There’s been a new discovery of a huge, tyrannosaur-sized dinosaur with feathers!  If true, that’s an exciting discovery, because it means that feathers must have evolved for insulation or some other reason, rather than flight!  I guess we can finally put to rest the old “what-good-is-half-a-wing?” arguement.

Naturally, my local conservative newspaper (the Augusta Chronicle) had to add this sub-title to the their version of the article—“Finding casts doubt on birds’ evolution”, even though any such controversy was barely hinted at in the actual article.  Any time there’s an article about evolution, the editor has to keep in mind all the Creationists who subscribe.  :(.

advocatus - 15 June 2007 09:46 AM

“Finding casts doubt on birds’ evolution”

I don’t see how it could do this anyhow. Nobody thinks that bird feathers evolved exclusively for flight.

Hm… interesting.

Have a link?

logicisrefreshing - 16 June 2007 12:00 AM

Have a link?

‘Fraid not.  Most of my information comes from newspapers and magazines, not on the Web.

Regarding the controversy about bird evolution, the article mentioned that most dinosaur authorities had thought that dinos became smaller as they became more bird-like.  This example of a tyrannosaur-sized specimen which not only had feathers but a beak-like structure on its skull and a bird-like pelvis seemed to indicate otherwise.  As I said, the “controversy” was barely hinted at in the article.

Yes, that’s right.  In evolution, things evolve to meet a specific need.  It has nothing to do with the fact that if a species that can’t fly happens to have a variation that causes it to be covered in feathers, that variation will continue to be passed on to future generations as long as it does not present such a disadvantage to survval as to mean that the organism will not survive to reproductive maturity.  The dinosaur just says “Ooh! I say! It’s rather a trifle nippy.  Could do with some insulation here,” and poof - as if by magic evolution provides.

No No No.  One of the more important principles of evolution is that any adaptation within a species will continue if it doesn’t provide a selective disadvantage.  Those feather’s may or may not have provided a selective advantage to that creature, but as long as it is able to stay alive until it matures sexually and can find a mate, it will pass the adaptation on.  Over many successive generations the accumulation of other adaptations within its lineage may render its decendants unable to reproduce with members of the species that this feathery ancestor originated from.  These decendants will be said to be a different species.

Sorry to sound so sarcastic and condescending, but I must nip this rival Lamark theory of evolution in the bud before it spreads.  Lamark was gracious enough to prove his own theory wrong on his own and that’s where it should have ended.

Still, being covered in feathers is not a trivial change in a species, so I would be surprised if it did not have a cost sufficient to make it a disadvantage unless this were counterbalanced by some positive adaptive value. Yes evolution makes use of available materials and doesn’t design from scratch, but significant morphologic changes seem unlikley to occur as random little quirks with no selective consequences, so it is reasonable to at least presume some adaptive value to such changes unless there is evidence to the contrary.

logicisrefreshing - 16 June 2007 12:00 AM

Hm… interesting.

Have a link?

Here’s a link.  Just summerizing the find.

http://news.bbc.co.uk/2/hi/science/nature/6750005.stm

mckenzievmd - 18 June 2007 06:42 PM

Still, being covered in feathers is not a trivial change in a species, so I would be surprised if it did not have a cost sufficient to make it a disadvantage unless this were counterbalanced by some positive adaptive value. Yes evolution makes use of available materials and doesn’t design from scratch, but significant morphologic changes seem unlikley to occur as random little quirks with no selective consequences, so it is reasonable to at least presume some adaptive value to such changes unless there is evidence to the contrary.

I’d say it’s unreasonable to assume that it had a selective advantage.  Please change it to “We can’t assume anything, but there might have been a selective advantage”.  That way, I will not be tempted into commiting the sin of argumentativeness.

Sorry narwhol can’t make that change. I think it is unproven, but still reasonable, to suspect a selective advantage to so major a physiological change as being covered in feathers. The idea that something so metabolically expensive and complex has no costs, seems unreasonable to me. And if it has costs, it had better have advantages that outweight them or it will be selected against and eventually disappear.

Okay, in a rare moment of self-control, I’ll live with that explanation.  But at least to change it from “We… “to “Everyone except Narwhol can reasonably assume… ...and he doesn’t count.”

Okay, in a rare moment of self-control, I’ll live with that explanation.  But at least to change it from “We… “to “Everyone except Narwhol can reasonably assume… ...and he doesn’t count.”

Fair enough.

narwhol - 18 June 2007 05:10 PM

Yes, that’s right.  In evolution, things evolve to meet a specific need….Sorry to sound so sarcastic and condescending, but I must nip this rival Lamark theory of evolution in the bud before it spreads.  Lamark was gracious enough to prove his own theory wrong on his own and that’s where it should have ended.

I didn’t think I was pushing some kind of Lamarkist notion that the bird was somehow DELIBERATELY trying to evolve better insulation.  But still, thank you for pointing that out.