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#21
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Steve Schaffner wrote:
"Dylan" writes: .. . . . No, that's not what he means. Blind cave fish *might* have lost their sight because blindness made them more fit, e.g. if they were able to redirect some resources previously used for vision. But they might also have lost their sight because their fitness became independent of whether they had sight or not. If a trait does not confer greater fitness, there is an excellent chance that it will disappear because of random mutations. -- Steve Schaffner .. . . . Suppose a population of fish gets trapped in a large cave with a large body of water in complete darkness. At first they are all sighted. But over time a blind percentage develops. Then, over more time, a percentage of the blind percentage develops antennae that help them better find food. Suppose, further, that at some point in time there are three subpopulations of equal size: original sighted, evolved blind, and further evolved blind fish with antennae. Now my questions: 1. Which subpopulation shows the greatest "survival of the fittest"? 2. Which shows the least? 3. And why? Thanks in advance, Dylan %0 |
#22
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On 17 May 2005 10:48:06 -0700, "Dylan"
wrote: Bobby D. Bryant wrote: On Tue, 17 May 2005, "Dylan" wrote: Bobby D. Bryant wrote: On Tue, 17 May 2005, wrote: survival of the fitest is based on chance. SotF describes a _bias_ to chance. Explain, Spock. SotF means that those that are "more fit" are more likely to survive and reproduce. Chance still plays a role -- even the fittest might be struck by lightning before breeding -- but chance isn't the *only* thing that goes into the determination of which creatures reproduce and which don't. I.e., SotF _biases_ the chance. -- Bobby Bryant Austin, Texas Do you mean that cave fish that have evolved into blindness are more fit than their ancestors? They are better adapted to live in total darkness. So why would a god decide to create fish with out eyes to live in darkness? |
#23
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On Tue, 17 May 2005, "Dylan" wrote:
I didn't, I just find the "survival of the fittest" concept fascinating, and I want to learn more. I'm not too crazy about the term myself, mostly because lots of people seem to read too much in to it. I prefer a very detatched point of view, namely that some individuals/populations/species propagate into future generations and others don't. Which do and which don't is _partly_ a matter of chance -- asteroid strikes, dangerous new prey moves in, climate change kill off food source, etc. -- but when all else is equal, some individuals/populations/species are better able to avoid certain problems and/or exploit certain opportunities, and that gives them a statistical advantage in the roll of the die that determines which propagate and which go extinct. Fitness isn't an absolute; what's advantageous in one context might be disadvantageous in another. But if you've got some trait that's advantageous in some context, *and* you're actually in that context, then you can reap the rewards for that advantage. Your answer is helpful. Thanks. You're welcome. -- Bobby Bryant Austin, Texas |
#24
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On 17 May 2005 11:40:57 -0700, "Dylan"
wrote: I didn't, I just find the "survival of the fittest" concept fascinating, and I want to learn more. Well first off, forget the idea that it means survival of the biggest and strongest and fiercest. The example I like to use is the tiger and the bunny rabbit. Which is fiercest and strongest? Which is an endangered species likely to soon be extinct? Fittest means best suited in some way to survive. In the case of the rabbit this means an ability to run fast and reproduce rapidly. It can mean having the right protective coloration or having developed a bad taste predators don't like. It often means fitting into some environmental niche better than other species. Nor does failure to survive necessarily imply a defect in a species. If a moist fertile area like North Africa used to be becomes a desert with the retreat of ice-age glaciers, many species will not survive the sudden change because they are not 'fittest' in a desert environment. See also: http://www.talkorigins.org/faqs/faq-...o-biology.html ## A mind stretched by new ideas ## can never go back to its original dimensions. |
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Dylan wrote:
Bobby D. Bryant wrote: On Tue, 17 May 2005, "Dylan" wrote: Bobby D. Bryant wrote: On Tue, 17 May 2005, wrote: survival of the fitest is based on chance. SotF describes a _bias_ to chance. Explain, Spock. SotF means that those that are "more fit" are more likely to survive and reproduce. Chance still plays a role -- even the fittest might be struck by lightning before breeding -- but chance isn't the *only* thing that goes into the determination of which creatures reproduce and which don't. I.e., SotF _biases_ the chance. -- Bobby Bryant Austin, Texas Do you mean that cave fish that have evolved into blindness are more fit than their ancestors? That may very well be the case - the cost of building eyes is not insubstantial. -- John S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project University of Queensland - Blog: evolvethought.blogspot.com "Darwin's theory has no more to do with philosophy than any other hypothesis in natural science." Tractatus 4.1122 |
#26
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In article ,
John Wilkins wrote: Dylan wrote: Bobby D. Bryant wrote: On Tue, 17 May 2005, "Dylan" wrote: Bobby D. Bryant wrote: On Tue, 17 May 2005, wrote: survival of the fitest is based on chance. SotF describes a _bias_ to chance. Explain, Spock. SotF means that those that are "more fit" are more likely to survive and reproduce. Chance still plays a role -- even the fittest might be struck by lightning before breeding -- but chance isn't the *only* thing that goes into the determination of which creatures reproduce and which don't. I.e., SotF _biases_ the chance. -- Bobby Bryant Austin, Texas Do you mean that cave fish that have evolved into blindness are more fit than their ancestors? That may very well be the case - the cost of building eyes is not insubstantial. And a large part of the brain to support it. It's like those battle tgames where you are given a number of points and are allowed to buy attributes for you characters with those points. There are more rats in NYC than humans. And I am sure more cockroaches than rats. -- Guns don't kill people; automobiles kill people. |
#27
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![]() Walter Bushell wrote: ..... Dylan wrote: ..... Do you mean that cave fish that have evolved into blindness are more fit than their ancestors? [Someone wrote:] That may very well be the case - the cost of building eyes is not insubstantial. Walter Bushnell wrote: And a large part of the brain to support it. It's like those battle tgames where you are given a number of points and are allowed to buy attributes for you characters with those points. There are more rats in NYC than humans. And I am sure more cockroaches than rats. ..... Dylan writes: Point taken. Now can you give me an example - such as long feelers - which might make blind cave fish more fit than their cousins who are still sighted but have not evolved the feelers? I'm suggesting feelers because while you (and others) have suggested that the blind cave fish could well be better fitted because they could transfer some of their energy budget away from building/maintaining eyes to something else. The theory makes sense. Any real-life examples? Any thought-experiment examples? I learn best by contemplating real-life examples. Thanks. |
#28
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On Thu, 19 May 2005, "Dylan" wrote:
Dylan writes: Point taken. Now can you give me an example - such as long feelers - which might make blind cave fish more fit than their cousins who are still sighted but have not evolved the feelers? I'm suggesting feelers because while you (and others) have suggested that the blind cave fish could well be better fitted because they could transfer some of their energy budget away from building/maintaining eyes to something else. The theory makes sense. Any real-life examples? Any thought-experiment examples? I learn best by contemplating real-life examples. Thanks. Just a point of clarification, that "something else" doesn't have to be a new feature. It could be stuff it needs to build anyway, such as skin or scales or teeth or whatever. The point is that the sightless fish needs less food and oxygen than it would if it had to support eyes and visual areas of the brain, and the reduced requirements themselves can be an advantage over an all-else-equal kind of fish. -- Bobby Bryant Austin, Texas |
#29
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In talk.origins Dylan sanoi, hitaasti kuin hämähäkki:
cousins who are still sighted but have not evolved the feelers? I'm suggesting feelers because while you (and others) have suggested that the blind cave fish could well be better fitted because they could transfer some of their energy budget away from building/maintaining eyes to something else. The theory makes sense. Any real-life examples? Any thought-experiment examples? I learn best by contemplating real-life examples. Thanks. It takes a lot of developmental and maintenance energy to run eyes. But I don't think you need to go as abstract as an energy budget. You probably increase survival by having less blood and fewer nerve endings concentrated in such a vulnerable area. rich -- -to reply, it's hot not warm +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ \ Rich Hammett http://home.hiwaay.net/~rhammett / "Better the pride that resides in a citizen of the world; \ than the pride that divides / when a colorful rag is unfurled." |
#30
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Any ichthyologists reading this? There are deep sea fish which have
developed long feelers as an alternative to eyes. Presumably they have had longer to adapt to their essentially lightless environment. Some deep sea critters, as you know, are bioluminescent. Perhaps in time some cave animals would develop this. Altho, they'd all be blind by then... For once google fails me, for I can find nothing but vague references to deep sea fish with feelers and useless eyes. Kermit |
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