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Is evolution as simple as we think?

Discussion of everything related to the Theory of Evolution.

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Re:

Postby Cat » Sun Apr 28, 2013 3:35 pm

thoffnagle wrote:Evolution does not respond to situations, it (through mutations) simply provides possibilities. For example, it the climate gets colder, evolution does not respond by providing fur, feathers, blubber, etc. to insulate against the cold. If there are individuals that are able to withstand the colder temperatures, they will survive better than those that can't. If no individuals of that species can tolerate the cold,the species goes extinct.


Exactly. Genes/alleles were always there in the gene pool. If the rest of the population would not have been eliminated by adverse conditions, the particular combination would have been rare...
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Re: Re:

Postby thoffnagle » Thu May 02, 2013 4:02 pm

Cat wrote:Genes/alleles were always there in the gene pool.


No, they got into the gene pool via mutation. They were retained in the gene pool because they were either beneficial or neutral.
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Re: Re:

Postby Cat » Sat May 04, 2013 8:07 pm

thoffnagle wrote:
Cat wrote:Genes/alleles were always there in the gene pool.


No, they got into the gene pool via mutation. They were retained in the gene pool because they were either beneficial or neutral.


Thanks. I will retract word "always". I meant to say "Genes/alleles were already there in the gene pool."
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Postby yourmother » Fri May 10, 2013 12:45 am

no, it's not
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Postby Cat » Mon May 20, 2013 2:01 pm

If they are not, organism would not be able to adapt and will become extinct.
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Re:

Postby animartco » Mon Jun 03, 2013 3:24 pm

dayren wrote:I mean that, like you said, complex organisms didn't evolve for a long time. If there was a sudden evolution into complex life, why did it happen in the first place? Surely the simple life forms that evolved into the more complex life forms would have benefited more in terms of survival by remaining as simple organisms. And why weren't the conditions previously suitable for complex life? Yes, today's complex organisms could not survive in such conditions, but if evolution sees complex life as an advantage surely it would have found a way to form complex organisms suited to the harsh conditions.

I think the reason that it took so long for rapid evolution to get under way was because it took ages for the simple life forms to create enough free oxygen to allow more complex forms to develop. Once they had developed they largely displaced the simple life forms, although most of them do still exist in smaller numbers.
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Re: Re:

Postby thoffnagle » Thu Jun 06, 2013 3:53 pm

animartco wrote:Once they had developed they largely displaced the simple life forms, although most of them do still exist in smaller numbers.


I seem to have read somewhere that the simpler life forms still far outnumber and outweigh the more complex life forms. E.g., there are ten times(?) as many bacterial cells in/on your body as there are human cells that make up your body. Without all of those bacteria, we'd be screwed!
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Postby Luxorien » Sat Jun 15, 2013 8:02 am

I just find the title of this thread hilarious. It would be like asking, "Is rocket science as simple as we think?!"

Admittedly, evolution is, at its heart, a deceptively simple idea, but the implications are endlessly complex and fascinating.
If arguing with people on the internet helps me understand science, then I will do it. FOR THE CHILDREN.
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Re: Re:

Postby thoffnagle » Thu Jun 27, 2013 6:22 pm

Cat wrote:
thoffnagle wrote:
Cat wrote:Genes/alleles were always there in the gene pool.


No, they got into the gene pool via mutation. They were retained in the gene pool because they were either beneficial or neutral.


Thanks. I will retract word "always". I meant to say "Genes/alleles were already there in the gene pool."


That does not mean that new genes aren't/can't be created through mutations and mistakes during mitosis/meiosis. A classic example is that DNA strands can break and be reattached in the wrong place causing duplication of genes or the entire genome can be duplicated erroneously. This extraneous DNA, if further modified can become an entirely new gene that provides the organism with a new trait. So, you are still not entirely correct that the "genes/alleles were already there in the gene pool." They may not have been.
"Nothing in biology makes sense except in the light of evolution."
Theodosius Dobzhansky
"Most people who hate the idea of evolution do so because if it was working properly, they'd be dead."
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Re:

Postby thoffnagle » Thu Jun 27, 2013 6:28 pm

Luxorien wrote:I just find the title of this thread hilarious. It would be like asking, "Is rocket science as simple as we think?!"

Admittedly, evolution is, at its heart, a deceptively simple idea, but the implications are endlessly complex and fascinating.


You're right about evolution being a simple concept but far more complex in practice. The simplicity of the concept and its everyday use in agriculture and animal husbandry is why it boggles my mind that people don't believe that it happened and continues to happen.

At a scientific meeting that I attended, a speaker pointed out that the commonly used phrase, "It ain't rocket science" really should be "it ain't ecology." Ok, it was a more ecologically-minded conference but he made a good point. Rocket science is based on Newtonian physics that is well understood. Ecology, on the other hand, is FAR more complex and not understood anywhere nearly as well.
"Nothing in biology makes sense except in the light of evolution."
Theodosius Dobzhansky
"Most people who hate the idea of evolution do so because if it was working properly, they'd be dead."
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Re: Re:

Postby Cat » Sun Jun 30, 2013 3:42 pm

thoffnagle wrote:That does not mean that new genes aren't/can't be created through mutations and mistakes during mitosis/meiosis. A classic example is that DNA strands can break and be reattached in the wrong place causing duplication of genes or the entire genome can be duplicated erroneously. This extraneous DNA, if further modified can become an entirely new gene that provides the organism with a new trait. So, you are still not entirely correct that the "genes/alleles were already there in the gene pool." They may not have been.


You are right and wrong at the same time. Translocation and duplication take place - fact. This can result in a new trait - fact. However, we talking about the SAME (already present in the gene pool) DNA material.

"This extraneous DNA, if further modified can become an entirely new gene that provides the organism with a new trait. " - Now this part is deduced and while it makes a lot of sense, it is only theoretical. There is no direct (experimental) proof of it.
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Re: Re:

Postby biohazard » Mon Jul 01, 2013 6:46 am

Cat wrote:You are right and wrong at the same time. Translocation and duplication take place - fact. This can result in a new trait - fact. However, we talking about the SAME (already present in the gene pool) DNA material.


What you say above does not make any sense. It is irrelevant whether the nucleotides were already in the gene pool - what matters is their sequence. If the sequence changes it is always new genetic material when compared to the previous "version" of the genome. Most of the time it does not cause new traits to be expressed or if it does, the change is harmful. But occasionally it can produce something that is beneficial for the organism in its current environment - which might be different from the environment for which the previous genotype was "optimized".

Furthermore, new genetic material can be (and is) introduced to the genomes constantly. Nucleotides can be deleted, added or replaced during DNA replication and if an extra nucleotide is added to the gene's sequence it is new DNA material in all senses of the word "new", including the fact that it was never in the gene pool before. This is an observed fact and happens in all known organisms from viruses to humans.
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