Biology food chain. Topic: Building a food chain
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.
Working process:
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 regularity, 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 that of first-level predators, and so on. to the very end of the food chain.
Lab #1
Food chain structure
The food chain is a connected linear structure of links, each of which is connected with neighboring links by the relationship "food - consumer". Groups of organisms, for example, specific biological species, act as links in the chain. A connection between two links is established if one group of organisms acts as food for another group. The first link in the chain does not have a precursor, that is, organisms from this group do not use other organisms as food, being producers. Most often in this place there are plants, mushrooms, algae. Organisms of the last link in the chain do not act as food for other organisms.
Each organism has a certain reserve of energy, that is, we can say that each link in the chain has its own potential energy. In the process of eating, the potential energy of food passes to its consumer. When transferring potential energy from link to link, up to 80-90% is lost in the form of heat. This fact limits the length of the food chain, which in nature usually does not exceed 4-5 links. The longer the trophic chain, the less the production of its last link in relation to the production of the initial one.
food web
Usually, for each link in the chain, you can specify not one, but several other links associated with it by the relationship "food - consumer". So, grass is eaten not only by cows, but also by other animals, and cows are food not only for humans. The establishment of such links turns the food chain into a more complex structure - food web.
Trophic level
The trophic level is a set of organisms that, depending on the way they eat and the type of food, make up a certain link in the food chain.
In some cases, in the food web, it is possible to group individual links into levels in such a way that the links of one level act for the next level only as food. This grouping is called a trophic level.
Types of food chains
There are 2 main types of trophic chains - pasture and detritus.
In the pasture trophic chain (grazing chain), the basis is autotrophic organisms, then go herbivorous animals (for example, zooplankton that feed on phytoplankton) that consume them (consumers), then predators of the 1st order (for example, fish that consume zooplankton), predators of the 2nd order (for example, pikefeeding on other fish). Food chains are especially long in the ocean, where many species (for example, tuna) take the place of fourth-order consumers.
In detrital trophic chains (decomposition chains), which are most common in forests, most of the plant production is not directly consumed by herbivorous animals, but dies off, then being decomposed by saprotrophic organisms and mineralized. Thus, detrital trophic chains start from detritus (organic remains), go to microorganisms that feed on it, and then to detritus feeders and their consumers - predators. In aquatic ecosystems (especially in eutrophic water bodies and at great depths of the ocean), part of the production of plants and animals also enters detrital food chains.
Terrestrial detrital food chains are more energy intensive, since most of the organic mass created by autotrophic organisms remains unclaimed and dies off, forming detritus. On a global scale, the share of grazing chains accounts for about 10% of the energy and substances stored by autotrophs, while 90% is included in the cycle through decomposition chains.
see also
Literature
- Trophic chain / Biological encyclopedic dictionary / chapters. ed. M. S. GILYAROV - M.: Soviet Encyclopedia, 1986. - S. 648-649.
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See what the "Food Chain" is in other dictionaries:
- (food chain, trophic chain), the relationship between organisms in which groups of individuals (bacteria, fungi, plants, animals) are related to each other by relationships: food consumer. The food chain usually includes from 2 to 5 links: photo and ... ... Modern Encyclopedia
- (food chain trophic chain), a number of organisms (plants, animals, microorganisms), in which each previous link serves as food for the next. Linked to each other by relationships: food consumer. The food chain usually includes from 2 to 5 ... ... Big Encyclopedic Dictionary
FOOD CHAIN, a system of energy transfer from organism to organism, in which each previous organism is exterminated by the next. In its simplest form, energy transfer starts with plants (PRIMARY PRODUCERS). The next link in the chain is... Scientific and technical encyclopedic dictionary
FOOD CHAIN- see Trophic chain. Ecological encyclopedic dictionary. Chisinau: Main edition of the Moldavian Soviet Encyclopedia. I.I. Grandpa. 1989... Ecological dictionary
food chain- - EN food chain A sequence of organisms on successive trophic levels within a community, through which energy is transferred by feeding; energy enters the food chain during fixation … Technical Translator's Handbook
- (food chain, trophic chain), a number of organisms (plants, animals, microorganisms), in which each previous link serves as food for the next. Linked to each other by relationships: food consumer. The food chain usually includes from 2 to ... ... encyclopedic Dictionary
food chain- mitybos grandinė statusas T sritis ekologija ir aplinkotyra apibrėžtis Augalų, gyvūnų ir mikroorganizmų mitybos ryšiai, dėl kurių pirminė augalų energija maisto pavidalu perduodama vartotojams ir skaidytojams. Vienam organizmui pasimaitinus kitu … Ekologijos terminų aiskinamasis žodynas
- (food chain, trophic chain), a number of organisms (rni, zhny, microorganisms), in which each previous link serves as food for the next. Linked to each other by relationships: food consumer. P. c. usually includes from 2 to 5 links: photo and ... ... Natural science. encyclopedic Dictionary
- (trophic chain, food chain), the relationship of organisms through the relationship of food consumer (some serve as food for others). At the same time, there is a transformation of matter and energy from producers (primary producers) through consumers ... ... Biological encyclopedic dictionary
See Power Circuit... Big Medical Dictionary
Books
- The dilemma of the omnivore. A shocking study of the modern human diet by Michael Pollan. Have you ever wondered how food gets on our table? Did you buy groceries at a supermarket or a farmer's market? Or maybe you yourself grew tomatoes or brought a goose with ...
Who eats what
Make a food chain that tells 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 diagram.
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.
Nature is arranged in such a way that some organisms are a source of energy, or rather, food, for others. Herbivores eat plants, carnivores prey on herbivores or other predators, and scavengers feed on the remains of living creatures. All these relations are closed in chains, in the first place of which are producers, and then consumers follow - consumers of different orders. Most chains are limited to 3-5 links. An example of a food chain: - hare - tiger.
In fact, many food chains are much more complex, they branch, close, form complex networks called trophic.
Most food chains start with plants - they are called pastures. But there are other chains: they are from the decomposed remains of animals and plants, excrement and other waste, and then microorganisms and other creatures that eat such food follow.
Plants at the beginning of the food chain
All organisms carry energy along the food chain, which is contained in food. There are two types of nutrition: autotrophic and heterotrophic. The first is to obtain nutrients from inorganic raw materials, and heterotrophs use organic matter for life.
There is no clear boundary between the two types of nutrition: some organisms can get energy in both ways.
It is logical to assume that at the beginning of the food chain there should be autotrophs that convert inorganic substances into organic matter and can be food for other organisms. Heterotrophs cannot start food chains, since they need to get energy from organic compounds - that is, they must be preceded by at least one link. The most common autotrophs are plants, but there are other organisms that feed in the same way, for example, some bacteria or. Therefore, not all food chains begin with plants, but most of them are still based on plant organisms: on land these are any representatives of higher plants, in the seas - algae.
There can be no other links in the food chain before autotrophic plants: they get energy from soil, water, air, light. But there are also heterotrophic plants, they do not have chlorophyll, they live off or prey on animals (mainly insects). Such organisms can combine two types of food and stand both at the beginning and in the middle of the food chain.
The energy of the sun plays a huge role in the reproduction of life. The amount of this energy is very high (about 55 kcal per 1 cm2 per year). Of this amount, producers - green plants - as a result of photosynthesis fix no more than 1-2% of energy, and deserts and the ocean - hundredths of a percent.
The number of links in the food chain may be different, but usually there are 3-4 (rarely 5). The fact is that so little energy is supplied to the final link of the food chain that it will not be enough if the number of organisms increases.
Rice. 1. Food chains in the terrestrial ecosystem
The set of organisms united by one type of food and occupying a certain position in the food chain is called trophic level. Organisms that receive their energy from the Sun through the same number of steps belong to the same trophic level.
The simplest food chain (or food chain) may consist of phytoplankton, followed by larger herbivorous planktonic crustaceans (zooplankton), and the chain ends with a whale (or small predators) that filter these crustaceans from the water.
Nature is complex. All its elements, living and non-living, are one whole, a complex of interacting and interconnected phenomena and beings adapted to each other. These are links in the same chain. And if at least one such link is removed from the general chain, the results may be unexpected.
Breaking food chains can have a particularly negative impact on forests, whether they are forest biocenoses of the temperate zone or biocenoses of the tropical forest that are rich in species diversity. Many species of trees, shrubs or herbaceous plants use the services of a particular pollinator - bees, wasps, butterflies or hummingbirds that live within the range of this plant species. As soon as the last flowering tree or herbaceous plant dies, the pollinator will be forced to leave this habitat. As a result, phytophages (herbivores) that feed on these plants or fruits of the tree will die. Predators that hunt phytophages will be left without food, and then changes will sequentially affect the rest of the food chain. As a result, they will also affect a person, since he has his own specific place in the food chain.
Food chains can be divided into two main types: grazing and detrital. Food prices that begin with autotrophic photosynthetic organisms are called pasture, or eating chains. At the top of the pasture chain are green plants. Phytophages are usually found at the second level of the pasture chain; animals that eat plants. An example of a pasture food chain is the relationship between organisms in a floodplain meadow. Such a chain begins with a meadow flowering plant. The next link is a butterfly that feeds on the nectar of a flower. Then comes the inhabitant of wet habitats - the frog. Its protective coloration allows it to lie in wait for the victim, but does not save it from another predator - the common grass snake. The heron, having caught the snake, closes the food chain in the floodplain meadow.
If the food chain begins with dead plant remains, corpses and animal excrement - detritus, it is called detritus, or decomposition chain. The term "detritus" means a decay product. It is borrowed from geology, where the products of the destruction of rocks are called detritus. In ecology, detritus is the organic matter involved in the decomposition process. Such chains are characteristic of the communities of the bottom of deep lakes and oceans, where many organisms feed on detritus formed by dead organisms from the upper illuminated layers of the reservoir.
In forest biocenoses, the detrital chain begins with the decomposition of dead organic matter by saprophage animals. Soil invertebrates (arthropods, worms) and microorganisms take the most active part in the decomposition of organic matter. There are also large saprophages - insects that prepare the substrate for organisms that carry out mineralization processes (for bacteria and fungi).
In contrast to the pasture chain, the size of organisms does not increase when moving along the detrital chain, but, on the contrary, decreases. So, gravedigger insects can stand on the second level. But the most typical representatives of the detrital chain are fungi and microorganisms that feed on dead matter and complete the process of bioorganic decomposition to the state of the simplest mineral and organic substances, which are then consumed in dissolved form by the roots of green plants at the top of the pasture chain, thereby starting a new circle of movement of matter.
In some ecosystems, pasture chains predominate, in others, detrital chains. For example, a forest is considered an ecosystem dominated by detrital chains. In the rotting stump ecosystem, there is no grazing chain at all. At the same time, for example, in the ecosystems of the sea surface, almost all producers represented by phytoplankton are consumed by animals, and their corpses sink to the bottom, i.e. leave the published ecosystem. These ecosystems are dominated by grazing or grazing food chains.
General rule concerning any the food chain, states: at each trophic level of the community, most of the energy absorbed with food is spent on maintaining life, dissipated and can no longer be used by other organisms. Thus, the food consumed at each trophic level is not fully assimilated. A significant part of it is spent on metabolism. With each subsequent link in the food chain, the total amount of usable energy transferred to the next higher trophic level decreases.