A Question About Evolution

[Mintaka]

most people take evolution for granted now. But the more I watch nature programs about animals which have 'adapted' to be camouflaged against a certain environmental background,

 

or an anteater which has evolved a super long snout and a super long tongue and defensive scales, or a giraffe which has evolved a long neck to reach its faviourite leaves,

 

my question is HOW does this happen? Preseumably giraffes started out with very short necks and they evolved to be longer and longer?

 

But how does one generation pass this change on to the next?

 

Simply through wishing it to happen, by WANTING to reach higher leaves?

 

I cannot fly.

 

I would really love to be able to,

 

I would love to have wings,

 

and I guess I'm not alone in wishing this.

 

If I pass this wish or desire to fly onto my offspring, or enough of us do this,

 

is it possible we will evolve to be able to fly one day?

 

Will we start to srpout wings over the next few thousand years?

 

I have no doubt you are right that animals do evolve.

 

My question is WHY and WHAT DRIVES THESE PHYSICAL changes?

[wendy reakes]

I'm with you, Mintaka. Excellent question and I've often pondered it myself.

 

Has it got something to do with interbreeding? Hypothetically, and staying with the 'wing' example, if a man breeds with a bird, does the offspring and descendants of said man then grow partial wings, until a few thousand years pass and then future man gets a full pair.

 

At what point does the change happen?

[Mintaka]

I'm with you, Mintaka. Excellent question and I've often pondered it myself.

 

Has it got something to do with interbreeding? Hypothetically, and staying with the 'wing' example, if a man breeds with a bird, does the offspring and descendants of said man then grow partial wings, until a few thousand years pass and then future man gets a full pair.

 

At what point does the change happen?

 

Thank you Mum

 

We've got them thinking ;-)

[wendy reakes]

You should try writing. You have an inquisitive mind and you think outside the box. All definite assets.

[Mintaka]

I'm with you, Mintaka. Excellent question and I've often pondered it myself.

 

Has it got something to do with interbreeding? Hypothetically, and staying with the 'wing' example, if a man breeds with a bird, does the offspring and descendants of said man then grow partial wings, until a few thousand years pass and then future man gets a full pair.

 

At what point does the change happen?

 

Thank you, nice of you to say so.

 

on the man breeding with bird thing, I tried it and believe me, not to be recommended. I never imagined that I would be feeding worms to gurgling feathery creatures with beaks in nappies. Every day I regret my laison with that Ostrich, but this is what living in Australia drives a man to.

[joekgamer]

Evolution happens more or less randomly.

 

With each generation, there is a chance of a mutation.

 

If a specimen mutates, and the mutation helps it, then it is likely to survive and pass the trait on.

 

And so evolution happens.

[wendy reakes]

Thank you, nice of you to say so.

 

on the man breeding with bird thing, I tried it and believe me, not to be recommended. I never imagined that I would be feeding worms to gurgling feathery creatures with beaks in nappies. Every day I regret my laison with that Ostrich, but this is what living in Australia drives a man to.

 

 

That's 'birds' of the feathered kind, right?

 

Those ostriches have really big bottoms.

[Mintaka]

That's 'birds' of the feathered kind, right?

 

Those ostriches have really big bottoms.

 

hmm....I don't think they've explained yet ;-)

[wendy reakes]

hmm....I don't think they've explained yet ;-)

 

 

Hm, still waiting.....zzzzzzzzzzzzzzzz

[Rade]

WAKE UP !!!!!

 

 

Your question was:

But how does one generation pass this change on to the next?

 

The change in phenotypic appearance (such as colors, shapes, size, functions, etc.) in one generation is passed to the next generation via a combination of natural selection acting on geneotypes (sets of genes). Very rarely a mutation can cause sudden phenotypic change within a population, but this is not the normal role of mutation.

 

Here is an example from 9th grade Biology class concerning your "How" question. A species of moth in England (The Peppered Moth) has been well documented to have changed appearance over time. The species 100s years ago (pre 1800) was collected by naturalists in England and the individuals had very light color wings, dark color individuals being very rare. In the 1800's the industrial revolution took hold across Europe and by the mid 1900's almost all of the moths of the Peppered Moth species had very dark wing color. The hypothesis given was that as air pollution from coal and oil burning resulted in darker background habitat (bark of trees, buildings, etc.) upon which a moth would come to rest. This resulted in light colored individuals to be easy visual prey for bird predators against a dark background. Over time, it was documented by naturalists that the Peppered Moth species had very few light colored individuals in the mid 1900s, most individuals having dark wing color.

 

How did this happened ? How did a single species of moth pass this change in wing appearance (from light pigment to dark pigment) from one generation to another ?

 

Well, there is only one way to pass such change in wing pigment in a large population, it is via a change in the frequency of gene(s) within the population that produce both light and dark wing color pigments. So, suppose pre-1800 the frequency of gene(s) that produce light color pigments was 0.97%, and for dark color 0.03%, before the industrial revolution. Then, as more and more dark soot caused the background color of the habitat of the moth to darken, those individuals with the gene(s) that produce dark color pigment gradually would increase in frequency over time, say from a low of 0.03%, to 0.08% the next generation, 0.10% the following generation, then 0.15%, then 0.20%, then 0.30%, with perhaps a major change in the gene frequency in a short period of time of widespread coal and oil burning to 0.955% of the population by 1950. Of course I use hypothetical numbers to explain "How" the change in appearance occurred for the entire species, the only fact being that there must have been some number increase from a very low frequency (such as 0.03%) to a very high frequency (such as 0.95%).

 

Now, if this hypothesis makes sense and is valid explanation to your "How" question, then one would predict that as government regulations in the mid 1900's in England kicked into place and the amount of air pollution and dark soot from coal burning lessened, the frequency of dark color gene(s) should have gradually decreased in the Peppered Moths of England. And, this is exactly what recent research suggests, as published in a peer reviewed journal I present below. So, read the research paper below and you will find the answer to your general "How" question for one specific example, which can be generalized to all possible "How" examples you can think of: http://www.pnas.org/content/105/42/16212.full

 

For a change in appearance in a population to be passed from one generation to another there must be some CHANGE IN THE ENVIRONMENT (this word has a very broad definition) that results in a selective advantage for some appearance or shape or size or length of neck or function, etc. (in terms of survival and reproduction of the breeding population).

[modest]

Here is a beginner's faq on evolution:

 

Frequently Asked Questions About Evolution

 

And, here is a site essentially outlining what raid said: natural selection.

 

Advantageous traits are passed on through reproduction. They are selected because they are advantageous.

 

~modest

[Mintaka]

"Then, as more and more dark soot caused the background color of the habitat of the moth to darken, those individuals with the gene(s) that produce dark color pigment gradually would increase in frequency over time, say from a low of 0.03%, to 0.08% the next generation"

 

You said that ALL butterflies were initially light -couloured. Trees went black with pollution....The butterflies had a light and dark wing colour gene. My question is, how does a gene know how to activate itself to the advantage of its species?

 

There must have been ONE butterfly which was the first to have darker wings, no? its parents looked around and saw its light-coloured brethren being eaten because their camouflage no longer worked and decided " ok , I decree that my little offspring will now have dark wings, so ACTIVATE, o dark wing gene! " ?

 

How does the fact that trees were now dark cause a gene to activate in a species? Surely, all light-winged butterflies should simply die out because they aren't camouflaged any more? Is it not possible that this is simply another species which took it's place, like the grey squirrel took over from the red one in the UK?

 

Sorry, I know I am probably missing a vital point, maybe i'm tired, but where did that butterfly get its dark wing gene in the first place?

[Mintaka]

"Whether or not an individual survives and reproduces depends on whether it has genes that produce traits that are well adapted to its environment."

 

I am one of four brothers in our 40's.

 

Only one of us has had children.

 

I am 43 and haven't.

 

Does this mean I am not genetically fit, and that only my second brother is, and that he has been chosen to pass down the most advantageous seed?

 

Are gay people therefore genetic losers for our species? I don't think this, I'm asking.

[Moontanman]

"Then, as more and more dark soot caused the background color of the habitat of the moth to darken, those individuals with the gene(s) that produce dark color pigment gradually would increase in frequency over time, say from a low of 0.03%, to 0.08% the next generation"

 

You said that ALL butterflies were initially light -couloured. Trees went black with pollution....The butterflies had a light and dark wing colour gene. My question is, how does a gene know how to activate itself to the advantage of its species?

 

There must have been ONE butterfly which was the first to have darker wings, no? its parents looked around and saw its light-coloured brethren being eaten because their camouflage no longer worked and decided " ok , I decree that my little offspring will now have dark wings, so ACTIVATE, o dark wing gene! " ?

 

How does the fact that trees were now dark cause a gene to activate in a species? Surely, all light-winged butterflies should simply die out because they aren't camouflaged any more? Is it not possible that this is simply another species which took it's place, like the grey squirrel took over from the red one in the UK?

 

Sorry, I know I am probably missing a vital point, maybe i'm tired, but where did that butterfly get its dark wing gene in the first place?

 

The "gene" for dark color already existed in that particular population of moths, it was rare and usually resulted in the bearer of this gene being eaten. But when trees started getting dark due to soot the darker colored moths suddenly had an advantage, the light colored moths were being eaten the but the dark colored moths survived and reproduced far better than their now easy to spot light colored brothers so the light colored moths slowly became a tiny part of the population and the dark ones became dominant.

 

The dark wings could have just been a bad or even neutral mutation that crops up from time to time naturally. Much like being double jointed in humans. It's not an uncommon thing in humans but it seldom returns any real reproductive advantage or disadvantage but if environmental pressure suddenly began to favor double jointed people over the normal population the double jointed people might become the norm and people who are not double jointed would be rare.

 

If this double jointed-ness conferred a sexual advantage it would no doubt spread faster though the population but even if it just allowed the double jointed people a slight advantage, over time double jointed humans would become the norm and if it was sexual it might result in a new species quite fast but even if it was just a slight advantage given enough time the "normals" humans might die out completely and leave only the double jointed ones as a new species of human.

[Mintaka]

Thank you, this was a great explanation of how dark coloured butterflies became dominant.

 

But how does this explain how, say, giraffes got long necks?

 

Was there a group of short-necked giraffes who died out because trees became taller and the leaves more innacessible, giving the giraffes with the hidden "tall-neck gene" an advantage?

 

What if for some reason humans could no longer get their food supply on the ground, and had to fly 100 m up into the air to obtain it,

 

is there some hidden / recessive gene which would enable us to adapt to be able to grow wings to fly and reach our food?

 

Would the necessity of our survival force us to grow wings in the same way giraffes got long necks?

 

 

 

 

 

 

 

The "gene" for dark color already existed in that particular population of moths, it was rare and usually resulted in the bearer of this gene being eaten. But when trees started getting dark due to soot the darker colored moths suddenly had an advantage, the light colored moths were being eaten the but the dark colored moths survived and reproduced far better than their now easy to spot light colored brothers so the light colored moths slowly became a tiny part of the population and the dark ones became dominant.

 

The dark wings could have just been a bad or even neutral mutation that crops up from time to time naturally. Much like being double jointed in humans. It's not an uncommon thing in humans but it seldom returns any real reproductive advantage or disadvantage but if environmental pressure suddenly began to favor double jointed people over the normal population the double jointed people might become the norm and people who are not double jointed would be rare.

 

If this double jointed-ness conferred a sexual advantage it would no doubt spread faster though the population but even if it just allowed the double jointed people a slight advantage, over time double jointed humans would become the norm and if it was sexual it might result in a new species quite fast but even if it was just a slight advantage given enough time the "normals" humans might die out completely and leave only the double jointed ones as a new species of human.

[Ken]

"Then, as more and more dark soot caused the background color of the habitat of the moth to darken, those individuals with the gene(s) that produce dark color pigment gradually would increase in frequency over time, say from a low of 0.03%, to 0.08% the next generation"

 

You said that ALL butterflies were initially light -couloured. Trees went black with pollution....The butterflies had a light and dark wing colour gene. My question is, how does a gene know how to activate itself to the advantage of its species?

 

There must have been ONE butterfly which was the first to have darker wings, no? its parents looked around and saw its light-coloured brethren being eaten because their camouflage no longer worked and decided " ok , I decree that my little offspring will now have dark wings, so ACTIVATE, o dark wing gene! " ?

 

How does the fact that trees were now dark cause a gene to activate in a species? Surely, all light-winged butterflies should simply die out because they aren't camouflaged any more? Is it not possible that this is simply another species which took it's place, like the grey squirrel took over from the red one in the UK?

 

Sorry, I know I am probably missing a vital point, maybe i'm tired, but where did that butterfly get its dark wing gene in the first place?

 

 

You need to learn the meaning of the word "MUTATION". There are a number of mechanisms that could contribute to the failure to make an exact copy of a gene sequence.

[Moontanman]

Thank you, this was a great explanation of how dark coloured butterflies became dominant.

 

But how does this explain how, say, giraffes got long necks?

 

Was there a group of short-necked giraffes who died out because trees became taller and the leaves more innacessible, giving the giraffes with the hidden "tall-neck gene" an advantage?

 

What if for some reason humans could no longer get their food supply on the ground, and had to fly 100 m up into the air to obtain it,

 

is there some hidden / recessive gene which would enable us to adapt to be able to grow wings to fly and reach our food?

 

Would the necessity of our survival force us to grow wings in the same way giraffes got long necks?

 

 

There are always natural variations in populations, in humans natural height varies at least by 24" across the human population, if height suddenly became a driving force for success as a human being (lets say suddenly only people who were good at basket ball could survive and reproduce) The natural human condition would move toward more tall people, if the selection pressure was height short people might disappear altogether. But to answer your question, no, humans are quite unlikely to grow wings so they can fly to get food even if it was a gradual process but if we did we would no longer be humans because our arms would become the wings... But for humans we are far more likely to build a ladder to reach the food than evolve wings, trust me on this, it's what we do....

 

As for giraffes their long necks didn't appear over night or due to a giraffe longing for the fresh tender leaves at the top of trees. But the giraffe ancestors that had slightly longer necks (much like the tall humans) would have a slight advantage, as their height increased this advantage would increase as they had access to food most other animals cannot get to. Over many many generations this has resulted in the long necks of the giraffe.