Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 88 (8927 total)
Current session began: 
Page Loaded: 08-23-2019 8:32 PM
28 online now:
dwise1, Faith, jar, RAZD (4 members, 24 visitors)
Chatting now:  Chat room empty
Newest Member: Jedothek
Post Volume:
Total: 860,347 Year: 15,383/19,786 Month: 2,106/3,058 Week: 480/404 Day: 84/63 Hour: 3/1


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
1
2Next
Author Topic:   Peter & Rosemary Grant, Darwin's Finches and Evolution
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(1)
Message 1 of 131 (725612)
04-29-2014 1:55 PM


http://paw.princeton.edu/.../2014/04/23/pages/5638/index.xml&

quote:
The People Who Saw Evolution
After 40 years of research on Darwin’s finches, Peter and Rosemary Grant have written their valediction.

Peter and Rosemary Grant sit in a cave on Daphne Major Island in 2004. The cave generally was used for cooking; here, Peter is shown measuring the beak of a finch.

Peter and Rosemary Grant are members of a very small scientific tribe: people who have seen evolution happen right before their eyes.

For the Grants, evolution isn’t a theoretical abstraction. It’s gritty and real and immediate and stunningly fast. To witness evolution, they needed cameras, measuring instruments, computer databases, and advanced laboratory techniques for genetic analysis. Most of all, they needed to be there in person ­— in the field, on the ground, enduring baking days and sweltering nights, cooking in a cave, sleeping in tents, and somehow sustaining themselves on a tiny island in the Galápagos that any reasonable person would declare to be uninhabitable.

Here’s what happened: In 1981, at a point in their research when they literally knew every finch on the island, a new bird arrived — a large one, 28 grams. The interloper, labeled 5110 (every bird gets a number), likely came from Santa Cruz, a large island visible from Daphne. It looked a lot like a fortis, but also like a scandens. Genetic analysis showed 5110 to be a cross between a fortis and a fortis-scandens hybrid. They called it “the Big Bird.”

The Big Bird had a unique song and, when mature, shiny black plumage that was different from the indigenous Daphne birds. It also was extremely “fit” in the Darwinian sense — and promiscuous, surviving another 13 years and mating with six females, producing 18 offspring. It mated with several fortis-fortis-scandens hybrids, then with fortis females, and began a new line of Big Birds that sang the song of the original immigrant.


Much more in the article.

Note that bird song is part of mate attraction, and thus a different song can lead to genetic isolation and a new species.

Their research is known for demonstrating natural selection from the 1980's drought, but that it hadn't reached speciation levels. It seems that this is closer, but still not definitive.


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

Replies to this message:
 Message 3 by Omnivorous, posted 04-29-2014 4:22 PM RAZD has acknowledged this reply
 Message 6 by Faith, posted 04-29-2014 11:11 PM RAZD has responded
 Message 13 by Tanypteryx, posted 04-30-2014 10:44 AM RAZD has acknowledged this reply

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(4)
Message 12 of 131 (725666)
04-30-2014 10:04 AM
Reply to: Message 6 by Faith
04-29-2014 11:11 PM


Only Evolution
I see somebody has already complained about an opinion given by ICR of this couple's work as not about evolution at all, but of course it isn't about evolution. Their work could have been done under the banner of Creationism just as well because it contributes absolutely zip to the ToE except the usual buttressing of the strange misconceptions people have.

Curiously, I note that they said evolution rather than the ToE.

The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities.

This is sometimes called microevolution, however this is the process through which all species evolve and all evolution occurs at the breeding population level.

Watching Evolution in action. Oh give us a break. You CAN'T observe evolution in the macro sense, all you can observe is the ordinary known variations of microevolution. There isn't even anything particularly special about the case of Big Bird, he's just a particularly hardy hybrid for pete's sake. Big Bird is an interesting fellow but he proves nothing about the ToE.

Again, I note that they talked about evolution rather than the ToE, and didn't mention "macroevolution" that I could see.

The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities.

Amazingly that is precisely what they observed, over several generations, so indeed the were "watching evolution in action" during their 40 year collection of data. Just like Jane Goodall did with the chimps they identified each individual member of each of the birds species and could tell them individually apart. They also used genetics to trace the changes in hereditary traits from generation to generation, and that is how they KNOW that "big-bird" is a fortis-scandens hybrid.

They are careful (scientific tentativity) to refrain from claiming that speciation has occurred, because full reproductive isolation has not yet been confirmed, but it is rather obviously in process. There is difference in mating song and there appears to be a growing division between the older fortis species population and the "big-bird" descendants, fortis-fortis-scandens hybrids.

This is of course all about microevolution, known ways that animals change over time within their own genome. Adaptation, natural selection, are all occurrences within the built in range of the genetic potentials of the Species. There is absolutely nothing in any of this that supports the ToE. This kind of variation accomplishes the same thing in Nature as is accomplished domestically in breeding.

Again, I note that this article is about evolution rather than the ToE.

Perhaps that is why the article is about seeing evolution rather than seeing the ToE ...

This ordinary fact of genetic variation is ALL Darwin observed, he mentally added macroevolution and claimed all these naturally occurring processes for his theory, but not one thing he ever observed supported anything more than microevolution. His different finches express only the various possibilities built into the finch genome and brought out under different circumstances. Sometimes this is the result of natural selection no doubt, by which a certain kind of food in the environment forces an appropriate new sort of beak to be selected in the population -- out of the built in range of possibilities in the genome. But really all it would usually take is the geographic isolation of small numbers from the overall population. This alone can bring about a change in a feature such as beak type over a few generations of inbreeding, and that change makes them gravitate to the sort of food that suits their beak type; there may also be selection factors involved but they don't have to be to any great extent. But it doesn't matter, whether selection is involved or not this is all about normal microevolution and says nothing about macroevolution.

Darwin's observation (and Wallace's as well) was that evolution can result in new species being formed and Darwin's insight (and Wallace's as well) was that this was sufficient to explain the diversity of life seen in the fossil record and alive today.

Curiously, Faith, it does matter very much that selection is involved. Selection is half of the mechanism of evolution, it is a two-step feedback response system that is repeated in each generation:

Like walking on first one foot and then the next. Selection is the part of evolution that is responsible for the division of a parent species into reproductively isolated daughter populations, a process that is underway with the fortis-fortis-scandens hybrids being larger birds, larger beaks and different mating songs than the fortis population. Choosing mates depending on mating songs will allow sympatric speciation to proceed to develop reproductive isolation while occupying the same geological area.

If we looked at each branch linearly, while ignoring the sister population, they would show phyletic change in species (accumulation of evolutionary changes over many generations), and this shows that the same basic processes of evolution within breeding populations are involved in each branch.

So, without reproductive isolation being reached, we are in the process of observing a potential speciation event. This indeed is very much evolution in action being observed and documented by the Grants.

This couple's work sounds quite heroic and meticulous in many ways, however, and should not be denigrated in itself, but it should be clearly criticized for claiming to be any kind of support for the ToE.

Seeing as they don't claim it is support for the ToE, your continued obsession with this is rather curious. It's like complaining that observing the sunset every day should be criticized for claiming to support the theory of gravity ...

ABE: Oh yes, and since the usual inane question will surely come up, "What keeps microevolution from going on to be macroevolution?" and even "What is a Kind?" First I'd say just stick to the observed facts, there is no evidence for anything beyond ordinary known microevolution. ...

And a good thing too, because the observed facts are that evolution, with speciation, is sufficient to explain the diversity of life seen in the fossil record and in life today. Evolution can lead to speciation events where new species evolve, just as the Grants are observing and documenting in the Galapagos. Evolution with speciation results in nested hierarchies (as we have previously discussed):

"Reproduction after their own kind" is just another way of saying "clade" as far as I can see ... and thus the only significant difference - imho - between evolution thought and creationist conjecturing is how far back one dares to look for the original breeding populations for the clades of life we see in the fossil record and in life today.

The process of forming a nested hierarchy by descent of new species from common ancestor populations, via the combination of phyletic change in species and divergent speciation, and resulting in an increase in the diversity of life, is sometimes called macroevolution. This is often confusing, because there is no additional mechanism of evolution involved, rather this is just the result of looking at evolution over many generations and different ecologies.

Thus if "evidence for anything beyond ordinary known microevolution" were found it would be contrary to the scientific thinking on evolution and the ToE. There is a difference in quantity\degree of evolution between "micro" and "macro" (as the terms are used by biological scientists), but not a difference in quality\sort of evolution (as many creationists mistakenly believe).

Of course, the continued failure to see some process other than evolution does support the ToE ... just like the failure to observe something other than a sunset does support the theory of gravity.

The Theory of Evolution (ToE), stated in simple terms, is that the process of evolution over generations, and the process of divergent speciation, are sufficient to explain the diversity of life as we know it, from the fossil record, from the genetic record, from the historic record, and from everyday record of the life we observe in the world all around us.

We observe evolution occurring every day in living species, and what we are observing is the ongoing process of both "micro" and "macro" evolution -- because it is the same process. That this is occurring, today, is now well documented by the Grants in the case of the finches ... just another strong assembly of observational and genetic evidence added to the volumes of evidence already accumulated.

... But second I HAVE argued at great length that wherever you have genetic changes occurring and creating new breeds or races you also have a reduction in genetic potential to keep on changing. This is intuitively obvious if you just think about it.

Of course, dear Faith, we all know about your obsessive denial of the increase in genetic diversity that occurs. Sadly, for you, that does not invalidate the rather overwhelming evidence that this has occurred and will continue to occur. Your opinion, like any other opinion, is woefully inadequate at affecting reality.

Perhaps you could tell us what genetic reduction occurred or is occurring with these finches ...


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 6 by Faith, posted 04-29-2014 11:11 PM Faith has responded

Replies to this message:
 Message 31 by Faith, posted 05-01-2014 6:07 AM RAZD has responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


Message 51 of 131 (725810)
05-01-2014 10:48 PM
Reply to: Message 45 by Dr Adequate
05-01-2014 10:06 PM


Re: You can't get evolution beyond microevolution
That would be Message 262Message 267, Message 272, Message 282 and Message 287

Edited by RAZD, : corrected


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 45 by Dr Adequate, posted 05-01-2014 10:06 PM Dr Adequate has responded

Replies to this message:
 Message 53 by Dr Adequate, posted 05-01-2014 11:07 PM RAZD has acknowledged this reply

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


Message 54 of 131 (725813)
05-01-2014 11:09 PM
Reply to: Message 31 by Faith
05-01-2014 6:07 AM


So what IS macroevolution Faith?
I can't deal with your extremely lengthy post right now. ...

Reality is hard.

... All I want to say here is that of COURSE they are observing microevolution, what they CAN'T observe is macroevolution, ...

Can you give me a definition of macroevolution and an example of what you mean?

... but when their work is presented as an actual experience of "evolution" with all that Wow stuff attached to it, it is properly understood to mean that it validates the ToE, which required me to say it does NOT.

You do realize that the science of evolution, the theory of evolution and the process of evolution are three different meanings for the word evolution don't you?

They most certainly did science and they most certainly studied the process of evolution with science, thus they did evolution science.

The article did not mention the theory of science once, but with your reading skills you see it dripping with references ... fascinating.

But again let's start with your definition of macroevolution ... should be easy to state and you should be able to provide examples ...

Edited by RAZD, : No reason given.


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 31 by Faith, posted 05-01-2014 6:07 AM Faith has not yet responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


Message 73 of 131 (725872)
05-02-2014 7:54 PM
Reply to: Message 69 by Faith
05-02-2014 3:52 PM


Re: Beneficial mutations and other facts that increase diversity
Which is true exactly as I've presented it. ...

Except that you have totally failed to show any decrease in diversity, even with these mutation-on-a-platter examples being singled out (from many possible examples of non-lethal mutations).

Is there any loss of diversity in the Galapagos Finches? Can you demonstrate that the diversity in finches is less now than 40 years ago?

No, you can't, because it isn't true.

... The example of breeding is the only accessible example of how this has to happen to get the new traits of a new breed, ...

Except for the new variety of finch on the Galapagos Islands ... and others ...

But what these cat examples show is a mutation that causes sufficient difference to develop a new breed, the old breed still exist so what we obviously have is an increase in diversity, more variation within the domestic cat species.

... and it's perfectly good as an example of what has to happen in the wild too. ...

Agreed, ... with the caveat that such mutations would add to variation within a breeding population and would not be segregated into different breeding populations.

Certainly if there were reproductive isolation between two cat populations and one of these mutations occurred in one that - because it is dominant - becomes the standard of that isolated population that you could see the beginning of speciation occurring.

Just as the Grants have been observing with the "big bird" becoming dominant within it's breeding population with reproductive segregation possible due to different mating songs.

... The alleles for other traits can't remain in the population, period.

Whether or not this is true is irrelevant because they will still remain in the OTHER population/s (other breeds) and thus there WILL be an increase in diversity: two populations with different alleles.

Singular linear thinking is hopelessly inadequate in a multi-linear world.

Enjoy.


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 69 by Faith, posted 05-02-2014 3:52 PM Faith has not yet responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


Message 82 of 131 (725884)
05-03-2014 1:31 AM
Reply to: Message 78 by Faith
05-03-2014 1:00 AM


Re: Beneficial mutations and other facts and repeat
... Yes a (putatively viable) mutation will add genetic diversity and if it's expressed also a new trait. There's nothing about that to challenge anything I'm saying.

Except that it keeps happening: evolution never stops.

You get a new population that is distinguished by only one trait and call it a new breed or subspecies. ...

Or a new variety to be more precise.

... OK, where do we go from there?

So now we do it again -- add another new mutation\trait, add more genetic diversity.

Only Evolution, msg 12 (that loong post you couldn't "deal with" "right now"): ... evolution, it is a two-step feedback response system that is repeated in each generation:

Like walking on first one foot and then the next. ...

One step adds new diversity the other step takes the worst (for survival or reproduction) diversity away, a stumbling walk, so the balance of traits is always shifting, changing, evolving:

The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities.

This is what the Grants observed occurring.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 78 by Faith, posted 05-03-2014 1:00 AM Faith has not yet responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(1)
Message 101 of 131 (725971)
05-05-2014 8:18 AM
Reply to: Message 92 by Faith
05-05-2014 3:46 AM


what is macroevolution Faith?
So back to the increase in diversity. Just go back to the original scenario. That increase has to be cut down IF the population is to evolve a new set of characteristics AS A POPULATION, and this is also what happens in genetic drift, it's simply another way this happens. Otherwise you'll have a nicely variegated population, perhaps millions of individuals with a very wide variety of traits among them.

Not quite, Faith. Natural selection means those able to survive and breed pass on traits to the next generation, and this happens every generation. Those individuals that do not survive and breed do not pass on their specific mix of traits to the next generation. Thus the traits that are least beneficial to survival and reproduction tend to be removed from the population by this process

Genetic drift does not enhance fitness, as it is stochastic - chance, just like mutations. Genetic drift is neutral to fitness.

The number of trait varieties in the population will depend on the selection pressure, and when the pressure is low there will be more variation than when it is high.

Are you REALLY saying MACROevolution doesn't depend on the formation of distinctively new populations, but that the normal variation from generation to generation without there being any sort of isolation or selection acting on it, would ultimately lead to MACROEVOLUTION just as well as the formation of distinctly different whole populations would?

What is macroevolution Faith? Your definition please?

I think YOU need to explain how you get new species without this reduction in genetic diversity. Of course you theoretically get new individual traits from the ongoing mutations, but unless they are selected or isolated so they can proliferate as a new population you aren't getting the kind of change that evolution is defined by.

Take a deck of cards and shuffle them. Now cut the deck into two piles. If you had 52 cards in the original deck, how many cards do you have in the two piles?

Is there more or less diversity in the two piles taken as a whole than in the original deck?

So the diversity is still there, what you don't have is gene flow from one pile to the other, but diversity looks at the whole ecosystem not just a single population. The individuals in the two populations will continue to behave and interact within the ecosystem just as they would as a combined population. Each daughter population will also acquire different new mutations, mutations not shared with the other daughter population and thus the differences that existed between the original daughter populations will grow as different diversity is added to each population by mutations.

Look at this image at two different levels, one at the "1000" elevation in the "Lysite" area and the other a the "1500" elevation mark in the "Lower Cabin" area.

The widths of each band represents the diversity of the population with regards to size. The population at the 1000 elevation is very spread out, and the two populations at the 1500 elevation are more clumped up (thicker bars means more individuals of that size): Notharctus nunienus on the left and Notharctus venticolus on the right.

Does the total width from smallest Notharctus nunienus to largest Notharctus venticolus exceed the total width of the population at the 1000 elevation?

quote:
... The two species later became even more distinct, and the descendants of nunienus are now labeled as genus Smilodectes instead of genus Notharctus.

As you look from bottom to top, you will see that each group has some overlap with what came before. There are no major breaks or sudden jumps. And the form of the creatures was changing steadily.


This same process occurs in each of the two branching populations and total diversity has increased.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 92 by Faith, posted 05-05-2014 3:46 AM Faith has responded

Replies to this message:
 Message 103 by Faith, posted 05-05-2014 8:28 AM RAZD has responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


Message 102 of 131 (725972)
05-05-2014 8:27 AM
Reply to: Message 93 by Faith
05-05-2014 4:16 AM


Re: Beneficial mutations and other facts
And I've tried to explain in that last post how you simply would never get anything you could call a New Species IF new variation did keep coming in and changing the whole population. Of course you will get new traits continuing to pop up in INDIVIDUALS within the population assuming there are still alleles for those traits in the mix [[ABE forgot here you are assuming mutations instead, but that works too/ABE]=, but unless they change the character of the whole population you are not getting a new species.

And at this point I've asked how you can have evolution if you are NOT getting new species. Which is something you are all claiming.

What is a species?

What makes a "new species" different from a previous one?

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 93 by Faith, posted 05-05-2014 4:16 AM Faith has not yet responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(2)
Message 105 of 131 (725977)
05-05-2014 9:12 AM
Reply to: Message 103 by Faith
05-05-2014 8:28 AM


Re: what is macroevolution Faith?
Fitness as an adaptive mechanism is just an article of faith, in reality there is hardly any struggle in the Darwinian sense to adapt. ...

How then do you explain the same level of populations from generation to generation even though more offspring are produced than are needed to fill the vacancies made by the dying? Take spawning salmon as an example -- how many eggs are produced and how many salmon return the following year?

How do you explain the peppered moth population swing from light to dark and from dark to light? If fitness was not involved would not there be the same number of light and dark moths each year?

... There are certainly some striking adaptations but they can just as easily be the right beak finding the right food as the available food determining the right beak.

And if the small beak cannot find seeds it can open does it just hang in stasis until the right food appears?

As for what is macroevolution: I define it functionally as the point at which microevolution so decreases genetic diversity that no further evolution is possible.

Which of course is a "Faith fantasy" definition not incorporated into biology or evolution science.

However, here's another attempt: It's whatever CAN vary in the given genome of the species, its peculiar traits and the genes for those traits with their various alleles. No variation is possible outside those built-in design limits.

Also a "Faith fantasy" definition not incorporated into biology or evolution science.

Do you understand that when you use words that you define one way and science defines another way that you are NOT talking about the same thing?

Faith: macroevolution is "x" and it never occurs
Science: macroevolution is "y" and it has been observed, so we know it occurs.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 103 by Faith, posted 05-05-2014 8:28 AM Faith has not yet responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(1)
Message 106 of 131 (725978)
05-05-2014 9:42 AM
Reply to: Message 94 by Faith
05-05-2014 4:44 AM


Re: " narrowing down of traits"
Need to say more about "narrowing down of traits" which I didn't grasp at first. You say this isn't happening. But it has to happen in Natural Selection, for instance, where only the adaptive traits are preserved. The ones that didn't work for the environmental situation drop out, are maybe even killed off by a predator. ...

That is how less fit individuals are removed from the breeding population.

... That's a narrowing down of traits isn't it?

Not necessarily. If the population grows by 20% due to reproduction success, but half of those don't make it to breeding age then the population still grows by 10%.

Whether a population grows, shrinks or remains the same size is a function of selection pressure: lower pressure means more survival\reproduction, while higher pressure means less survival\reproduction.

But even the simple case of microevolution by migration of a small number of founders ...

A very confused phrase.

Consider this instead: a population grows and spreads into adjoining ecosystems, some that are marginal for survival and reproduction. Individuals that move into these marginal areas will be under different selection pressure than the parent population, and those that survive to breed will be those individuals more able to take advantage of the resources in that marginal ecosystem. Let's say larger harder seeds, so birds with larger stronger beaks will have an easier surviving than ones with smaller weaker beaks.

... has to lead to the same situation, and a new species could develop from that new population, which really could happen in a short time if it has favorable conditions for long term inbreeding. ...

When does breeding become inbreeding?

What is a new species?

So the daughter population in the marginal ecology develops larger stronger beaks on average than the parent population.

This would be evolution, but not necessarily speciation at this point.

... It's going to develop its own traits that are different from those of the mother population. ...

Depending on the gene flow between the parent population and the population in the adjoining ecosystem. As gene flow decreases more differences will develop, and it is also likely that as more differences develop that gene flow will decrease (individuals from the other population may be less desirable as mates than individuals in their own population)

... If the old traits are low frequency enough their alleles will disappear from the new population altogether. ...

So the traits for small beaks will tend to be eliminated, while the variation around beak size will be the same, just with a larger average beak size in the adjoining population, ... and the variation of beak size in the parent population remains as before.

... This is a "narrowing down of traits" isn't it?

Or an increase in traits overall between both populations, more than existed previously, with room to increase further.

Enjoy.


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 94 by Faith, posted 05-05-2014 4:44 AM Faith has responded

Replies to this message:
 Message 107 by NoNukes, posted 05-05-2014 10:34 AM RAZD has acknowledged this reply
 Message 108 by Faith, posted 05-05-2014 3:31 PM RAZD has responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(2)
Message 109 of 131 (726069)
05-06-2014 11:02 AM
Reply to: Message 108 by Faith
05-05-2014 3:31 PM


Re: " narrowing down of traits" and the "expansion of traits"
Yes, RAZD, but the point I'm making is ...

... still wrong.

... that this process brings about the [abe] removal of traits [/abe] along with reduction of genetic diversity I've been focusing on, ...

While ignoring the addition of traits by mutations -- a process you now admit can cause "curly ears" in cats.

... and if the culling is radical even possibly the complete loss of some alleles from the population, ...

Some alleles are probably lost every generation -- ones less able to provide ability to survive and reproduce and certainly new ones that are lethal. The loss of less viable alleles does not cause extinctions.

... and this loss of genetic diversity is what compromises the ability of the species to vary further ...

Which doesn't happen: the amount of mutation is independent of the number of alleles. The amount of new diversity introduced into a breeding population is related to the size of the population. This is why small founding populations have restricted variations in traits at the start, but this still doesn't inhibit new traits from occurring due to mutations.

... as it continues to evolve down the path of variation or speciation, which is the whole thing I'm focusing on here. The very processes that bring about a new species eventually make it impossible for the species to continue to vary.

So you will be relieved to know that this doesn't occur.

If you are still talking about traits that's not at all evident from this statement and you may want to rewrite it, as the size of the population is another subject from the frequency of the traits and their alleles in the population. ...

But here again you are talking about population size which is at best incidental in the context of loss of traits and their alleles.

No Faith, population size is directly related to the degree of diversity available in a breeding population. A small population cannot have as much diversity as a large population.

However, when you divide a breeding population into two isolated breeding populations you do not lose diversity relative to the ecological whole, rather you increase the opportunity for new traits to survive in different ecological space.

... Their frequency is affected by their selection for fitness if that is in fact in operation, which is the subject here. ...

Sadly, for you, this is not a matter of debate, it is a fact that natural selection occurs, it is an observed and documented process, and denial of it is delusional.

The Grants alone have observed and documented natural selection occurring on the Galapagos Islands for 40 years.

... Again if the selection is severe there may be no alleles left at all except those that underlie the successful traits. ...

Which still leaves the population viable with successful survival and reproductive traits as more new traits are added due to mutations.

... (And of course if it's even more severe extinction may be the result.) This is certainly a "narrowing down of traits."

Extinction would be a "narrowing down of traits" ... but the cause of extinction is not the loss of traits, it is the failure to survive and reproduce, natural selection at its most stern implementation, regardless of the diversity of traits in the population.

The problem is that we are thinking of different things. There's nothing confused about it in the context of what I'm talking about which is what happens to the TRAITS and their alleles, which is brought about by the reproductive isolation of a small number of individuals, which can be brought about by migration of those individuals or by natural selection of those individuals or even by sexual selection of those individuals within the larger population. The size of the population that develops subsequently is something else.

Indeed, I am talking about evolution occurring according to the observed and documented processes (scientific facts) of mutations adding new traits and selection removing the less viable traits from the populations

OK, yes, of course, but accepting your scenario my point is how such selection of traits leads to reduced genetic diversity for that population. This is the more severe the more such pressures exist, pressures of natural selection, adaptive requirements for particular beaks and so on. The more pressure, the more culling of the unfit beaks and their alleles, and the less genetic diversity in the population as a whole.

And with pressure for larger stronger beaks we see the survival and reproduction of those with the largest beaks being more pronounced than before, that the average beak size increases, that new even larger beaks survive and reproduce as mutations in that direction that were deleterious before now become beneficial.

The amount of variation in size in a population is typically a normal distribution around the average size. This whole pattern shifts towards larger beaks allowing the opportunity for even larger beaks to survive.

Your thinking is hampered by your false preconceptions.

When you have a daughter population that is reproductively isolated it helps to use the term inbreeding to describe the confinement of the genetic possibilities to that gene pool exclusively and the absence of gene flow between the daughter and parent populations. ...

So you are misusing a word again. Inbreeding is generally considered the mating or breeding of individuals or organisms which are closely related genetically, such as parent, brother, sister, child, such that they share almost all of the same traits.

With your usage every breeding population is "inbreeding" and the term become meaningless.

... Since speciation is defined as the loss of ability to INTERbreed with the former populations I'm simply looking for ways to keep the different populations conceptually distinct from each other.

The actual loss of ability to interbreed does not necessarily occur, what usually happens is that reproductive isolation occurs for any of a number of factors, including plain loss of attraction. Of course the further your daughter populations diverge the greater is the opportunity for inviable offspring to occur, but this can be many generations after interbreeding has ceased.

A new population that is separate from other populations of the larger Species the parent population that has developed distinct traits of its own that clearly differentiate it from the mother population from which it has diverged, as well as any cousin populations , which happens because of reproductive isolation of the new population between the populations, which may be the result of geographic isolation or natural selection etc. Over time this can lead to inability to interbreed with the other populations which is of course where standard evolutionary theory identifies it as a new species.

All that's needed is the loss of interbreeding between populations such that each population evolves without gene flow from the other population/s.

Yes, and I'm focused on EVOLUTION, which is the change in the character of a new population that occurs through the reproductive isolation of a portion and a number of generations of inbreeding. Speciation as formally understood may or may not occur. Call it a new "subspecies" then.

Ah, you are talking about macroevolution ... rather than microevolution.

Tell me Faith, if a whole breeding population moves into a new ecology (or the ecology changes around them) and they develop new frequency distribution of traits plus the new traits from mutations, in response to the opportunities and challenges of the new ecosystem ... the very same process as your daughter population above, but for the whole population (no parent population left behind) ... would that be a new species?

As gene flow decreases more differences will develop,

Yes, RAZD, which is a condition I have been emphasizing all along.

Allow me to rephrase for clarity: As gene flow decreases new differences will develop between populations with restricted gene flow due to more and more new traits not being shared.

Yes that is very likely to happen also. But the main thing that I want to keep in view here, that is happening in the absence of gene flow and the development of the distinctive traits of the new population, is the decrease in genetic diversity of that population.

Which is still wrong on two counts:

(1) as far as the rest of the ecology is concerned it makes no difference whether there is a homogeneous population of diverse individuals or two separated populations with the same overall diversity: total diversity within the ecology has not decreased.

(2) while this process of isolation is going on, new traits are constantly being added and tested by selection within each population -- which will necessarily have different results in isolated population under different selection pressures -- and thus total diversity within the ecology will increased.

Yes, the small beaks will tend to be eliminated, and the ALLELES for small beaks will tend to be eliminated..

And the alleles for larger beaks would tend to increase within the population. New alleles for larger beaks would be selected as they occur.

I'm not sure what you mean or if it is true that "the variation around beak size will be the same" or why this would be the case, since if a larger beak has been selected it should eventually become a consistent feature of the new population. ...

These aren't quantum size jumps Faith, it is a spectrum of sizes, where beaks run from "too big" to "too small" and a fairly large group of "good enough to survive and breed" ... and what changes is the "good enough to survive" size, increasing within the variation already occurring within the population (selection only works on what is available), while providing opportunity for larger beaks to exist than before within the overall population variation.

... But I can completely agree that "the variation of beak size in the parent population remains as before" ASSUMING it is appreciably larger in numbers than the daughter population (because if it's not that population too would have appreciably new allele frequencies and also develop some change in its phenotypic presentation)

Unless caused by catastrophic separation the parent population will tend to be comprised of the individuals most fit to meet the challenges and benefit from the opportunities in the parent ecology, and the individuals less fit will tend to foray into neighboring ecologies. Think of the dark pocket mice moving onto the lava beds while the parent tan mice remain in the desert sands. There is no reason for the frequency of alleles to shift appreciably for the tan mice, but there is for the dark mice.

Yes there is always room for the increase in TRAITS, the phenotypic presentation, even more than previously, yes, this is what evolution does, it brings out new traits, ...

Close. It allows new traits to be positively selected that previously were negatively selected. It allows new traits to arise that did not exist before, building on the mix of traits in the population. Like stepping stones. First you get a plume feather on the head, then it becomes red ...

... but what I keep trying to point out is that it does this WITH RESPECT TO ANY GIVEN POPULATiON by culling the traits that don't fit, ...

Which happens in all populations every generation, it's called natural selection. The other half of evolution is the mutations that provide new variety within the population which is then subject to the next round of selection ... a two-step feedback response system that is repeated in each generation:

Like walking on first one foot and then the next.

... so that their alleles disappear from that particular population along with the traits themselves, ...

A process underway all the time as less viable traits are selected against in favor of new successful traits.

... which is a decrease in genetic diversity, so that any further selection, isolation, culling itself will further reduce that genetic diversity ...

Only as long as you ignore and deny the addition of genetic diversity from new mutations. They may not balance every generation, but they would tend to balance over time as long as the ecology doesn't become lethal (global climate change?).

... WHILE BRINGING OUT EVEN MORE NEW TRAITS in subsequent daughter populations, ...

From new mutations that are selected for their viability at survival and reproduction within the daughter population ecology (which is necessarily different from the parent population ecology).

... so that at every stage you are getting the development of populations characterized by new collections of traits ...

That are viable within the ecology and provide sufficient success at survival and reproduction, a process that occurs in all population in all generations.

... AND the loss of genetic diversity, so that if these processes continue you ultimately reach a point where you can't get further variation of traits because the traits you have at that extremity of the evolving pathway are going to be predominantly or even exclusively homozygous throughout the whole group.

Except for all those new traits from mutations that survived selection in the new ecologies.

Certainly if the new traits cannot keep up with the challenges of the ecologies populations can go extinct, but one can just as easily have the quantity of new traits exceed the needs of the population to survive and breed so that some will be culled by selection, changing the types of diversity involved while leaving the degree of diversity of the population as a whole basically unchanged.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 108 by Faith, posted 05-05-2014 3:31 PM Faith has responded

Replies to this message:
 Message 110 by Faith, posted 05-06-2014 3:46 PM RAZD has responded
 Message 113 by Faith, posted 05-06-2014 5:01 PM RAZD has responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(1)
Message 116 of 131 (726181)
05-06-2014 10:36 PM
Reply to: Message 110 by Faith
05-06-2014 3:46 PM


The simpler explanation: biological evolution
This is getting waaay too long, so rather than attempt to reply to your repeated points I am going to take desperate measures and lay out how biological evolution explains the diversity we see around us. I've broken it into a couple of sections so you may want to review each independently.

Biological Evolution

(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities.

This is sometimes called microevolution, however this is the process through which all species evolve and all evolution occurs at the breeding population level.

Mutations and mixing existing hereditary traits in different combinations (ie for eyes and ears) can cause changes in the composition of hereditary traits for individuals in a breeding population, but not all mutations do so (many are in non-hereditary areas). In addition there are many different kinds of mutations and they have different effects (from small to large), especially if they affect the developmental process of an organism.

Natural Selection and Neutral Drift can cause changes in the frequency distribution of hereditary traits within a breeding population, but they are not the only mechanisms known that does so. Selection processes act on the expressed genes of individual organisms, the phenotype, so bundles of genetic mutations are selected rather than individual genes, and this means that some non-lethal less viable mutations can be preserved. The more an individual organism reproduces the more it is likely to pass on bundles of genes and mutations to the next generation, increasing the selection of those genes.

The ecological challenges and opportunities change when the environment changes, when the breeding population evolves, when other organisms within the ecology evolve, when migrations change the mixture of organisms within the ecology, and when a breeding population immigrates into a new ecology. These changes can result in different survival and reproductive challenges and opportunities, affecting selection pressure, perhaps causing speciation, perhaps causing extinction.

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

Like walking on first one foot and then the next.

Mutations of hereditary traits have been observed to occur, and thus this aspect of evolution is an observed, known objective fact, rather than an untested hypothesis.

Different mixing of existing hereditary traits (ie Mendelian inheritance patterns) have been observed to occur, and thus this aspect of evolution is an observed, known objective fact, rather than an untested hypothesis.

Natural selection has been observed to occur, along with the observed alteration in the distribution of hereditary traits within breeding populations, and thus this aspect of evolution is an observed, known objective fact, and not an untested hypothesis

Neutral drift has been observed to occur, along with the observed alteration in the distribution of hereditary traits within breeding populations, and thus this aspect of evolution is an observed, known objective fact, and not an untested hypothesis.

Thus the process of evolution is an observed, known objective fact, and not an untested hypothesis.

This is basic simple biological evolution as observed in the world around us.


Phyletic Change\Speciation

If we look at the continued effects of evolution over many generations, the accumulation of changes from generation to generation may become sufficient for individuals to develop combinations of traits that are observably different from the ancestral parent population. This lineal change within species is sometimes called phyletic change in species , or phyletic speciation . This is also sometimes called arbitrary speciation in that the place to draw a line between linearly evolved genealogical populations is subjective, and because the definition of species in general is tentative and sometimes arbitrary.

If phyletic speciation was all that occurred, then all life would be one species, readily sharing DNA via horizontal transfer (asexual) and interbreeding (sexual) and various combinations. This is not the case, however, because there is a second process that results in multiple species and increases the diversity of life.


Divergent Speciation

(2) The process of divergent speciation involves the division of a parent population into two or more reproductively isolated daughter populations, which then are free to (micro) evolve independently of each other.

The reduction or loss of interbreeding (gene flow, sharing of mutations) between the sub-populations results in different evolutionary responses within the separated sub-populations, each then responds independently to their different ecological challenges and opportunities, and this leads to divergence of hereditary traits between the subpopulations and the frequency of their distributions within the sub-populations.

Over generations phyletic change occurs in these populations, the responses to different ecologies accumulate into differences between the hereditary traits available within each of the daughter populations, and when these differences have reached a critical level, such that interbreeding no longer occurs, then the formation of new species is deemed to have occurred. After this has occurred each daughter population microevolves independently of the other/s. These are often called speciation events because the development of species is not arbitrary in this process.

If we looked at each branch linearly, while ignoring the sister population, they would show phyletic change in species (accumulation of evolutionary changes over many generations), and this shows that the same basic processes of evolution within breeding populations are involved in each branch.


Nested Hierarchies

An additional observable result of speciation events, however, is a branching of the genealogical history for the species involved, where two or more offspring daughter species are each independently descended from the same common pool of the ancestor parent species. At this point a clade has been formed, consisting of the common ancestor species and all of their descendants.

With multiple speciation events, a pattern is formed that looks like a branching bush or tree: the tree of descent from common ancestor populations. Each branching point is a node for a clade of the parent species at the node point and all their descendants, and with multiple speciation events we see a pattern form of clades branching from parent ancestor species and nesting within larger clades branching from older parent ancestor species.

Where A, B, C and G represent speciation events and the common ancestor populations of a clade that includes the common ancestor species and all their descendants: C and below form a clade that is part of the B clade, B and below form a clade that is also part of the A clade; G and below also form a clade that is also part of the A clade, but the G clade is not part of the B clade.

The process of forming a nested hierarchy by descent of new species from common ancestor populations, via the combination of phyletic change in species and divergent speciation, and resulting in an increase in the diversity of life, is called macroevolution in biology. This is often confusing to people, because there is no additional mechanism of evolution involved, rather this is just the result of looking at evolution over many generations and the effects of spreading into different ecologies.


Now your argument is basically that species run out of variation the more they evolve, having to discard alleles\traits in the process (the basis of the traits is genetic, but selection is on the phenotype).

Even with mutations you argue -- if I have it right -- that the rate of loss is greater than the rate of gain:

It has to, RAZD, you are not going to get a new breed in domestic programs OR a new species or even subspecies in the wild UNLESS this happens. ... This will happen in any given population that is evolving. ...

And you don't get a new species without mutations introducing new traits that are foreign to the parent population. That is what allows species to take advantage of different ecologies, and that increases diversity.

Every individual in every generation has new mutations, thus no matter how small a population is, there is still new variations, new traits. They may be small -- longer fur, larger beak, different color, etc. What is important is that they will be different, and those differences can add up to make a difference in different ecologies.

This has been observed. Not all species survive, but enough to carry on. There have been times of mass extinction, but life has rebounded with new diversity after each one.

Enjoy.


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 110 by Faith, posted 05-06-2014 3:46 PM Faith has responded

Replies to this message:
 Message 118 by Faith, posted 05-07-2014 6:25 AM RAZD has responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(1)
Message 119 of 131 (726227)
05-07-2014 7:16 AM
Reply to: Message 113 by Faith
05-06-2014 5:01 PM


Re: " narrowing down of traits" and the "expansion of traits"
OK as a general rule, but large populations are generally not evolving as I keep trying to keep in focus. ...

Except that they are. All populations are evolving, it is a continual process.

... It is WHEN you get the reduced numbers with the reduced diversity that you get the best examples of evolution of new traits ...

I think you are confusing populations in stable ecologies where evolution centers on the most fit for that ecology (creating an apparent stasis) with a lack of evolution: mutation and selection still occur. Neutral traits still arise that add variations within the population, and new trait still occur, but selection for the most fit individuals for survival and reproduction will act against changing the population once it has reached a relative equilibrium fitness.

The larger population may be relatively static but you CAN can get the same effect even in a larger population if there is strong genetic drift which favors some traits over others, ...

Genetic drift doesn't come in flavors nor does it favor some traits over others -- it is stochastic - chance - and it is more noticeable in small populations than large ones. It is one mechanism for how neutral traits spread in populations

This may be the case but all I'm talking about is the mechanisms or processes that bring about a divergence in traits between two separate populations, and this is always the same no matter what else is going on. If strong selection pressure occurs you'll get a dramatic development of adaptive traits with a more dramatic loss of the unadaptive traits. It will simply speed up the normal processes.

What brings about divergence is the appearance of new traits that allow the daughter populations to take better advantage of the opportunities in different ecologies -- a gain in diversity for the total population as well as a gain available resources.

Sad? I've never denied natural selection, I've only said I think it is far less a factor than it is reputed to be. Which you might like to hear since it only speeds up the processes I'm describing that you don't much like. NS more dramatically demonstrates them than the neutral situation of simple geographic isolation I keep focusing on, because the adaptive characters proliferate more rapidly while the unadaptive die out a lot faster than they would if only low frequency alleles were the cause.

It doesn't matter to me. They may or they may not have. It doesn't affect the point I'm making, and in fact only dramatizes it if it is happening. I just don't think it happens as much as you all think it does, that evolution is going to occur just as well without it.

Yes sad, because you insist on being totally ignorant of how evolution works. Let me show you this picture once more:

Evolution is a two-step feedback response system that is repeated in each generation, like walking on first one foot and then the next. It is rather difficult to walk across the country if you don't use both legs.

In every generation there are individuals that do not survive to breed. That is selection.

No, this is not happening in this context. What I'm describing is how you get a new species or subspecies. ...

Except that you aren't. You don't understand the process well enough to describe it.

... If mutations are added you will lose your species or subspecies. ...

Bizarre. Do you think mutations are some kind of infection?

Except that mutations are what cause new traits that allow a daughter population to diverge from the parent population as they take advantage of different opportunities in different ecologies. They are what cause the new species/subspecies/varieties to diverge from the parent population.

... And again it's not that you have to have a new species or subspecies it's just that when one develops it is by losing genetic diversity, not adding it.

Which curiously is a statement at odds with the facts.

... You have your source of traits and then you have the processes that mold or evolve them into a new population. ...

Again, you do not understand the process. Mutations change traits randomly, natural selection favors those traits that provide better survival and reproduction. When a species moves into a marginal ecology (or the ecology changes) there will be different traits selected in response to the opportunities and challenges of that ecology.

In other words, Faith, natural selection picks the traits best suited in the population for the population, natural selection "molds" the population ...

... The processes that evolve them, the selection that removes the less viable traits does exactly what I'm describing: it favors the proliferation of the adaptive traits WHILE IT ELIMINATES THE UNADAPTIVE TRAITS, which creates an overall loss of genetic diversity in that population.

In favor of new traits that are better suited for survival and reproduction in the new ecology. Ones that enable the population to survive and grow.

I'm stopping again for now.

Read Message 116. Again. ... and try for comprehension instead of denial. It is lengthy and it may seem complicated to you, but it describes how evolution actually works.

Enjoy.

Edited by RAZD, : ..


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 113 by Faith, posted 05-06-2014 5:01 PM Faith has responded

Replies to this message:
 Message 120 by Faith, posted 05-07-2014 7:32 AM RAZD has responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(1)
Message 121 of 131 (726232)
05-07-2014 8:35 AM
Reply to: Message 118 by Faith
05-07-2014 6:25 AM


Re: "the simpler explanation" still includes mutations, mutations and more mutations
It amazes me the extent you go to in order to insist on being wrong.

Which occur regularly simply with ordinary sexual recombination in any population ...

And which ACTUALLY occurs from ordinary sexual recombination PLUS mutations.

You deny ignoring mutations and yet here you are denying mutations. They are an observed and documented part of the equation. Ignoring them makes you reach false conclusions.

It's like you want to count to 100 using only odd numbers, ... which makes it difficult to get 100.

... where the genetic diversity is fairly high. ...

Which is due to mutations.

... That is, hereditary traits are based on allele combinations and these get shuffled with each new sexual recombination event.

And altered by new mutations.

Failure to consider mutations leads you to false conclusions.

... which isn't going to happen to any noticeable extent without selection ...

Correct: genetic variation with mutations plus selection for survival and breeding occur in every generation of every population -- that is evolution.

Notice that this contradicts earlier statements you made about selection (Message 113): "... I've only said I think it is far less a factor than it is reputed to be. ... I just don't think it happens as much as you all think it does, that evolution is going to occur just as well without it."

... or isolation, which is what brings about new allele frequencies. This CAN happen entirely within a large population with genetic drift though, ...

Allele frequencies are always in flux, even in fairly stable populations. Larger variations can be caused by ecological change or by moving into a different ecology. The change in frequencies is caused by the selection response to the ecological changes or variation.

... a subpopulation having reproductive isolation from random factors that change the allele frequencies for that breeding group within the larger group.

The different allele frequencies are caused by ordinary sexual recombination PLUS mutations PLUS selection. In different ecologies selection will be different due to different challenges and opportunities posed by the ecology. Selection is the process that determines the mix of alleles that is favored for survival and growth of the population. Selection occurs in response to the ecology.

... The mixing of new allele frequencies is all it takes to develop a new subspecies.

Nope. False. Wrong. Incorrect. Invalid. Without mutation you don't get new species.

The introduction of new traits due to mutations is necessary for the new species to diverge from the parent population: it is what makes them different.

So can simple sexual recombination of preexisting alleles.

But not to the degree that can occur with mutations included in the mix.

So far this is all very similar to what I’ve been describing except you make it all hinge on the environmental pressures whereas I’m saying the changes also come about just by simple neutral random isolation of traits and their alleles, then being mixed by ordinary sexual recombination.

And that would make you wrong again.

And ALL these scenarios require the reduction of genetic diversity to bring out the new traits.

Only because you say so and because you refuse to include mutations in your thinking and this leads you to false conclusions.

Fortunately, for life on earth, mutations do occur, mutations do cause genetic change, mutations do provide beneficial traits, mutations do enable speciation to occur.

Enjoy.


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 118 by Faith, posted 05-07-2014 6:25 AM Faith has not yet responded

Replies to this message:
 Message 123 by NoNukes, posted 05-07-2014 8:52 AM RAZD has responded

  
RAZD
Member
Posts: 20061
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(1)
Message 124 of 131 (726236)
05-07-2014 9:07 AM
Reply to: Message 120 by Faith
05-07-2014 7:32 AM


continuous evolution is ... continuous (surprise)

Yeah yeah yeah but this is an academic point because they aren't actively involving evolving as a selected or isolated smaller population is, ...

No, Faith it is important to know that populations in static ecologies are constantly evolving to remain near optimum for fitness to the ecology, that significant changes are resisted by selection when there is no pressure to change.

Climate changes from year to year mean that the frequencies of traits in the populations change in response. This was observed by the Grants many times.

It is also critical because a developed population that fills their habitat to the carrying capacity will push less viable individuals into marginal surrounding ecologies and this is particularly applicable when new traits that arise in the developed population enable individuals to move into and take advantage of neighboring ecologies.

The dark mice were able to take advantage of the lava beds.

... as new allele frequencies are making a difference in every generation as new traits are bring brought out and blended into the whole population so that it clearly diverges phenotypically from the former population. ...

Because of mutations and continued selection to meet the opportunities and challenges of the different ecology.

... but all I mean is that it isn't ACTIVELY evolving because there is nothing happening to bring that about. Mutation would be going on supposedly but all that would do is cause various novel traits to pop up in individuals now and then (which I think is going to happen without mutations anyway), and selection is NOT going on because that's what brings about the active evolution I'm talking about.

Except that it is ACTIVELY evolving to remain fit for the ecology, and selection is continuous in every generation, still removing traits that are less viable for survival and breeding.

Fine, all that does is describe the same situation I'm describing where ACTIVE evolution isn't occurring.

ACTIVE evolution is occurring in ALL breeding populations. That active evolution includes active production of variations in hereditary traits by recombination and mutation, and it involves active selection of the traits best suited for the ecology, ... whether that ecology is different or not.

Every new generation is different from the parent generation. What survives and reproduces depends on the selection response to the challenges and opportunities of the ecology, whether that ecology changes by normal climate variations or by the population moving into a new ecosystem or by other species evolving around them.


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 120 by Faith, posted 05-07-2014 7:32 AM Faith has not yet responded

Replies to this message:
 Message 128 by NoNukes, posted 05-07-2014 11:12 AM RAZD has responded

  
1
2Next
Newer Topic | Older Topic
Jump to:


Copyright 2001-2018 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2019