• Question: could a species ever de-evolve (evolve backwards)?

    Asked by wesaal786 to Ezzy, Sam on 23 Mar 2012.
    • Photo: Sam Vinko

      Sam Vinko answered on 23 Mar 2012:

      Defining a direction in evolution is a tricky thing. Evolution by natural selection tends to select those traits which are advantageous to the species at that specific time/place. So there would not be a de-evolution in the sense that you get species with are increasingly less adapted to their environment!

      What you can get however is that certain traits become obsolete (like eyes in a cavern) so that they eventually disappear – it costs the organism energy to make such things and if they don’t need it to survive it’s a waste. You’ve probably consider eyes a pretty cool evolutionary thing, so this might seem like de-evolution, but it’s not! Its the evolution of a species adapting to a new environment.

      There is a fascinating paper that just came out a week ago on what happend to some flies kept in complete darkness for 1400 generations (57 years!) and what evolutionary changes they underwent:

    • Photo: Elizabeth Pearson

      Elizabeth Pearson answered on 23 Mar 2012:

      I don’t think animals evolve back wards exactly. The track of their evolution might retrace itself, so somehting we evolved away from comes back if its useful again due to a change in environment or something. It’s still progress forward though.