Category Environment

Animals and plants which live on the bottom of the sea or lake are called benthos. 

Very small plants and animals living in water are called planktons. They are an important source of food for larger water animals.

Parasites are those animals or plants which live on the living plants and in the bodies of living animals. Parasites that live inside the host such as liver flukes and tapeworms are called entroparasites; those that live on exterior, such as fleas and lice are called ectoparasites. They are harmful for the host.

The living beings that feed on dead or decayed organic matter are called saprophytes. Most saprophytes are fungi and bacteria which contain no chlorophyll. Many other animals eat dead plants and animal matter. They are useful scavengers and in sewage farms and refuse dumps break down organic matter into nutrients and easily assimilable by green plants. 

When food chains are interconnected in an ecosystem they are called food webs. Sometimes one type of plant or animal is eaten by more than one kind of animal. In this way, two or more than two food chains get interconnected and form a food web. The more complex food web shows a greater variety of relationships. 

 In ecology, a sequence showing feeding relationship between organisms in particular ecosystem is known as food chain. Each organism depends on the next lowest member of the chain for its food. For example, grass is eaten by a deer and deer is eaten by a lion. Other examples of food chains are algae-duck-otter and flower-butterfly-lizard-snake-peacock.