|The Open Door Web Site|
The Ecosystem : An Inter-acting Community
Where does the energy come from in an ecosystem?
Every ecosystem is home to a community of plants and animals. All of the organisms in an ecosystem are continually inter-acting with each other, as well as with their non-living environment, such as the atmosphere. The study of these inter-actions is called ecology and scientists who study them are called ecologists.
An ecosystem depends upon a supply of energy. All living things need energy for growth, movement and other essential activities. The energy needed by living things comes from the sun. Every ecosystem depends on green plants to trap the energy in sunlight and change it into chemical energy. The process by which green plants convert the sun's energy is called photosynthesis. Green plants also take minerals, such as nitrates and phosphates, into their bodies through their roots. These minerals are needed for the healthy growth of the plants.
In an ecosystem the green plants are called the producers because they are able to make sugars, which contain chemical energy, using the energy from the sunlight.
The role of the herbivores in the ecosystem
Some of the animals in an ecosystem gain their energy by feeding on the producers. These animals are the herbivores. Some herbivores eat the green leaves of plants and others eat the fruits and seeds. A few herbivores, such as the elephant and the termite, eat the woody parts of trees and shrubs. Ecologists call the herbivores the primary consumers because they gain their energy directly by eating the plants which have trapped and converted the sun's energy.
The role of the carnivores in the ecosystem
The primary consumers are the food of the secondary consumers. These carnivores are predators which are adapted to catch and kill their prey. The secondary consumers feed on the bodies of the primary consumers. In this way energy is transferred from the primary to the secondary consumer.