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Member (Idle past 1653 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: How do "novel" features evolve? | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1653 days) Posts: 20714 From: the other end of the sidewalk Joined:
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idscience raised the old creationist question - how does macroevolution explain the development of novel features.
The big problem with this question is that macroevolution does not cause any evolutionary change. All evolution occurs at the breeding population level by the process of microevolution - or just plain evolution:
(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities. This is a feedback response system that is repeated in each generation:
What separates (micro) evolution from the macro view of evolution (macroevolution) is the process of speciation, as evolution occurs within the breeding population, and nested hierarchies are formed by speciation events, and macroevolution is just a macro view of what occurs over several generations via evolution and speciation. If we look at the continued effects of evolution over many generations, the accumulation of changes from generation to generation may become sufficient for individuals to develop traits that are observably different from the ancestral parent population. This lineal change within species is sometimes called phyletic change in species. This is also sometimes called arbitrary speciation in that the place to draw the line between linearly evolved geneological populations is subjective and because the definition of species in general is tentative and sometimes arbitrary. If phyletic change in species was all that occurred, then all life would be one species, readily sharing DNA via horizontal transfer (asexual) and interbreeding (sexual) and various combinations. This is not the case, however, because there is a second process that results in multiple species and increases the diversity of life.
(2) The process of divergent speciation involves the division of a parent population into two or more reproductively isolated daughter populations, which then are free to (micro) evolve independently of each other. Over generations phyletic change occurs in these populations, the responses to different ecologies accumulate into differences between the hereditary traits available within each of the daughter populations, and when these differences have reached a critical level, such that interbreeding no longer occurs, then the formation of new species is deemed to have occurred. After this has occurred each daughter population microevolves independently of the other/s. These are often called speciation events because the development of species is not arbitrary in this process.
So is divergent speciation necessary to explain novel features? Short answer: no. Longer answer: it could occur during the process of the evolution of the feature, and it may even result in a speciation event, but it isn't necessary to explain the evolutionary process for developing a novel feature. Thus we really only need look at phyletic change within species, or the basic process of evolution occurring over several generations. How many generations? But before we can begin to answer that, we first need to answer the question: what is a novel feature?
So a novel feature would be one that did not appear in the ancestral population. We can look at dogs and ask couple of questions:
quote: bold added. I could not find any examples of wolves with these characteristics, so are they novel features? Creationists like to argue (pointlessly) that descendants of dogs will always be dogs (while evolution says the descendants will always be members of the dog clade), but what happens when these dog descendants develop novel features, like webbed feet? We know that our dog breeds occurred by standard evolutionary processes, with artificial selection of traits that appear in the dog populations chosen by the breeders. The breeders do not cause mutations to occur, just select those they want in the breed from the ones that occur. Is that enough? Enjoy. Edited by RAZD, : clrty Edited by RAZD, : changed picture Edited by RAZD, : titleby 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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RAZD Member (Idle past 1653 days) Posts: 20714 From: the other end of the sidewalk Joined: |
this could also be added to Introduction to Evolution
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AdminModulous Administrator (Idle past 233 days) Posts: 897 Joined: |
Thread copied here from the How "novel" features evolve thread in the Proposed New Topics forum.
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NoNukes Inactive Member |
I'm glad to see this thread started.
I'm not competent to contribute much to it. But I'd like to see a PRATT addressed during the discussion. A creationist might state that nature cannot create the "information" required to produce novel features and "macroevolution" . Dog breeding includes human intervention which can be viewed as being similar to an ID agent stepping in to add information allowing new features like wiener-dog legs.Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison
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Tangle Member Posts: 9580 From: UK Joined: Member Rating: 7.0 |
Similarly, the golden oldie of the peppered moth - they can switch between black/grey and white/grey but they can't switch to red or barber's pole stripes.
Life, don't talk to me about life - Marvin the Paranoid Android
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RAZD Member (Idle past 1653 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi Tangle
Similarly, the golden oldie of the peppered moth - they can switch between black/grey and white/grey but they can't switch to red or barber's pole stripes. The natural selection that was observed in the peppered moth is addressed in Peppered Moths and Natural Selection. Expecting "red or barber's pole stripes" to occur on demand is a grave misunderstanding of how evolution works -- it is a reactive system not a purpose directed system. There has to be a cause for it to be beneficial to survival and breeding, and then there have to be mutations that can be selected. Expecting the peppered moths to be about the evolution of new features is a misunderstanding of what the peppered moths are used for: evidence of natural selection. Enjoy. Edited by RAZD, : subtitleby 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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RAZD Member (Idle past 1653 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi NoNukes,
A creationist might state that nature cannot create the "information" required to produce novel features and "macroevolution" . Dog breeding includes human intervention which can be viewed as being similar to an ID agent stepping in to add information allowing new features like wiener-dog legs. Curiously, the mutations that cause short legs are fairly common in many species, including humans - it's called Dwarfism. The difference is between a random mutation occurring and it being spread into the breeding population is selection. Within the ecological challenges and opportunities imposed by artificial selection, there is a survival and reproductive benefit to having short legs for the dogs being bred that have them, and not having them would be detrimental. This is a rather demanding ecology to survive in, yes? Now the problem with the creationist\IDologist claim about information is that they don't define what the concept means or even more importantly, how it can be measured. There is, however, some evidence that we can look at which shows that either the concept "nature cannot create the information" is either falsified or irrelevant See Figure 1 from Nature 421, 264 - 267 (16 January 2003); doi:10.1038/nature01313
Walkingstick insects originally started out as winged insects (blue at start and top row). That diversified. And some lost wings (red). And diversified. And some regained wings (blue again). And diversified. And one lost wings again (Lapaphus parakensis, red again). And this doesn't even address the ones where one sex (usually male) has wings and the other sex doesn't (the red includes these, so it is hard to determine from this graphic how many times the female sex gained and lost wings independent of the winged males). But the issue is -- if the loss of wings is information loss, then regaining wings is information gain ... or whatever was lost is not important to evolution. Then there is http://www.millerandlevine.com/km/evol/DI/AcidTest.html Where a gene that enabled the bacteria to metabolize lactose was intentionally deleted (information removed?) and the bacteria regained the ability to metabolize lactose (information regained? ... or doesn't constrain evolution). There are other examples, and we could probably have a whole thread just on evidence that either information is gained, or the concept is irrelevant, to what can or cannot constrain evolution. Enjoy Edited by RAZD, : changed img to thumb for faster loadingby 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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RAZD Member (Idle past 1653 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi NoNukes,
A creationist might state that nature cannot create the "information" required to produce novel features and "macroevolution" . Dog breeding includes human intervention which can be viewed as being similar to an ID agent stepping in to add information allowing new features like wiener-dog legs. Curiously, the mutations that cause short legs are fairly common in many species, including humans - it's called Dwarfism. The difference is between a random mutation occurring and it being spread into the breeding population is selection. Within the ecological challenges and opportunities imposed by artificial selection, there is a survival and reproductive benefit to having short legs for the dogs being bred that have them, and not having them would be detrimental. This is a rather demanding ecology to survive in, yes? Now, if we take an ecology that selects for a carnivore with short legs ...
quote: We would not be surprised. And if we then take a similar ecology and modify it to select for aquatic behavior with webbed feet ...
quote: We would not be surprised. And here we have just two members of the same family evolving according to different ecological challenges and opportunities, with the same kind of evolution seen in dogs. Enjoy. Edited by RAZD, : changed img to thumb for faster loadingby 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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Dr Jack Member (Idle past 123 days) Posts: 3514 From: Immigrant in the land of Deutsch Joined:
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With respect, the adaptive short legs of weasels and the dechondroplastic legs of those dogs are fundamentally different in genetics and morphology.
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Tangle Member Posts: 9580 From: UK Joined: Member Rating: 7.0
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RAZD writes: Expecting the peppered moths to be about the evolution of new features is a misunderstanding of what the peppered moths are used for: evidence of natural selection.
The argument used by creationists against the peppered moth is the same as you're discussing in this thread - how 'novel' features evolve. They would say that the moth already has the genes to be light or dark so that they can be selected. So it's no big deal that they actually do get selected for when the trees change colour. If the trees in the woods all suddenly got painted red and white, the moth would be wiped out because it can't develop a red and white gene to be selected for. So in their eyes, God put the whole moth genome together and included a light and dark gene but omitted red. The moth can't produce red from nowhere. Now of course many moths have red and white colouration in their palette and it's likely our peppered moth actually does too. But that doesn't help our cause here, because if the moth already has the gene then god put it there for the purpose of surviving a red pole event - the moth did not gain the gene as a result of the event. Just saying........ Edited by Tangle, : No reason given.Life, don't talk to me about life - Marvin the Paranoid Android
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zi ko Member (Idle past 3868 days) Posts: 578 Joined:
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A creationist might state that nature cannot create the "information" required to produce novel features and "macroevolution"
There could be anotther responce version:organism-environment interaction provides the needed information for mutations tobe somehow guided.
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Panda Member (Idle past 3961 days) Posts: 2688 From: UK Joined:
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zi ko writes:
Yes. But the list of unevidenced fantasy causes is almost infinite in number. There could be anotther responce version:organism-environment interaction provides the needed information for mutations tobe somehow guided. So we try to ignore them - along with fairies, unicorns and flying spaghetti monsters. When they become evidenced: then they are of interest. If I were you And I wish that I were you All the things I'd do To make myself turn blue
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Admin Director Posts: 13106 From: EvC Forum Joined:
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Hi Zi Ko,
Unless you're including evidence to support your arguments, please do not post in this or any other science thread. Also, in this case you're trying to introduce your own preferred hypothesis of environment-directed evolution. That is not the topic.
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RAZD Member (Idle past 1653 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi Mr Jack
With respect, the adaptive short legs of weasels and the dechondroplastic legs of those dogs are fundamentally different in genetics and morphology. But the point is that the dechondroplastic legs could be selected for a specific ecology, such as occupied by the weasel. I also saw where the age of the Mustelidae clade was quite old and also undergoing some revisions due to genetic information. Mustelidae - Wikipedia
quote: That is quite a diversity of behavior, with each of the different behaviors being enabled by specific variations within this clade. We can posit a link between behavior and selection, with successful behaviors(1) enabling survival and reproduction. When we look again at the Newfie dog we see more adaptation than just the webbed feet.
quote: We also see "great lung capacity for swimming extremely long distances, and a thick oily and waterproof double coat which protects them from the chill of icy waters" and a "down-and-out motion, which can be seen as a modified breaststroke" swimming behavior. It is unlikely, imho, that the webbed feet, oily coat or swimming pattern were specifically selected by the breeders, as it is more likely that they selected for basic swimming ability or simply for a dog that was good for a cold marine coastal ecology. These adaptations certainly enable a more active marine behavior than seen in most other dogs, which could easily maintain selection for even more active marine behavior.
Thus we see that an initial small novel trait due to random mutations can enable modified behavior that allows the carriers to move into a slightly different ecology. In that ecology the novel trait is beneficial, and this causes the feedback selection to maintain the trait and increase further adaptation to that ecology. This fixes the novel trait in a breeding population, and can start the process of speciation or varietal diversification. Traits like shorter legs and webbed feet are seen in many species (including human), however selection generally returns the population to more normal legs and feet. Enjoy. (1) - while meme is defined as "an idea, behavior or style that spreads from person to person within a culture" this is more of an enabled modification of existing behavior than a newly learned one.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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RAZD Member (Idle past 1653 days) Posts: 20714 From: the other end of the sidewalk Joined: |
In Message 1 I asked
I could not find any examples of wolves with these characteristics, so are they novel features? Creationists like to argue (pointlessly) that descendants of dogs will always be dogs (while evolution says the descendants will always be members of the dog clade), but what happens when these dog descendants develop novel features, like webbed feet? According to the (adjective) definition of novel as something "not seen before; new" and as webbed feet do not appear to be a characteristic of wolves, then technically they are a novel feature in this clade (wolves and dogs), a derived trait developed by mutation and adaptation of an existing trait. What if the finger\toe bones become elongated, so the webbing fills a larger area? That's just genetic variation, yes? Is that a novel trait? What if the elongated finger\toe bones enable new behavior? Page not found – METROGAYA
My favorite frog, (Rhacophorus nigropalmatus), commonly known as Wallace's flying frog.
quote: So when we combine webbed feet with extended finger\toe bones and other continued adaptations for a coastal marine environment (lungs, fur, etc) do we end up with something that is not a dog?
quote: Again we see the homologies in the bones of the seal to those of dogs or wolves, typical of homologies for all mammals, with only a little (derived) modification of the arm and foot lengths. Is this what creationists mean by novel? (or do I have a sense of impending goal-post moving ... )
quote: Again, the skeleton will show typical mammal homologies in the rest of the bones, and here we can see the homologous finger and arm bones through the thin webbed skin where the derived traits are the lengths of the bones. Is this a novel trait? It looks like nothing more than continued adaptation of webbed limbs to enable modified behavior, and perhaps open up ecological opportunities. Is this not a major innovation? Is this the result, accumulated over several generations, of normal evolution - the change in the frequency distribution and composition of hereditary traits within breeding populations, from generation to generation, in response to ecological challenges and opportunities - or is this something else, some other, perhaps major\significant\wondrous process? Enjoy. Edited by RAZD, : word orderby 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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