Problems with the fossil record

[idiotseven]

Scientifically, 1)what can the fossil record tell us, and 2)what difficulties are there in its interpretation?

 

I ask a question that I promise is not loaded. I've just spent an hour with my jaw hanging off my face after reading a load of Creationist propaganda. I can pick holes in all their arguments, except when it comes to the fossil record, which I know nothing about. They state all these problems with the data, and I'm sure they're spinning the facts to suit themselves, but I have no grounds to dispute those claims. That makes me a sad panda.

 

Edit: Also, can anyone suggest some good textbooks where I can learn more about the fossil record? I've had a look through Skelton's Evolution, but it's a tad dated, I feel.

[Daecon]

http://talkorigins.org/indexcc/list.html#CC

 

[CDarwin]

I like to use this example to demonstrate what the fossil record can tell us:

Rip up a piece of paper with writing on it, and then discard 90% of all the fragments, but keep the ones you leave behind in order (in reality geological process mess with the order in the fossil record but that can be spotted).

 

From that, chances are that you could tell that there was a piece of paper and that it did have writing on it which seems to have flowed in some way or another. That's analogous to seeing that evolution has occured. The tricky part will be in reconstructing individual words or sentances, and that's what the entire field of paleontology seeks to do with fossils.

[Mr Skeptic]

Paleontologists occasionally make mistakes (as does anyone). My country, Paraguay, had a type of pig living there that was supposed to have been extinct 50 million years ago, for example. Sometimes very few fragments of a skeleton remain, and it is very difficult to reliably identify them. For example, "Nebraska man" was a single tooth misidentified as a hominid ape. Then the media jumped on it, drew a pretty picture for Joe Public to ogle, called it a missing link (aka, "good headline") and generally did as journalists do best. The tooth turned out to be a peccary (piglike creature) tooth.

[SkepticLance]

It is not easy making a fossil. It requires a very special set of circumstances. Some organisms fossilise easily, since they are large and lumpy to begin with and are found in places where they easily get covered by sediment to preserve them. For this reason, there are billions of fossil oysters in the world.

 

However, a number of organisms live in places where they are unlikely to have their remains preserved. Those living things leave minimal records as fossils. Humans and pre-humans are a good example. Since we and our ancestors lived on land, few skeletons ended up buried in sediment to fossilise. It is remarkable how great a job of work has been done by those studying human and pre-human fossils, bearing in mind how few there are.

 

Creationists like to avoid the fossil record of those organisms that fossilise well, and pick on the record of those that do not. Where fossils are rare, due to the organism living in conditions not conducive to fossilisation, creationist theories are thick on the ground.

[CDarwin]

Paleontologists occasionally make mistakes (as does anyone). My country, Paraguay, had a type of pig living there that was supposed to have been extinct 50 million years ago, for example. Sometimes very few fragments of a skeleton remain, and it is very difficult to reliably identify them. For example, "Nebraska man" was a single tooth misidentified as a hominid ape. Then the media jumped on it, drew a pretty picture for Joe Public to ogle, called it a missing link (aka, "good headline") and generally did as journalists do best. The tooth turned out to be a peccary (piglike creature) tooth.

 

Well, that wasn't just the media. Nebraska Man was a product of the scientific politics of the age and the ego of Henry Fairfield Osborn, but that's a separate discussion.

[chemkid]

True fossils may be rare to form. But keep in mind there are lots and lots of animals to be fossilized. While the shreaded piece of paper example is good, we need a gigantic sheet of paper (to reprsent the gigantic bioshpere which exists) making 10% stil be a good amount of paper. Despite having no record of 90% of life on earth millions of years ago, 10% is still a tremendous amount of data.

 

Chemkid

[CDarwin]

True fossils may be rare to form. But keep in mind there are lots and lots of animals to be fossilized. While the shreaded piece of paper example is good, we need a gigantic sheet of paper (to reprsent the gigantic bioshpere which exists) making 10% stil be a good amount of paper. Despite having no record of 90% of life on earth millions of years ago, 10% is still a tremendous amount of data.

 

Chemkid

 

Right. And that works with the metaphor too, because the more fossil we find the better our understanding of evolution.

[SkepticLance]

Creationists often use the 'God of the Gaps' argument. That says that every gap in scientific knowledge is explained by invoking God. As far as the fossil record is concerned, there are always gaps. In fact, the more the fossils that are discovered, the more the number of gaps.

 

Take the evolution of birds. Once, there were 3 stages known.

Dinosaurs.

A feathered dinosaur ((Archaeopteryx)

Birds

 

That leaves two gaps.

Today, a number of 'missing links' have been discovered. There are now nine 'missing links' known in the fossil record. Scientific American, February 1998 has an excellent article showing these links.

So what happens? The number of gaps increases.

 

If you fill in 20 fossils as no longer missing links, that leaves 21 extra gaps for the creationists to quote. It actualy does not matter how complete the fossil record is; the creationists will always point out gaps.

[Edtharan]

In fact, the more the fossils that are discovered, the more the number of gaps.

Wehn I was at collage (years ago) I got into a conversation with a friend who was a creationist. They were going on about this "Missingl link" thing. They kept saying that there was not "intermediate" fossils proving that dinosaurs evolved into birds. When I brought up the Archaeopteryx as the "missing link", then then said that just made the problem for evolution wors as now they had to produce the missing liks for the two more gaps.

 

If you think aobut it, it is a bit like Zeno's Paradox. The idea behind this is that if you fire an arrow at a tortise, then the arrow must first cover half the distance to the tortise and in that time the tortise has move on a bit, then it must cover half that distance and the tortise move on further, and so on. There is alwayse a "Half" distance the arrow has to cover giving the tortise more time to move and so can never reach the tortise.

 

It is the same problem with the "God fo the Gaps" argument. You will alsways be able to argue that there is a gap in the fossil record that needs to be explained.

 

This kind of argument can not be used to prove one side or the other, which means that anybody using it to prove their side of the debate is really just throwing a red herring (logical fallacy) at you. They are trying to distract you from the actual issue at hand.

[Ophiolite]

The correct way for a creationist to challenge the 'missing links' would be to query exactly how form A had evolved into form B. This is an approach that would have scientific merit and would produce more fumbling on the science side than a simplistic cacophony of cries of "missing ling, missing link", which are easily rejected.

[CDarwin]

The correct way for a creationist to challenge the 'missing links' would be to query exactly how form A had evolved into form B. This is an approach that would have scientific merit and would produce more fumbling on the science side than a simplistic cacophony of cries of "missing ling, missing link", which are easily rejected.

 

Eh, not really. You only have to point out that there's really no such thing as "form A" or "form B," only species of variable populations containing variable individuals.

[chemkid]

wow, the missing link argument is extremely poor. EXISTANCE IS DISCRETE. Even if we had a fossil of every single creature that was ever to exist, one could still say - look there is a gap between the parent and it's child. When did that gene mutate? Look there's a gap between parent and child. We can never have on continuous line of evolution. I doubt we will ever get close. Then again, paleontology is not about making continuous lines of evolution, but taking what we have and putting it together.

 

Chemkid

[Ophiolite]

Eh, not really. You only have to point out that there's really no such thing as "form A" or "form B," only species of variable populations containing variable individuals.

Yes, really. Try telling any Ordovician palaeontologist that there are not distinctive forms of thecal geometry in his key graptolites and he will point you to the nearest exit. Variations of any feature are around a norm and within specific constraints.

[CDarwin]

Yes, really. Try telling any Ordovician palaeontologist that there are not distinctive forms of thecal geometry in his key graptolites and he will point you to the nearest exit. Variations of any feature are around a norm and within specific constraints.

 

Mhm. And specific instances of change from one norm to another are what paleontologists do. If you consider the fossil record in the context of ecology, which tells us that organisms are variable and that the frequencies of variations can change through time, then you really have no problem with change from thecal geometry A to thecal geometry B. I don't see how that would make a terribly powerful Creationist argument.