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Author Topic:   Why Evolution works inside Ecologies
RAZD
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(2)
Message 16 of 37 (720402)
02-22-2014 5:58 PM
Reply to: Message 15 by Faith
02-22-2014 1:42 PM


Island Biogeography
Anything observable is microevolution. But do carry on.

All observed evolution from one generation to the next is "microevolution" -- the evolution that occurs within each and every breeding population -- and this is the way "microevolution" is defined in science (and what is meant when talking about evolution in breeding populations).

All the processes that produce evolutionary change are processes of "microevolution" -- the processes that produce variation/s within breeding populations and the process that continue in daughter populations that become isolated from other populations within an overall species breeding population that lead to reproductive isolation and (divergent) speciation.

Again, this is already covered in Message 12.

What we are looking for is how the overall ecology reacts to environmental change, and the shifts in selection pressures on the breeding populations within ecologies as they become fragmented (climbing mountains or moving towards the poles).

Geographic isolation is bound to occur for many species, or if not for the species themselves then ones they interact with (prey\predator, symbiosis, plant\animal\bacterial, etc).

One way to look at it is via invasive species as Herebedragons has mentioned, another is to look at island biogeography. An excellent very readable book on this topic is:

The Song of the Dodo by David Quammen:

quote:
The Song of the Dodo, is a brilliant, stirring work, breathtaking in its scope, far-reaching in its message -- a crucial book in precarious times, which radically alters the way in which we understand the natural world and our place in that world. It's also a book full of entertainment and wonders.
In The Song of the Dodo, we follow Quammen's keen intellect through the ideas, theories, and experiments of prominent naturalists of the last two centuries. ...

Here we have a good introduction to Wallace, Darwin's main competitor in developing his theories of natural selection and speciation.

http://en.wikipedia.org/wiki/Alfred_Russel_Wallace

quote:
Alfred Russel Wallace OM FRS (8 January 1823 7 November 1913) was a British naturalist, explorer, geographer, anthropologist, and biologist. He is best known for independently conceiving the theory of evolution through natural selection; his paper on the subject was jointly published with some of Charles Darwin's writings in 1858.[1] This prompted Darwin to publish his own ideas in On the Origin of Species. Wallace did extensive fieldwork, first in the Amazon River basin and then in the Malay Archipelago, where he identified the faunal divide now termed the Wallace Line, which separates the Indonesian archipelago into two distinct parts: a western portion in which the animals are largely of Asian origin, and an eastern portion where the fauna reflect Australasia.

He was considered the 19th century's leading expert on the geographical distribution of animal species and is sometimes called the "father of biogeography".


http://en.wikipedia.org/wiki/Biogeography

quote:
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area.

Knowledge of spatial variation in the numbers and types of organisms is as vital to us today as it was to our early human ancestors, as we adapt to heterogeneous but geographically predictable environments. Biogeography is an integrative field of inquiry that unites concepts and information from ecology, evolutionary biology, geology, and physical geography.

Modern biogeographic research combines information and ideas from many fields, from the physiological and ecological constraints on organismal dispersal to geological and climatological phenomena operating at global spatial scales and evolutionary time frames.


And again, we see that global climate change is going to have an effect that can be studied through observations on the changes in biogeographic diversity.


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Taq
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Posts: 6799
Joined: 03-06-2009
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(1)
Message 17 of 37 (720493)
02-24-2014 11:27 AM
Reply to: Message 11 by Faith
02-22-2014 12:34 AM


Re: extinction event?
This is a very interesting thread, thanks. But of course I do have to point out that the evolution you are talking about is nothing but evolution within the Kind or "microevolution" as opposed to your implication that such changes validate the ToE itself.

Can you point to differences between closely related species that could not be produced by microevolutionary mechanisms?


This message is a reply to:
 Message 11 by Faith, posted 02-22-2014 12:34 AM Faith has responded

Replies to this message:
 Message 18 by Faith, posted 02-24-2014 12:42 PM Taq has responded

  
Faith
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Posts: 25604
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 18 of 37 (720499)
02-24-2014 12:42 PM
Reply to: Message 17 by Taq
02-24-2014 11:27 AM


Re: extinction event?
Can you point to differences between closely related species that could not be produced by microevolutionary mechanisms?

First, "closely related" to you implies genetic relatedness although I believe all that is based on is physical similarities which imply only similar design and not genetic relatedness.

No I couldn't point to such diferences, although they may exist; I'd also suspect there may be indicators in the genomes of each Species though I can't point to them either.

But the way I've been arguing this is by suggesting that the processes that bring about evolution / microevolution tend toward reduced genetic diversity, so that down any particular line of evolution or variation, theoretically eventually the point is reached similar to the cheetah where genes for major characteristics have become fixed so that further evolution is not possible. It may be that genetic mismatch between the new "species" and the former population may not involve completely fixed loci to that extent for further evolution to have become impossible. This trend is where I locate the end of microevolution such that macroevolution never can occur. It's not by defining the Kind, but the processes that vary the Kind. If they have a natural end as I'm suggesting, that confines evolution within the Kind.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


This message is a reply to:
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Taq
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Posts: 6799
Joined: 03-06-2009
Member Rating: 3.9


(1)
Message 19 of 37 (720500)
02-24-2014 12:49 PM
Reply to: Message 18 by Faith
02-24-2014 12:42 PM


Re: extinction event?
First, "closely related" to you implies genetic relatedness although I believe all that is based on is physical similarities which imply only similar design and not genetic relatedness.

I simply mean sharing a large percentage of DNA. This makes it a bit easier to compare sequences, that's all.

But the way I've been arguing this is by suggesting that the processes that bring about evolution / microevolution tend toward reduced genetic diversity,

Too bad you can't evidence it. You seem to think that simply saying something carries weight. It doesn't. Evidence carries weight. In the real world, mutations in each generation increase genetic diversity. This is what is evidenced. We also observe that with each generation, the human and chimp genomes continue to diverge, consistent with macroevolution.


This message is a reply to:
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Faith
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Posts: 25604
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 20 of 37 (720501)
02-24-2014 12:54 PM
Reply to: Message 19 by Taq
02-24-2014 12:49 PM


Re: extinction event?
I do think it's intuitively obvious, yes, so that if I describe it clearly enough it should simply be recognized. But I've also proposed tests that could be done. Unfortunately I'm not in a position to do them.
This message is a reply to:
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Taq
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Posts: 6799
Joined: 03-06-2009
Member Rating: 3.9


Message 21 of 37 (720511)
02-24-2014 3:02 PM
Reply to: Message 20 by Faith
02-24-2014 12:54 PM


Re: extinction event?
I do think it's intuitively obvious,

It's wrong.

But I've also proposed tests that could be done. Unfortunately I'm not in a position to do them.

Nature has already done the experiments for us. Mutations add diversity to a population over time, and isolated populations will diverge over time. That is what we see in nature.


This message is a reply to:
 Message 20 by Faith, posted 02-24-2014 12:54 PM Faith has responded

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Faith
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Posts: 25604
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 22 of 37 (720512)
02-24-2014 3:07 PM
Reply to: Message 21 by Taq
02-24-2014 3:02 PM


Re: extinction event?
But if mutations are counted as increased diversity while in fact they don't contribute anything beneficial to the organism the whole thing is being misinterpreted. What you "see in nature," then isn't what you think it is.
This message is a reply to:
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Taq
Member
Posts: 6799
Joined: 03-06-2009
Member Rating: 3.9


Message 23 of 37 (720515)
02-24-2014 3:34 PM
Reply to: Message 22 by Faith
02-24-2014 3:07 PM


Re: extinction event?
But if mutations are counted as increased diversity while in fact they don't contribute anything beneficial to the organism

They can and do contribute beneficial characteristics. Among the differences between us and chimps are the mutations that have produced beneficial adaptations in humans, such as our increased brain, upright stance with effecient jogging gait, fine motor skills in hands, etc.


This message is a reply to:
 Message 22 by Faith, posted 02-24-2014 3:07 PM Faith has responded

Replies to this message:
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 Message 27 by Faith, posted 02-25-2014 4:18 AM Taq has responded

  
RAZD
Member
Posts: 18790
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


Message 24 of 37 (720523)
02-24-2014 4:41 PM
Reply to: Message 23 by Taq
02-24-2014 3:34 PM


topic???
Can we get back to ecological change and the effect on the webs of life ?

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
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This message is a reply to:
 Message 23 by Taq, posted 02-24-2014 3:34 PM Taq has responded

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Taq
Member
Posts: 6799
Joined: 03-06-2009
Member Rating: 3.9


Message 25 of 37 (720524)
02-24-2014 5:16 PM
Reply to: Message 24 by RAZD
02-24-2014 4:41 PM


Re: topic???
Can we get back to ecological change and the effect on the webs of life ?

It is all related. For example, a single mutation can lead to the acquisition of antibiotic resistance. This adds to the genetic variability of a population. When antibiotics are introduced to your GI tract, it kills off a ton of competing bacteria. Suddenly, that massive change in environment makes that mutation a windfall.

Having Faith outright deny these simple known and understood facts makes it impossible to discuss ecosystems in such a way.


This message is a reply to:
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RAZD
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Posts: 18790
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


Message 26 of 37 (720525)
02-24-2014 5:23 PM


Example: Forest Succession
http://en.wikipedia.org/wiki/Ecological_succession

quote:
Ecological succession is the observed process of change in the species structure of an ecological community over time. The community begins with relatively few pioneering plants and animals and develops through increasing complexity until it becomes stable or self-perpetuating as a climax community. The ʺengineʺ of succession, the cause of ecosystem change, is the impact of established species upon their own environments. A consequence of living is the sometimes subtle and sometimes overt alteration of one's own environment.[1]

The forests, being an ecological system, are subject to the species succession process.[15] There are "opportunistic" or "pioneer" species that produce great quantities of seed that are disseminated by the wind, and therefore can colonize big empty extensions. They are capable of germinating and growing in direct sunlight. Once they have produced a closed canopy, the lack of direct sun radiation at soil makes it difficult for their own seedlings to develop. It is then the opportunity for shade-tolerant species to become established under the protection of the pioneers. When the pioneers die, the shade-tolerant species replace them. These species are capable of growing beneath the canopy, and therefore, in the absence of catastrophes, will stay. For this reason it is then said the stand has reached its climax. When a catastrophe occurs, the opportunity for the pioneers opens up again, provided they are present or within a reasonable range.


With global warming we should expect succession like behavior in moving towards more favorable conditions for existing plants that are intolerant of the changes, and this should also result in movement of the species dependent on the vegetation and predators that depend on the ones dependent on the vegetation.


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Rebel American Zen Deist
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Faith
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Posts: 25604
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 27 of 37 (720545)
02-25-2014 4:18 AM
Reply to: Message 23 by Taq
02-24-2014 3:34 PM


Re: extinction event?
They can and do contribute beneficial characteristics. Among the differences between us and chimps are the mutations that have produced beneficial adaptations in humans, such as our increased brain, upright stance with effecient jogging gait, fine motor skills in hands, etc.

Ah Taq, this is precisely what I meant. Mutations are assumed to be the source of beneficial genetic changes. and chimps are assumed to be genetically related to humans, but all you can do is assert the connection the theory prescribes, that you believe in with implicit faith. None of this is proved nor can it be proved. It's pure assumption and must be taken on faith. As I said, if mutations don't contribute anything beneficial to the organism, despite the fact that you claim they do, which is one of the things you have not shown and apparently cannot show, the whole thing falls apart. It WON'T fall apart of course because you guys just go on asserting it no matter what, but it SHOULD fall apart because there is NO -- real, physical -- evidence for any of it.

Edited by Faith, : No reason given.


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RAZD
Member
Posts: 18790
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


(1)
Message 28 of 37 (720548)
02-25-2014 7:11 AM
Reply to: Message 27 by Faith
02-25-2014 4:18 AM


Finch adaptation to drought conditions
Let's take another example: the Galapagos\Darwin finches as studied by the Grants:

http://www.pbs.org/wgbh/evolution/library/01/6/l_016_01.html

quote:
The Grants wanted to find out whether they could see the force of natural selection at work, judging by which birds survived the changing environment. For the finches, body size and the size and shape of their beaks are traits that vary in adapting to environmental niches or changes in those niches. Body and beak variation occurs randomly. The birds with the best-suited bodies and beaks for the particular environment survive and pass along the successful adaptation from one generation to another through natural selection.

Natural selection at its most powerful winnowed certain finches harshly during a severe drought in 1977. That year, the vegetation withered. Seeds of all kinds were scarce. The small, soft ones were quickly exhausted by the birds, leaving mainly large, tough seeds that the finches normally ignore. Under these drastically changing conditions, the struggle to survive favored the larger birds with deep, strong beaks for opening the hard seeds.

Smaller finches with less-powerful beaks perished.

So the birds that were the winners in the game of natural selection lived to reproduce. The big-beaked finches just happened to be the ones favored by the particular set of conditions Nature imposed that year.

Now the next step: evolution. The Grants found that the offspring of the birds that survived the 1977 drought tended to be larger, with bigger beaks. So the adaptation to a changed environment led to a larger-beaked finch population in the following generation.

Adaptation can go either way, of course. As the Grants later found, unusually rainy weather in 1984-85 resulted in more small, soft seeds on the menu and fewer of the large, tough ones. Sure enough, the birds best adapted to eat those seeds because of their smaller beaks were the ones that survived and produced the most offspring.

Evolution had cycled back the other direction.


The environment changed to dryer conditions, and that affected the plants that were growing, favoring plants with hard seeds.

The finches then changed to larger beaks that are better able to break the seeds.

So we should expect drought conditions to favor birds with larger beaks as the drought becomes prolonged, as in California.

The finches were on an island without competition from other birds, while here on the continent I would expect the change would be reflected in the different frequencies of the species of birds in the area.


we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


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This message is a reply to:
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Taq
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Posts: 6799
Joined: 03-06-2009
Member Rating: 3.9


(1)
Message 29 of 37 (720602)
02-25-2014 10:44 AM
Reply to: Message 27 by Faith
02-25-2014 4:18 AM


Re: extinction event?
Ah Taq, this is precisely what I meant. Mutations are assumed to be the source of beneficial genetic changes.

We observe mutations producing beneficial genetic changes. Concluding that the differences between the human and chimp genome are the product of the observed mechanisms of mutation is no different than concluding a fingerprint at a crime scene came from a finger instead of a Leprechaun. No faith involved since we are working from observed mechanisms.

As I said, if mutations don't contribute anything beneficial to the organism

We observe that mutations confer beneficial phenotypes. One example that is fitting for this thread is the evolution of dark coats in pocket mice.

http://www.pnas.org/content/100/9/5268.long

Here is a picture of the black mice that evolved in an ecosystem that included dark lava, compared to their original ecosystem which was a light colored desert.

Edited by Taq, : No reason given.


This message is a reply to:
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 Message 30 by Faith, posted 02-25-2014 2:20 PM Taq has responded

  
Faith
Member
Posts: 25604
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 30 of 37 (720627)
02-25-2014 2:20 PM
Reply to: Message 29 by Taq
02-25-2014 10:44 AM


Re: extinction event?
As usual, all you are doing is ASSERTING that mutations are the cause of genetic changes. The evidence does not prove that mutation caused any of it, such as the blackness of the pocket mice. All that is necessary is that a normally-occurring recessive allele become paired up [abe]: and prolific in the population under selection pressure, and perhaps there are other genetic routes to the same result, but mutation does not have to be one of them. [/abe] It's the same situation as with the peppered moth. All this is is Mendelian type inheritance. Again you are merely ASSUMING mutation.

Edited by Faith, : No reason given.


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