The food chain describes who eats whom in the wild. Every living thing—from one-celled algae to giant blue whales—needs food to survive. Each food chain is a possible pathway that energy and nutrients can follow through the ecosystem.
For example, grass produces its own food from sunlight. A rabbit eats the grass. A fox eats the rabbit. When the fox dies, bacteria break down its body, returning it to the soil where it provides nutrients for plants like grass.
Of course, many different animals eat grass, and rabbits can eat other plants besides grass. Foxes, in turn, can eat many types of animals and plants. Each of these living things can be a part of multiple food chains. All of the interconnected and overlapping food chains in an ecosystem make up a food web.
Trophic Levels
Organisms in food chains are grouped into categories called trophic levels. Roughly speaking, these levels are divided into producers (first trophic level), consumers (second, third, and fourth trophic levels), and decomposers.
Producers, also known as autotrophs, make their own food. They make up the first level of every food chain. Autotrophs are usually plants or one-celled organisms. Nearly all autotrophs use a process called photosynthesis to create “food” (a nutrient called glucose) from sunlight, carbon dioxide, and water.
Plants are the most familiar type of autotroph, but there are many other kinds. Algae, whose larger forms are known as seaweed, are autotrophic. Phytoplankton, tiny organisms that live in the ocean, are also autotrophs. Some types of bacteria are autotrophs. For example, bacteria living in active volcanoes use sulfur compounds to produce their own food. This process is called chemosynthesis.
The second trophic level consists of organisms that eat the producers. These are called primary consumers, or herbivores. Deer, turtles, and many types of birds are herbivores. Secondary consumers eat the herbivores. Tertiary consumers eat the secondary consumers. There may be more levels of consumers before a chain finally reaches its top predator. Top predators, also called apex predators, eat other consumers.
Consumers can be carnivores (animals that eat other animals) or omnivores (animals that eat both plants and animals). Omnivores, like people, consume many types of foods. People eat plants, such as vegetables and fruits. We also eat animals and animal products, such as meat, milk, and eggs. We eat fungi, such as mushrooms. We also eat algae, in edible seaweeds like nori (used to wrap sushi rolls) and sea lettuce (used in salads).
Detritivores and decomposers are the final part of food chains. Detritivores are organisms that eat nonliving plant and animal remains. For example, scavengers such as vultures eat dead animals. Dung beetles eat animal feces.
Decomposers like fungi and bacteria complete the food chain. They turn organic wastes, such as decaying plants, into inorganic materials, such as nutrient-rich soil. Decomposers complete the cycle
3. I. Objectives
After going through this lesson, the learners
are expected to:
• Explain the purpose of a food chain and able
to give examples of food chains.
• Distinguish among the roles of producer,
consumers and decomposers; give example of
each
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4. Food Chain: the transfer of energy from
one another organism to the next from
sun to producer to consumer, food chain
is just part of the overall food web found
in nature.
Herbivore: animal that eats only plants
Omnivore: an animal that can eat
plants and animals
Carnivore: a meat-eater
Decomposer: an organism that eats the
organic material that from the death and
decay of other life forms.
Science Concept:
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Habitat: The place where an animal or
plant finds the food, water, shelter and
space in arrangement they need to
survive.
Producer: a green plant that can make its
own food through photosynthesis
Consumer: an organism that eats another
organism in order to get food
Predator: an animal that catches, kills
and eats other animals
Prey: animals that are killed and eaten by
predator
8. Food chain is a linear sequence of organisms
through which nutrients and energy pass as
one organism eats another. In a food chain,
each organism occupies different tropic level,
defined by how many energy transfers
separate it from the basic input of the chain.
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9. 9
Producers
Producer also known as autotrophs,
make their own food. They make up
first level of food chain. The green
plants or producers represent first
tropic level (T1). Autotrophs are usually
plants or one-celled organisms. Nearly
all autotrophs use a process called
photosynthesis to crate “food’’ (a
nutrient called glucose) from sunlight,
carbon dioxide and water.
10. 10
Consumers
Consumers constitute the upper tropic levels.
Unlike producers, they cannot make their own food. To
get energy, they eat plants or other animals, while some
eat both. Primary consumers make up the second trophic
level (T2). They are also called herbivores.
Secondary consumers, which eat primary consumers.
Secondary consumers are mostly carnivores, from the
Latin words meaning “meat eater. Some
secondary consumers eat both plants and animals. They
are called omnivores, from the Latin words that mean
“eats everything.” Represent third tropic level (T3).
Ecosystem can also have tertiary consumers, carnivores
that eat other carnivores.
11. 11
Decomposers
Decomposer is the last tropic level
(T5) plays a critical role in the flow of
energy through an ecosystem. They
break apart dead organisms into
simpler inorganic materials, making
nutrients available to primary
producers.
14. A. Identification:
Direction: Write your answer in the blank provided.
Herbivores 1.What do we called that animals eat only plants?
Carnivores 2.Animals that eat other animals called?
Omnivores 3. Animals that eat both animals and plants are called?
Producer, consumer and decomposer 4. Food chain consists of?
Food chain 5.A linear sequence of organisms through which nutrients
and energy pass as one organism eats another animals are
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15. B. Multiple choice
Direction: choose the letter of the correct answer.
1. Which among of this is the primary consumer?
A. sun
B. chayote
C. dandelion
D. woodchuck
2. Which of this is the producer?
A. oak acorn
B. gray squirrel
C. snake
D. hawk
3. A food chain starts with
(a) Nitrogen fixing organisms
(b) Photosynthesis
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16. 4. In a food chain, lion is a
(a) Secondary consumer
(b) Primary consumer
(c) Tertiary consumer
(d) Secondary producer
5. Which is the correct sequence in the food chain in grassland?
(a) Grass > wolf > deer > buffalo
(b) Bacteria > grass > rabbit > wolf
(c) Grass > insect > birds > snakes
(d) Grass > snake > insect > deer
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(c) Respiration
(d) Decomposers
Notes de l'éditeur
You can see here a links in food chain all you need to do is to identify the elements in food chain and its tropic level.
What is in the lower level of triangle? Very good it is producers make their own food. They do not have to obtain energy from other organisms. They obtain their energy from the sun and make food with that energy through the process of photosynthesis. Producers may also be called autotrophs.
