Ecosystems and Habitats

About this topic

An ecosystem is a community of living organisms (biotic factors) interacting with each other and with their non-living environment (abiotic factors such as light, temperature, water and soil). A habitat is the particular place where an organism lives. Ecosystems range from a puddle or a rotting log to a whole forest or ocean, and they matter because every living thing depends on the others and on the physical conditions around it.

Within an ecosystem, energy flows in one direction, from the Sun through producers to consumers, while materials such as carbon and nitrogen are recycled. Organisms are grouped into levels: an individual, a population of one species, a community of all the populations, and finally the ecosystem itself. Changing one factor, such as drought, can ripple through the whole system.

Consider a pond. Algae and water plants are producers, tadpoles and snails graze on them, dragonfly larvae and fish eat the grazers, and bacteria break down dead matter. Temperature, oxygen level and pH are abiotic factors that decide which species can live there. Understanding ecosystems helps people manage fisheries, protect wildlife and plan farmland.

A common mistake is mixing up habitat and ecosystem: a habitat is where a species lives, while an ecosystem includes all the organisms and the physical environment together. Remember also that abiotic factors are non-living but still shape life.