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Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: "Macro" vs "Micro" genetic "kind" mechanism? | |||||||||||||||||||||||||||
olivortex Member (Idle past 4808 days) Posts: 70 From: versailles, france Joined: |
Thank you! i'll study the copy/paste codes, etc. I'm really not a good geek... Computers sometimes call me names, even when they don't have any soundboard.
It seems that the red panda case is far from being closed! that's exactly why i mentioned it and his "cousin" the giant panda. The few slight similarities can cast some doubt on the official taxonomy for these wonderful animals. You may know how we call a BAT in france... Back to topic: funny thing is that without a single drop of knowledge about evolution, biology or genetics, i had the feeling that "macroevolution" and "microevolution" were not necessarily to be confronted since it appeared, according to my reading of the scientific research in and out of the lab, that evolution is a continual, over time process.
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IchiBan Member (Idle past 4968 days) Posts: 88 Joined: |
Heavier than air powered flight = maintaining level flight at a given altitude under its own power.
There is no evidence that the flying squirrel, the flying fish, or any of the other gliding creatures ever mutated into a creature capable of heavier than air powered flight, which is what the bird, bat, insects and airplane are capable of. The gliding creatures (save the gliding fish) all have fairly steep glide ratios meaning they are in a descent for the entire trip unless they catch a momentary thermal to override their descent velocity. The flying fish is operating/gliding in ground effect which greatly extends his glide path, and powering himself with his tailfin in the water, not the air.
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olivortex Member (Idle past 4808 days) Posts: 70 From: versailles, france Joined: |
You make a good point here. But ostriches have wings, and we could reverse the problem, maybe.
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Thank you IchiBan,
Heavier than air powered flight = maintaining level flight at a given altitude under its own power. I fully agree, however this thread is not about flight, but about finding out if some barrier to evolution exists as creationists claim. You may be just using this as an example, which is how I will answer. However, if you want to discuss the evolution of flight, please start a new thread. You may want to read How do you evolve a BAT? first. The creationist claim being discussed is whether there is a genetic limit to evolution, a limitation from within the organism that limits how much it can evolve. Convergent evolution invalidates the concept that there is some mechanism that stops two types of animals from evolving to be similar organisms, as two different types of animals have evolved to be similar organisms in order to take advantage of similar ecologies. That's all it takes to show such a concept is invalid in science.
There is no evidence that the ... any ... gliding creatures ever mutated into a creature capable of heavier than air powered flight, .... This seems to imply you think that there should be a direction to evolution, a progression from gliding to flight: there isn't. The failure of gliding animals to evolve full flight is simply because they do not need to evolve the rest of the mechanisms of flight to survive and breed. In addition, the organisms that can fly did not necessarily start with gliding. Interestingly, there are an amazing number of species that can glide with varying degrees of lift to drag ratios. Many different existing features have been adapted to provide wing surfaces with varying success. Frogs, lizards, snakes, spiders, plant seeds, etc. - and none of these species have any genetic block that prevents this evolution. http://www.squidoo.com/wildgliders (cool information on lots of gliders: lizards, snakes, geckos, frogs ...)
... which is what the bird, bat, insects and airplane are capable of. And aside from the airplane (that is not an organism subject to evolution through inheriting genetic traits), these are organisms that have evolved flight independently. Bats and birds are also convergent evolution products, taking advantage of opportunity to expand their ecologies. Bugs apparently have evolved flight many times. We also see pterodactyls in wide variety that evolved flight similar to bats -- another example of convergent evolution.
The difference between flying organism and gliding organism is a function of opportunity and selection pressure, rather than genetic limitation. For instance the flying fish: it just needs to outrun it's predator, a much larger, heavier fish that is too big and heavy for similar wing fins to evolve. This predator is also limited to how fast it can swim, so all the flying fish needs is to go faster, which it does. It also is not capable of living in the air very long, so flight would be impractical even if there were more pressure to evolve flight to escape the predators. As long as all the current known many kinds of gliders are currently able to survive and breed, and as long as additional flight ability does not offer any selection advantage, then they will not evolve further in ability to move through the air. But the lack of a flight inducing ecology, or the lack of flight to provide an opportunity for improved survival and breeding is not a genetic limitation, not a limitation from within the organism. Different ecologies, different opportunities will result in different evolution from a common ancestor population. Enjoy. Edited by RAZD, : from within by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. • • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •
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IchiBan Member (Idle past 4968 days) Posts: 88 Joined: |
Thank You RAZD
I see your post has some built in assumptions that have not been borne out IMO. What I was keying on is that very often the gliding creatures are interjected into the discussion with the inference that they were/are an example of creature in an early stage of evolution into another creature towards powered flight. Darwin even had it in his own writings specifically about the flying fish evolving into something more. This genetic barrier to macro-evolution, It is a false challenge to the creationists because it assumes evolution as true, when the evidence shows only adaption and variation within limits.
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Coyote Member (Idle past 2136 days) Posts: 6117 Joined: |
This genetic barrier to macro-evolution, It is a false challenge to the creationists because it assumes evolution as true, when the evidence shows only adaption and variation within limits. I beg to differ. Religious belief prescribes "only adaption and variation within limits" because of the biblical mention of "kinds." Science has not supported that limitation. It has, in fact, shown the opposite: there is no known mechanism that prevents micro-evolution from progressing to macro-evolution over time. I have asked creationists to provide me with a mechanism that prevents micros from adding up over time to macros. I have never received a satisfactory answer. Perhaps you can be the first to provide such an answer? Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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IchiBan Member (Idle past 4968 days) Posts: 88 Joined: |
Macro evolution has not been demonstrated, it was only inferred by Darwin and there has been no evidence for it since then that has stood the test of time. If you have the specific evidence of that pls bring it here.
So therefore you are asking for a mechanism to stop a result that has not been demonstrated. IOW, You are talking mechanisms that dont exist in nature.
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Coyote Member (Idle past 2136 days) Posts: 6117 Joined: |
Macro evolution has not been demonstrated, it was only inferred by Darwin and there has been no evidence for it since then that has stood the test of time. If you have the specific evidence of that pls bring it here. So therefore you are asking for a mechanism to stop a result that has not been demonstrated. IOW, You are talking mechanisms that dont exist in nature. Sorry, that is not correct. Scientific evidence supports macroevolution as the mechanism for evolution. Only the bible states otherwise. When you start looking at the evidence, there is overwhelming support for the former position, and a complete lack of evidence for the latter position. Does it not mean anything to you that scientists from all over the world, of various religions or no religion, all come with the same answer while only biblical fundamentalists come up with an opposing answer? Doesn't it ever occur to you that you are doing religion, rather than science; relying on belief rather than evidence? And that science has provided the answers that you steadfastly deny? Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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IchiBan Member (Idle past 4968 days) Posts: 88 Joined: |
"Scientific evidence supports macroevolution as the mechanism for evolution"
Well lets talk about the evidence then, bring your best most comprehensive evidence here to the forum.
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AdminNosy Administrator Posts: 4754 From: Vancouver, BC, Canada Joined: |
Well lets talk about the evidence then, bring your best most comprehensive evidence here to the forum. Not to this thread! One of the claims made against macro evolution (perhaps the only one) is that it can't happen because there is a barrier. That is the topic of this thread. We are 2/3 through 300 posts and no one has supported that claim. If you don't know about the voluminous evidence for macro-evolution then you might want to brush up a bit before joining this thread unless you are actually prepared to support the "kind-barriers" existence with substantiated fact. Edited by AdminNosy, : No reason given.
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IchiBan Member (Idle past 4968 days) Posts: 88 Joined: |
LOL! I know plenty about the "voluminous evidence" for macro-evolution. But okay not on this thread.
About the voluminous evidence for macro-evolution, that is a whole nuther topic on its own I guess. On that note, what would you define as substantiated fact when it comes to macro-evolution?
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Coyote Member (Idle past 2136 days) Posts: 6117 Joined: |
About the voluminous evidence for macro-evolution, that is a whole nuther topic on its own I guess. On that note, what would you define as substantiated fact when it comes to macro-evolution?
If you want to stay on topic show us the mechanism that prevents one genus, say the ancient primate ancestor, from evolving into all of the subsequent genera of ape (i.e., orangutans, gorillas, chimpanzees, and humans). But to do this, you first have to counter all of genetics, supported by paleontology, as those fields show that the ancient primate ancestor did evolve into those more recent genera. Then you have to show the mechanism that prevented that evolution. And please, I've had a long day. Stick to science. Leave the religious belief and creation "science" for another day, eh? Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Thanks for the clarification, Ichiban.
What I was keying on is that very often the gliding creatures are interjected into the discussion with the inference that they were/are an example of creature in an early stage of evolution into another creature towards powered flight. Darwin even had it in his own writings specifically about the flying fish evolving into something more. But the basic assumption here, is that there is some kind of "progress" involved from gliding to flight, that once gliding was accomplished, that this "progress" would continue to flight. This is not how evolution works. Darwin may have speculated on what further evolution might occur for flying fish as he did for swimming bears, however, this too, does not mean that such speculations must occur in general and in the last 150 years specifically. Again, if you want to have a discussion about the evolution of flight, a new thread is called for. As pointed out by Ned, the topic of this thread is whether there is a genetic barrier to evolution. So far, no such barrier has been demonstrated. The thesis of this debate topic is really simple, Message 1:
quote: Those arguing for the proposition that there is a genetic mechanism have failed to present any evidence that this in fact is true. Those arguing against the proposition have shown evidence that there is no barrier, evidence like convergent evolution, where quite different evolutionary lineages have produced similar adaptations to similar ecologies. Sugar gliders and flying squirrelsBats and pterosaurs and birds Sharks and killer whales This genetic barrier to macro-evolution, It is a false challenge to the creationists because it assumes evolution as true, when the evidence shows only adaption and variation within limits. No, all it assumes is that if there is "only adaption and variation within limits" that there must then be a barrier that prevents macroevolution at the genetic level. Clearly the evidence of convergent evolution demonstrates that there is no barrier to what can evolve starting from different ancestral lineages. What stops macroevolution at the genetic level? Enjoy. by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. • • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •
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PaulK Member Posts: 17828 Joined: Member Rating: 2.5 |
quote: I think you're wrong there Coyote. The Biblical mention of "kinds" is exaggerated and misrepresented to support creationist ideas. There's no reason to believe that the biblical usage matches the creationist usage.
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Coyote Member (Idle past 2136 days) Posts: 6117 Joined: |
quote: I think you're wrong there Coyote. The Biblical mention of "kinds" is exaggerated and misrepresented to support creationist ideas. There's no reason to believe that the biblical usage matches the creationist usage. I'll have to take your word on that, as that's far outside my field. I am only going by what I have read on creationist websites and seen posted on threads like this. One example is:
What are the Genesis “kinds”? Baraminology”classification of created organisms If you could, while staying within the topic, I would like to hear your thoughts on the "kind" problem. To stay on topic you'll probably have to relate it to the mechanism that prevents microevolution from becoming macroevolution over extended periods of time, or looked at from the other direction, the mechanism that keeps kinds from "branching out" (if you'll pardon the pun). Thanks! Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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