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Modern debates in evolution?

by kosovo dave
Tags: debates, evolution, modern
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Ygggdrasil
#19
May16-14, 09:51 AM
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Quote Quote by Pythagorean View Post
Hrmm.. I wonder what the chance of the same gene showing up independently in two different species is? (Not the aforemention polymerases, just in genera). I know there's morphological examples of convergent evolution, but are there precise genetic examples?
Horizontal gene transfer is one example which produces this phenomena at the genetic level.
willbell
#20
May16-14, 04:28 PM
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Quote Quote by Cal King View Post
There is a problem with kin selection theory, identified early by social scientists who rebutted E.O. Wilson's book "Sociobiology: The New Synthesis." They point out that kin selection theory is a tautology, meaning it can explain everything. For example, selfish behavior can be explained by individual fitness, but seemingly altruistic behavior can also be explained, by "inclusive fitness." A tautology can never be falsified. Therefore a kin selectionist can invent all sorts of stories and never have to be subjected to falsification.
It could be falsified, by altruism that is geared specifically towards non-kin or even different species. I'm curious, if you'd still consider that tautology, what exactly would you want out of a theory of altruism? After all, any theory that explains altruism would fit into "selfish behaviour can be explained by individual fitness, but seemingly altruistic behaviour can be explained by <insert theory of altruism here>".
jk22
#21
May25-14, 09:35 AM
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It's sometimes said that evolution cannot be falsified, but what about if we consider this experiment : we take a black person and put for some years in a world region with less sun. Then analyzing the genes for reproduction we could maybe see a diminution in the probability for the genes coding for melatonine ? (or the reverse way, a white in africa), thus proving an adaptation of the genome to the environnement...
Pythagorean
#22
May25-14, 10:46 AM
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Quote Quote by jk22 View Post
It's sometimes said that evolution cannot be falsified, but what about if we consider this experiment : we take a black person and put for some years in a world region with less sun. Then analyzing the genes for reproduction we could maybe see a diminution in the probability for the genes coding for melatonine ? (or the reverse way, a white in africa), thus proving an adaptation of the genome to the environnement...
That wouldn't falsify evolution and it's not a contested point that adaptation depends on environment. Genetics is only half of evolution.
willbell
#23
May25-14, 12:26 PM
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Quote Quote by jk22 View Post
It's sometimes said that evolution cannot be falsified, but what about if we consider this experiment : we take a black person and put for some years in a world region with less sun. Then analyzing the genes for reproduction we could maybe see a diminution in the probability for the genes coding for melatonine ? (or the reverse way, a white in africa), thus proving an adaptation of the genome to the environnement...
Evolution requires several generations to act, mutations don't just happen like that (the only ones that have a chance of getting passed on happen in your reproductive organs). Plus, we've already seen changes in species to suit their environment, so it would hardly be something new.
willbell
#24
May25-14, 12:28 PM
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Quote Quote by Ygggdrasil View Post
Horizontal gene transfer is one example which produces this phenomena at the genetic level.
Pythagorean seems to be trying to talk about it happening through evolutionary means (two separate genes evolving to be the same), rather than Horizontal Gene Transfer, in which the gene only evolves once.
jk22
#25
May25-14, 02:04 PM
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Quote Quote by Pythagorean View Post
That wouldn't falsify evolution and it's not a contested point that adaptation depends on environment. Genetics is only half of evolution.
But how would evolution act on a lot of generation if it's not transfered in the genes ?
Ryan_m_b
#26
May28-14, 04:39 AM
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Quote Quote by jk22 View Post
But how would evolution act on a lot of generation if it's not transfered in the genes ?

An individuals genome doesn't change, you have the same genome through out your life. When reproduction occurs the offspring gets half its genetic material from one parent and half for another but when that DNA is made it is not copied perfectly. There will be errors such as changes in the sequence, duplicated segments, deleted segments etc. This means the organism will be ever so slightly different. Going back to your example of a population of black people moved to higher latitudes: some children will randomly be born with mutations causing slightly less melanin to be produced. These children will have a slight advantage in terms of vitamin D synthesis and be more likely to stay healthy and have kids of their own, thus spreading the genes for lighter skin. This process repeats itself over and over until an optimum level is reached.
Pythagorean
#27
May28-14, 07:24 AM
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Quote Quote by willbell View Post
Pythagorean seems to be trying to talk about it happening through evolutionary means (two separate genes evolving to be the same), rather than Horizontal Gene Transfer, in which the gene only evolves once.
Yeah, I was thinking convergent evolution, where the same thing evolves in two separate lines. Morphological convergence is quite common, but molecular convergence is rare:

http://www.ncbi.nlm.nih.gov/pubmed/20539788
Torbjorn_L
#28
Jul20-14, 11:54 AM
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Quote Quote by Cal King View Post
There is a debate raging on as to whether birds evolved from an advanced theropod dinosaur, or whether they evolved from a thecodont like Longisquama insignis. On one side are most of the paleontologists ...
"Based on fossil and biological evidence, most scientists accept that birds are a specialized subgroup of theropod dinosaurs. ... A small minority of researchers, such as paleornithologist Alan Feduccia of the University of North Carolina, oppose the majority view ..." [ http://en.wikipedia.org/wiki/Birds#D...rigin_of_birds ]

I don't think that is much of a debate or raging, or a useful idea which is imperative in science. It has the telltale signs of a rejected minority opinion that awaits its defenders to die the usual extinction death of failed differential reproduction.

In the context, I don't think thecodonts are recognized anymore. "Thecodontia (meaning "socket-teeth"), now considered an obsolete taxonomic grouping,". [ http://en.wikipedia.org/wiki/Thecodontia ]
DiracPool
#29
Jul22-14, 08:00 PM
P: 585
Quote Quote by Pythagorean View Post
More formally, from John Kaas
There's no "h" in Jon's name Pythagorean, just for the record. I must say, though, I am impressed with your reference here. In my mind, Jon Kaas is the premier evolutionary neuroscientist we have. Northcutt is great as well. A lot of my research is based off Kaas' work. Here's a cool article if you're interested: http://www.ncbi.nlm.nih.gov/pubmed/?term=kaas+mice+men

He had a graduate student, Leah Krubitzer, who's work I also love. I don't know either of them personally, but I do know Georg Striedter (just going through your reference list there). He is of hyperstriatum bird fame and gave me kind reviews on several publications of mine. Of course, a couple years back I sent him a major review article I published that he never got around to reading because he was too busy with his new job as the editor of Brain, Behavior, and Evolution. I'm sure that's a tough gig, but he could have at least pretended that he was interested in my paper. That still miffs me.
atyy
#30
Jul22-14, 10:14 PM
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Quote Quote by Pythagorean View Post
Hrmm.. I wonder what the chance of the same gene showing up independently in two different species is? (Not the aforemention polymerases, just in genera). I know there's morphological examples of convergent evolution, but are there precise genetic examples?
Quote Quote by Pythagorean View Post
Yeah, I was thinking convergent evolution, where the same thing evolves in two separate lines. Morphological convergence is quite common, but molecular convergence is rare:

http://www.ncbi.nlm.nih.gov/pubmed/20539788
Another example: http://phys.org/news/2014-06-truth-electric-fish.html?


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