Going Different Directions in the Same Space

| 9 Comments

As many of you know, I’m a graduate student in a zoology department. When I tell kids that, most of them think I’m studying to become a zookeeper. They also usually think that’s something pretty cool. When I explain that I’m really studying to be a scientist who studies how animals change, it usually turns out to be a letdown. For some reason, kids are usually happier thinking that I might get eaten by the lion or stepped on by an elephant.

Anyway, what I actually study is speciation mechanisms. What that means is that I’m trying to look at the DNA of closely related species in order to figure out why they wound up as different species. There are a lot of questions left to answer, and lots of scientists are working in this area.

I’m guessing that right about now at least some of you are thinking something along the lines of, “Hey, wait a minute! Haven’t you guys been telling us that Darwin figured that out way back when?”

Read More (at The Questionable Authority):

9 Comments

I liked that. Especially the closing paragraph. Good point, well made.

Mike:

I read something recently that you seem to be an expert on, and I have some simpleminded questions.

The case concerned a breeding population of birds, that all breed in the same summer location. However, the population splits roughly in half and each half migrates to different wintering grounds.

According to this article, really minute analysis established that during the communal breeding season, each bird picked a new mate, but 80% of the time the new mates wintered in the same location. Somehow, it seems the birds can tell which individuals winter where, and prefer those who share that characteristic.

So my question is, does this represent speciation in progress? How close to 100% differentiation in breeding would be required to reduce the gene flow to the point where differentiation of other characteristics could accelerate? Or does that question even make sense?

Finally, if we assume that these two ‘populations’ are splitting rather than merging, can we estimate how long a full split might require? If they are merging, how long for a full merge? Would merging be faster than splitting? Is merging possible?

What that means is that I’m trying to look at the DNA of closely related species in order to figure out why they wound up as different species. There are a lot of questions left to answer, and lots of scientists are working in this area.

I’m guessing that right about now at least some of you are thinking something along the lines of, “Hey, wait a minute! Haven’t you guys been telling us that Darwin figured that out way back when?”

Considering Darwin didn’t know of the existence of DNA, it would be very surprising if he had figured out the answer to every question about speciation that can now be addressed by analyzing the DNA of closely related species.

I hope that no competent biologist is going around suggesting that Darwin had speciation all figured out. This most he could do is observe that speciation had to happen in some way not fully understood. So if “some” people believe that they’ve been told “Darwin figured that out way back when” I hope their recollection is faulty.

I’m trying not to sound like a pedantic nag. I’m sort of wondering how prevalent is the faulty belief: “Scientists believe that Darwin had speciation all wrapped up.” As a non-biologist, I still cannot imagine that thought ever crossing my mind; Darwin just didn’t have sufficient data available. Is it true that the lay person accepts the creationist false dichotomy that Darwin either had speciation nailed down completely or else speciation must be impossible?

These discoveries should convince all but the most unreasonably skeptical that sympatric speciation almost certainly has happened.

I agree that that’s an interesting finding. I also have trouble understanding why anyone could believe that sympatric speciation is impossible, rather than relatively rare compared to other kinds of speciation. Once a population is split into groups that are less likely to interbreed it seems reasonable that this could be self-reinforcing over generations. You don’t need to have zero interbreeding, just statistically less than you have within populations for the descendants from within the same group to overwhelm those from between two groups. This gives you the equivalent of a physical barrier since the small interbred part of the population is insignificant for statistical purposes. Since I don’t know Mayr’s argument, maybe I’m missing something here.

wow god computer chill out man you crazy.

Paul population genetics models are the main reason that folks have questioned the efficacy of sympatric speciation. turns out that just a little mixing can spoil the batch…

An inappropriate and unproductive comment has been unpublished, as has a response to that comment. I’m hoping to keep this thread from wandering completely over to lala land.

For some reason, kids are usually happier thinking that I might get eaten by the lion or stepped on by an elephant.

What do you mean by “kids…” ;)

Cool article! Thanks.

More facetiously, I think what “kids” might really like to see would be your getting stepped on by the lion and then eaten by the elephant.

Sick kids, perhaps, but if we’re talking cool spectacle here, we might as well go whole hog, er, tusker, er, oliphaunt.

hi i love pandas and nick

About this Entry

This page contains a single entry by Mike Dunford published on February 9, 2006 4:43 AM.

Intelligent Design and String Theory was the previous entry in this blog.

Does ID Get a Pass? is the next entry in this blog.

Find recent content on the main index or look in the archives to find all content.

Categories

Archives

Author Archives

Powered by Movable Type 4.381

Site Meter