Evolution should neither be equated with progress nor with the elimination of older, less efficient species. Continuation of old species depends upon the environment. The new species may or may not be better. Formation of new species depends upon the occurrence of physical or reproductive barriers, genetic drift and natural selection that leads to the formation of new population or species which is unable to interbreed with the original population.
In fact, there is no real ‘progress’ in the idea of evolution. Evolution is ‘simply the generation of diversity and the shaping of the diversity by environmental selection’. The only progressive trend in evolution seems to be that more and more complex body designs have emerged over time. However, again, it is not as if the older designs are inefficient. Many of the older and simpler designs still survive. In fact, one of the simplest life forms – bacteria – in-habitat the most inhospitable habitats like hot springs, deep – sea thermal vents and the ice in Antarctica. In other words, human beings are not the pinnacle of evolution, but simply yet another species in the teeming spectrum of evolving life.
Thus, there is no such thing as ladder of progress but there are branches from the family tree of species.
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