Lizards Rapidly Evolve After Introduction To Island

[Guest Nicholas]

Lizards Rapidly Evolve After Introduction to Island, very nice article with shows a nice example of active evolution.

NOTE! This is a nice article please don't turn this into a debate, discussion is encouraged but be nice.

Find the article HERE!

[Guest solius symbiosus]

I was just reading an article by an evolutionary biologist on the evolution of language. In the article he writes "that about 20 percent of genetic changes among species occur when they first split off, whereas the rest happen gradually."

Link to the article:

http://www.sciam.com/article.cfm?id=runnin...alog-new-langua

[Boesse]

Hmm, the observation of 20% of genetic changes occur during speciation more or less supports a mild form of punctuated equilibrium. Steven Jay Gould and Steven Stanley would be excited to hear about this.

For once, some good evidence of PE... I'm not a big fan of PE, and in most cases I believe it is invoked in order to explain patterns that are probably caused by sampling error, time averaging, and the incompleteness of the stratigraphic record.

Bobby

[marnixR]

any type of evolution that you can see happen in real life will register as instantaneous (hence a possible example of punctuated equilibrium) in geological terms, where your time resolution is often in the order of millions of years

if you look at the studies made on the galapagos finches, you'll notice that on a year-to-year basis, quite large changes happen, but that over longer periods these tend to even out since quite often changes of one el nino event are reversed a decade later during a la nina event - it's only when the accumulated changes point in the same direction most of the time that they have a chance of showing up in the geological record

[ashcraft]

I think alot of people mis-interpret puncturated equilibrium. It's not the rapid change to species (that is geologically relative), but rather that a species remains in relative stasis for many, many years. According to Gould's book, there are few actual proven examples of one species slowly changing into another (anagensis). Species will adapt to environmental conditions, but rarely reach new species status under these patterns. Any extreme adaptation would tend to get diluted out by the total volume of the "normal" alleles in the gene pool.

Think of a human, with an IQ of 300, certainly a "good" adaptation. He (or she) has to marry someone, and that someone will more then likely have an IQ nearer the norm of 100. Same with their children, and on down the line, leading to loss of this adaptation due to dilution.

On the other hand, if the individual is in a very small population, maybe gets isolated with a few other individuals, then the gene is much more likely to become dominate, or at least common in the population in general, potentially leading to speciation.

I read too much,

Brent Ashcraft

[Guest solius symbiosus]

Wow! Deleted my post. Perhaps the administrators/moderators could answer my question in a PM. Though, I think the deleted post rather succinctly answered the question.