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Member (Idle past 1425 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: Evolution and Increased Diversity | |||||||||||||||||||||||
Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes:
Isn't that like saying the color of your new car is the result of your choice in the showroom and not the result of the pigmentanation in its paint?
That part of evolution is included in the ToE under the sections on natural selection. The environment is what drives changes in diversity, not something inherant to the process of evolving. If the environment is favorable, diversity increases, if it is unfavorable, diversity decreases. Random mutation and selective factor that are not associated with the environment, will not necessarily lead to an increase in diversity and can actually have a decrease. It the effects of the environment that effect the diversity.
I'm gonna strain my brain to get this, Catholic. Are you saying that only environmental factors independednt from biological evolution can account for biodiversity? ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
Martin, question: Would you say the overall increase of biodiversity in Sepkoski's graph shown below is or is not associated with of biological evolution?
I can agree that an increase in biodiversity is NOT the automatic outcome of biological evolution. We have plenty of evidence on lesser timescales supporting that claim. But I am saying that on a macroscopic timeframe since the Permian Extinction biological evolution has produced a overall increase in biodiversity. No! ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes:
I agree”when lesser timescales are inviolved. And I already have said so. Do you think the macro timescale represented in Sepkoski's graph has any bearing on this issue? Environmental factors drive the increase in biodiversity. Species can evolve independent of environmental factors. Therefore, evolution does not necessarily lead to an increase in biodiversity. ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes:
Yes, I got it, like a holy shitball smack in my corpus whatever. But I've already agreed to that. Now, please tell me this: If you let loose a population of microorganisms on the surface of a biofriendly Mars, would that population necessarily diversify without Mars' environment changing in any way? Holy Shitballs! That's my whole point. That's what I'm trying to get you to understand. It looks like you get it. My answer: Not necessarily, if you can assume that those microorganisms would have no effect on Mar's enviromnmet. Can you assume that? ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes:
Why doesn't it also show that the extant biota and its potential for evolution also favored an increase in biodiversity? Yes, it shows that the environment has been favorable to an increase in biodiversity. ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes:
I agree. (But, oops, people who live in glass houses, you know.)
It does. It just doesn't show that its necessary. The extant biota tends to diversify.
With or without evolution? ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
RAZD writes:
I do like this one, RADZ. It reminds me of a line from a county-western song: "There ain't no safer sex than the sex I ain't having with you." But you can't become less diversified than extinct. I think I see your point about randomness...maybe something like the random walk idea. Do I copy you correctly by saying that if a single species of bacteria were to be placed in sterile but fertile environment the only thing it could do evolutionarily would be to diversify. Otherwise it's extinction. ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes:
How could this viewed in an evolutionary context? Are you going to tell me that a single that doesn't evolve is engaged in evolution? Or stasis. It could thrive and not evolve and not go extinct. ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes:
Well...yes...if you say so.
If the allele frequencies in the population changed then it would be evolving, but if it remained as one species, then there was not an increase in biodiversity. I've come to understand biodiviersity to mean, in this thread at lease, the number of species present.
Why can't it be numbers of genera or families?
Certainly, you could argue that if the allele frequency changed, then that one species would be more biodiverse. But that would be conflating definitions.
Paraphrasing what RAZD already said: 'To a single species, there's nothing less diverse than no species at all.'
...it could thrive and not evolve and not go extinct....Make sense?
Sure, so long as you agree that if a species neither evolves nor goes extinct has not been engaged in that biological process we call evolution. If this doesn't make sense then I must goin' nuts! ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
From Message 77:
CS writes:
And from your last post:
If the allele frequencies in the population changed then it would be evolving, but if it remained as one species, then there was not an increase in biodiversity. You've basically said that if a species isn't evolving then it isn't evolving. Quite tautological.
I'm getting dizzy. I better back off my medicine.
I don't think its possible for a species to not be engaged in that biological process we call evolution.
Probably true, but hard to prove.
It sounds like I'm contradicting myself but it really boils down to the way people use the word "evolve".
What people? Most biologist I know of think that biological evolution is a process of change rather than a process of maintianing the staus quo. Back to RADZ's question. Does biological evolution necessarily lead to biodiversity? I think most biologists would have to say 'no'...at least for microscopic timeframes. But what still bothers me is that interesting increase of marine families since the Permian Extinction, shown in Sepkoski's graph in Message 56. Makes me want to get foolish and conclude that the last 245 million years of evolution on Earth have demonstrated a rather steady increase in biodiversity. Just coincidendal with environmental conditions and nothing more? Or an embedded law of macroevolution? One obvious thuth cannot be ignored: No environmental condition remains unchanged for very long, not in geological timesframes. ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
RADZ writes:
RADZ, this is a nice challenge to my early morning brain. I apprerciate it. Let me try to deconstruct your argument, if I actually can do it: HM writes:
Think of it this way: it happened because back then the ecology and the habitability of the planet was such that it could happen, and because it could happen there was a 50-50 chance that it would, meanwhile life muddled along evolving as it went. But what still bothers me is that interesting increase of marine families since the Permian Extinction, shown in Sepkoski's graph in Message 56. 1. You are saying that macro-biodiversity is purely a consequence of "the ecology and habitability of the planet." I could hardly disagree with this. If Earth's atmosphere, for example, had been hotter 1000 C and made of nothing but mercury vapors I don't think we'd see much of a record of macro-biodiversity. 2. And you are saying that because macro-biodiversity "could happen there was a 50-50 change that it would." Here's where I start having trouble. What enables you to assume that macro-biodiversity has a "50-50 chance" of happening? Why not a 60-40 or 99-1 chance of biodiversity happening. Wouldn't that also depend on inherent factors in the biological populations, such as alleles that can be exapted for bio-diversification? Is there no biological component to your argument that allows for integrated participation with ecology and habitability? Didn't cyanobacteria once radically alter Eath's ecology and habitability in ways that accommodated increasing bio-diversity? 3. And you say that "meanwhile life muddled along evolving as it went." Does this automatically mean then that biological evolution could not muddle in the direction of macro-diversification? Or does it mean that such muddling is totally limited by environmental conditions...independed of life itself? RADZ, why couldn't that obvious trend of increasing biodiversity in the last 245 million years be the result of an integrated sort of muddling, wherein the biota and their habitats do not change independently but are instead push and pulled by each other in combination? That's the best I can do for this issue. You and CS may be right about the Post hoc ergo propter hoc falacy, which means "After this therefore because of this'." But I stiil don't see how this negates the obvious trend toward macro-diversification on Earth. Not if biota and their habitats historically evolved together, leaving a chicken-and-egg conundrum impossible to separate using your Post hoc ergo propter hoc argument. Did I score any points at all this morning? ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes:
Yes, I suppose, if 245 million years of macro-evolution on earth is not enough to test the idea. Maybe what we need is a sterile-but-fertile planet to infect with life to see what happens. I'll bet that bio-diversification happens automatically on that panet, assuming that life can actually survive there and proliferate. We need more information to determine if evolving causes the increase. ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes: You could put a species in a biodiverly neutral environment and see if there is diversification by default. You could then introduct selective pressure for either an increase or a decrease in biodiversity. If there was no increase without the pressure and the biodiversity increases and decreases with the respective pressures, then we could determine that the environment is what is causeing the changes in the diversity and not something inherant to the process that drives the diversification. Make sense? Maybe. Because it could go either way. And there would be matters of ecological capacity to consider. My problem is that I can't tell where the organism ends and the environment begins. And I can't tell the difference between "before" and "after" in your rule: "Post hoc ergo propter hoc falacy, which means "After this therefore because of this'." Catholic, I'll posit one in your favor: ecological succession. Usually ecological succession leads to a decrease in biodiversity, climaxing to stability with fewer extant species. Again, I'm only sinning off from Sepkoski's graph, wherein I find evidence of macro-diversification. Then I'm taking the precarious next step to say that macro-evolution inherently proceeds toward macro-diversification. Side question: Isn't all evidence reducible and refutable by using your "Post hoc ergo propter hoc argument? ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
CS writes: Without other evidence, it is the post hoc fallacy. Well, then the theory of the expanding universe is a post hoc fallacy, too, since there are no other universes with which to "correlate" (your term) the observation. ”HM
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Fosdick  Suspended Member (Idle past 5520 days) Posts: 1793 From: Upper Slobovia Joined: |
RADZ writes:
If it can be shown that the random walk principle of Cope’s rule is reasonable and verifiable with empirical evidence , I don’t see why that same random-walk principle shouldn’t also apply to evolution, with regards to macroscopic increases in biodiversity. Cope's rule states that the size of a species will increase over time - is that a necessary result of evolution (it's called a "rule" after all eh)? Nope, but it is more common than not. ”HM
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