Evolution \ Darwinism and the gaps in the fossil record

[Will__]

I thoroughly believe in Darwinsim and evolution. However, having recently been made more aware of continuing problems that people have with it (other than herd-like tendencies to gather in churches and make "oh he�s wonderful" noises) I thought I would ask about them in here.

(An aside - is it just me or is the AB search engine more than usually god-awful - nothing found for Darwinism? I somehow doubt it.....just noticed....no pun intended.....)

The gap in the fossil record - how is this explained by fervent Darwinists? Is it explained? Should I worry about this? Do we think it realistically damages Darwinism as the main non-religious answer to our current existence?

Just for the record - what I refer to as the gap in the fossil record goes something like this:

If we accept Darwinism as the basis for all life as it exists on earth in its current state, then we would argue, for example, that the giraffe has not always been so - there must have been, according to Darwinism, at one time, a giraffe with a much shorter neck. So why has no evidence of such an animal ever been found? Religious types claim this refutes Darwinism and therefore they don�t need to worry about it.

Is there an generally accepted answer to this question? Or even any answer at all? Darwin himself was very worried by it, and speculated that there simply hadn�t been sufficient evidence collected either way. Yet 100 years later we still don�t have that evidence....

Thanks

[trilobite]

There are actually huge gaps in the fossil record. Out of all the species that have ever existed, only a few examples get to be preserved. And by far the majority of these are marine species, land animals are comparatively rare.

Obviously the opportunities for preservation of a land based animal are few and far between compared with an aquatic animal that could be buried by marine sands, lacustrine sediments etc.

Imagine a modern day mammal, say, a wildebeest. The likelihood of an entire carcass being preserved is extremely unlikely. More likely is it being eaten by carrion eaters, insects, maaggots and the bones crushed by hyaena.

So it is a case of interpreting the evidence we do have. The 'short necked giraffe' argument and it's absence is oft quoted by creationists as somehow proof that evolutionary theory is wrong. (Though how the lack of something constitutes proof i don't know.) Also, creationists seem to concentrate on the 'important' animals, such as the higher mammals, usually those with a modern counterpart, whilst conveniently forgetting about the 'less important' animals such as molluscs.(Though I thought they told us all animals were equal in god's eyes?) Conveniently forgotten, perhaps, because the molluscs from the Palaeozoic era show a remarkable completeness within the stratigraphic column, showing a definite evolutionary path.

These 'missing links' are there, but for the less 'glamorous' species - the 'not-quite-an-oyster' rather than the 'not-quite-an-elephant'.

[drbsparks]

I dont answer this from any religious stand point just my own feelings. I have struggled for years to come to terms with Darwin's Theory and as far as I can compehend, it is as it says on the tin, a theory and will remain such until concrete proof is found.

[NetSquirrel]

I think this "problem" can be fairly easily explained.  (Don't shoot me if I'm wrong though - I'm not basing my assumptions on any new scientific evidence or knowledge.)

The first important fact to consider is that only a tiny, tiny percentage of the total number of fossilised skeletons of a species are ever found and dug up by humans.  For example, billions of tyrannosauruses must have lived and died in the distant past.  Only a tiny fraction of the total-tyrannosauruses-that-ever-lived would be alive at any given point in time, but this doesn't matter because the total number is massive.  I.e. tyrannosauruses were successful and survived for millions of generations.  It stands to reason that, unlikely as it is that any individual tyrannosaurus skeleton will become fossilised, through chance many will fossilise and therefore the total number of fossilised tyrannosauruses in existence in the Earth's crust is also large.  This makes it relatively likely that a fossilised skeleton of this species will be dug up, found, and become known to science.

Now consider the �intermediate� organisms � such as the elusive short-necked giraffe � that fill the evolutionary gaps between successful species such as tyrannosauruses, crocodiles, sparrows etc.  They are still in the process of becoming adapted to their environment through evolution � and so are a rapidly-changing species.

 

[Continued]

[NetSquirrel]

[...]

 

This kind of full-speed evolution might be caused by something like a sudden change in climate or environment.  When this happens, most of the organisms of the species (that was adapted to the old conditions) will probably die, leaving behind just those individuals with genes that happen to favour the new environment (e.g. climate gets colder, thick-furred badgers survive while not-so-furry ones die; from then on all badgers are thick-furred).  But even then, the fur of the thick-furred badger could do with being thicker still, if the badger is going to be able to stay out in the cold for long periods to find food etc.  So obviously over time you get a gradual thickening of the fur up to a point where any badger born with fur slightly longer or shorter than normal is going to be at a disadvantage compared to its siblings, because the best fur length has been reached to match the badger's environment.  Once this point has been reached, the badger population could conceivably be maintained for many millions of years without significant genetic change, yielding many similar badger-skeleton fossils.  You can see that any archaeologists (or whatever) digging for fossils would find the following:

A whole load of thin-fur badger fossils...(Gap)...A whole load of thick-fur badger fossils.  Where are the ones in between?  (�Oh no � there is a mistake with Darwin's theory!� etc. etc.)  The fossils of the intermediate species (the ones that would, if found, prove evolution to be true) are in fact there, in the ground.  But there will be extremely few of them compared to the successful, stable, species (plural) that they bridged the gap between.  Therefore, the chances of digging up the fossil of a �gap� species are small.  It may have happened, but many more will need to be found for the evidence to be irrefutable.

[Will__]

Well, that more or less confirms what I'd already concluded myself. Thanks to all posters.

Absence of evidence is not evidence of absence.

(The only problem with that little gem is it also sort of legitimises the quest for a god.....hmm.....another thread perhaps?)

[NetSquirrel]

I know there's no point me posting it now, but I know I speak unclearly and I'm damned if I'm going to spend 45 minutes struggling through Paint Shop Pro's "ingenius" drawing system foir nothing!

 

http://images.dpchallenge.com/images_portfolio/16982/med ium/122801.jpg

[newtron]

Nice job at describing what I believe is called "punctuated equilibrium" NetSquirrel.  Evolution by itself is obviously a very attractive theory with much supporting evidence.  One of the things that I like most about the theory is how evolution fits so nicely into the bigger picture.  So what is the driving force of evolution?  How do certain species become isolated?  Why do environments change?  The answers to these questions can be found in the relatively new theory of plate tectonics.  When these two theories are combined, it becomes clear that the driving force of both living and non-living systems is the cooling of the earth's core.  These theories elegantly demontrate how everthing is interconnected. 

[RichWheeler]

This is a great debate - National Geographic November 2004 chooses to update its readership with the "latest" on Darwin's flagship theory (apparently he had manyothers - some of which were hopeless). The article is wonderful and reallybrings the debate to...life, as it were.  The authors' explanation addresses head-on the issue of proof and describes how Darwin's theory, whilst unproven in laboratory, is supported by "overwhelming evidence". I defy anyone who reads it to suggest that believing in 'God' is more compelling than Darwin's theory.

[Will__]

Of course, the eye is a difficult to ascribe to evolution. Any part of the eye is useless on its own, and therefore no individual part can be said to have evolved on its own (so they say). So it evolved on its own, more and less complete with all its constituent parts. Now I don't use this as an argument for anything by itself, but it's an interesting one, no?

It makes Mama Nature pretty damn impressive in my book, seeing as I don't ascribe to any theory of god.

[inferno]

Will - its not as difficult to ascribe the eye to evolution as you may think. See:

http://www.pbs.org/wgbh/evolution/library/01/1/l_011_01. html

[inferno]

Sorry that link doesn't work when clicked on - type it in instead - you will find it helpful and interesting.

[Korel]

There is also evidence for evolution in the inner ear what eveolved in mamals to be a balance system is shown in fish as their Gills the bones are very very similar and a fish has a completely different system for regulating ballance, there is also several spices of salamander that have these bones which are almost identicle to scale for some purpose that escapes my memory, this suggests that everything eveolved from one thing.

These bones are present in one way or another in most vertibrae.

[Matheous]

Inferno -thanks for the link -a very impressive QT clip explanation!