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Author Topic:   When does a species undergoing natural selection, change more?
aristotle
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Message 1 of 21 (812364)
06-16-2017 5:18 AM


Does a species change more through natural selection if the weaker, less favored individuals reproduce more, or if the stronger, more favored individuals reproduce more?

For an individual of a species to be weaker than the other members of it's species, it must be genetically imperfect in some way, in other words, there is a variation in it's genetic code that is not in the stronger individuals.

For an individual of a species to be strong, it must be closer to genetic perfection, in other words there is less variation in it's genetic code than in the weak members.

If this is true, then according to evolution by 'survival of the fittest', if the stronger individuals succeed in reproducing more often than the weaker ones (as is claimed by evolutionists), then the genetic code would in fact vary less, as there would be less imperfections/variations in the stronger individuals to pass on to their offspring.

Would natural selection then actually narrow the variation of species instead of broadening it, as is claimed?

Any feedback appreciated

Regards, aristotle

Edited by aristotle, : No reason given.


"I have learned from my own embarrassing experience how easy it is to concoct remarkably persuasive Darwinian explanations that evaporate on closer inspection." - Daniel Dennet

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Message 2 of 21 (812366)
06-16-2017 8:12 AM


Thread Copied from Proposed New Topics Forum
Thread copied here from the When does a species undergoing natural selection, change more? thread in the Proposed New Topics forum.
    
RAZD
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Message 3 of 21 (812395)
06-16-2017 10:51 AM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


Does a species change more through natural selection if the weaker, less favored individuals reproduce more, or if the stronger, more favored individuals reproduce more?

Either.

The problem is in the use of words like weaker and stronger, as they can be irrelevant to survival and sexual selection. That is why the oxymoron "fit" is used, where fitness is defined by the ability to survive and breed. Those that are "fit" breed more than those that are not fit (dead, sterile, etc).

For an individual of a species to be weaker than the other members of it's species, it must be genetically imperfect in some way, in other words, there is a variation in it's genetic code that is not in the stronger individuals.

Or it could be malnourished, but generally there are genetic differences between all individuals in a breeding population, and some variations may be better fit in some ecosystems while others are better fit in different ecosystems.

Pocket mice for example, the population is typically tan, living in a sandy desert ecology. Some however have a mutation that turns their fur black, these individuals are not as fit as the tan mice for the sandy desert ecology, but they are better fit for the neighboring lava bed ecology, where the tan mice are not as fit as the black mice.

Which is "weaker?" Which is "stronger?" Those terms do not adequately describe the situations, and thus give a false impression, one that leads people to these misinformed type questions.

If this is true, then according to evolution by 'survival of the fittest', ...

Another dubious phrase, as it can mean a range of fitness (all that survive) or it can mean the best most fittest (which is misleading). Better to say "survival of those able to survive and breed" as this includes those just barely able and those that are very able.

... if the stronger individuals succeed in reproducing more often than the weaker ones (as is claimed by evolutionists), ...

Actual evolutionary biologists would actually say "... if the better adapted individuals succeed in reproducing more often than the less adapted ones ... " which is observed as well nourished healthy individuals are generally more successful at breeding than poorly nourished sick individuals ...

... , then the genetic code {pool of the breeding population} would in fact vary less, as there would be less imperfections/ variations in the stronger {better adapted} individuals to pass on to their offspring.

Correct, the less advantageous traits are removed by selection.

Would natural selection then actually narrow the variation of species instead of broadening it, as is claimed?

Nobody claims that natural selection increases diversity, that role is taken by mutations, which occur in every individual in every generation, some altering traits in the phenotype (and thus subject to selection in the next round) and some biding their time (neutral). Some mutations of course are also deleterious and either cause death during development or make the individual susceptible to selection in the next round.

Mutations that survive selection add to the genetic diversity of the breeding population.

Evolution is a two-step feedback response system that is repeated in each generation:

Like walking on first one foot and then the next.

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Message 4 of 21 (812397)
06-16-2017 10:58 AM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


Does a species change more through natural selection if the weaker, less favored individuals reproduce more, or if the stronger, more favored individuals reproduce more?

There is no hard and fast rule on that.

For an individual of a species to be weaker than the other members of it's species, it must be genetically imperfect in some way, in other words, there is a variation in it's genetic code that is not in the stronger individuals.

Nah man, maybe they just caught a cold.

For an individual of a species to be strong, it must be closer to genetic perfection, in other words there is less variation in it's genetic code than in the weak members.

Genetic perfection is not a thing.

If this is true, then...

It's not true.

...

I see your avatar. Evolution is not religion. I'm religious, and I accept evolution, and they are two different things.


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ringo
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Message 5 of 21 (812433)
06-16-2017 12:43 PM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


Aristotle writes:

For an individual of a species to be strong, it must be closer to genetic perfection, in other words there is less variation in it's genetic code than in the weak members.


That doesn't make sense. The MORE variation there is within a species, the more likely some individuals are to survive under different conditions. And the more likely that subsequent generations will be different.
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NoNukes
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Message 6 of 21 (812501)
06-16-2017 10:50 PM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


For an individual of a species to be weaker than the other members of it's [sic] species, it must be genetically imperfect in some way, in other words, there is a variation in its genetic code that is not in the stronger individuals.

Not necessarily the case. Humans, for example, are not genetically superior to other apes in lots of areas including strength, ability to survive in temperature extremes, speed, climbing ability, etc.

Natural selection picks the phenotypes with the best ability to survive in their environment. What makes it possible to survive in one environment may make it hard/impossible to survive in another environment.

That's why scientists are careful to use terms like fitness rather than emotion-laded terms like weaker, superior, or more perfect.

For an individual of a species to be strong, it must be closer to genetic perfection, in other words, there is less variation in its genetic code than in the weak members.

Perhaps you should rethink this. Human variety has lead to the traits which make it easier to survive in different locations. Things like lactase tolerance, dark or light skin color, and even variation in blood type make it easier to survive on certain diets, to thrive in certain locations, and to immune to different diseases than any single phenotype could produce.

Given that the major premise of your post is wrong, can we end this early?

Edited by NoNukes, : No reason given.


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Taq
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Message 7 of 21 (812683)
06-19-2017 12:53 PM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


Aristotle writes:

Does a species change more through natural selection if the weaker, less favored individuals reproduce more, or if the stronger, more favored individuals reproduce more?

The less favored individuals would not be reproducing more, by definition.

Think of it like a car race. In the paragraph above you are asking what happens when the leaders of the race are behind other cars in the running order. That makes no sense. If they are not at the front of the running order then they are not the leaders.

Continuing with our car race analogy, different cars will different advantages on different race courses. An F1 car is the most fit on a smooth road course, but it will lose to a rally car on gravel road. An F1 car will also lose to a drag car on a 1,000 foot straight, while the F1 car will cream the drag car on a road course.

So which is most fit? The F1 car, rally car, or drag car? The answer is that it depends on the environment. The same applies to variations within a species.


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Message 8 of 21 (812693)
06-19-2017 3:17 PM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


Only if they survive
aristotle writes:

If this is true, then according to evolution by 'survival of the fittest', if the stronger individuals succeed in reproducing more often than the weaker ones (as is claimed by evolutionists), then the genetic code would in fact vary less, as there would be less imperfections/variations in the stronger individuals to pass on to their offspring.

You're absolutely right. If that's true... then genetic code would vary less.

But, of course, your "if" statement is false simply because what you think happens with evolution does not happen. As explained by the other posts here. Therefore, genetic code may or may not 'vary less' and your logical idea doesn't mean anything to reality.

There could be an animal (or human) that is born with a "perfect genetic code."
And then they die before they have any kids.

Or maybe they have kids, and those kids have kids... but they all die in a fire.

No more perfect genetic code.

That's how evolution works.

It doesn't matter if your genes are "strong" or "weak."
All that matters is if you survive and have kids and your kids survive.

Surviving doesn't take 'perfect genes.' It doesn't even require "good genes."
Surviving can sometimes simply be lucky.
Other times it can be focused by the environment.

Whatever it is, though, survival is all that matters.


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NoNukes
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Message 9 of 21 (812735)
06-19-2017 9:58 PM
Reply to: Message 8 by Stile
06-19-2017 3:17 PM


Re: Only if they survive
There could be an animal (or human) that is born with a "perfect genetic code."

The concept of a "perfect genetic" code, from which any change or mutation would be a loss of perfection, is a strictly Creation Science idea. Perfection is not a part of the theory of evolution.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

History will have to record that the greatest tragedy of this period of social transition was not the strident clamor of the bad people, but the appalling silence of the good people. Martin Luther King

I never considered a difference of opinion in politics, in religion, in philosophy, as cause for withdrawing from a friend. Thomas Jefferson

Worrying about the "browning of America" is not racism. -- Faith

Some of us are worried about just how much damage he will do in his last couple of weeks as president, to make it easier for the NY Times and Washington post to try to destroy Trump's presidency. -- marc9000


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Message 10 of 21 (812740)
06-19-2017 10:42 PM
Reply to: Message 9 by NoNukes
06-19-2017 9:58 PM


Re: Only if they survive
There could be an animal (or human) that is born with a "perfect genetic code."

The concept of a "perfect genetic" code, from which any change or mutation would be a loss of perfection, is a strictly Creation Science idea. Perfection is not a part of the theory of evolution.

"Perfect" in relation to what?

Climates, microclimates, environments, habitats, and biomes are always changing in a variety of ways, some slowly and some more rapidly.

What may be "perfect" in one setting may not be so good in another.


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Message 11 of 21 (812750)
06-20-2017 12:38 AM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


aristotle, in the Nothing in biology makes sense except in the light of evolution. topic, Message 495, you brag:
I have studied evolution a long time, learned a lot about it, ...

So why is it that you had never learned about fitness, one of the most basic concepts of evolution? It would be like claiming to have studied chemistry and learned a lot about it without having any clue about the most basic atomic theory.

I believe that instead, you had been learning the creationist "evolution model", which is a gross misrepresentation of evolution, so gross that it has virtually nothing to do with evolution except for its misnaming. If you really want to criticize evolution, then you should learn something about it first. Not from the creationists, because they are lying to you.

As has been explained to you already, fitness has nothing to do with "strong" or "weak" in most environmental contexts. For example you have a stronger individual who can get anything he wants from the others because he is a bully (identifiable by their yellow eyes or orange skin -- two different cultural references there). Is he more fit than his not-as-physically-strong brethren who are able to work together for their mutual survival. The big strong loner out on his own will have far less chance of producing offspring who can survive than his weaker brethren who can band together. Is being physically strong also fit? In a species of loners, yes. In a social species, not necessarily.

Nor is there any concept of "genetic perfection". Whom are you reading? What creationist cretin wrote such garbage? You are being lied to!

Now as for the varying rate of change. There was a TV popularization hosted by Christopher Reeve before his accident in which he described a varying rate of change in evolution. That didn't make any sense to me at the time, but I figured it out later. There was an article on a conference in which punctuated equilibria was presented. One of the graphics presented the gradual generational change as a series of bell curves on a sloping line.

OK, picture this in your mind. You have a population of individuals in an environment/ecology. We could think of an ideal level of adaptation, such that an individual with those characteristics would be ideally adapted to that environment. But this population is not yet ideally adapted. They form a bell curve. When they produce the next generation, that next generation forms a larger bell curve extending further in both directions, towards being less adapted and more adapted. Statistically, it is the group closed to that ideal adaptation point who survive and reproduce more, thus shifting the center of the population closer to being more adapted. The further away from being ideally adapted the population is, the more rapid their progress towards being adapted will be. Hence, they will experience faster and greater change.

Now skip to the future where the population is basically centered about that ideal adaptation level. The population's bell curve grows with each new generation and again it's the ones centered about that adaptive ideal who are the most prolific reproducers. The rate of change has slowed down to near zero as the population is in stasis.

So, what happened to the forces/processes that had produced all that rapid change in the past? Did they suddenly change or stop working? No, they are still at work. All that changed was whether they were away from or centered on the set-point, in this case the ideal adaptation level.

I was trained as a digital electronics technician specializing in power supplies (an analog system in our computer systems). In the vast majority of power supplies, you want to provide a constant output voltage regardless of how much current is being drawn by the load (ie, the system you are supplying power to). A key component of any such power supply is the voltage regulator, which basically monitors the output voltage constantly and varies its internal impedance accordingly via negative feedback.

Now here's the question: when the output voltage is being held at a constant voltage, is the voltage regulator doing its job? Obviously yes, but think about it. If we start with the voltage far from the voltage regulator's set-point, such as at power-up, the voltage regulator changes that output voltage rapidly to the set-point. And then it holds it there. In those two different cases, is the voltage regulator doing anything different? No. It is doing exactly the same thing. The only difference is how far the output voltage is from the set-point.

So are evolutionary processes doing anything different when a population is changing rapidly than when it is in stasis? No. Those evolutionary processes are doing exactly the same thing. The only difference is how far the population is from the ideal adaptation level.

Would natural selection then actually narrow the variation of species instead of broadening it, as is claimed?

Complete and utter bullshit straight from your creationist handlers.

You have mutation, recombination, and whatever else increasing genetic variation, and natural selection filtering through that. The one increases variation while the other, natural selection, decreases it. The two work in tandem with each other.

To characterize evolution as being purely natural selection is a damnable lie. To characterize evolution as being purely mutation is a damnable lie.

Please stop with your damnable lies.


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Pressie
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Message 12 of 21 (812777)
06-20-2017 7:56 AM
Reply to: Message 11 by dwise1
06-20-2017 12:38 AM


Creationists always tell untruths, dwise1. Always. That's all they have. Nothing else.
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Message 13 of 21 (812982)
06-22-2017 2:23 AM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


For an individual of a species to be weaker than the other members of it's species, it must be genetically imperfect in some way, in other words, there is a variation in it's genetic code that is not in the stronger individuals.

For an individual of a species to be strong, it must be closer to genetic perfection, in other words there is less variation in it's genetic code than in the weak members.

There's something weird about talking about the amount of variation in an individual. Variation is a property of groups. There is, for example, no variation in my height, or my eye color, or my sex. This is because there is only one of me.

Would natural selection then actually narrow the variation of species instead of broadening it, as is claimed?

That depends on circumstances. Always bear in mind that there is no such thing as "less favored" or "more favored" except with relation to an environment. When a group has an opportunity to spread between environments or between niches within the environment, then natural selection will act differently on the subgroups in different circumstances, thus increasing the variation of the group.

For example, natural selection worked differently on bears living in the Arctic Circle to those outside of it: white fur was favored in those living against a perpetual background of snow and ice. The result was that the lineage became more diverse with the addition of a white species of bear.


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Pressie
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Message 14 of 21 (813001)
06-22-2017 8:28 AM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


aristotle writes:

Does a species change more through natural selection if the weaker, less favored individuals reproduce more, or if the stronger, more favored individuals reproduce more?

Hold on, cowboy, hold your thoughts. The best adapted for the environment tend to pass on their genes. Weaker, stronger, etc. all are relative terms in the environment organisms live in. What's weak in one environment is strong in another. What's strong in one environment is weak in another.
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Stile
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Message 15 of 21 (813021)
06-22-2017 10:14 AM
Reply to: Message 1 by aristotle
06-16-2017 5:18 AM


An answer to the title of the thread
Your first post tends to lead more into issues with strengths, weaknesses and the ability of evolution to continue to function in the long term.

If you read the many posts responding to those problems, I hope you'll see that the questions you asked regarding them don't make much sense.

In all of that, however, I never actually attempted an answer for the question you posed in the title of your thread.

Title Thread writes:

When does a species undergoing natural selection, change more?

The basic answer is "as soon as enough generations have gone by."

There really is no set time. And, actually, "never" is a completely possible answer as well.
It all depends on the selective pressures in question and the ability of mutations-occurring-during-reproduction and inheritance-of-traits to keep up.

For some creatures, like bacteria, this can be in the order of weeks or months.
For other creatures, like wolves, this can be in the order of hundreds to thousands or even millions of years.

It's not like a few wolves after thousands of years "change a lot."
It's more like the entire population of wolves continually changes little-by-little over the course of each generation or two. Then, eventually, if you compare the 'original wolves' to the 'thousands of years later wolves' there will be "more" change that you can see directly.

But no single generation of wolves ever changes "more." That's not how evolution works.


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