Scientists Find Missing Link in Bird Evolution

BlueCup writes "Dozens of fossils of an ancient loon-like creature that some say is the missing link in bird evolution have been discovered in northwest China. The remains of 40 of the nearly modern amphibious birds, so well-preserved that some even have their feathers, were found in Gansu province, researchers report in Friday's issue of the journal Science. Previously only a single leg of the creature, known as Gansus yumenensis, had been found."

Comments

Re:Doubious Dating Techniques

[NosTROLLdamus]

Though the method of dating the fossil was not stated in the article, carbon dating can be used up to, like, 60,000 years, which is well beyond the creation of the earth according to biblical timelines, but still, loses some usefullness depending on the age of the specimen. Carbon-14 has a HALF-LIFE of 5730 years. HALF-LIFE. You know how that works don't you?

Often proponents of creationism and intelligent design tend to choose the dating technique that fits the picture they have in their minds. For example, the poster above me stated a single, unrefined example of a dating technique being off in order to set a mindset that this technique is unreliable, and, unjustifiably, useless in all situations. He or she also states the half life of carbon-14, and a continued presence of it in fossils to understate the possible age of the fossil, conviently fitting into creationary mold set by the bible. How old is the world again? 6,000 years?

Re:Doubious Dating Techniques

[Smidge204]

Carbon dating is only reliable to ~60k years because it is a naturally occuring isotope. It can be found anywhere at any time. However, living things tend to have higher levels of radioative C-14 than non living things, because of hte way carbon is recycled through living organisms.

After ~60k years, the level of C-14 in a sample can not be reliably seperated from the "background noise" of the C-14 that might just happen to be lingering around.

Potassium-argon dating can not be used on once-living things because radioactive Potassium-40 decays into Argon, a gas, which tends to escape into the environment -- unless it's in solid rock. Thus is is useful for dating lava flows. Also, the half-life of radioactive Potassium-40 is very long, about 1.3 million years (compare to C-14 at a mere 5730 years). Therefore K-Ar dating is only useful for dating "really old non-organic things" like... ancient lava flows.

It's simply a matter of using the right tool for the job.
=Smidge=

Re:FSM Strikes Again!

[yankpop]

So, they took the evidence and looked at it through the lense of their pre-determined conclusions got the answer they wanted to find? I seem to remember a lecture in a science 101 class that included strong, almost vehement admonition to never ever do exactly what they just did.

I'm just an evolutionary biologist, so you'll have to take this with a grain of salt, but that's bullshit. What they did was note that most species of birds near that occur near the base of the evolutionary tree are aquatic. That's it: they described a pattern. I suppose you could be right, maybe they have some vested interest in early birds being aquatic. I can't imagine what possible motivation you might have for fabricating such an esoteric claim, but you're the one who (anonymously) claims to know so much more than us biologists.

Of course, you could very easily and objectively test this yourself. Look up the latest evolutionary tree for birds, figure out which ones the ecology is known for, and label your tree accordingly. Then look at the tree, and see if the species near the base of the tree are mostly aquatic. If they are, then the guys in the article are ok. I don't think this is pressing enough that I'm going to rush out and do it myself. But you can be sure that there are more than enough fanatical ornithologists in the world to check these things out.

If you really can't find an "evolutionist" who knows more about the subject than you do, you are looking in the wrong places.

yp.

Re:Doubious Dating Techniques

[jc42]

I am not a fundie but there has to be a reliable way to date something. Otherwise scientists would not claim things like the age of the ducks in the article or any scientific paper.

Uh, no; there doesn't have to be a reliable way to date something. There are a great many ways of dating old things. Usually, scientists consider a date determined by a single method to be preliminary and requiring verification. The verification usually happens by using several different methods. If they all come up with a similar date, that is considered good support for the date.

Most of the methods used by paleontlogists are based on various sorts of decay processes, mostly the decay of radioactive isotopes. Taken singly, each of these has ways that that the samples can be contaminated, giving a bad date. But different chemical elements or compounds have different kinds of contamination that produce different kinds of dating errors. If you use N different dating methods, it's unlikely that all would be contaminated in such a way as to produce the same error. So if all N (or N-1) give the same date, that implies that there's little or no contamination, and the date is reliable.

The first scientific papers dealing with a new discovery often have tentative dates due to the use of a single dating method. But with new fossil beds, once good fossils have been excavated, it's routine to apply several different dating methods to pin down the fossils' ages more precisely.

This whole topic is a serious scientific field in it own right. Explaining how it all works would take several years of intensive study.