rice. 3. An example of a food chain.

The top of the food chain is always occupied by a predator, which is the consumer of the last order in its range. The number of top predators is not regulated by other predators and depends only on external environmental factors. Examples are killer whales, monitor lizards, large sharks.

What have we learned?

We found out what food chains are in nature and how the links are located in them. All living organisms on Earth are interconnected by food chains through which energy is transferred. Autotrophs make their own nutrients and are food for heterotrophs, which, when dying, become a breeding ground for saprotrophs. Decomposers can also become food for consumers and produce a nutrient medium for producers without interrupting the food chain.

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Target: expand knowledge of biotic environmental factors.

Equipment: herbarium plants, stuffed chordates (fish, amphibians, reptiles, birds, mammals), insect collections, animal wet preparations, illustrations of various plants and animals.

Progress:

1. Use the equipment and make up two power circuits. Remember that a chain always starts with a producer and ends with a decomposer.

Plants → insects→lizard → bacteria

Plants → grasshopper→ frog → bacteria

Recall your observations in nature and make two food chains. Sign producers, consumers (1st and 2nd orders), decomposers.

Violet → Springtails→predatory mites→carnivorous centipedes→ bacteria

Producer - consumer1 - consumer2 - consumer2 - decomposer

Cabbage→ slug→ frog →bacteria

Producer - consumer1 - consumer2 - decomposer

What is a food chain and what underlies it? What determines the stability of the biocenosis? Formulate a conclusion.

Conclusion:

food (trophic) chain- rows of species of plants, animals, fungi and microorganisms that are related to each other by relationships: food - consumer (a sequence of organisms in which there is a phased transfer of matter and energy from source to consumer). Organisms of the next link eat the organisms of the previous link, and thus a chain transfer of energy and matter is carried out, which underlies the cycle of substances in nature. With each transfer from link to link, a large part (up to 80-90%) of the potential energy is lost, dissipating in the form of heat. For this reason, the number of links (species) in the food chain is limited and usually does not exceed 4-5. The stability of the biocenosis is determined by the diversity of its species composition. Producers- organisms capable of synthesizing organic substances from inorganic, that is, all autotrophs. Consumers- heterotrophs, organisms that consume ready-made organic substances created by autotrophs (producers). Unlike reducers

, consumers are not able to decompose organic substances to inorganic ones. Decomposers- microorganisms (bacteria and fungi) that destroy the dead remains of living beings, turning them into inorganic and simple organic compounds.

3. Name the organisms that should be in the missing place of the following food chains.

1) Spider, fox

2) caterpillar tree eater, snake hawk

3) caterpillar

4. From the proposed list of living organisms, make a food web:

grass, berry bush, fly, titmouse, frog, snake, hare, wolf, decay bacteria, mosquito, grasshopper. Indicate the amount of energy that passes from one level to another.

1. Grass (100%) - grasshopper (10%) - frog (1%) - already (0.1%) - decay bacteria (0.01%).

2. Shrub (100%) - hare (10%) - wolf (1%) - decay bacteria (0.1%).

3. Grass (100%) - fly (10%) - titmouse (1%) - wolf (0.1%) - decay bacteria (0.01%).

4. Grass (100%) - mosquito (10%) - frog (1%) - already (0.1%) - decay bacteria (0.01%).

5. Knowing the rule of energy transfer from one trophic level to another (about 10%), build a biomass pyramid of the third food chain (task 1). Plant biomass is 40 tons.

Grass (40 tons) - grasshopper (4 tons) - sparrow (0.4 tons) - fox (0.04).

6. Conclusion: what do the rules of ecological pyramids reflect?

The rule of ecological pyramids very conditionally conveys the pattern of energy transfer from one level of nutrition to the next, in the food chain. For the first time, these graphic models were developed by C. Elton in 1927. According to this pattern, the total mass of plants should be an order of magnitude greater than that of herbivorous animals, and the total mass of herbivorous animals should be an order of magnitude greater than the first level predators, and so on. to the very end of the food chain.

Laboratory work № 1

For me, nature is a kind of well-oiled mechanism, in which everything is provided for to the smallest detail. It's amazing how everything is thought out, and it is unlikely that a person will ever be able to create something like this.

What does the term food chain mean?

According to the scientific definition, this concept includes the transfer of energy through a number of organisms, where the first link is the producers. This group includes plants that absorb inorganic substances, from which they synthesize nutritious organic compounds. Consumers feed on them - such organisms that are not capable of independent synthesis, which means that they are forced to eat ready-made organic matter. These are herbivores and insects, which act as a "lunch" for other consumers - predators. As a rule, the chain contains about 4-6 levels, where the closing link is represented by decomposers - organisms that decompose organic matter. In principle, there can be much more links, but there is a natural "limiter": on average, each link receives little energy from the previous one - up to 10%.

Examples of food chains in a forest community

Forests have their own characteristics, depending on their type. Coniferous forests do not have rich herbaceous vegetation, which means that food chains will have a certain set of animals. For example, a deer enjoys eating elderberry, and he himself becomes the prey of a bear or lynx. For a broad-leaved forest there will be a set. For example:

• bark - bark beetles - titmouse - falcon;
• fly - reptile - ferret - fox;
• seeds and fruits - squirrel - owl;
• plant - beetle - frog - already - hawk.

It is worth mentioning the scavengers who "recycle" organic remains. There are a great many of them in the forests: from the simplest unicellular to vertebrates. Their contribution to nature is enormous, because, otherwise, the planet would be covered with the remains of animals. They also convert dead bodies into inorganic compounds that plants need, and everything starts anew. In general, nature is perfection itself!