Who eats what the world around him is working. Who eats what
In order to receive energy for vital processes, all creatures must eat. The diversity of the animal world is reflected in the way of eating: someone eats fresh meat, someone - berries and grass, and someone can eat both. Let's find out who eats what and how he gets his food.
Meals
Our planet is inhabited by very different animals: from the simplest microorganisms to such giants as the African elephant or the blue whale. In order to move, breathe, reproduce, all animals must regularly receive their usual food.
Depending on the way of feeding, animals are divided into the following groups:
- Herbivores
Animals that eat exclusively plant foods. Among domestic animals, these are horses, sheep, cows, goats. Among the wild animals are hares, roe deer, deer, elk. Their teeth have a special structure that helps them to pluck and grind tough plants with ease.
Since plant foods are not high in calories, herbivores have to spend a lot of time every day eating them.
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Fig. 1. Sheep in the pasture.
Herbivores are helped by special bacteria that live in the intestines or stomach to digest large portions of plant foods quickly and efficiently.
- Carnivores or predators
Animals that need meat from other animals to maintain their vitality. Domestic predators - dogs, cats, wild carnivores - foxes, wolves, tigers and lions and many others.
The feeding process of carnivores is very different from that of herbivores. To capture and firmly hold prey, they have well-developed, sharp and often very large canines. The incisors are responsible for tearing off pieces of meat, and the molars are responsible for grinding it.
Fig. 2. Lion with prey.
To track down, catch up and capture prey, predators sometimes have to spend more than one day. However, it's worth it: after a successful hunt, carnivores can go without food for a long time.
- Omnivores
There are animals that can equally eat both plant and animal food. These include bears, pigs, hedgehogs.
In nature, there are also such animals that feed on carrion, thereby preventing the development of infections. Such animals include hyenas, crows, vultures, some types of beetles and worms. They are called scavengers or orderlies of nature.
Who eats what: food chains
All animals, one way or another, are connected to each other in the food chain: someone eats plants, and someone - other animals.
Since plants are the main food of herbivores, they occupy the first place in the food chain.
Only plants are able to synthesize nutrients from water and carbon dioxide when exposed to the sun. Thus, they are an excellent food source for many species of animals.
Fig. 3. Plants are a valuable food source.
The second place is given to herbivorous animals.
The third place is taken by the predatory representatives of the animal world.
An example of a food chain: grain - mouse - fox.
At first glance, it may seem that life on Earth would be much more pleasant if there were no insects, snakes, frogs. But they are all important links in the food chain. If they were not on the planet, such a fragile ecological balance would be violated: sick animals would spread infections, infecting other animals and people, plants would not be pollinated and crops would be lost. Absolutely all animals on Earth are of great value!
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 omnivores (they eat both plant and animal food).
Supply chains
Living things are linked together in the food chain.
Here's an example. Aspen trees 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.
Another example. Wood mice feed on the acorns of oak trees. But the mice themselves are the prey of owls. The food chain is as follows: oak - wood mouse - owl.
Food chains begin with plants. This is the first link. The second link in the chain is herbivorous animals. The third link is insectivorous or carnivorous animals.
Power circuits can be depicted using models.
- Make models of the power circuits presented in the tutorial. Test each other with illustrations and text from the tutorial. If necessary, correct errors by moving parts of the models.
- Read the text "How fit". Find examples of the adaptability of animals in it: a) to get food; b) to protect against enemies.
Who is fit
Quiet steps, excellent hearing, sharp teeth - all this helps the fox to hunt. But an owl ... Huge eyes can see it perfectly at night and day, soft plumage makes the flight noiseless, sharp claws and a strong curved beak help to hold and eat prey.
Predators are well adapted to foraging for food. But even the animals they hunt are adapted to defend themselves. The hare has fast legs, so it is difficult to catch up with it. The color of the fur coat also saves the hare: in summer it is gray, in winter it is white. The hedgehog's protection is needles. The lizard, if the enemy grabs her by the tail, leaves it to the predator, and she runs away. Then the lizard grows a new tail.
The green color saves the grasshopper - the grasshopper becomes invisible in the grass. And the ladybug, on the contrary, attracts attention with its bright color. Ladybug's blood is acrid. The brightly colored cows seem to warn enemies: “We are inedible! Dont touch!"
Let's discuss
- Why do food chains begin with plants?
- What would happen if there were no frogs, snakes, owls, dragonflies left on Earth?
check yourself
- What groups are animals divided into depending on their nutrition?
- What is a power chain? Give an example.
Homework assignments
- Make a model of a power circuit that was not covered in the tutorial. In class, compare it to the models that your comrades have made.
- In the book "Green Pages" read the story about ladybirds. Pay attention to what they eat. How do you feel about ladybugs? What can you do to protect them?
Pages for the curious
A kind word about predators
People noticed that where there were no predators left, herbivorous animals - hares, wild boars, deer, black grouse - first became more, and then less and less. Why?
It turned out that predators mainly catch sick animals, but it is difficult for them to catch up and overcome healthy and strong ones. Where predators were destroyed, diseases spread among the animals and many animals died. The predators turned out to be the orderlies of nature.
In the next lesson
We will learn how different animals reproduce and develop. We will learn to depict the process of animal development using models.
Remember if you had to watch how animals reproduce in a living corner, how animals take care of their offspring.
Our projects
The diversity of the nature of the native land
More than a hundred years ago, the outstanding scientist Dmitry Nikiforovich Kaigorodov wrote the following lines: “I am depicted in the distant future (or maybe not so far!) Such a wonderful ideal: with the appearance of the first green leaf on the tree the doors of all classes are closed and all lessons ... are transferred to that great auditorium 1 in the open air, in the chair 2 of which the greatest professor in the world sits - Nature itself. "
D. N. Kaigorodov and his house in St. Petersburg
Yes, Dmitry Nikiforovich dreamed of schoolchildren studying nature not only in classrooms, but also in nature itself!
Well, let's do it. And let's not wait for spring. Nature surrounds us at all seasons, and it is always amazing. And the most amazing thing about nature is its incredible diversity. How many plants, mushrooms, animals surround us! And each has a name!
Organize a study of this amazing diversity in your area. You have a good helper - an atlas-determinant "From Earth to Heaven". In addition to the atlas, you can take other books about nature.
- When getting started, clearly define the purpose of the project. Agree on the form of work: individually, in pairs, groups or as a whole class. Think over the stages of work, assign responsibilities, agree on deadlines.
- In such a study, adults are indispensable. Go with them to the park, to the forest, to the meadow, to the reservoir. Write down the names of natural objects in a special diary, take photos, sketches. Collect additional information from various sources.
- According to the results of the research, compile the "Book of the nature of the native land" Think over the general plan of the book in advance. You can take as a basis the plan of the atlas-determinant.
- Summarize the results of the research at a conference-holiday. Invite the adults who helped you with the project and other guests. Together with them, evaluate the results of your work.
1 Auditorium - a room where lectures, reports are read, other classes are held.
2 Department - the place from which the professor (teacher) reads a lecture, conducts a lesson.
Let's start our lesson.
To become a friend of nature,
Find out all her secrets
Solve all the riddles
Learn to observe.
We will develop together
I have attentiveness
And it will help to find out everything
Our curiosity.
Guys, in the last lesson we learned about the diversity of the animal world, got acquainted with several groups of animals. Now I will check if you remember these groups well.
Gives tasks for working at the board.
Stepan and Vika will go to the board to carry out tasks.
Stepan connect the names of the animals with the name of the group with arrows:
COW EARTHWATER
CHICKENS INSECTS
TOAD MAMMALS
BEES BIRDS
Vika find an extra animal:
Butterfly, spider, bee, mosquito.
Perch, pike, crayfish, crucian carp.
Crocodile, squirrel, fox, goat.
Conducts a frontal survey.
I will ask questions, and you listen carefully and answer.
1.These lilies, cucumbers, stars and even hedgehogs live on the seabed, are the bodies of these sea animals covered with thorns or needles?
2.Animals whose body is covered with wool. They feed their cubs with milk. What is this group called?
3. Representatives of this group spend part of their life on land (i.e. on land), and part in water, for which they got their name.
4. What group of animals do leeches belong to?
5. In animals of this group, the body is covered with feathers. Name the representatives of this group.
6. Guess the riddle:
Creeps on the contrary
Backwards.
Everything is under water
Grabs with a claw. What group of animals does cancer belong to?
7.Animals with 6 legs.
8. Animals of this group have a soft body, which in many of them is protected by a shell.
9. The body of these animals is covered with dry scales, and some have shells.
What else is this group of animals called?
What groups of animals have we not named yet?
Define these groups. Name the representatives of these groups.
Now let's check how the guys worked at the blackboard.
Guys, list the signs of living organisms.
What do you think is necessary for the growth and development of an animal?
Today in the lesson we will talk about animal nutrition.
I hang out a sign with the word Animals.
What do you think is the topic of the lesson?
How do we answer the question "Who?" and the question "What is eating?"
Well done, thanks. What is the purpose of the lesson? Help me name it.
Tell me, is food the same for all animals?
I exhibit pictures of animals.
The guys on the board are pictures with animals. I suggest you group them and divide them into groups.
Polina and Sasha will go to the board.
What do you think hare and elk eat?
How can you call these animals in one word?
Hanging out the herbivorous sign.
Give your examples.
What do the swallow and frog eat?
- How can you call them, in one word?
Hanging out a sign Insectivores.
Give your examples.
- What do the fox and the wolf eat?
- How to call these animals, in one word?
Hanging out the Predators sign.
Give your examples.
List the animals that we have left.
- What does the bear eat?
- What group do you think he belongs to?
Hanging out a sign Omnivores.
Give your examples.
- What groups of animals have we met by way of feeding?
On the board is a diagram. Attached during the conversation.
Animals
Confirm your assumption with the text of the textbook on page 94
Summarizes.
Animals that need plant food are called herbivores.
- Insectivores feed on insects.
Predatory animals feed on the flesh of other animals,
therefore they are also called carnivores.
Omnivores eat both plant foods and animal foods.
Bunnies gallop across the lawn.
Suddenly a shadow flashed in the forest,
Bunnies hid behind a stump
They rose on their toes
Gray bunny, look around
Isn't he sitting behind a bush
A gray wolf with a large tail.
As you already understood, animals feed on plants or other animals. Therefore, they say that living things are connected to each other in the food chain.
Guys, I put pictures on the board.
I post pictures of wheat, a mouse and a fox; grass, elk, wolf.
Let's try to put together a power supply chain.
Timur and Victoria will go to the board.
Let's see what happened with Timur, Victoria.
Read the Power Chains tutorial on pages 94 - 95.
What examples of power circuits are given in the tutorial?
Where does the food chain begin?
This is the first link.
I hang out a sign: I link - a plant.
Why do you think?
What's going on in the second link?
This is the second link.
I hang out the sign: II link - herbivorous animals.
What's in the third link?
I hang out the sign: III link - insectivores or predators.
Nutritional chains are nutritional connections of all living things. There are a lot of 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 suggest you divide into 3 groups.
I distribute envelopes.
Now listen to the assignment. Each group, using cards, must make up a power circuit. Determine right away who will present your circuit to the class. Consider if you need all the cards.
1 envelope Field: rye, mouse, snake (fish)
2 envelope Pond: algae, crucian carp, pike (hare)
3 envelope Vegetable garden: cabbage, slugs, toad (bear)
Will represent the power circuit 1 group, 2 group, 3 group.
Do you guys need to destroy predatory animals, such as wolves?
If at least one link falls out of the supply chain, then the whole chain will be broken. A person needs to know very well that everything in nature is interconnected. We must take good care of nature, not harm it.
Read the text “How fit” on pages 95-96.
How did predators adapt to foraging?
How have animals adapted to defend themselves from predators?
Read the tutorial for the output on p. 96.
What groups are animals divided into according to the way of feeding?
In what order are the links in the power chain?
Guys, who put a smiley face in all columns?
| I know the nutritional features of animals | I know what food chains are | I can simulate power circuits |
And now Katya and Artyom will read the poem "About everyone in the world"
R.T. p.44 # 3, p.46 # 6.
- The lesson is over. Thanks for your work.
Every organism must receive energy for life. For example, plants consume energy from the sun, animals feed on plants, and some animals feed on other animals.
The food (trophic) chain is the sequence of who eats whom in a biological community () to obtain nutrients and energy that support life.
Autotrophs (producers)
Autotrophs - living organisms that produce their food, that is, their own organic compounds, from simple molecules such as carbon dioxide. There are two main types of autotrophs:
- Photoautotrophs (photosynthetic organisms) such as plants recycle energy from sunlight to produce organic compounds - sugars - from carbon dioxide in the process. Other examples of photoautotrophs are algae and cyanobacteria.
- Chemoautotrophs obtain organic substances through chemical reactions involving inorganic compounds (hydrogen, hydrogen sulfide, ammonia, etc.). This process is called chemosynthesis.
Autotrophs are the backbone of every ecosystem on the planet. They make up the majority of food chains and webs, and the energy from photosynthesis or chemosynthesis supports all other organisms in ecological systems. When it comes to their role in food chains, autotrophs can be called producers or producers.
Heterotrophs (consumers)
Heterotrophs, also known as consumers, cannot use solar or chemical energy to produce their own food from carbon dioxide. Instead, heterotrophs gain energy by consuming other organisms or their byproducts. People, animals, fungi and many bacteria are heterotrophs. Their role in food webs is to consume other living organisms. There are many species of heterotrophs with different ecological roles, from insects and plants to predators and fungi.
Destructors (reducers)
Another consumer group should be mentioned, although it does not always figure in the diagrams of food chains. This group consists of decomposers, organisms that recycle dead organic matter and waste, converting them into inorganic compounds.
Reducers are sometimes considered a separate trophic level. As a group, they feed on dead organisms arriving at various trophic levels. (For example, they are able to process decaying plant matter, the body of a squirrel eaten by predators, or the remains of a deceased eagle.) In a sense, the trophic level of decomposers runs parallel to the standard hierarchy of primary, secondary, and tertiary consumers. Fungi and bacteria are key decomposers in many ecosystems.
Reducers, as part of the food chain, play an important role in maintaining a healthy ecosystem, as they return nutrients and moisture to the soil, which are then used by producers.
Food (trophic) chain levels
Food (trophic) chain level diagram
The food chain is a linear sequence of organisms that transfer nutrients and energy from producers to top predators.
The trophic level of an organism is the position it occupies in the food chain.
First trophic level
The food chain starts with autotrophic organism or producerproducing its own food from a primary source of energy, usually solar or hydrothermal energy from the mid-ocean ridges. For example, photosynthetic plants, chemosynthetic, etc.
Second trophic level
This is followed by organisms that feed on autotrophs. These organisms are called herbivorous animals or primary consumersand consume green plants. Examples include insects, hares, sheep, caterpillars, and even cows.
Third trophic level
The next link in the food chain is the animals that eat the herbivores - they are called secondary consumers or carnivorous (carnivorous) animals (for example, a snake that feeds on hares or rodents).
Fourth trophic level
In turn, these animals are eaten by larger predators - tertiary consumers (for example, an owl eats a snake).
Fifth trophic level
Tertiary consumers eat quaternary consumers (for example, a hawk eats owls).
Each food chain ends with a top predator or superpredator - an animal without natural enemies (for example, a crocodile, polar bear, shark, etc.). They are the "masters" of their ecosystems.
When an organism dies, it is eventually eaten by detritivores (such as hyenas, vultures, worms, crabs, etc.), and the rest is decomposed by decomposers (mainly bacteria and fungi), and energy exchange continues.
Arrows in the food chain indicate the flow of energy, from the sun or hydrothermal vents to apex predators. As energy flows from body to body, it is lost at every link in the chain. The collection of many food chains is called food web.
The position of some organisms in the food chain can vary because of their diet. For example, when a bear eats berries, it acts as a herbivorous animal. When it eats a rodent that feeds on plants, it becomes the primary predator. When a bear eats salmon, it acts as a superpredator (this is due to the fact that salmon is the primary predator, since it feeds on herring, and it eats zooplankton, which feeds on phytoplankton, which produces its own energy thanks to sunlight). Think about how the place of people in the food chain changes, even often during the same meal.
Types of food chains
In nature, as a rule, two types of food chains are distinguished: grazing and detrital.
Pasture food chain
Pasture food chain diagram
This type of food chain begins with living green plants intended to feed the herbivorous animals that predators feed on. Ecosystems with this type of circuit are directly dependent on solar energy.
Thus, the pasture type of the food chain depends on the autotrophic capture of energy and its movement along the links of the chain. Most ecosystems in nature follow this type of food chain.
Examples of a pasture food chain:
- Grass → Grasshopper → Bird → Hawk;
- Plants → Hare → Fox → Lion.
Detrital food chain
Detrital food chain diagram
This type of food chain begins with decaying organic material - detritus - that is consumed by deposit feeders. Then, predators feed on detritivores. Thus, such food chains are less dependent on direct solar energy than grazing. The main thing for them is the influx of organic substances produced in another system.
For example, this type of food chain is found in decaying litter.
Energy in the food chain
Energy is transferred between trophic levels when one organism feeds on and receives nutrients from another. However, this movement of energy is inefficient, and this inefficiency limits the length of the food chain.
When energy enters the trophic level, part of it is stored as biomass, as part of the body of organisms. This energy is available for the next trophic level. Typically, only about 10% of the energy that is stored as biomass at one trophic level is stored as biomass at the next level.
This principle of partial energy transfer limits the length of food webs, which are typically 3-6 levels.
At each level, energy is lost in the form of heat, as well as in the form of waste and dead matter, which are used by decomposers.
Why is there so much energy coming out of the food web between one trophic level and another? Here are some of the main reasons for inefficient power transmission:
- At each trophic level, much of the energy is dissipated as heat as organisms perform cellular respiration and move around in daily life.
- Some organic molecules that organisms feed on cannot be digested and are expelled as feces.
- Not all individual organisms at the trophic level will be eaten by organisms from the next level. Instead, they die without being eaten.
- Feces and uneaten dead organisms become food for decomposers, which metabolize them and convert them into energy.
So, none of the energies actually disappear - all this ultimately leads to the release of heat.
Significance of the food chain
1. Food chain studies help to understand the feeding relationships and interactions between organisms in any ecosystem.
2. Thanks to them, it is possible to assess the mechanism of energy flow and circulation of substances in the ecosystem, as well as to understand the movement of toxic substances in the ecosystem.
3. Studying the food chain provides insight into the problems of biomagnification.
In any food chain, energy is lost every time one organism is consumed by another. Due to this, there must be many more plants than herbivorous animals. There are more autotrophs than heterotrophs, and therefore most of them are herbivorous rather than predators. Although there is intense competition between animals, they are all interconnected. When one species goes extinct, it can affect many other species with unpredictable consequences.
