Fafhrd on 12/3/2006 at 04:50
Quote Posted by nickolae
your missing the point. I've said before that micro-evolution happens all the time. (d0oms goats and Darwins finches).
Your forgetting the tree of life and all that jazz. The rat-like animal to whale deal or the reptile to mammal deal. Where is that? no where.
No, YOU'RE missing the point. A. Micro-evolution and macro-evolution = same damn thing over different time scales. The terms "micro-evolution" and "macro-evolution" aren't even a part of scientific parlance, they were made up by creationists to poke holes in the theory that don't actually exist.
B. "The tree of life and all that jazz." You're CLEARLY, and perhaps INTENTIONALLY misinterpreting the symbolism of descent diagrams. The branches represent
permanent genetic change. There's no going back, and there's no going from side to side after the branches. In order for a housefly to turn into a fish, it would first have to regress genetically practically all the way back to the first organic particle from which all life sprang, and then back up the tree, taking different branches until it got to "fish."
Convict on 12/3/2006 at 04:55
Under artificial selection why can't fruit flies regress to e.g. a fish (given enough time and the correctness of evolution)?
SD on 12/3/2006 at 05:01
Quote Posted by Convict
Are you making stuff up or do you have evidence of this?
And I bet that's a question you asked your Sunday School teacher, right?
Quote:
Under artificial selection why can't fruit flies regress to e.g. a fish (given enough time and the correctness of evolution)?
A fruit fly cannot "regress" to a fish because it didn't evolve from a fish.
RyushiBlade on 12/3/2006 at 05:09
Fruit flies evolved from certain types of crustaceans (actually called something else which I can't remember. Basically there were three types of animals in the sea: the soft bodies, such as seaslugs and squids, the crustaceans with their exoskeletons, and the vertebrates. We had the short end of the stick and may have become extinct if not for two timely mass extinctions.)
Fruitflies could, possibly, regress back into an aqueous form if given a billion years. This isn't an exaggeration. It takes a very long time. And remember that life in water would be considerably more dangerous for a swimming fruitfly.
Convict on 12/3/2006 at 05:34
Quote Posted by Strontium Dog
And I bet that's a question you asked your Sunday School teacher, right?
An admission of guilt on your part I take it.
Quote:
A fruit fly cannot "regress" to a fish because it didn't evolve from a fish.
I was merely quoting an example given above - it could be replaced with the question "Under artificial selection why can't fruit flies regress to e.g. a
crustacean (given enough time and the correctness of evolution)?
SD on 12/3/2006 at 05:46
Quote Posted by Convict
An admission of guilt on your part I take it.
Not at all. I could give you so much evidence, it would make your brain hurt. But you're not really interested in evidence that supports the theory of evolution. What you want is to be able to pick holes in what is admittedly a less-than-watertight body of evidence for the origins of life on Earth, just to suit your own agenda.
Putting that question back at you was merely a suggestion that perhaps your critical eye would be better cast over the idea of creationism, for which there is no supporting evidence whatsoever.
Quote:
I was merely quoting an example given above - it could be replaced with the question "Under artificial selection why can't fruit flies regress to e.g. a
crustacean (given enough time and the correctness of evolution)?
Okay. They couldn't regress into a crustacean, because evolution works forwards, not backwards. What they could do is to evolve into something similar to a crustacean, although of course, it wouldn't be a crustacean, just something that was rather like a crustacean.
RyushiBlade on 12/3/2006 at 05:56
There are many examples of animals that have moved from water and back again. Whales are an example. I believe they still have vestigial leg bones at the back (but there are no longer any 'nubs' for legs.)
There's even a diagram:
Inline Image:
http://evolution.berkeley.edu/evosite/evo101/images/whaleancestors.gif I think it would look better if there were another skeleton between the last, however. So even though a... 'dog' (mesonychid, but work with me) didn't evolve into a fish, it did evolve into something remarkably fish like.
A few more hundreds of millions of years and an extraordinarily bigger whale population and they could go to gills.
mopgoblin on 12/3/2006 at 06:17
Quote Posted by Convict
Under artificial selection why can't fruit flies regress to e.g. a fish (given enough time and the correctness of evolution)?
For a start, "regress" is a misleading term to use, as the space of potential creatures doesn't really have a logical and objective ordering that we can measure - fitness being defined with respect to specific states of the system (including the other species in that system) makes it pretty much impossible. Flies evolving to fish wouldn't be regressing any more than you regress to your house after you leave work/university/church/whatever.
The reason flies aren't turning into fish or whatever is that there's no advantage to taking the first steps in that direction. They're probably quite close to a local maximum right now, so the ones that don't change much will outperform those that do. If there was a big change in the system so that their current form becomes less viable or a new path opens up that leads to a better form, we probably would see some change if we waited long enough.
SD on 12/3/2006 at 06:18
Quote Posted by RyushiBlade
There are many examples of animals that have moved from water and back again. Whales are an example. I believe they still have vestigial leg bones at the back (but there are no longer any 'nubs' for legs.)
Yeah, it's an example of Convergent Evolution, although I'm not sure that's what Convict meant. I could be wrong, but I'm pretty sure he's talking about a fly
literally returning to a form it took millions of years ago, way before it was a fly.
Quote:
A few more hundreds of millions of years and an extraordinarily bigger whale population and they could go to gills.
Indeed they could - but it still wouldn't be a fish ;).
RyushiBlade on 12/3/2006 at 06:30
Hey, if it walks like a fish...
