h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Gif, one of the other big extinctions was at the Permian / Triassic boundary (~130mya), where reptiles began to take over from amphibians. There was also a preceding extinction event which put paid to the trilobites. Is it not correct to say that the geological record is divided into phases where completely new species began to appear / dominate? This does not imply a preceding mass extinction, of course.

Montana, from what I know (and I'll be the first to admit that thats not much), there is not much evidence to relate a switching of the magnetic polar axis and die-offs. They are actually quite a regular occurance, geologically speaking - we just had one a "mere" 700,000 years ago! During the last 2 million years, there were multiple axis-switching events, but the dominant influence on animal survival was the Ice Age. Also, there is no correlation between the polarity of the Magnetic North Pole and the earth's axis (i.e. the line around which the planet revolves). They are completely separate, and the earth's axis of movement follows a quite well understood pattern involving minor variations over long periods of time (which incidentally fits well with the ice-age glaciation pattern). The axis of rotation could never do anything as significant as a switch - ever, unless something really, really big hit it, like a large planet.

Woodpigeon. Not to detract from your point, the Permian-Triassic boundary was 250 ma, and reptiles appeared in great numbers at the Carboniferous-Permian boundary, the period before the Triassic. The Permian saw the rise of the archaeosaurs, the predecesors to dinosaurs, including that sail-backed schoolboy favourite, Dimitrodon.

Redhead, although I am in agreement with Woodpigeon about the pole shifting having non-lethal effects, was your original point that shifts in environment don't have to be sudden to lead to increased speciation?

thats what you get from not bothering to look up any references before you post... lets not split hairs over a mere 120 million years

Better get back to my day job...

You raised an interesting period, though. The Permian extinction wiped out all but one species of ammonite - the hundreds of species that aorse afterwards were all descended form that one surviving species. This is often a point overlooked by evolutionists/creationist dusring their fight of adaption.

Ahem. "During their fight *over* adaption".

So to refine my question a little further then:

Do periods during which many new species appear always coincide with periods where many old species disappear? From what has been said above, it would appear so.

btw, does anyone know how much any long-lived species have changed during their lifetime? Is a 65 million year-old croc fossil identical to a modern skeleton?

Gif

Forgive me if I'm wrong, but I had thought that was one of those "commonly known facts" which doesn't necessarilly have a basis in reality, like the idea of lemmings committing mass suicide or humans using 10% of their brains.

Something very much like crocodiles, sharks or opossums may have existed once upon a time, but it's hard to imagine that they wouldn't have changed at all, isn't it? I mean, according to evolutionary theory, land animals and sea animals as we would recognize them emerged 500 mya, yes? And in that time, a huge number of different kinds of species emerged.

So, in all that shifting history, I don't see how it's possible to avoid any changes. But feel free to disagree if you think I'm just blowing smoke.

-Eagle 1

Hi Eagle,

Yes, so that's what I'm asking. Coelacanths are another example - when they were discovered, we were told that they are 'identical' to x-million-year-old fish. So by Darwinian evolution, they should have undergone 65 million years of change, whereas by punctuated evolution they might have changed very little in that time provided that their environment has not changed significantly. I was just wondering how much they had actually changed.

I also asked a little earlier how things like livers (as an example of an internal organ) could have evolved. I was thinking perhaps that the various functions the liver performs might have developed seperately, perhaps being carried out in the bloodstream, and only gradually become assimilated into the more centralised single organ. (I realise that there is probably no evidence to indicate what pathway was actually taken - certainly no fossil evidence - but I wonder what, if any, the competing possibilities are.) It's such a complex organ that I have difficulty in visualising it being generated spontaneously from random mutation, yet surely it's quite hard to get by without one, at leat if you have a circulatory system.

Gif

btw, following up on something Eagle1 said a couple of pages ago (I seem to be working my way through this thread backwards!) I have started a thread on the Problem of Evil.

Can't work out how to put in a link to it though

Gif

Can you give us the ID#?

"So by Darwinian evolution, they should have undergone 65 million years of change, whereas by punctuated evolution they might have changed very little in that time provided that their environment has not changed significantly. "

Well, both and neither, really Gif. The modern coelacanth is a different species from the fossil one. Also, if its environment hadn't significantly changed, the driver for adaption/evolution would have been abscent, and change unnecessary.

A good example of punctuated equilibrium/Darwinism is the impact of myxomatosis on rabbit population in Sussex. They used to live in warrens, and now they live in hedgerows. This wasn't a decision on their part, it works like this;
In any given population there will be a small amount of evolutionaty drift; not all members of that population will be identical in appearance/behaviour. So with the rabbits there was always a small number that lived in hedgerows, and a large large (more noticable) number that lived in warrens. Warrens harboured the myxomatosis virus, so the larger populations were wiped out, and any rabbits that tried to live in the old warrens were also wiped out. The rabbits that were least effected by the virus were the ones living in hedgerows. They of course increased in numbers until, as is the case now, the majority of rabbits live in hedgerows, and a small population in warrens.

Frogbit, yes, that was essentially what I was alluding to. Perhaps there is such a thing as "pruning" in evolution. By that I mean over time, the changes are minute, but at some point, something changes, be it a stronger predator, or a colder winter, or less grazing, that makes a natural mass die-off, as it were, occur. The changes don't have to be as drastic as a meteor, or a flood, or an Ice Age. It could be as simple as a drought year.

Looking at that, it just occured to me. perhaps the mass exstinction of the dinosaurs was both cataclysmic (i.e., the meteor theory) and not so much, perhaps the meteor was carrying a parasite that weakened the dinos that did survive.

As far as non-evolving species, I do believe that croc skeletons have changed in small ways, but not as dramatically as say, us. Also, there are prehistoric creatures still on earth, as witnessed by the coelancanth. That fish had no need to evolve. It lives in a stable region of the deep ocean, and until humans came along, there was no cause *to* change.

Giford's *The Problem of Evil* thread = F19585?thread=216084

pointing to a particular thread
Fxxxxx?thread=xxxxxxx

pointing to a specific post (or posts) within a thread
Fxxxxx?thread=xxxxx&skip=xx&show=xx

pointing to the latest post in a particular thread
Fxxxxx?thread=xxxxxx&latest=1

Thanks six7s. I really ought to have figured that out for myself by now

Gif

You're welcome Gif

To be honest, until now (given your ness) I had a suspicion that your *can't work out how to put in a link to it* comment was some sort of coded message

Anyhow, the *problem of evil* is more food for thought, so

six7's
*a curious *

Curses, foiled!

Even now my armies prepare to roll forth across the face of the nation. Their secret orders contained in the coded phrase *can't work out how to link to put in a link to it* will ensure my global domination, and now all that remains is to set the final date for international destruction.

What are you guys doing on Tuesday?



Gif

From The Onion - http://www.theonion.com

Georgia School Board Bans 'Theory Of Math'
COGDELL, GA—The Cogdell School Board banned the teaching of the controversial "Theory Of Math" in its schools Monday. "We are simply not confident of this mysterious process by which numbers turn, as if by magic, into other numbers," board member Gus Reese said. "Those mathematicians are free to believe 3 times 4 equals 12, but that dun [sic] give them the right to force it on our children." Under the new ruling, all math textbooks will carry a disclaimer noting that math is only one of many valid theories of number-manipulation.


Spot on.

Ste

Hello Gilford is this site you was talking about in your message to me?

Adib

Right then I don't know if niz is still here or not but she said:

"Is it just by chance that Chimps are 99% genetically identical to humans, is it just by chance that you can see animals actually evloving in some fossil finds."

Biologists have long held that the genes of chimps and humans are about 98.5 percent identical. But Roy Britten, a biologist at the California Institute of Technology, said in a study that he published that a new way of comparing the genes shows that the human and chimp genetic similarity is only about 95 percent.
He based this on a computer program that compared 780,000 of the 3 billion base pairs in the human DNA helix with those of the chimp. He found more mismatches than earlier researchers had done, and concluded that at least 3.9 percent of the DNA bases were different.

This led him to conclude that there is a fundamental genetic difference between the species of about 5 percent.

That may not sound much when talking about genetics it is much.

Here is a part of a article from new scientist in the 23 september issue of 2002:

We are more unique than previously thought, according to new comparisons of human and chimpanzee DNA. It has long been held that we share 98.5 per cent of our genetic material with our closest relatives. That now appears to be wrong. In fact, we share less than 95 per cent of our genetic material, a three-fold increase in the variation between us and chimps.

To read the rest of the article go to http://www.newscientist.com/news/news.jsp?id=ns99992833.

When we look at genetic comparisons in general, we find surprising similarities which do not fit within the alleged evolutionary relationships between species. For example a genetic analysis has revealed a surprising 75 % similarity between the DNAs of nematode worms and man.
According to the family tree made by evolutionists, the Chordata phylum, which man is included in, and Nematoda phylum were unrelated to each other even 530 million years ago. This makes the %70 similarity - a very high figure for humans and nematode worms, completely different and dissimilar life forms - does not imply any evolutionary relationship.

Another facter to remember is that there are about hundred thousand genes, and therefore 100 thousand proteins coded by these genes in humans. For that reason, there is no scientific basis for claiming that all the genes of man and ape are 98 % similar only because of the similarity in 40 out of 100,000 proteins.
Scientists have not worked out the entire chimp DNA code and so they can't see how much it actually is close to humans.

All you can say is that from the experiment done so far it appears that man and apes could be 98 percent the same.

Adib