Even as biologists and others are now trying to explain there is nothing inherently progressive about the evolutionary process, that it is fittest within a particular and changing environment, it has become almost impossible to separate the idea of progressive march from the word evolution. Evolution is not a progressive, unilineal track. There is no guidance inherent to the process, no in-built directionality. Organisms can become simpler or can become more complex. Sometimes a simpler organism will be better adapted to a changing environment.
the entire article is worth reading… Come to find out, the way we classify evolution, natural selection, and the such may not be the way they should be classified.
And there is another point in that article worth noting… Good luck