Talk:Parallel evolution

Why is there a "bee hovering in flight" image on the page? There's no mention of bees in the article. Did they evolve in parallel? --Kaz 22:31, 15 February 2006 (UTC)

It was orphaned when a convergent evolution example (hovering bees vs hovering hummingbirds) was removed. I will remove it. StuRat 05:39, 14 March 2006 (UTC)

Parallel evolution, convergent evolution, and evolutionary relay

I am somewhat disturbed by the way in which these articles attempt to establish these three nonoverlapping categories. To begin with, evolutionary relay is a relatively obscure classification --- for example, a Google search turns up 125 hits, many copied from Wikipedia. By comparison, "convergent evolution" turns up 432,000 hits. I think that it is fair to say that many sources are not attempting to exclude evolutionary relay from what they describe as convergent or parallel evolution.

Secondly, the given distinction "parallel evolution refers to the independent evolution of similar traits in closely related lineages of species, while convergent evolution refers to the appearance of striking similarities among lineages of organisms only very distantly related." doesn't seem altogether consistent with how some people are using these terms. For example, Zhang and Kumar [1] define these terms in the context of amino acid evolution as follows, "Here, a convergent change at an amino acid site refers to changes from different ancestral amino acids to the same descendent amino acid along independent evolutionary lineages... It is distinguished from a parallel change, in which amino acid changes along independent lineages have occurred from the same ancestral amino acid". Thus, T->S and A->S changes are convergent, but A->S in two lineages is parallel. By this definition, convergence or parallelism can occur between the same species at different points in the genome.

There is some history to the convergent vs. parallel definition (see [2]), and I may not have the best sense of the consensus usage, but my understanding was that what matters is whether the two organisms proceed from a similar starting condition for the trait in question, as for the amino acid example, and not whether they are "only distantly related", which seems to me to be a very relative term. According to this sense, similarity between the wing patterns of two butterflies in a mimicry ring may represent the effect of both convergent evolution - the initial process by which the wing patterns of two species, starting from fairly different ancestral patterns, eventually come to resemble one another - followed by parallel evolution, if the pattern shared by both butterflies then continues to change over time. Nonetheless, this definition has a similar problem to the last - one must decide whether the ancestors of the species in question have become "different" from one another before converging again.

The Wikipedia entry on "evolutionary relay" suggests another criterion - parallel evolution must involve organisms evolving "at the same time in the same ecospace" This conflicts with examples given here, and seems in my opinion to be exceptionally harsh, since it would exclude cases like the repeated evolution of direct development in sea urchins or the development of flightlessness in certain island birds, at least unless a very generous definition of 'same' is used...

In any case, we could surely use a cogent explanation here! Mike Serfas 04:28, 30 April 2006 (UTC)

I agree. I wanted to add some examples but had no way to know which of these three cases they were, so just guessed. I would think even a scientist would have difficulty determining if things evolved from "similar" or "different" starting points, and at the same time, or not. I would prefer a single article, under "parallel evolution", which includes the other two terms. Those articles could then be redirects here. To me, it's like having one article on cars which includes mentions of front-wheel drive, rear-wheel drive, and all-wheel drive, versus having different articles on front-wheel drive cars, rear-wheel drive cars, and all-wheel drive cars. The different articles would be excessive. StuRat 12:46, 30 April 2006 (UTC)