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Author | Topic: Evidence for Evolution: Whale evolution | |||||||||||||||||||||||||||||||||||||||
Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
Dredge writes: If you could wave a magic wand and remove from human consciousness the notion that species evolve from other species - evolution's core doctrine - it wouldn't make an iota of difference to anything pertaining to the real world. So the theory of evoltion isn't "essential" in ANY way, let alone "a myriad" of ways. It's as irrelevant as a fairy tale. I said essential to our understanding. Evolution is the central unifying concept of biology. For one example of practical utility, evolutionary concepts allow us to track and predict which strain of flu will dominate each flu season, so that flu vaccines tuned to the right virus can be produced months in advance. For another example, understanding descent and mutations allows us to track ancient human migration patterns around the globe. For yet another example, evolutionary concepts drive new design approaches where constructions "evolve" toward a final design. --Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2
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The evolutionary change that moved the whale nose from the tip of the snout to the top of the head is thought to have occurred gradually over millions of years. One source of evidence is whale embryology, where during development the nose originally develops at the tip of the snout, then gradually moves to the top of the head. Fossils are another source of evidence, found this here:
These are Pakicetus (50 million years ago), Rodhocetus (45 mya) and modern whales. Here's a brief Richard Dawkins video on whale evolution that shows the positioning of blowholes on fossils beginning around the 1 minute mark:
--Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
Dredge writes: You seem to saying that the theory of evolution is useful because certain things pertaining to human existence, like technology, evolve. If this is your argument, it's a very poor one. That is not my argument. What I said was, "Evolutionary concepts drive new design approaches where constructions 'evolve' toward a final design." In other words, genetic algorithms. I also pointed out other ways in which evolution is useful. Besides being the central unifying concept of biology, I mentioned predicting flu viruses and tracking human migration. But something doesn't have to be of practical use to humans to be true. Of what practical use is knowledge of the distance to the nearest star, yet it is true nonetheless. --Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
Faith writes: That's built-in variability or "microevolution," which has nothing to do with the ToE. Some of it is inherent variation, some of it is mutation, and all of it is part of the theory of evolution. --Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
We seem to be forgetting that this thread's topic is evidence for whale evolution.
--Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
I'm not planning to step in as moderator at this point, but I would like to remind folks that the topic is the evidence for whale evolution.
--Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2
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Dredge writes: Perhaps I choose the wrong words and didn't express myself properlly previously. What I need is an example of how the belief that all life evolved from a single-cell organism (macroevolution) is useful. You've given some examples of microevoluton, which is not what I'm after. I already know that microevolution has many uses. Say you had two types of walking, microwalking and macrowalking. Microwalking is about minor changes in position, say walking from the front door to the end of the driveway, while macrowalking is about major changes in position, say walking from the front door into town. But microwalking and macrowalking are just different amounts of the same thing: walking. This is analogous to microevolution and macroevolution. Microevolution is about a few mutations and allele mixings after a single generation or perhaps a few generations. Macroevolution is about many mutations and allele mixings after many generations. They're just different amounts of the same thing: evolution. Evolution is descent with modification followed by natural selection. A single generation of descent with modification followed by natural selection can be considered microevolution. Many generations of descent with modification followed by natural selection can be considered macroevolution. The minute changes of microevolution gradually accumulate into significant changes, such as significant structural change. The fossil record is evidence of oftentimes significant structural change over time. The fossils we find in successive geologic layers show small doglike creatures become gradually larger over time to become horses. They record small rodent like creatures becoming mammals. And they record a small weasel-like creature evolving into whales. --Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
Dredge writes: Actually, I was hoping you could help Tangle out and give me an example of how the belief/theory/"fact" that all life evolved from a single-cell organism has "enormous scientific value". Evolution is the central organizing principle of biology. --Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
Dredge writes: Thanks for your "walking" analogy. But I see micro- and macro-evolution like more like this:Micro' is observing that human beings are running the 100 meter sprint faster and faster. Macro' is concluding from the evidence that humans are running the 100 meter sprint faster and faster that humans will keep running faster and faster, until the world record will be less than one second. Whether this is observation or analogy, it fails. No one in biology views microevolution and macroevolution in anything like this way. Microevolution is a evolution that occurs over a few numbers of generations, while macroevolution is evolution that occurs over a great many generations. There is no limit on evolutionary change, just as there is no limit on walking. One can walk to the end of the street or to the other end of the country, it's all just walking. In the same way, evolution can make a bird have a slightly larger beak, or, over a much longer time period, it can turn a weasel-like creature into a whale.
In the same way, the evidence that small changes are observed in organisms cannot be used to predict with certainty that massive changes are possible and inevitable. The observation of small changes over small numbers of generations leads directly to the conclusion of large changes over larger numbers of generations. Experiments with short-generation organisms like bacteria prove this is true.This inevitable accumulation of changes is consistent with the history of change seen in the fossil record, where similar forms follow one after another for millennia, but where the oldest is frequently very different from the youngest. --Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
Dredge writes: Contrary to your claim, experiments with short-generation organisms such as bacteria have not proved that large changes over many generations are possible. There is no limit to evolutionary change, as experiments with short-generation bacteria show. The longer the bacteria are followed the more change is observed. More generally, species evolve gradually into new species in response to adaptation pressures. I'm not sure this is the right topic for you - you don't seem interested in the evidence for whale evolution. --Percy
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Percy Member Posts: 22394 From: New Hampshire Joined: Member Rating: 5.2 |
Dredge writes: If I'm hearing you right, you are claiming that experiments which show changes in bacteria prove that there is "no limit to evolutionary change" and that therefore it is possible that whales evolved from some deer-like land animal. Actually it's a rebuttal to your arguments that there are limits to evolutionary change, and that therefore species in general and whales in particular do not evolve from predecessor species. There are no genetic limits we're aware of to evolutionary change.
So what evidence is left for this tale about whale evolution? The fossil record, of course. Or is there more? The fossil record is one of change over time. It records species change from Indoyus and Pakeicetus through intermediate species up to modern whales. --Percy
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