Butterfly unlocks evolution secret

[Dover]

Butterfly unlocks evolution secret
By Julianna Kettlewell
BBC News science reporter

Why one species branches into two is a question that has haunted evolutionary biologists since Darwin.

Given our planet's rich biodiversity, "speciation" clearly happens regularly, but scientists cannot quite pinpoint the driving forces behind it.

Now, researchers studying a family of butterflies think they have witnessed a subtle process, which could be forcing a wedge between newly formed species.

The team, from Harvard University, US, discovered that closely related species living in the same geographical space displayed unusually distinct wing markings.

These wing colours apparently evolved as a sort of "team strip", allowing butterflies to easily identify the species of a potential mate. This process, called "reinforcement", prevents closely related species from interbreeding thus driving them further apart genetically and promoting speciation...cont'd

http://news.bbc.co.uk/1/hi/sci/tech/4708459.stm

[beam me up scottie]

1. Dupe

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=228x8879

[Desertrose]

2. This is pretty impressive....

Scientists are excited about this new research



"This pattern would therefore support the interpretation that it was brought about by reinforcement, hence natural selection."

snip

Although many of the Agrodiaetus species are close enough genetically to breed, their hybrid offspring tend to be rather weedy and less likely to thrive.

Therefore natural selection will favour ways of distinguishing the species, which is why the clear markings exist.

"For me, this is a big discovery just because the system is very beautiful," said Dr Kandul. "As much as we can we are showing that is the most likely mechanism."

[On the Road]

3. Thanks, Dover

I've always had difficulty understanding the speed at which evolution progresses -- differential survival rates seem too slow a mechanism. I've come to understand that mate selection is a key accelerating factor.

[Dover]

4. So how does this apply in human evolution?

What would the "team strip" be that guides the reinforcement?

[On the Road]

5. I Hadn't Thought About Humans

It may not even be a physical thing. Cohesive tribes would certainly have that effect. In that, any species that organizes in tribes, troops, or colonies that remain separate from other groups would diverge more rapidly.

[phantom power]

6. there are multiple mechanisms that drive speciation

Many of them we probably don't know yet. There is circumstantial genetic evidence that retrovirus infections may have influenced primate evolution, including humans.

Gene-hopping between plants appears to be common, which is throwing a monkey wrench into the use of genetically engineered crops.

Bacteria and viruses regularly swap genes, to the extent that the entire concept of "species" at this level is questionable, maybe even misleading.

So, even if human speciation isn't driven by the "team-strip" effect, there are probably lots of other mechanisms.