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MuhammedGoldstein
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201 Posts

Posted - 06/07/2008 :  22:01:20  Show Profile Send MuhammedGoldstein a Private Message
is it a phenotypic difference ?

It does mention phenotype, just without using the word "phenotype."... DAVEW

Dude
SFN Die Hard

USA
6891 Posts

Posted - 06/07/2008 :  22:11:01   [Permalink]  Show Profile Send Dude a Private Message
No.


Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson

"god :: the last refuge of a man with no answers and no argument." - G. Carlin

Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth
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Cuneiformist
The Imperfectionist

USA
4954 Posts

Posted - 06/07/2008 :  22:16:37   [Permalink]  Show Profile Send Cuneiformist a Private Message
From the wiki:
A phenotype is any observable characteristic of an organism, such as its morphology, development, biochemical or physiological properties, or behavior.
So, as Dude noted, no.

Interesting question, though. Sort of.
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MuhammedGoldstein
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201 Posts

Posted - 06/07/2008 :  22:59:25   [Permalink]  Show Profile Send MuhammedGoldstein a Private Message
Thank you for your quick replies.
Can I do some followups on this?
I the definitiion, it says any observable characterists are included in phenotype. My question is about change, as evolution is.

I've noticed that there are some subtler shades hiding in the definitions and understandings of this topic.

I see mention of phenotype, phenotypic difference.
I see that a much wider view is being propagated than I was consciously aware of, and I would have, even last week, answered the same way as you have.

In the definition given, it shows several examples of categories, but it seems not an exclusive list .

What precisely disqualifies hair length or a difference in hair length, as not fitting the requirements of consideration as observable change or difference ?

It does mention phenotype, just without using the word "phenotype."... DAVEW
Edited by - MuhammedGoldstein on 06/08/2008 11:13:05
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MuhammedGoldstein
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201 Posts

Posted - 06/07/2008 :  23:04:26   [Permalink]  Show Profile Send MuhammedGoldstein a Private Message
http://evolution.berkeley.edu/evosite/evo101/IIIA1Genotypevsphenotype.shtml



Why would a change in colour of flamingos result in two phenotypes ? Would dying my hair qualify ?

It does mention phenotype, just without using the word "phenotype."... DAVEW
Edited by - MuhammedGoldstein on 06/08/2008 11:14:05
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MuhammedGoldstein
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Posted - 06/07/2008 :  23:06:07   [Permalink]  Show Profile Send MuhammedGoldstein a Private Message
I'll try again. . sorry
http://evolution.berkeley.edu/evosite/evo101/IIIA1Genotypevsphenotype.shtml

It does mention phenotype, just without using the word "phenotype."... DAVEW
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Dave W.
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Posted - 06/07/2008 :  23:13:06   [Permalink]  Show Profile  Visit Dave W.'s Homepage Send Dave W. a Private Message
As soon as you can pass your dyed hair color on to your children (through only the act of having children), then you can call it a characteristic as the biologists mean it.

Learned or acquired features are not characteristics. Otherwise, every scar or blemish would be a speciation event. Characteristics must be hereditable.

- Dave W. (Private Msg, EMail)
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MuhammedGoldstein
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201 Posts

Posted - 06/07/2008 :  23:28:21   [Permalink]  Show Profile Send MuhammedGoldstein a Private Message
you mean is has to be heritable, and thus must have encoding for any differences seen ?
not in congruence with what the Berkeley Evolution 101 people say ? It's
a seemingly respectable enough site...has some checking going on for quality , and so on..you can check the names and see if they are familiar to you. If it's a bogus site, then I should bring up another

thank you !
MG

It does mention phenotype, just without using the word "phenotype."... DAVEW
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MuhammedGoldstein
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Posted - 06/07/2008 :  23:33:01   [Permalink]  Show Profile Send MuhammedGoldstein a Private Message
A change in the environment also can affect the phenotype. Although we often think of flamingos as being pink, pinkness is not encoded into their genotype. The food they eat makes their phenotype white or pink.
from the Berkeley site. It explicitly states the opposite...? And I now can see why, I think

MG

It does mention phenotype, just without using the word "phenotype."... DAVEW
Edited by - MuhammedGoldstein on 06/08/2008 11:14:31
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MuhammedGoldstein
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Posted - 06/08/2008 :  00:00:43   [Permalink]  Show Profile Send MuhammedGoldstein a Private Message
Can you think of any reasons for that, outside of a mistake ?
A mistake is a very boring proposition to consider, especially as it would mean correcting so many sites.

It does mention phenotype, just without using the word "phenotype."... DAVEW
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Dude
SFN Die Hard

USA
6891 Posts

Posted - 06/08/2008 :  01:18:59   [Permalink]  Show Profile Send Dude a Private Message
The reason for what? Your failure to understand a very basic concept?


Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson

"god :: the last refuge of a man with no answers and no argument." - G. Carlin

Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth
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Simon
SFN Regular

USA
1992 Posts

Posted - 06/08/2008 :  07:39:05   [Permalink]  Show Profile Send Simon a Private Message
What they mean is that the environment does not create new phenotypes. But it can impact how often these phenotypes are observed in a given population...

Let's take your example...
A gene exist in two forms (each form is named an allele of the gene): one producing long hair and one coding for relatively shorter hairs.
Two individual each carrying a different allele of the gene will present different phenotypes. One would have short hair, and the other one would have longer hair.

Of course, you can always take the longer hair individual for a trim, but it won't affect its genes (or the fact that his descendants would have longer hair).

Now, where the environment plays a role, is that if you have a population composed of individuals of both phenotypes and bring part of the population into a warm environment, and one in an artic/cold environment.

The short hair individuals would thrive in the hot environment while the long haired ones would be handicapped.
Because the short haired individuals would be more successful, they would, in average, produce more siblings than the long haired ones. Generation after generations, the balance between the two genes will shift until only the short hair allele is left.

In the cold environment, of course, the opposite mechanism would take place and, after several generations, the long hair allele would be the only one.

So, we can see that the environment does not affect the existence of the two genes or which individual caries which allele. However, it select which gene is present in a given population (natural selection).

Of course, there is many way a certain genotypes could be better adapted to hot or cold and a given environment is selecting a populations on many hundreds, if not thousands, of factors at a time.
Not to mention, some variant are indirectly selected (they are not beneficial in themselves but happen to be carried on the same chromosome and are selected at the same time than the beneficial gene).
That explains how two populations can quickly diverge in term of genetic make-up until the differences are just two big for the two populations can no longer inter-breed, effectively producing two separate populations.

Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there on a mote of dust suspended in a sunbeam.
Carl Sagan - 1996
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MuhammedGoldstein
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Posted - 06/08/2008 :  08:48:16   [Permalink]  Show Profile Send MuhammedGoldstein a Private Message
What they mean is that the environment does not create new phenotypes. But it can impact how often these phenotypes are observed in a given population...


May I propose that we use words as they are given, rather than imposing our own understanding of "what they mean to say "? ... which is the opposite of what is clearly expressed by the authors ? And further, a clear example is given, though not as clearly environmental ans influence as a hypothetical haircut as example ?


Let's take your example...
A gene exist in two forms (each form is named an allele of the gene): one producing long hair and one coding for relatively shorter hairs.
Two individual each carrying a different allele of the gene will present different phenotypes. One would have short hair, and the other one would have longer hair.


But this is not my example ! Please, again, use the words given instead of a substitution.

Of course, you can always take the longer hair individual for a trim, but it won't affect its genes (or the fact that his descendants would have longer hair).
there are no other individuals in my example of me getting a haircut, and asking if I now changed as to phenotype. But I agree that you have it as is "normally" understood ! It is lacking though, and we will get to that later.

Now, where the environment plays a role, is that if you have a population composed of individuals of both phenotypes and bring part of the population into a warm environment, and one in an artic/cold environment.
this is clearly the common understanding.

The short hair individuals would thrive in the hot environment while the long haired ones would be handicapped.
I agree, that you have the usual idea.

Because the short haired individuals would be more successful, they would, in average, produce more siblings than the long haired ones. Generation after generations, the balance between the two genes will shift until only the short hair allele is left.

In the cold environment, of course, the opposite mechanism would take place and, after several generations, the long hair allele would be the only one.

So, we can see that the environment does not affect the existence of the two genes or which individual caries which allele. However, it select which gene is present in a given population (natural selection).
This is absolutely the common understanding of it, I agree.

Of course, there is many way a certain genotypes could be better adapted to hot or cold and a given environment is selecting a populations on many hundreds, if not thousands, of factors at a time.
Not to mention, some variant are indirectly selected (they are not beneficial in themselves but happen to be carried on the same chromosome and are selected at the same time than the beneficial gene).[quote]yes, you have a good grasp of the common understanding of it[quote]
That explains how two populations can quickly diverge in term of genetic make-up until the differences are just two big for the two populations can no longer inter-breed, effectively producing two separate populations.


Yes, much agrees with common appreciation of the subject. Now. let's use words as they are written, and attempt to see the terms in more useful ways.

Phenotype is relating to any of the observable characteristics of an organism. If we insist on our own definition without proper basis to do so, so that it only covers for those characteristics that have a heritability coefficent above zero, THEN we are messing with the equations and definitions, aren't we ? dWe need to KNOW a priori if there is a coefficient above zero, we have to know a {i]priori[/i] that there is a genetic influence, thus imposing supposed "knowledge" where we are suppposed to be finding out ( to investigate as to whether or not there is a genetic cause for flamingos turning pink on being fed a diet.)


Is it not more profitable to use a method to ascertain what is not known from the known, , rather to impose what we think we know , for the unknown, asserting a priori "knowledge" ?

Take it to an example where we know nothing of the genetic component or not..an example where we intend to find out if there is a genetic component !


In the case of flamingos, as they CLEARLY explain, the bird turn pink from white on the basis of a purely environmental change, that of diet.
All flamingos do it.

You can feed a flock of flamingos from hatching with "pigment food" or "no pigment in food", and one half will turn pink, the other 50% will remain white.
Kill all pink flamingos for a hundred generations, and white birds will still produce the genetics for "turning pink when fed pigment" ability. And and all normal offspring of white ( undyed ) flamingos will turn pink when fed pigment.

Please let's use words as they are written !

It does mention phenotype, just without using the word "phenotype."... DAVEW
Edited by - MuhammedGoldstein on 06/08/2008 10:12:26
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Dave W.
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USA
26001 Posts

Posted - 06/08/2008 :  08:57:18   [Permalink]  Show Profile  Visit Dave W.'s Homepage Send Dave W. a Private Message
"Hereditable." Yeah, I must have been pretty tired last night.

Phenotype is genetics plus environment, not genetics or environment. And of course, raw phenotypic differences are not, themselves, the basis for classification of different species.

But, scarring is a genetic (physiological) response to environment, so every scar is a phenotypic difference. And the ability to scar is passed along in one's genes.

Given the broadest possible reading of "phenotype," hair-cutting is a behavior determined by genes and environment together, and differences in gene and environment will result in different hair cuts. So that'd be a "yes." But then that sort of means that everything about a person is "phenotype," including, for example, the length of the inhalation I was in the middle of at 11:53:17 AM on June 8th, 2008. van Gogh's Starry Night would have to be considered a phenotypic difference from all humans who failed to conceive and execute that exact-same painting. Is this getting absurd?

- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
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MuhammedGoldstein
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201 Posts

Posted - 06/08/2008 :  09:45:23   [Permalink]  Show Profile Send MuhammedGoldstein a Private Message
I think the problem is that you guys are getting ahead of the conversation a bit, rushing to show how evolution works, and applying what you "know" to investigative reasoning that is not connected so far at all, in my basic question.

for instance, I've been given explanations of selection and evolution, and other things, whereas I am really asking for definition on phenotype from an investigation aspect.

The first definition did not rule out hairdcuts, the list was not exclusive. Others tell me what biologists really mean.

I am quoting directly from some good biologists. Or am I ?
Is the Berkeley site not suitable? Please look at what they are saying in very clear language !

a mistake or not ?...Berkely 101 is in direct opposition to the statements made here, which, in which all do requirea heritability component in order to qualify.

Not so says Berkeley, and I agree now that I've examined the issues.


It does mention phenotype, just without using the word "phenotype."... DAVEW
Edited by - MuhammedGoldstein on 06/08/2008 09:54:44
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Cuneiformist
The Imperfectionist

USA
4954 Posts

Posted - 06/08/2008 :  10:11:26   [Permalink]  Show Profile Send Cuneiformist a Private Message
Originally posted by MuhammedGoldstein
The first definition did not rule out hairdcuts, the list was not exclusive.
Sure it did. The website you linked to also notes:
The relationship between the genotype and phenotype is a simple one ...
The Genotype codes for the Phenotype

The "internally coded, inheritable information", or Genotype, carried by all living organisms, holds the critical instructions that are used and interpreted by the cellular machinary of the cells to produce the "outward, physical manifestation", or Phenotype of the organism.

Thus, all the physical parts, the molecules, macromolecules, cells and other structures, are built and maintained by cells following the instructions give by the genotype. As these physical structures begin to act and interact with one another they can produce larger and more complex phenomena such as metabolism, energy utilization, tissues, organs, reflexes and behaviors; anything that is part of the observable structure, function or behavior of a living organism.
So the human genotype does code for a haircut.
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