Ecology and environment:

Today, we hear people from different walks of  life, using the terms ecology and environment. Politicians,  leaders. town planners, students and architects  speak of 'environmental  issues' and  'ecological concerns'.  Of  course, these phrases are very common, but are they really understood by the speaker  and the listener alike? Often these are interpreted  in many different ways. So we need to establish some common understanding of these terms. Ecology is a branch of biology which deals with the relationships betweeii organisms  and their 'environment'. Everything  that affects  an organism from outside, during its life, is  collectively known as its Environment.  

These environmental influences can be divided into two categories. The living things  that affect an organism are called biotic factors, and those that are not alive are called abiotic factors. Let us understand this with the help of an example. Consider a fish  in a stream, we can identify many different environmental factors that are important in  its life. The temperature of the water is an important abiotic factor but, it may be influenced by  the presence of trees, a biotic factor, along the bank of  the stream that shade the stream and prevent the sun from heating  it. The kind and number of organisms that serve as food for the fish, are important biotic  faitors as well.

The type of materials that make the bottom of the  stream, and the amout'of oxygen dissolved  in the water are two other abiotic factors, which are related  to the. speed of flow of water. In brief, the environment of an organism  is complex, and its various factors are interrelated.