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Feel free to ask questions about evolution.

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Feel free to ask questions about evolution.
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Nesslig20User avatarPosts: 260Joined: Wed Mar 16, 2016 6:44 pm Gender: Male

Post Re: Feel free to ask questions about evolution.

he_who_is_nobody wrote:Selection or Drift?


Both, but mostly drift. That is quite a surprise that chance often has a greater effect on evolution rather than selection. I rather be careful at this, because you know the creationist will take this out of context and say "aha! see, it is al just random chance!!" well it is not ALL random chance (selection still plays an important role)

Drift has a greater influence on small populations, because alleles have a greater chance to change their frequency within the population if the population size is small enough. Evolution happens much faster in this scenario.

Larger populations are more difficult to influence. It takes time for an new allele to spread and be fixed in a larger population, and it is less likely to happen by change and more likely to happen by selection (if it is beneficial).

That is not to say that selection doesn't play a significant role. We do have mutations subjected under strong positive selection like the one responsible for the lactose persistence and the one (or more) that occur in people living at high altitudes yet not being affected by altitude sickness. It is just that most mutations that happen are largely neutral and some of those do show in the phenotype slightly different shape nose or eye color (blue eyes and blond hair like that), etc. And because these happen allot with each individual, just a few are bound to be inherited just by chance alone. Like the earlobe. Why do some of us have that and other don't, is there a benefit? Probably not.
"Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science."
Charles Darwin
Last edited by Nesslig20 on Sat Jan 21, 2017 6:44 pm, edited 1 time in total.
Thu Jan 19, 2017 10:37 pm
he_who_is_nobodyBloggerUser avatarPosts: 3347Joined: Tue Feb 24, 2009 1:36 amLocation: Albuquerque, New Mexico Gender: Male

Post Re: Feel free to ask questions about evolution.

Nesslig20 wrote:Both, but mostly drift.


I am so glad to hear that. I recently had a run-in with a philosopher of science who would not accept this. Glad to hear that at least among real science student, the reality of selection and drift is taught.

Nesslig20 wrote:That is quite a surprise that [chance] often has a greater effect on evolution rather than selection.

[Emphasis added]


Honestly, that has been the only grammatical mistake I have seen you make on this forum.
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Thu Jan 19, 2017 11:01 pm
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Nesslig20User avatarPosts: 260Joined: Wed Mar 16, 2016 6:44 pm Gender: Male

Post Re: Feel free to ask questions about evolution.

he_who_is_nobody wrote:
Nesslig20 wrote:Both, but mostly drift.


I am so glad to hear that. I recently had a run-in with a philosopher of science who would not accept this. Glad to hear that at least among real science student, the reality of selection and drift is taught.

Nesslig20 wrote:That is quite a surprise that [chance] often has a greater effect on evolution rather than selection.

[Emphasis added]


Honestly, that has been the only grammatical mistake I have seen you make on this forum.


Yes, thank you. I often confuse change for chance when writing fast. They look so similar.

However, I want to ask, what philosopher of science doesn't accept what? The philosopher doesn't accept that drift is a significant mechanism (if not the mostly dominant mechanism) when it comes to small populations sizes wherein evolution can occur much faster? Or doesn't he accept that this is taught?
"Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science."
Charles Darwin
Fri Jan 20, 2017 7:43 pm
he_who_is_nobodyBloggerUser avatarPosts: 3347Joined: Tue Feb 24, 2009 1:36 amLocation: Albuquerque, New Mexico Gender: Male

Post Re: Feel free to ask questions about evolution.

Nesslig20 wrote:However, I want to ask, what philosopher of science doesn't accept what? The philosopher doesn't accept that drift is a significant mechanism (if not the mostly dominant mechanism) when it comes to small populations sizes wherein evolution can occur much faster? Or doesn't he accept that this is taught?


He did not accept that drift is a significant mechanism. I actually did not point out population size, but anyone well versed in this subject should know that drift is a factor and can be a huge factor at times.

I was making the point that perhaps in philosophy classes, they are still stuck with Neo-Darwinian evolution as their paradigm, but was happy to see that science classes are actually teaching modern evolutionary theory.
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Sat Jan 21, 2017 5:20 pm
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hackenslashLime TordUser avatarPosts: 2399Joined: Mon Feb 23, 2009 3:43 pm Gender: Cake

Post Re: Feel free to ask questions about evolution.

Indeed. Drift drives fixation, which is hugely important in small populations. In larger populations, this tends to be attenuated, because fixation in large populations takes a lot of generations.

So, in large populations, selection is king while, in small ones, drift rules the roost, and there's a clear correlation between population size and influence of each on a spectrum.
Thu Jan 26, 2017 1:03 am
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