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Author Topic:   Two species of crow evolving ...
Tanypteryx
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Posts: 4597
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 9.4


(1)
Message 3 of 14 (850368)
04-06-2019 6:33 PM
Reply to: Message 1 by RAZD
04-06-2019 3:56 PM


An interesting article RAZD.
I didn't come to appreciate sexual selection as a mechanism of evolution separate from natural selection until I read The Evolution of Beauty: How Darwin's Forgotten Theory of Mate Choice Shapes the Animal World”And Us by Richard O. Prum.
From Goodreads:
quote:
A major reimagining of how evolutionary forces work, revealing how mating preferences--what Darwin termed "the taste for the beautiful"--create the extraordinary range of ornament in the animal world.
quote:
In the great halls of science, dogma holds that Darwin's theory of natural selection explains every branch on the tree of life: which species thrive, which wither away to extinction, and what features each evolves. But can adaptation by natural selection really account for everything we see in nature?
Yale University ornithologist Richard Prum--reviving Darwin's own views--thinks not. Deep in tropical jungles around the world are birds with a dizzying array of appearances and mating displays: Club-winged Manakins who sing with their wings, Great Argus Pheasants who dazzle prospective mates with a four-foot-wide cone of feathers covered in golden 3D spheres, Red-capped Manakins who moonwalk. In thirty years of fieldwork, Prum has seen numerous display traits that seem disconnected from, if not outright contrary to, selection for individual survival. To explain this, he dusts off Darwin's long-neglected theory of sexual selection in which the act of choosing a mate for purely aesthetic reasons--for the mere pleasure of it--is an independent engine of evolutionary change.
Mate choice can drive ornamental traits from the constraints of adaptive evolution, allowing them to grow ever more elaborate. It also sets the stakes for sexual conflict, in which the sexual autonomy of the female evolves in response to male sexual control. Most crucially, this framework provides important insights into the evolution of human sexuality, particularly the ways in which female preferences have changed male bodies, and even maleness itself, through evolutionary time.
The Evolution of Beauty presents a unique scientific vision for how nature's splendor contributes to a more complete understanding of evolution and of ourselves.

What if Eleanor Roosevelt had wings? -- Monty Python
One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie
If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy
The reason that we have the scientific method is because common sense isn't reliable. -- Taq

This message is a reply to:
 Message 1 by RAZD, posted 04-06-2019 3:56 PM RAZD has replied

Replies to this message:
 Message 5 by Percy, posted 04-06-2019 8:03 PM Tanypteryx has replied
 Message 10 by RAZD, posted 04-07-2019 6:58 AM Tanypteryx has seen this message but not replied

  
Tanypteryx
Member
Posts: 4597
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 9.4


(1)
Message 6 of 14 (850375)
04-06-2019 9:02 PM
Reply to: Message 5 by Percy
04-06-2019 8:03 PM


Sexual selection is completely natural, so couldn't it be just one type of natural selection?
That is what I thought also.
There could be natural selection by food source, by terrain, by weather variations, by sexual cues, etc.
Natural selection has a positive feedback loop that means increased frequency of certain alleles in a population and there may be a negative feedback loop decreases the frequency of others. We think of this as fit and less fit, when considering competition within a species or population, but it also can impact competition between species and whether one thrives and another goes extinct.
Prum lays out a really compelling argument with many, many examples where characters are selected, usually by females, that have no positive effect on fitness. These characters can be appearance, behaviors or calls and are often combinations of features.
I was quite surprised to have to revise my view on this topic.

What if Eleanor Roosevelt had wings? -- Monty Python
One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie
If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy
The reason that we have the scientific method is because common sense isn't reliable. -- Taq

This message is a reply to:
 Message 5 by Percy, posted 04-06-2019 8:03 PM Percy has seen this message but not replied

Replies to this message:
 Message 7 by Faith, posted 04-06-2019 10:55 PM Tanypteryx has replied

  
Tanypteryx
Member
Posts: 4597
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 9.4


(1)
Message 8 of 14 (850381)
04-07-2019 12:23 AM
Reply to: Message 7 by Faith
04-06-2019 10:55 PM


This ought to be elementary my dear Watson, but evo theory manages to complicate the simplest things.
Yep, facts and evidence are just so complicated.
And of course it makes sense to categorize sexual selection as a type of natural selection
And of course, you don't have a fucking clue what you are talking about.
And again, all this is within microevolution, it's ridiculous to make the arbitrary fact that the two populations don't interbreed into "speciation."
Oh ok, I'll send out an alert right away that a YEC is making up a new rule. You should expect action soon.
It's nothing but two variations that happen to separate, and may possibly have a genetic barrier to interbreeding although that is not necessary. If it does it could be because of the greater homozygosity of the characteristic feather color in each population and the more fixed loci each has the less ability to combine the two.
Right, so you're just winging it, so to speak?

What if Eleanor Roosevelt had wings? -- Monty Python
One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie
If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy
The reason that we have the scientific method is because common sense isn't reliable. -- Taq

This message is a reply to:
 Message 7 by Faith, posted 04-06-2019 10:55 PM Faith has not replied

  
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