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Author | Topic: Is there evidence for macroevolution? | |||||||||||||||||||||||
jar Member (Idle past 424 days) Posts: 34026 From: Texas!! Joined: |
There are moments though when I do question Evolution.
Man with Hyenaand Baboon edited to change images to links. [This message has been edited jar, 05-04-2004] Aslan is not a Tame Lion
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 9.2 |
I don't get your point?
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Buzsaw Inactive Member |
I understand what you are saying, and this salmon-example may just be microevolution, but it surely indicates how one specie can start on the path of macroevolution. By that reasoning about any adaptation you wanta cite, environmental or otherwise could be construed to the beginning of macro. Imo, that's just not good science. Would it be correct to say that microevolution does not become macro until interbreeding becomes impossible between two of a species?
I'm not sure how to tell when macroevolution would occur in an evolutionary lineage, but I know that you can interbreed two animals with an anscestor quite far back, like i.e. a goat and a sheep, named 'geep'. 1. Has it ever been documented to have occurred naturally with no outside help or manipulation? 2. What kind of offspring do geeps produce? My bet is that they tend towards reversion back to one or the other of the original species if allowed to breed naturally.
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Buzsaw Inactive Member |
There are moments though when I do question Evolution. Must be you've been visiting my imperial supernaturalistic Exodus Revealed video thread.
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sfs Member (Idle past 2564 days) Posts: 464 From: Cambridge, MA USA Joined: |
Skeptic, your link simply says the two groups of fish prefer not to interbreed. According to Crashfrog's explanation of what makes a new species, there is no new species until it becomes impossible for the two groups to interbreed. It looks like the 70 year event is simply miroevolution.
No, the requirement is not that they be unable to interbreed, but that they don't (normally) interbreed, and that they won't start interbreeding as a result of simple change in the environment (like building a bridge between two geographically separated subpopulations). What matters for evolution is whether the two groups will evolve as a single population (i.e. that genes will flow from one to the other) or as two distinct populations. If the populations aren't in contact, it can be difficult or impossible to tell whether they meet the standard criteria, and the boundary is pretty fuzzy, since there can be limited hybridization long after two populations have largely become reproductively isolated.
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John Paul Inactive Member |
NN:
In the sense that we use the term, creationsists didn't exist 200 years ago. John Paul:In the way I use the term Creationists have existed for eons. Theories of evolution have also existed for eons. What is a Kind? Well science should be able to help us make that determination. Just like some scientists are using science to try to determine LUCA (last universal common ancestor). Seeing evolutionists haven't been able to pin that down I would say it is a little short sighted to put the burden on Creationists.
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 9.2 |
What is a Kind? Well science should be able to help us make that determination. Just like some scientists are using science to try to determine LUCA (last universal common ancestor). Seeing evolutionists haven't been able to pin that down I would say it is a little short sighted to put the burden on Creationists. You're comparing apples and oranges. We know what the luca is, we just haven't found it yet. You don't even know what a kind is, let alone how to indentify one.
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John Paul Inactive Member |
MJ:
We know what the luca is, we just haven't found it yet. John Paul:Do you have a reference for that claim? MJ:You don't even know what a kind is, let alone how to indentify one. John Paul:Actually some work has been done. However I would doubt any of the original Created Kinds are alive today and the same goes for LUCA. More work needs to be done. That is what science is for. If we knew the answers we wouldn't need science.
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Loudmouth Inactive Member |
quote: But they have pinned down human common ancestory with new world apes. If kinds do exist, humans and chimps would be in the same kind. As to micr/macroevolution, the terms are not meant to be an objective or even quantitative definition. Instead, micro and macro evolution are meant to be arbitrary, subjective, and qualitative descriptions that biologists tentatively agree on. Like Crash said earlier, it is the same as microwalking to the store and macrowalking to the other side of the city. There is no line between micro and macro, it is just a judgement call. However, we have seen speciation resulting in non-viable offspring. From talkorigins.org: (here specifically) In 1964 five or six individuals of the polychaete worm, Nereis acuminata, were collected in Long Beach Harbor, California. These were allowed to grow into a population of thousands of individuals. Four pairs from this population were transferred to the Woods Hole Oceanographic Institute. For over 20 years these worms were used as test organisms in environmental toxicology. From 1986 to 1991 the Long Beach area was searched for populations of the worm. Two populations, P1 and P2, were found. Weinberg, et al. (1992) performed tests on these two populations and the Woods Hole population (WH) for both postmating and premating isolation. To test for postmating isolation, they looked at whether broods from crosses were successfully reared. The results below give the percentage of successful rearings for each group of crosses. WH WH - 75%P1 P1 - 95% P2 P2 - 80% P1 P2 - 77% WH P1 - 0% WH P2 - 0% They also found statistically significant premating isolation between the WH population and the field populations. Finally, the Woods Hole population showed slightly different karyotypes from the field populations. Also notice that there are karyotype differences between the two populations. Karyotype is the "anatomy" or morphological characteristics of the chromosomes. So there were DNA differences between the two populations as well. Given the fact that broods from crosses did not survive means that even though the two groups are interfertile, their offspring will never live to reproduce. PS: The worms in the Woods Hole, Massachussetts lab (went there a year ago, beautiful place) were used in toxicology experiments. However, you still have to have a healthy breeding population. This means that the speciatiation event in Woods Hole was not due to a toxic environment, just genetic isolation and adaptation to being breed in a lab under optimal conditions. [This message has been edited Loudmouth, 05-04-2004] [This message has been edited Loudmouth, 05-04-2004]
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SkepticScand Inactive Member |
By that reasoning about any adaptation you wanta cite, environmental or otherwise could be construed to the beginning of macro. Imo, that's just not good science. I didn't claim for it to be evidence, I just pointed out the obvious. Wounded King recites Macroevolution in #6 post:
Futuyma writes: Macroevolution: A vague term for the evolution of great phenotypic changes, usually great enough to allocate the changed lineage and its decendants to a distinct genus or higher taxon. This doesn't tell me much about how to show Macroevolution in progress. Since it is a vague term, how would you suggest I show it? My guess would be that Macroevolution is a conscequence of many Microevolution traits to help a creature adapt to their enviroment.
1. Has it ever been documented to have occurred naturally with no outside help or manipulation?
I think it mostly have been manipulated with outside help No webpage found at provided URL: http://members.aol.com/jshartwell/hybrid-mammals.html, but nonetheless, they have successfully managed to create them by insamination. We wouldn't go and mate with a chimp just because it is possible. We stick to the ones we find sexually attractive (our own kind).
2. What kind of offspring do geeps produce? My bet is that they tend towards reversion back to one or the other of the original species if allowed to breed naturally.
They do offcourse produce 'geep'-offspring. If they were introduced back to goats and sheeps they might tend to reverse back to one or the other. But if they were kept away for some generations, they would adapt more and more to their own kind (like the salmons in the article)This is not that different from what we humans have been doing to our livestock and dogs for centuries.
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John Paul Inactive Member |
LM:
But they have pinned down human common ancestory with new world apes. John Paul:You mean they think they have that common ancestor pinned down. Until they can verify that claim all it will be is just another evolutionary assertion. LM:If kinds do exist, humans and chimps would be in the same kind. John Paul:I doubt that very much. Too many differences. Also we still don't have any objective evidence that an ape-like organism can evolve into a human.
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Loudmouth Inactive Member |
quote: There are more differences among the "cat kind" and the "dog kind" than there are amongst humans, chimps, and apes.
quote: We have objective evidence that humans DID evolve from ape-like ancestors. It is called genetics. Through evolution, we can make sense of the genetic similarities and characteristics between humans and apes. The same objective evidence that ascertains paternity in humans is also able to ascertain common ancestory between apes and humans.
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FliesOnly Member (Idle past 4175 days) Posts: 797 From: Michigan Joined: |
Hello All:
The original premise of this thread was to question whether or not we have concrete evidence for macroevolution. I think it is Crashfrog that has stated many times that macro is simply the accumulation of multiple micros (correct me if I’m wrong Crashfrog). None-the-less though, inevitably we get to the point in the discussion where examples are given, but these are always said to be microevolution. We read things like yeah, but it’s still just a maggot, or yeah, but it’s still just a fruit-fly or yeah, but it’s still just a dog, etc.,etc.,etc. To these critics I say,yeah, it is still just a maggotbut so what? I mean, what did you expect it to become? This argument shows a basic lack of knowledge of the evolutionary process. Yes, it is still just a maggot and in all likely-hood will remain just a maggot, for thousands (and more likely millions) of years. It’s not going to magically turn into a puppy or something. As a matter of fact, if it does evolve into something other than just a maggot, it will be something novel, NOT something that we’ve already seen, and certainly not something we currently see now. I get so tired of reading this ridiculous argument. Once something starts down a basic phylogenetic lineage, it’s not going to produce something in some other phylogeny that followed a different pathway. Fruit-flies are not going to evolve into birds. Frogs are not going to become primates. For that matter, fruit-flies are not even going to become house-flies. Get it? Each will remain within their lineage and may eventually evolve into a novel organism, but will not jump into other groupings. So we never expect a fruit-fly to become anything other than just another fruit-fly (or maybe after a few thousand generations, something closely related to fruit-flies genetically but morphologically quite different). Does what I’m trying to say make any sense? The whole yeah, but it’s still just a bla, bla bla argument is meaningless. Oh, and by the way, if you want to see concrete evidence for macro-evolution, simply look at the fossil record.
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Loudmouth Inactive Member |
quote: Exactly Fly. I get tired of it as well. A novel species is a novel species, no matter what it looks like. Genetic isolation is the only taxonomic level in nature, the rest is derived by humans to explain phylogenetic tendencies in an evolutionary lineage. I'll give an example of why the creationist name game doesn't work in real life, and can always be used to conclude microevolution: Dalmation to German Shepard, still in the dog kind.Cat to Dog, still in the mammal kind. reptile to mammal, still in the vertebrate kind. metazoan to reptile, still in the animal kind. And the list could go on. Creationists adjust what they consider in the same kind only to keep humans and chimps from being in the same kind. Hence, macroevolution is anything that might lead us to conclude that chimps and humans evolved from a common ancestor. It is not the data that the kind and macroevolution arguments try to describe, but a presupposed conclusion that must be upheld at all costs. Creationists are not looking for examples of macroevolution, but for definitions that will keep humans as a special creation.
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SkepticScand Inactive Member |
Couldn't agree more
Cheers,SkepticScand
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