Ancient Skull Challenges Human Origins

[unworthyone]

http://www.cnn.com/2002/TECH/science/07/10/ancient.skull/index.html

Its probably too early to tell but it looks like it it may be time for more timeline changes.

 

[Chris†opher Paul]

"Scientists describe Toumai as having characteristics of both apes and humans. Detailed study of the fossil shows a braincase that is ape-like, while the face is short, and the teeth look like those of a human. Toumai is so unlike fossils that currently exist, that it is being assigned a new genus and a new species. "

Interesting...transitional?

 

[unworthyone]

Or maybe just an animal that is extinct?

Heheh. I don't know but I do find it interesting.

 

[Morat]

If so, it's an important one. There are a wealth of hominid transitionals over the last 5 million years or so, but then there's a fairly large gap before you start getting decent sequences again.

It'd be nice to see some the gap between the earliest hominids and our last ancestors with the primates filled.

 

[seebs]

This is the kind of thing that is generally taken as support for the theory that humans and apes are members of the same "family tree".

Might the timeline change? Sure. But all that does is strengthen the theory that there *IS* a timeline.

If I have a bus schedule, and I find out that it's wrong because there's a stop I didn't know about, and I have witnesses of the bus stopping there, my schedule may not be correct - but I have just gotten support for my belief that there's a bus.

 

[unworthyone]

LOL. Thanks Seebs. Remember now I don't advocate creation or evolution. I just like to read about it.

 

[Morat]

Yep. This might cause them to shove back the split from the primate line a million years or so. Might not. It's quite close to the primate split, so it represents a "Lucy" level find.

 

[Chris†opher Paul]

Interesting.

 

[unworthyone]

Does any of this contradict the dating which was done on the skulls already dated?

Which method is used to date these skulls?

 

[Morat]

No. Hominid skulls were dated by different methods, depending on the sort of strata they were laying in. Or between.

You don't date fossils directly, but the rock they're laying in. Or between.

The timeline changes have to do with the split from the primate line, and wouldn't change any of the dates already measured. How could they?

A skull is X years old, with a certain error bar (depending on the sample and method). Finding another skull doesn't change the date.

All it can do is point to a rearrangement in a tree. No dates could possibly be changed.

 

[unworthyone]

So this new one was found in a layer lower then the other ones?

Maybe I don't understand "strata" very well.

Isn't it layers going down?

 

[Jerry Smith]

Generally (except in cases where the strata have been disturbed), the younger strata are closer to the top. This fossil was found in "lower" (meaning older) strata than other hominid fossils are found in...

 

[Morat]

Strata are rock layers. For the most part (there are things like overthrusting) the further "down" the rock is, the older it is.

However, you have to look at local geologic context. The topmost rock in Area A might be a billion years old, because the area has been heavily weathered for millions of years. Whereas the topmost rock in Area B might be only tens of thousands of years old.

Superposition merely claims that, in the absense of overthrusting, the rock on top is younger than the rock it's covering. But it says nothing about how old or young that topmost layer is.

This skull would probably have been field-dated by index fossil (assigned a quick geologic epoch), but to get a fine-grained age (with decent error bars) the paleontologists would have (if possible) dated the rock layer is was embedded in. Or, failing that, dated a layer below and above it to establish boundaries.

 

[unworthyone]

So is the earth slowly becoming more hollow?

If I fill a cup half-full of sand and I want the sand level to rise without adding anything to the content of the cup how will the sand rise?

What are some major reasons that a strata layer gets another new layer put on top of it?

I can think of a few: meteorites, volcanos, floods.

Am I on the right track?

 

[Jerry Smith]

There are oodles of rock building processes, and at least one process (subduction) that recycles the rock of the earth's crust back into the mantle. Most of the rock building processes are well enough understood, and most rock is built "on top" of existing rock. That is why the strata are older as you go "down" through the crust of the earth... The reason the "top" layer varies in age is because of varying trends in deposition and erosion of rock.. area A may have been greatly eroded, and area B may have been built up by sediments eroded from elsewhere during that same time. Geology is a science unto itself, and I only know about the "high" spots of it.. Looks like Morat may have more answers in that field than I. Keep asking questions though... if we can't answer, we will try to point you to someone who can!

 

[Jerry Smith]

I can think of a few: meteorites, volcanos, floods.

Am I on the right track?

another is organic sedimentation: Chalk deposits are formed from the fossilized remains of gazillions of microscopic sea-critters (I will look up the name of them so I can tell you more)...

& yes, you are on the right track

 

[unworthyone]

So the "height" of the planet is not really getting more elevated, but its merely recycling the layers at the bottom and placing it back on top.

Hmmm...

But how do you know the strata is older/younger?

Geology is confusing.

 

[unworthyone]

How deep is the strata where things such as dinosaurs are found? I've heard its not deep and a lot of geological pictures are of men digging on the side of a hill out in bright day light???

Tell me if I'm wrong or whatever....

 

[Jerry Smith]

Originally posted by unworthyone
So the "height" of the planet is not really getting more elevated, but its merely recycling the layers at the bottom and placing it back on top.

More or less.. I hate to oversimplify, but I hate to try to get into the details when I am somewhat fuzzy on them myself. The elevation of a mountain depends on whether it is still forming or not. When two plates collide, they push mountains up from the previously level crust... when the energy of the collision is eventually dissipated, and there is no more force pushing mountains up, they begin to erode...

Sea level varies depending on climate as well...

When two plates collide, one of them may run underneath the other and be pushed back into the mantle, where it is melted and forms more magma..

Hmmm...

But how do you know the strata is older/younger?

All of the processes we know of that produce stratified rock proceed by depositing a new layer of rock on top of the existing rock (think volcanic eruption). If each new layer is deposited on top of an older layer, then generally, the youngest layers have to be on top, unless a layer underneath is pushed up through it. When that happens, it leaves evidence that geologists recognize.

Radiometric dating help by confirming stratigraphic dating methods (and vice versa)...

 

[Morat]

How do we know? Well, we know relatively: In the layers under our feet, the stuff on top is younger than the stuff on bottom. (Excluding overthrusts, which are obvious).

After all, we couldn't put Layer A ontop of Layer B if Layer B wasn't there in the first place.

So relative ages are pretty simple. (There are, as I noted, mechanisms that can thrust older layers onto of younger ones. But, as I noted, they're really obvious. *really* obvious).

Geologists have long noted (pre-Darwin) that certain fossils are only found in certain layers. Over time, it became a method to quickly identify any given layer. If Fossil X is found only in Layer Y, and you've got a layer with Fossil X, you know what layer it is.

Quite laboriously, geologists built the "geologic column". That is, the history of layering from the beginning up (and I do mean from the part where "it's not all lava anymore"). Layers are named, and sequenced, and it's known what time-frame they were deposited.

All of this was (and still is) constantly checked anytime anyone uses radiometric dating. Radiometric dating is independent of layering, so the fact that multiple independent dating methods all agree with the ages derived from the geologic column is pretty potent evidence.

Now, mind you, radiometric dating isn't without error. Half the papers published on it are about samples that can't be dated, or discussing how a sample was contaiminated, and how to adjust for it. How to recognize it in the field. How to notice it in the lab.

But, it's pretty well known what's reliable when. And, best of all, the methods reach agreement with each other. Which says a lot, as if it were random dates, or skewed dates from the sample, or any of the stuff Creationists like to claim, dating methods would rarely, if ever, agree.

You'll find, if you bother to trace them down, that the Creationist claims of "bad dates" are always examples of samples being dated by methods that cannot be used on them for one reason or another, outright falsehoods, or selective quotes from articles about why a given sample gave a bad date.

Hovind, I believe, is very found of discussing a mollusc that was C-14 dated (Carbon dating is a little different than radiometric dating, as it needs to be calibrated) at an obscenely wrong age. He didn't bother to mention that no one would date molluscs that way because they don't get their carbon from respiration.