"Evolution should not be equated with progress". Why?

Explanation

Evolution is simply the generation of diversity and the shaping of the diversity by environmental selection. Species adapt to the conditions available in their environment. Some older and simple species live on quite effectively. The only progressive trend in evolution seems to be that of more and more complex body designs have emerged over time.
In fact, one of the simplest life forms like bacteria - inhabit the most inhospitable habitats like hot springs, deep-sea thermal vents and the ice in Antarctica.