Explain the idea of evolution.

Explanation

Evolution creates the diversity and then shapes it by environmental selection.
The only progressive trend in evolution seems to be that more and more complex body designs have emerged over time. However it does not mean that older designs are inefficient. So many of the older and simpler designs still survive. Example : One of the simplest life forms - bacteria inhabit in most adverse habitats like hot springs, deep-sea thermal vents and the ice in Antarctica.
Human beings are not the peak (pinnacle) of evolution, but simply yet another species in the teeming spectrum of evolving life.