Evolution in action ?

[dang65]

I read this story yesterday and can't get my head round the "evolution in action" bit. It doesn't actually say anywhere in the article that anyone has ever seen this particular species rolling dung. It might be the other way round - that all dung beetles used to eat millipedes but then decided they preferred dung, except for this one.

It's not as if there's loads of footage of D. valgum rolling dung and then suddenly one of them goes for a millipede. They might have been doing this for tens of thousands of years. I thought there were loads of examples like this... like snakes that live in the water and eat lobsters or whatever.

[EternalOptimist]

I read this story yesterday and can't get my head round the "evolution in action" bit. It doesn't actually say anywhere in the article that anyone has ever seen this particular species rolling dung. It might be the other way round - that all dung beetles used to eat millipedes but then decided they preferred dung, except for this one.

It's not as if there's loads of footage of D. valgum rolling dung and then suddenly one of them goes for a millipede. They might have been doing this for tens of thousands of years. I thought there were loads of examples like this... like snakes that live in the water and eat lobsters or whatever.

You miss the point. The species does roll dung, and their bodies are well suited to it. Some members of the species are slightly different, and it is these differences that make it able to catch and eat the millipedes.

[NotAllThere]

I always wondered if I would live long enough to see a fusion reactor, life on other planets, man on mars.

I also wanted to see a species actually evolve into something different


could this be it ?


http://news.bbc.co.uk/1/hi/sci/tech/7840404.stm

I doubt it. Is it more astonishing than the huge variety of dogs that came from a single wolf species?

When does selective breeding become evolution?

[EternalOptimist]

I doubt it. Is it more astonishing than the huge variety of dogs that came from a single wolf species?

When does selective breeding become evolution?

when the dung beetle moves on from millipedes, to millibands, reads the Daily Mail and rolls his own reefers and says
'Now THATS what I call heavy tulip'


?

or when the accumulated changes make it unrecognisable as a former dung beetle ?

[expat]

I doubt it. Is it more astonishing than the huge variety of dogs that came from a single wolf species?

When does selective breeding become evolution?

When a new species comes into being. That's why this might be important.

[dang65]

You miss the point. The species does roll dung, and their bodies are well suited to it. Some members of the species are slightly different, and it is these differences that make it able to catch and eat the millipedes.

That's not what the BBC article says. It says that this whole species (D. valgum) is different from other dung beetle species:

They found D. valgum fed exclusively on the millipedes, preferring prey which were alive but injured.

[...]

Despite its close relationships with dung feeding species, D. valgum has entirely abandoned its ball-rolling behaviour.

[...]

The beetles were never seen rolling dung balls. Instead, they used their powerful hind legs to drag a killed millipede to a safe site and then begin devouring it.

Dung beetles' heads are usually flat and wide like a shovel in order to roll balls of dung but D. valgum has a narrow, pointy head which it uses to get right inside the millipede's body and feed on its insides.

So, it's basically not a dung beetle, but is a variant on a dung beetle which has evolved a different shaped head and different eating habits, presumably over thousands of years??

No one has actually seen this species rolling dung - they just think they should because they're related to dung beetles. But loads of species are closely related to other species which act very differently. What's the particular big deal about this one? This one hasn't even got the right shape head for rolling dung!

[NotAllThere]

When a new species comes into being. That's why this might be important.

Trouble is, biologists have difficult defining what "species" is.

This is much more interesting than some purported new species.

[EternalOptimist]

That's not what the BBC article says. It says that this whole species (D. valgum) is different from other dung beetle species:


So, it's basically not a dung beetle, but is a variant on a dung beetle which has evolved a different shaped head and different eating habits, presumably over thousands of years??

No one has actually seen this species rolling dung - they just think they should because they're related to dung beetles. But loads of species are closely related to other species which act very differently. What's the particular big deal about this one? This one hasn't even got the right shape head for rolling dung!

Didn't read the BBC article, but according to ScienceNow it is still a dung beetle. The parts of the millipede it eats are the dung parts, i.e. the digestive tract.

'It's a "pretty spectacular finding," says biologist Armin Moczek of Indiana University, Bloomington. But he points out that millipedes have a high proportion of feces inside them because they feed on rotting plants. So if the dung beetles are eating their guts, he speculates, they're essentially still eating dung.'

http://sciencenow.sciencemag.org/cgi...ull/2009/122/1

[dang65]

Didn't read the BBC article, but according to ScienceNow it is still a dung beetle. The parts of the millipede it eats are the dung parts, i.e. the digestive tract.

OK, sure, but the point I'm trying to make is that this particular species has not (as far as I can make out from either of those articles) EVER been observed acting like other dung beetles. This is not a case of a species being observed changing its way of life. It's a type of dung beetle which has a different head shape and feeding habit to other dung beetles, that's all. It might have started eating millipedes 20,000 years ago, or whatever. What makes this different to, say, different bird species which have adapted to open shells of molluscs, or to get nectar from inside flowers, or insects from holes in trees?

Maybe I'm missing something, but this dung beetle thing just seems like a big fuss about nothing.

[EternalOptimist]

OK, sure, but the point I'm trying to make is that this particular species has not (as far as I can make out from either of those articles) EVER been observed acting like other dung beetles. This is not a case of a species being observed changing its way of life. It's a type of dung beetle which has a different head shape and feeding habit to other dung beetles, that's all. It might have started eating millipedes 20,000 years ago, or whatever. What makes this different to, say, different bird species which have adapted to open shells of molluscs, or to get nectar from inside flowers, or insects from holes in trees?

Maybe I'm missing something, but this dung beetle thing just seems like a big fuss about nothing.

ok . so why the fuss?
What excited some people is that this fits nicely with the theory of slight changes building up into a major change. This is set against the other side of the coin which is that major changes occur as a result of a single mutation.
You are right that no one was filming when one of the changes actually happened but the excited people would say, 'hey we were close enough'.

It's like hearing a bang, seeing the strike, then saying 'I didn't actually see the bullet leave the barrel, but I am convinced it did'