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Author | Topic: Evidence for Evolution: Whale evolution | |||||||||||||||||||||||||||||||||||||||
herebedragons Member (Idle past 888 days) Posts: 1517 From: Michigan Joined: |
When questioning whether evolution could have evolved whales, keep in mind that human evolution took only 6 million years. Evolution could happen because evolution did happen? Circular reasoning. My question is not so much "could" it happen as "did" it happen. I am not questioning evolution in the traditional sense. I am only trying to make sense of it. For the most part I accept evolution, but I don't just "believe" because of a well placed "series". I need to examine it and decide for myself if the evidence is sufficient. That's what we should all be doing, correct?
First, the most important dates are when the species start. So lets use that. True. But those dates don't necessarily tell you when the species started, only when that particular animal lived. Can it be logically deduced that was one of the earliest specimens? Especially when a sister group is significantly older. I also question using Wikipedia as a source. It is just not reliable. I am going to do some more work on this and will get back to you in a couple of days. The trend looks good on both ends, but the middle group sure looks like they all lived at the same time in the same area. I am also uncertain as to why these creatures would be adapting more and more to life in the water when India was crashing into the continent, closing the Tethys and pushing up the himalayas. Any insights here? HBD
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
According to wikipedia "Himalayacetus is an extinct genus of carnivorous aquatic mammal (from the same link you provided). This aquatic mammal was one of the earliest mammals on your list, alongside Pakicetus and even the Pakicetus seemed to roam dry land. What is your thoughts around this? Hold on, weren't you the one saying that loads of intermediate forms should have survived even to the present day? So if the evidence is consistent with the idea that some of them did survive for a while, is that not what you would expect to see?
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
I am also uncertain as to why these creatures would be adapting more and more to life in the water when India was crashing into the continent, closing the Tethys and pushing up the himalayas. Any insights here? They should have got out of the water and learned to climb mountains instead? Bear in mind that each proto-whale would have had a limited range. There was probably none whose lifestyle required a circumnavigation of India. The closing of the Tethys might have restricted the total range of the group, but that's no reason why animals which already lived in the sea should have got less well-adapted to doing so.
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TheArtist Junior Member (Idle past 2681 days) Posts: 14 Joined: |
Dr Adequate writes: Hold on, weren't you the one saying that loads of intermediate forms should have survived even to the present day? So if the evidence is consistent with the idea that some of them did survive for a while, is that not what you would expect to see? I don't see how this brings my previous arguments into question in any way? If you looked back at my previous arguments, my main point was that one still sees a big enough gap between these species to easily assume that they were different animals not one that evolved out of the other. You don’t see a smooth enough transition in the fossils and neither do you see it today as part of continuing evolution. What about the fact that this species survived for a while questions my reasoning? Please explain.
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TheArtist Junior Member (Idle past 2681 days) Posts: 14 Joined: |
Dr Adequate writes: It's as suspect as my great-grandparents not being alive today, and my great-great grandparents, and my great-great-great-grandparents ... if I really am descended from them, shouldn't some of them still be alive? Please explain how this is relevant to my point. Human KIND is alive today, or not extinct, sure people die, that doesn’t mean that the human species is extinct. Please explain how this argument answers: It does not matter how you look at this, 49 920 transition steps being absent today seems a bit suspect. Edited by TheArtist, : No reason given.
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jar Member (Idle past 425 days) Posts: 34026 From: Texas!! Joined: |
Are you claiming that 49,920 transition steps are missing?
Anyone so limited that they can only spell a word one way is severely handicapped!
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
Please explain how this is relevant to my point. Human KIND is alive today, or not extinct, sure people die, that doesn’t mean that the human species is extinct. No, but our ancestors sure are. What difference does it make if adaptive radiation took place at the same time?
Please explain how this argument answers: It does not matter how you look at this, 49 920 transition steps being absent today seems a bit suspect. That's not an argument, that's an assertion. Two assertions, in fact, since you're using a figure that someone just pulled out of his ass. Now, how about you produce an actual argument that it's "a bit suspect"? Explain to me why whales with hind legs should still be alive if they were transitional species. In framing this argument, bear in mind that transitional or not, all the whales with hind legs are in fact dead. I really don't see what you're thinking here. You're talking as though the mere fact of being transitional should have offered them some protection from extinction, like the Mark of Cain, over and above considerations of their phenotype. But how can this be? A whale that couldn't cut it couldn't cut it, no matter how it was produced. We know that whales with hind legs couldn't cut it. Ergo, they couldn't have cut it if they were transitional species. If you have any argument to the contrary, I should like to hear it. If all you have is assertion, then you should note that I have an actual argument based on observable facts, which is better.
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
If you looked back at my previous arguments, my main point was that one still sees a big enough gap between these species to easily assume that they were different animals not one that evolved out of the other. And if I don't post here for a few hours, you can assume that I spent the intervening time in Heaven having tea and crumpets with the Archangel Gabriel. But it wouldn't be a very sensible assumption.
You don’t see a smooth enough transition in the fossils ... Show your working. Really, given the small number of actual fossils we have, we wouldn't expect to see a "smooth" transition between forms. If we had millions of fossil proto-whales, and they could all be put in a few discrete groups, you'd have a point.
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RAZD Member (Idle past 1436 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi again TheArtist,
One of your problems is unreasonable expectations for evidence. You expect evidence to show you every step. Evidence does not just turn up to support your scientific thesis, the scientific thesis is developed from the evidence available. If the evidence were complete it would not be a thesis but a statement of the facts shown by the evidence. If you walked across the US and took a video of every step, then you would have a smooth transition from east to west (or vice versa). If instead you took a series of photos, then you would have a set of stepping stones that could be placed by time and location into a series that travels from east to west (or vice versa).
... You don’t see a smooth enough transition in the fossils ... Why should all the intermediate fossils have been preserved in this case? If you want to see a smooth transition, there are examples of that.
quote: This shows a smooth transition from one species of ancestral primate to two daughter species of primate. They diverge further after this speciation event, each evolving within a different ecology, the ecologies overlap initially but later diverge as they evolve.
quote: Virtually every species of foraminifera that lived in the last 65 million years is represented. That's a lot of species, a lot of speciation events, and a lot of smooth transitions.
If you looked back at my previous arguments, my main point was that one still sees a big enough gap between these species to easily assume that they were different animals not one that evolved out of the other. Curiously, science does not argue that each one evolved directly from the other, just that the known fossils show an overall pattern that is consistent with evolution, it shows descent from a common ancestor by the nested hierarchy of hereditary traits that relate one group to the next, and the existence of certain traits that are not shared with other animals. There are many smooth transitions known to science, but not all the evidence of past life is available, so we don't expect smooth transitions to show up in all cases. Instead what we expect to find are stepping stones that show the path of the development of the diversity of life on this planet, stepping stones that may diverge into different paths, but which lead back in time in a pattern of nested hierarchies of hereditary traits. This is precisely what the whale fossils show.
What about the fact that this species survived for a while questions my reasoning? Species A is adept at living in a shallow sea environment, occasionally climbing out on a shoreline. Species B is more adept at living in the sea than A, but less adept at using the shoreline, and can venture into the deep sea. Species A becomes extinct (it survived for a while but the ecology challenges and opportunities changed, in part due to the new existence of species B). Species C is more adept at living in the deep sea than B, and has no need to use shorelines at all. Species B becomes extinct (it survived for a while but the ecology challenges and opportunities changed, in part due to the new existence of species C). 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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herebedragons Member (Idle past 888 days) Posts: 1517 From: Michigan Joined:
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It does not matter how you look at this, 49 920 transition steps being absent today seems a bit suspect. 1 mutation does not equal 1 species by any stretch of the imagination. For example, you likely have up to 300 mutations that neither of your parents had and you are not a new species are you? I suppose that one mutation could cause such a change and that a new species could be described because of a single mutation (for example polyploidy), but it is not necessary so. Some mutations are rather large, such as inversions, deletions (of whole segments), transposons, and so on. If 1000bp of DNA are inverted, is this one mutation or 1000? The other problem is most mutations are neutral mutations. This means they occur in regions that have little or no affect on the fitness or phenotype of the individual. These neutral mutations can then accumulate until a subsequent mutation utilizes them and then can cause significant changes in phenotype. One mutation of many? So the assertion that it requires 50,000 mutations, and therefore 50,000 transition steps is completely unfounded.
quote: The statement of 50,000 mutations itself is a baseless assertion Where did he come up with that number? Did he study genomic differences between cows and whales or just pull the number out of his ***? (*** = hat) But ascribing that number to transition steps goes even farther out into left field (out of the park even, and I don't mean a home run!). It does not take into account size of the steps, or mutations that accumulate before a transition, or the types of mutations. So lets speculate and say that maybe it takes 1,000 mutations to produce a new species (3 times what you could have in your DNA right now). That only leaves us with 50 transitions. Would that be feasible? Now, had you asserted that the changes happened to rapidly too be accounted for by RM/NS (Darwinian style evolution), this may be something we could work with. Evolutionists use a metric for evolutionary change called the Haldane (some still refer to the Darwin). I won't try to explain the concept here, you will have to research it (or perhaps you are already familiar with it?). If you could show that the evolution change from Indohyus to Dorudon measured in Haldanes greatly exceeds the rate of change we observe today, measured in a way that scientists accept you may actually be able to build a case. You have to realize that it takes a lot of work to understand and argue this stuff. You can't just parrot what you read on creationist web sites, you have to learn what evolutionists really believe and what is actually a fact. I used to hate the comeback "Go read a Biology book", but it is appropriate. Understand what you are arguing, don't just repeat what others say because it may just be inaccurate or misleading. Research, research, research! HBD ABE: After posting saw that ZD had responded in a similar vein, Didn't mean to dogpile you> Edited by herebedragons, : No reason given.
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herebedragons Member (Idle past 888 days) Posts: 1517 From: Michigan Joined: |
They should have got out of the water and learned to climb mountains instead? No. That was not my logic. I have not corroborated this date with other sources yet, but Wikipedia has the Tethys closed by 50mya. So the Pakicetids and Ambulocetids would have been faced with a dwindling marine environment as the ocean closed. As the Indian plate slid under the continental plate and lifted it, it would have created isolated bodies of water. And indeed, Pakicetids and Ambulocetids are believed to have spent time in both freshwater and marine environments.
but that's no reason why animals which already lived in the sea should have got less well-adapted to doing so. Pakicetids and Ambulocetids were still dependent upon land or at least shallow waters similar to modern crocs. Rodhocetus, while it inhabited coastal areas, was completely aquatic and could not have gotten around on land. However, Rodhocetus (45mya) fossils are found about halfway between the modern Indian coast and the Himalayas. If the Tethys was indeed closed by 50mya, they were trapped. Would their evolutionary course continued to favor life in the open ocean? I wouldn't think so, but this series shows that they did. By about 37mya Dorudon managed to have worldwide distribution. Just an expansion on my reasoning behind
quote: It very well could have worked the opposite way. The violent formation of the Himalayas was trapping them against the coast and this drove them to seek shelter and food in the Tethys eventually completely retreating into the sea to escape the intensity of mountain building. However, it seems that we would need to delay the closing of the Tethys by 10my in order for this scenario to make sense. So, my logic is not quite as ridiculous as "getting out of the water and learning to climb mountains" is it? HBD
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caffeine Member (Idle past 1055 days) Posts: 1800 From: Prague, Czech Republic Joined:
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If Rodhocetus did live only in an enclosed sea, cut off from the Indian Ocean, then modern whales didn't descend from them. They would have died out at some point as their ocean shrunk (or perhaps before, for some unrelated reason).
However, before the gap closed, blocking off the Tethys ocean from the wider seas, there would have been a traversable passage, with either Rodhocetus or similar relatives living on either side of it. The whales we can find fossils of would be those on the inside, since where they died is now above sea level and accessible to palaeontolgists. There were still other whales in the open ocean, however, continuing to adapt to life there.
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dan4reason Junior Member (Idle past 4173 days) Posts: 25 Joined: |
quote: Keep in mind that there are a few factors that make the fossil record imperfect. As you see, each species is only a side-branch off the family tree, and may have added unique characteristics after it split off. If those unique characteristics (of a primitive form) are similar to those of more evolved forms (more whalelike), then we are seeing convergent evolution. Lets say that Pakicetus splits off from the line of species leading up to whales. Further forms of Pakecitus hypothetically evolve more whale-like forms, but then eventually die out. This is convergent evolution. It makes it seem as if more advanced species appeared earlier. Also notice that more primitive forms can exist along-side more advanced forms. E.g. bacteria are still around even when they evolved before mammals. Another fact is that sometimes a fossil is placed in slightly wrong strata e.g. a deer dies in a pit that contains strata that is 5 million years old. Sometimes the dating method is off (sometimes by 5%). Sometimes we may not have a 100% accurate representation of a species morphology so it may really be more primitive or more advanced than it appears. Sometimes we may not have an accurate view of when a species has been around because we have not found all the fossils yet. E.g. Pakecitus may actually have started at 65 million years ago, not 55 million years ago (making it earlier than Himalayacetus), and we may just not have found the oldest fossils yet. Some species may not be the earliest representative of their step in evolution. E.g. Pakecitus may be not be the earliest representative of its evolutionary grade, and it may have an ancestor very much like it that precedes Himalayacetus, and Pakecitus is only a primitive species that has survived to live along-side more advanced ones. So this tends to fuzzy up the evolutionary trend, but we still usually tend to see a trend.If you take a look at the graph herebedragons made in message 43, we still see a general statistical trend from more primitive to more advanced. Here are some articles about it. Here is an article by the people who found the fossil.Just a moment... Here is another description of the fossil.Found from Jaw bone. As you see from this source, it is only known from a few jaw remnants.Thylacosmilus - Facts and Pictures Here is another discussion of this fossil.http://www.sciencenews.org/sn_arc98/10_10_98/fob3.htm Since we know very little about this controversial fossil, lets not use it to mess up whale evolution.
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herebedragons Member (Idle past 888 days) Posts: 1517 From: Michigan Joined: |
However, before the gap closed, blocking off the Tethys ocean from the wider seas, there would have been a traversable passage, with either Rodhocetus or similar relatives living on either side of it. The whales we can find fossils of would be those on the inside, since where they died is now above sea level and accessible to palaeontolgists. There were still other whales in the open ocean, however, continuing to adapt to life there. Sure, that's reasonable. I would like to see how the fossil evidence supports the idea, but I still have some work to do putting that information together. The timing still seems a bit off. But, it would certainly have been an intense time of geographic change in that area. Perhaps that is indeed what caused the diversity and changes. Thanks for the reply HBD
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jar Member (Idle past 425 days) Posts: 34026 From: Texas!! Joined: |
Remember that you are talking about 50 to 60 million years for closing the Tethys Ocean, maybe longer.
Anyone so limited that they can only spell a word one way is severely handicapped!
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