Evolution: Horses, speciation and environment (Evolution)

by dhw, Monday, February 13, 2017, 13:24 (2630 days ago) @ David Turell

DAVID: You did not read the article carefully:
"In other words, new traits and new species evolved because environmental changes allowed greater genetic diversification. This contradicts the idea of “adaptive radiation”, which holds that the evolution of new traits allowed species to move into previously unoccupied environments."
'Adaptive radiation' has been a standard part of Neo-Darwinism for years.

According to Wikipedia: “In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches.[1

I can’t see how this means that organisms change first and then find a suitable environment. They diversify when they are confronted by change. However, in certain environments birds with longer beaks may survive better than birds with shorter beaks, so by natural selection the longer beaked version will finish up as the surviving “species” (narrow sense). That’s Darwinian. Nothing to do with a brand new organ preceding a search for a suitable environment in which to use it. Anyway, clearly the latest research proposes environmental change first and adaptation second, in contrast to your fish adaptation first, exploration of dry land second.