​Environment in Brief

Environment is defined as the surroundings or conditions in which an organism lives or operates. It encompasses two components- biotic and abiotic.

• However, the present state of environment which makes planet Earth the only place to sustain life is the culmination of sequence of steps involved in origin and evolution of Earth.

Changes in Environment and Biological Evolution

• Early Earth: The conditions on early Earth were inhospitable for life. There was no atmosphere. Water vapor, methane, carbon dioxide and ammonia released from molten mass covered the surface. There was abundant water vapor in the atmosphere but there was no free oxygen. ....