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Modern debates in evolution?

by kosovo dave
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kosovo dave
#1
Mar31-14, 04:24 PM
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I'm curious about what debates are currently going on within the scientific community. Are there still things about evolution that scientists don't understand or agree upon? Links/sources would be greatly appreciated!
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D H
#2
Mar31-14, 05:08 PM
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Current trends in evolutionary biology -- that certainly is a good discussion topic. Discussions of evolution vs creationism is not. Creationism is pure nonsense.

To those who wish to post a reply, please keep the above in mind.
Greg Bernhardt
#3
Mar31-14, 05:27 PM
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Here are a few questions that are being worked on


1. Does evolution tend to proceed slowly and steadily or in quick jumps?

2. Why are some clades very diverse and some unusually sparse?

3. How does evolution produce new and complex features?

4. Are there trends in evolution, and if so, what processes generate them?

http://evolution.berkeley.edu/evolibrary/article/evo_50

Ygggdrasil
#4
Mar31-14, 06:52 PM
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Modern debates in evolution?

Here are some more interesting questions in evolutionary biology, along with some scientific articles on the subjects:

1) To what extent is evolution deterministic? If we were to "replay the tape of life" (i.e. go back in the evolutionary history of an organism and let it evolve again under the same or similar circumstances), would you get the same result? To what extent can we predict how a system will evolve and use that knowledge to fight disease (e.g. pathogens or cancer)?

Lobkovsky and Koonin. 2012. Replaying the Tape of Life: Quantification of the Predictability of Evolution. Front Genet 3: 246. doi:10.3389/fgene.2012.00246 PMCID:3509945

Łuksza & Lässig. 2014. A predictive fitness model for influenza. Nature, 507: 57. doi:10.1038/nature13087

2. How did eukaryotes evolve? What gave rise to the unique features of eukaryotes such as the nucleus and innermembrane system, the widespread use of introns and gene splicing, the spatial separation of transcription and translation, the ability to form complex, multicelular organisms, etc.?

Williams et al. 2013. An archaeal origin of eukaryotes supports only two primary domains of life. Nature 504: 231. doi:10.1038/nature12779

The Birth of the Nucleus (non-peer-reviewed news article from Science) http://www.sciencemag.org/content/305/5685/766.full
phinds
#5
Mar31-14, 07:13 PM
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I cannot give you sources but I read recently that there have been some very surprising discoveries about the fact that evolution can in some circumstances proceed much more rapidly than was previously believed, even by those who are firmly in the "jumps and starts" camp. Since this is a relatively new discovery, there is debate about how widely it might apply. That is, were the instances discovered one-offs or something more systemic?
atyy
#6
Apr1-14, 08:39 AM
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I found this hilarious. Nowak et al attacked the concept of "inclusive fitness" for explaining eusociality. Many disagreed.

http://www.ncbi.nlm.nih.gov/pubmed/20740005 (free link at top right)
The evolution of eusociality.
Nowak MA, Tarnita CE, Wilson EO.
Nature. 2010 Aug 26;466(7310):1057-62.
Eusociality, in which some individuals reduce their own lifetime reproductive potential to raise the offspring of others, underlies the most advanced forms of social organization and the ecologically dominant role of social insects and humans. For the past four decades kin selection theory, based on the concept of inclusive fitness, has been the major theoretical attempt to explain the evolution of eusociality. Here we show the limitations of this approach. We argue that standard natural selection theory in the context of precise models of population structure represents a simpler and superior approach, allows the evaluation of multiple competing hypotheses, and provides an exact framework for interpreting empirical observations.

http://rspb.royalsocietypublishing.o...1723/3313.full
The validity and value of inclusive fitness theory.
Bourke AF.
Proc Biol Sci. 2011 Nov 22;278(1723):3313-20. doi: 10.1098/rspb.2011.1465.
"If the analysis of these authors is correct, then inclusive fitness theory has been a decades-long distraction in the field that is theoretically unsound, unnecessarily focused on genetic relatedness and poorly supported by the empirical evidence. If it is not correct, then the theory has been on the right lines all along and it is the critiques that are shaky. The critique by Nowak et al. [38] has met with both support [39–41] and rebuttal [42–50]. In a response, Nowak et al. [51] maintained their view that ‘Inclusive fitness theory is neither useful nor necessary to explain the evolution of eusociality or other phenomena’."

By googling "The evolution of eusociality", I see that Jerry Coyne disliked the paper. The following commentary is not peer-reviewed, but I think we can make an exception for Jerry Coyne.

http://whyevolutionistrue.wordpress....kin-selection/
A misguided attack on kin selection
Jerry A. Coyne
willbell
#7
May10-14, 09:58 PM
P: 27
Quote Quote by atyy View Post
I found this hilarious. Nowak et al attacked the concept of "inclusive fitness" for explaining eusociality. Many disagreed.
This is probably the most major debate in evolution nowadays, kin selection is being brought into the spotlight, even being questioned by the person who proposed it E.O. Wilson. However it seems to be still on fairly firm ground.

Another common issue is adaptationism (the belief that everything is the way it is because it serves a purpose) vs neutral theory (the belief that some alleles are fixed due to genetic drift), and to what extent each applies.
Cal King
#8
May15-14, 02:08 PM
P: 3
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 and their employers, the museums that spend millions constructing exhibits. They are firmly on the side of the dinosaurian origin of birds. On the other side are a few knowledgeable paleontologists who point out that flight from the ground up is extremely unlikely, that there is no known tree climbing dinosaur and that if a theropod dinosaur tries to launch itself into the air, it would end up as a grease spot on the ground. Many paleontologists do not like the debate and they want us to stop arguing and accept as fact that birds evolved from a dinosaur. Others disagree, and claim that there is a mountain of evidence opposing the dinosaurian origin of birds.

http://www.aou.org/auk/content/130/1/0001-0013.pdf
willbell
#9
May15-14, 04:01 PM
P: 27
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 and their employers, the museums that spend millions constructing exhibits. They are firmly on the side of the dinosaurian origin of birds. On the other side are a few knowledgeable paleontologists who point out that flight from the ground up is extremely unlikely, that there is no known tree climbing dinosaur and that if a theropod dinosaur tries to launch itself into the air, it would end up as a grease spot on the ground. Many paleontologists do not like the debate and they want us to stop arguing and accept as fact that birds evolved from a dinosaur. Others disagree, and claim that there is a mountain of evidence opposing the dinosaurian origin of birds.

http://www.aou.org/auk/content/130/1/0001-0013.pdf
For some reason I think I can guess which side you're on. ;)
Pythagorean
#10
May15-14, 04:08 PM
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The existence of "master genes". (edit: Actually, existence is probably the wrong term. It's more about the interpretation of what such genes imply about the process of evolution).

More formally, from John Kaas Evolutionary Neuroscience:
Ch 1.1, "Common plan vs. diversity"

many biologists proceeded to search for molecular genetic
homologies that could reveal previously unimagined
morphological homologies (Janies and DeSalle, 1999).
Geoffroy would have been thrilled. There are, however,
problems with the view that animals are all alike.
The most serious problem, in my view, is that
homologous genes may sometimes be involved in
the development of adult structures that are clearly
not homologous (Striedter and Northcutt, 1991).
For example, insect wings and vertebrate nervous
systems both depend on hedgehog function for normal
development, but this does not make neural
tubes and insect wings homologous (Bagun˜a and
Garcia-Fernandez, 2003). Instead, findings such as
this suggest that evolution tends to work with highly
conserved ‘master genes’ (Gehring, 1996) or, more
accurately, tightly knit assemblies of crucial genes
(Nilsson, 2004), which it occasionally reshuffles by
altering their upstream regulatory elements and/or
downstream targets.
willbell
#11
May15-14, 05:49 PM
P: 27
Quote Quote by Pythagorean View Post
The existence of "master genes".

More formally, from John Kaas Evolutionary Neuroscience:
Ch 1.1, "Common plan vs. diversity"
I am confused, what are these in relation to hox genes?
Pythagorean
#12
May15-14, 06:07 PM
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Quote Quote by willbell View Post
I am confused, what are these in relation to hox genes?
My understanding is that hox genes would be an example of master genes. They control more large scale morphology. Gehring's master genes were particular to eye morphology.
willbell
#13
May15-14, 07:53 PM
P: 27
Quote Quote by Pythagorean View Post
My understanding is that hox genes would be an example of master genes. They control more large scale morphology. Gehring's master genes were particular to eye morphology.
Okay, before your edit I was confused because it seemed to be describing hox genes but said their existence was debated.
Pythagorean
#14
May15-14, 08:14 PM
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Quote Quote by willbell View Post
Okay, before your edit I was confused because it seemed to be describing hox genes but said their existence was debated.
Yes, the genes themselves definitely exist; my impression from my first reading of Kaas was that the concept of "master genes" is what's disputed... but I thought "master genes" implied some kind of universal homology. Now that I've looked a little closer, the term just more loosely describes the direct observation that these genes are at the top of the hierarchy of a series of coordinated processes.
willbell
#15
May15-14, 08:23 PM
P: 27
Quote Quote by Pythagorean View Post
Yes, the genes themselves definitely exist; my impression from my first reading of Kaas was that the concept of "master genes" is what's disputed... but I thought "master genes" implied some kind of universal homology. Now that I've looked a little closer, the term just more loosely describes the direct observation that these genes are at the top of the hierarchy of a series of coordinated processes.
Okay, that makes more sense. The only universal gene is DNA+RNA polymerase AFAIK, the central dogma is the only thing that life accepts... dogmatically. ;)
Pythagorean
#16
May15-14, 08:31 PM
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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?
willbell
#17
May15-14, 08:40 PM
P: 27
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?
Very very small, most traits have many ways to the same result (bee's and bird's wings for example), especially because the biochemical environment in which the traits are evolving are different (as they would be in unrelated species).
Cal King
#18
May15-14, 10:35 PM
P: 3
Quote Quote by willbell View Post
This is probably the most major debate in evolution nowadays, kin selection is being brought into the spotlight, even being questioned by the person who proposed it E.O. Wilson. However it seems to be still on fairly firm ground....
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.


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