Every plant and animal species, no matter how big or small, depends to some extent on another plant or animal species for its survival. It could be bees taking pollen from a flower, photosynthesis of plants, deer eating shrub leaves or lions eating the deer. A food chain shows how energy is transferred from one living organism to another via food. It is important for us to understand how the food chain works so that we know what are the important living organisms that make up the food chain and how the ecology is balanced. Photosynthesis is only the beginning of the food chain. There are many types of animals that will eat the products of the photosynthesis process. Examples are deer eating shrub leaves, rabbits eating carrots, or worms eating grass. When these animals eat these plant products, food energy and organic compounds are transferred from the plants to the animals.
These animals are in turn eaten by other animals, again transferring energy and organic compounds from one animal to another. So for how many levels does this go on? To follow the food chain to its different levels and know how it works go to this site.
The page also contains names and definitions of terms used to describe the 'players' in the food chain- producers, consumers, herbivores. You can also refer to the diagrammatic representations of food chains, food webs and ecological pyramids.A food chain describes how energy and nutrients move through an ecosystem. At the basic level there are plants that produce the energy, then it moves up to higher-level organisms like herbivores. After that when carnivores eat the herbivores, energy is transferred from one to the other. To understand how this happens visit the link.
In the food chain, energy is transferred from one living organism through another in the form of food. There are primary producers, primary consumers, secondary consumers and decomposers- all part of the food chain. Follow this link for a good introduction to how food chains work. There are links to types of energy and also simple explanations to how photosynthesis is the starting point of the food chain. This site also tells us that because of our eating habits, we are in two food chains- marine and land.
Plants that have photosynthesis are supplying us with the first product of the food chain. Not only that, they are the source for oxygen, the food we eat, our clothes, and even our furniture, among other things. Plants also remove greenhouse gas from the air, provide habitat to many animals.Therefore we should understand the ecology of the environment with respect to plants. What is their number in terms of individuals (the population), and with respect to other living beings in the environment. Go to this page to see where plants are placed with respect to other living organisms.
In typical grassland, for example, the plants outnumber all other levels in the pyramid combined. However in the forests, other living organisms compete for space with plants. But a balance is maintained in the ecosystem.There may be special relationships that have evolved within the community in which one particular species grows in obligate association with one other particular species, upon which still others depend. This site explores such relationships.
Pearls of the Planet
Powered by explore.org
Mpala Research CentreThe Annenberg FoundationExpore.org
- PO Box 137 Riderwood, MD 21139-0137 USA (410) 244-7507
- PO Box 555 Nanyuki 100400 KENYA +254-62-32758
If you're seeing this message, it means we're having trouble loading external resources on our website.
If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.
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 of life, returning nutrients to the soil or oceans for use by autotrophs. This starts a whole new food chain.
Food Chains
Different habitats and ecosystems provide many possible food chains that make up a food web.
In one marine food chain, single-celled organisms called phytoplankton provide food for tiny shrimp called krill. Krill provide the main food source for the blue whale, an animal on the third trophic level.
In a grassland ecosystem, a grasshopper might eat grass, a producer. The grasshopper might get eaten by a rat, which in turn is consumed by a snake. Finally, a hawk—an apex predator—swoops down and snatches up the snake.
In a pond, the autotroph might be algae. A mosquito larva eats the algae, and then perhaps a dragonfly larva eats the young mosquito. The dragonfly larva becomes food for a fish, which provides a tasty meal for a raccoon.