Question about evolution?

Question

http://news.yahoo.com/s/ap/20071016/ap_on_sc/new_marine_species

Seriously. When a species has been isolated for millions of years, like these discoveries, do they still evolve? Or, because of the isolation, they *don't* evolve, because there have been no new stimuli in their environment?

I'm not asking to prove any "religous" point, I seriously want to know. I know that there are lots of people here on R&S that know more about evolution than the folks over in the science section. :o)

SEE??? i knew y'all would know!!! thank y'all so much; i see by the smart people that i trust on here, that creatures do still change, even in isolation. that's interesting.

skalite: sorry about the wrong category, but i've been on R&S so long, i don't trust the answers from any other scientists (or category, for that matter), than the ones here!

Mark: if you read the article, that was the authors words, not mine, sweetcakes.

Mr. CC: how in the world, from this question, do you get that i'm saying there is no God? man, i hope you don't own any pistols.

Answer 1

1. The theory of evolution does not say that organisms must evolve morphologically. In fact, in an unchanging environment, stabilizing selection would tend to keep an organism largely unchanged. Many environments around today are not greatly different from environments of millions of years ago.

2. Some so-called fossil species have evolved significantly. Cockroaches, for example, include over 4,000 species of various shapes and sizes. Species may also evolve in ways that are not obvious. For example, the immune system of horseshoe crabs today is probably quite different from that of horseshoe crabs of millions of years ago.


Edit: Unfortunately "catholic crusader" is repeating a lie without realizing it - more details at http://www.talkorigins.org/faqs/abioprob/

Answer 2

What people have referred to as "evolve" I would just term it as "mutate". This is a scientific fact and is guided by the laws of genetics. The genetic constitution of the organism does not change. Only a rearrangement of different allelles already present in the chromosomes occurs under varying conditions. This is an intra-species variation designed for better survival of the species. In order for these changes to 'accumulate' in such a way that it will give rise to an altogether new species is not something that can be demonstrated scientifically. It can only be inferred from certain observations. The scientists have still not been able to identify the stimuli that cause a species to change into another species. That part falls outside the scientific realm into the realm of speculation. Therefore, while I'm all praise for the tremendous amount of work done by the scientist in this field I beg to differ with their conclusions on this matter unless proper scientific methods prove otherwise.

Answer 3

It depends upon whether or not there have been changes to that particular environment or not... Take the coelocanth, a very deep water fish - its environment hasnt changed in millions of years, so it hasnt evolved much - it looks pretty much like the million year old fossils examples we have. However, coral reef areas are notorious for constantly changing - just a couple of degrees difference in temperatures can cause the corals to die - which would change the environment in some small ways... Also, some species might evolve from another to fill some other area of the ecological niche that has been created from the changes in the environment.

Answer 4

Its not stimuli - its selection pressure.

For example, a species of insect that finds a niche in a cave might not be 'stimulated' but because of its environment it will eventually evolve to an eyeless form, simply because over millions of years the animals which made the extra effort to grow eyes had no advantage. That's a combination of weak selection with genetic drift.

'a blob of primordial ooze morphing into a man'

Thanks crusader. Good to see what a fundamentalist understands by evolution.

Oh THAT article! There is plenty of stimuli down there - predator/prey relationships and all sorts. Evolution is always happening, its not directional don't forget. Just about survival and the changes that happen over time.

Answer 5

If the creature is adapted to its environment and the environment does not change and there are no pressures against the creature then it might not evolve anymore. There is no guarantee that it won't evolve more. You never can tell what new mutation could give the animal an edge over the otheres.

Evolution does not depend on isolation. It depends on what the environment the creature is in and how it affects how the creature lives.

Answer 6

In actuality perhaps both. If an isolated species "prospers" in it's biological niche--there is no driving force--no survival trait that nature would select for, and therefore one would expect changes in that species to be slow. (The shark as an example has not changed much--it fulfills it's function well). If for example the environment changed slowly in the isolated area--(became drier, colder etc)-the survival trait in a species that would be selected for would be ability to use less water--ability to conserve heat. Offspring in any generation that had a superior characteristic in this regard would have a greater probability of survival and a greater probablility of passing that trait on to future generations. Over millenium as nature winnows the weak--the animal changes until eventually it no longer resembles the original species. An example of this is in human beings. The alcoholism rates among southern europeans is very very very low compared to that of the american indian. Over thousands of years in southern europe those genetically predisposed to alcholism were selected out of the gene pool--if dad was drunk all the time the family didn't eat). The american indian had alcohol introduced a mere 500 or so years ago--not enough time to winnow out the genetic predispostion to alcoholism. In either society--the gene has not been winnowed out--simply because of the much longer time span--the proportion of those predisposed in the gene pool is much higher for native americans than southern europeans.

Answer 7

I'm a theist and not an evolutionist but even I can answer this one;

Evolution is composited of two parts; natural selection and gene mutations... meaning over a "long period of time" species will have "gene mutations", if these gene mutations are in benefit of their surrounding enviroments then that certian species will have much a greater chance of survival, concluding that the ones who could not adapt through gene mutation would eventually die out. If no change in the enviroment then mutated genes occurring would not become the dominant gene. If there was little change in the enviroment then there would only be a small transformation. Regards to Charles Darwin.

Answer 8

Well, it's their isolation that made them evolve their unique traits, and presumably the inability to breed outside their community.

There have been some changes in their general genetic frequency over the millions of years they've been alone, so they may actually be a different species NOW than they used to be, but you can't test that unless you go back in time and try to breed them...lol. Some species have incredibly stable DNA. Horseshoe crabs, for example, have very little variation between population groups.

They evolved to be different from jellyfishes than those they were separated from. Geographic isolation is a huge factor in speciation.

If they find multiple jellyfishes unique to the area, they probably all evolved from the same ancestors.

Answer 9

Yes, they still evolve. Take Australia for example; The animals there were isolated from the rest of the world but also evolved. That's why Australian animals are so unique to that country.

Answer 10

Yes. The forces at work are genetic drift, natural selection and mutation more than gene flow.

You still have changes in allele frequency within an isolated population because you can't isolate the entire system. I guess in theory you could possibly have a population that goes relatively unchanged but in all practicality that type of broad scale isolation doesn't happen.