Thread: is there any negative evolution?

ie humans converted back into single cell organism.

That wouldn't be negative evolution, it would just be evolution (although pretty implausible). Evolution doesn't have direction, it just happens.

Originally Posted by Strange

That wouldn't be negative evolution, it would just be evolution (although pretty implausible). Evolution doesn't have direction, it just happens.

ok, without direction, can humans be converted back to bactaria, virus etc?

Firstly, we didn't evolve from bacteria or viruses. Any common ancestor with bacteria is going back a really long way.

But apart from that ...

There are many instances where evolution has "reversed"; i.e. where organisms have lost features that their ancestors had. Whales can no longer walk on land. Many species of cave dwelling animals have not just lost their sight but their eyes. As far as a multicellular organism evolving to single-celled; I am not aware of any cases of this happening but that doesn't mean it couldn't.

Evolution to a simpler form is quite common, but is not 'negative' evolution. It is just evolution in a different direction, and it does not reverse earlier evolution. It is evolution down a new road.

It is very common among organisms that evolve to be parasites. Viruses, for example, are possibly a parasitic bacterium that evolved simplicity, since it better suited the parasitic way of life. Many parasites lose functions suited to mobility, since as a parasite they no longer need to move. etc.

Originally Posted by skeptic

Evolution to a simpler form is quite common, but is not 'negative' evolution. It is just evolution in a different direction, and it does not reverse earlier evolution. It is evolution down a new road.

It is very common among organisms that evolve to be parasites. Viruses, for example, are possibly a parasitic bacterium that evolved simplicity, since it better suited the parasitic way of life. Many parasites lose functions suited to mobility, since as a parasite they no longer need to move. etc.

Aaah, Prince is too slow, but you guys have said it better than he could have anyway. Troglomorphism, wherein creatures are adapting to darkness, is most interesting. In dark of ocean abyss, some creatures develop huge eyes and/or bioluminescence. In caves, total loss of vision is opposite responses to similar environment, so, why one and not the other?

Returning to parasites, homosexuality has been observed in liver flukes, what evolutionary advantage this provides remains obscure.

Precious has talent for asking provocative questions, well done.

Overwhelming unlikely.