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 living thing is a part of multiple food chains – for example, the grass is a part of the food chain: grass → grasshopper → frog → snake → eagle, and the food chain: grass → deer → tiger.
All of the interconnected and overlapping food chains in a habitat make up a food web.
What is the Food Chain?
A food chain is a sequence of organisms through which nutrients and energy is transferred in the form of food from organism to organism. The food chain describes who eats whom for survival in an ecosystem.
The food chain is also the pathway for the transfer of energy in an ecosystem. The energy is produced by the ‘Producers’ and is transferred to the ‘Consumers’ and thereafter to ‘Decomposers’.
Food chains show how energy passes through an ecosystem. When one organism is eaten by another, most of the energy is lost and a little bit gets transferred to the consumer.
- Level 1 in a chain goes to the producers, like plants. They use energy from sunlight to make their own food through the process of photosynthesis.
- In level 2 consumers get their energy from the food they eat. The primary consumers, like rabbits or insects, eat plants. They are also known as herbivores.
- The next few levels in a chain consist of animals that eat other animals. The first one is carnivores, like snakes or weasels, who eat herbivores. You might also find omnivores, who eat both plants and other animals. Often there are multiple levels, such as secondary consumers, tertiary consumers, and quaternary consumers, that all occupy this space. The consumer at the top of the food chain is often called the apex predator or top-level consumer.
- The last step of a chain goes to decomposers, like fungi, that use the remains of organisms to grow.
These feeding orders are needed to maintain a delicate balance in the environment. Each member of the food chain helps keep population sizes within the carrying capacity. If any part of the chain were damaged, the entire ecosystem would be in trouble.
Examples of Food Chain
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 provides 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.
Here are some additional food chain examples:
- Grass → Grasshopper → Frog → Snake → Hawk
- Algae → Zooplankton → Small Fish → Large Fish → Shark
- Acacia Tree → Giraffe → Lion
- Grass → Rabbit → Fox → Eagle
- Phytoplankton → Krill → Blue Whale
- Decaying Leaves → Detritivores (Earthworms, Millipedes, etc.) → Raccoon
- Grass → Deer → Cougar
- Seagrass → Sea Urchin → Sea Otter → Bald Eagle
- Plants → Caterpillar → Wren → Hawk
- Phytoplankton → Zooplankton → Jellyfish → Sea Turtle → Tiger Shark
- Seaweed → Fish → Seal → Killer Whale
- Algae → Shrimp → Squid → Cod → Seal → Polar Bear
- Algae → Insects → Lizards → Snakes → Hawks
- Grass → Bison → Wolf
- Phytoplankton → Krill → Penguin → Leopard Seal → Orca
- Seaweed → Fish → Osprey → Bald Eagle
- Grass → Grasshopper → Mouse → Snake → Hawk
- Algae → Shrimp → Herring → Dolphin → Killer Whale
- Grass → Rabbit → Coyote → Wolf
- Algae → Zooplankton → Small Fish → Squid → Tuna → Shark
- Plants → Caterpillar → Blue Jay → Hawk
- Phytoplankton → Krill → Penguin → Fur Seal → Killer Whale
- Seagrass → Manatee → Tiger Shark
- Grass → Wildebeest → Lion → Vulture
- Phytoplankton → Zooplankton → Small Fish → Swordfish → Tiger Shark
- Algae → Shrimp → Flounder → Sea Bass → Sea Lion → Killer Whale
- Grass → Gazelle → Cheetah
- Algae → Zooplankton → Sardine → Penguin → Leopard Seal → Orca
- Seagrass → Sea Turtle → Tiger Shark
- Grass → Rabbit → Bobcat → Cougar
- Phytoplankton → Krill → Squid → Penguin → Leopard Seal → Orca
- Seaweed → Small Fish → Sea Lion → Orca
- Grass → Buffalo → Lion → Hyena
- Algae → Zooplankton → Salmon → Bear → Bald Eagle
- Algae → Shrimp → Tuna → Sea Lion → Killer Whale
- Grass → Antelope → Cheetah
- Phytoplankton → Zooplankton → Small Fish → Dolphin → Shark
- Seagrass → Dugong → Tiger Shark
- Grass → Hare → Lynx → Wolf
- Algae → Zooplankton → Herring → Seal → Orca
- Plants → Grasshopper → Frog → Snake → Hawk
- Phytoplankton → Krill → Squid → Fur Seal → Orca
- Seaweed → Small Fish → Penguin → Leopard Seal → Orca
- Grass → Elephant → Lion → Hyena
- Algae → Zooplankton → Trout → Heron → Bald Eagle
- Algae → Shrimp → Mackerel → Dolphin → Shark
- Plants → Deer → Bobcat → Cougar
- Phytoplankton → Zooplankton → Small Fish → Shark
- Seagrass → Green Sea Turtle → Tiger Shark
- Grass → Rabbit → Lynx → Wolf
Food Chain Diagram
Trophic Levels
Trophic level refers to the sequential stages in a food chain, starting with producers at the bottom, followed by primary, secondary, and tertiary consumers. Every level in a food chain is known as a trophic level.
The trophic level of an organism is the number of steps it is from the start of the chain. A food web starts at trophic level 1 with primary producers such as plants, can move to herbivores at level 2, carnivores at level 3 or higher, and typically finish with apex predators at level 4 or 5.
The path along the chain can form either a one-way flow or a food “web”. Ecological communities with higher biodiversity form more complex trophic paths.
The word trophic derives from the Greek τροφή (trophē) referring to food or nourishment.
The concept of trophic level was developed by Raymond Lindeman (1942), based on the terminology of August Thienemann (1926): “producers”, “consumers”, and “reducers” (modified to “decomposers” by Lindeman).
The three basic ways in which organisms get food are as producers, consumers, and decomposers.
- Producers (autotrophs) are typically plants or algae. Plants and algae do not usually eat other organisms but pull nutrients from the soil or the ocean and manufacture their own food using photosynthesis. For this reason, they are called primary producers. In this way, it is energy from the sun that usually powers the base of the food chain. An exception occurs in deep-sea hydrothermal ecosystems, where there is no sunlight. Here primary producers manufacture food through a process called chemosynthesis.
- Consumers (heterotrophs) are species that cannot manufacture their own food and need to consume other organisms. Animals that eat primary producers (like plants) are called herbivores. Animals that eat other animals are called carnivores, and animals that eat both plants and other animals are called omnivores.
- Decomposers (detritivores) break down dead plant and animal material and wastes and release it again as energy and nutrients into the ecosystem for recycling. Decomposers, such as bacteria and fungi (mushrooms), feed on waste and dead matter, converting it into inorganic chemicals that can be recycled as mineral nutrients for plants to use again. Thus, starting a whole new food chain.
Food Web
All of the interconnected and overlapping food chains in an ecosystem make up a food web. A food web is similar to a food chain, but the food web is comparatively larger than a food chain.
Occasionally, a single organism is consumed by many predators, or it consumes several other organisms. Due to this, many trophic levels get interconnected. The food chain fails to showcase the flow of energy in the right way.
But the food web can show the proper representation of energy flow, as it displays the interactions between different organisms.
When there are more cross-interactions between different food chains, the food web gets more complex. This complexity in a food web leads to a more sustainable ecosystem.