reverse-evolution

[JOY]

can we reverse the evolutionary changes even in lab-model base,i.e.complex organism to simpler ones?

[druid]

Bring an example of your hypothetical reversion.

[canalon]

Shortly, no.

You can lose feature, but usually what appears "reverse evolution" is merely the evolution going on. And the now useless feature lost will have left some trace at a level or another in the organism.

[AstusAleator]

and even if you are able to get an organism to the exact morphology and genotype its ancestor had, this is still not a "reversal" because evolution is not directional any more than time itself is directional. Just because I can stand at point a, then move to point b, and then back to point a, doesn't mean I've reversed time and gone back to point a.

[Schröder]

can we reverse the evolutionary changes even in lab-model base,i.e.complex organism to simpler ones?

complex organisms to simpler ones? That is probably possible however it still can be considered as evolution. Remember their is no intrisnic drive towards a more complex species. It all depends on the environment. If an organism's environment changes in such a way that nature must select for certain traits that would be considered "simpler" then you have evolution but the resulting species after several generations would have traits that are less complex than the former.

However I hate using the word "complex" and "simpler" when talking about evolution because those two words are both relative and depends almost strictly on the environment.

[mith]

If you look at the evolution of lactic acid bacteria, you'll see that it's been shedding a lot of it's genes

[sachin]

so do you think it is becoming Simpler and simpler day after day????Hmmmmmm

[AstusAleator]

Aside from the semantic issues anyone might have with the bacteria becoming "simpler":
Much of the genetic material in animal's genomes is "junk" DNA, and shedding it doesn't change a thing. Mith is this the kind of DNA being shed by the bacteria?

[mith]

No actually, it's because LAB grows in a very rich medium(milk and animal guts) so it can discard a lot of it's ancestral genes related to amino acid synthesis or other nutrients and instead incorporate transporters.

[February Beetle]

Echinoderms like sea stars are said to have evolved to be simpler since there adult form is radial (seeming simpler) but their larval form is bilateral (... more complex).

Also if something like marine mammals are thought to have evolved to land, then evolved back into the sea could maybe be seen as backwards evolution. But that is just a phrase where it isn't truly backwards evolution. It isn't even adapted to the ocean in the same way.