Another question regarding evolution.

[Yossi]

1) what causes a species to change over time? Example: what made the ancestor of the whale develop the rudimentary elements of fins from legs? Mutations?

[Sensei]

Adaptation to environment.

Organisms which have better adaptation to certain environment, easier survive in that environment. Therefore their genes are spreading in offspring.

And vice versa.

Therefore you don't see polar bears in Africa.

White fur is adaptation to snow, to easier hide, and being able to hunt.

Darker bears simply died unable to catch anything.

 

Mutation is random. If it's useful mutation, organism survives, spreading genes to further generations. If it's adverse, organism dies.

What is useful or adverse is typically environment dependent.

Edited February 3, 2017 by Sensei

[OldChemE]

To elaborate a little on what is above, mutations arise from a variety of causes in terms of changes in DNA (cosmic rays, among other things can damage DNA, which can produce a mutation).

 

Mutations in an individuals sex cells can be passed on to their children. At this point, the question becomes "How will the DNA change affect the child?"

 

In the extreme worst case, a mutation can prevent proper development-- and the child never survives to birth.

 

Slightly less worst case would be a mutation that allows the child to live, but either prevents the child from living to adulthood or prevents the adult from being able to have children. Such a mutation will not continue in future generations (it goes away).

 

Next on the list is mutations that are innocuous--they neither hurt or benefit significantly. A good example is ear lobes-- some of us have ear lobes that hang down and some are attached to the side of our neck. This type can be passed on to future generations and adds to our genetic diversity.

 

Top of the list is mutations that actually enable an organism to survive better and/or produce more offspring. Because these mutations survive better and/or produce more offspring, they tend to become a larger and larger part of the population in future generations.

 

The reason for improved survival is assumed to be because the mutation works better in the environment. When an organism acquires this type of mutation we say it has "Adapted to its Environment."

 

The important thing to realize is that organisms do not choose to adapt to their environment-- it is the random DNA change that makes it happen, but because other mutation types don't help survival as much, the favorable mutations build up over time in future generations.

[mistermack]

1) what causes a species to change over time? Example: what made the ancestor of the whale develop the rudimentary elements of fins from legs? Mutations?

The above answers are all agreed with. But it's an incredibly complicated process, as it's natural selection operating on not just a new mutation, but the millions of historic mutations, stored in our genes. Each individual has a unique selection of genes (except identical twins). So it's usually a new combination that either works or fails. New mutations are rare, but new combinations happen each time something is born. So evolution doesn't have to wait for a new mutation, it's happening with every new individual.

 

In the case of whales, I suspect that limbs finally got the chance to be real fins once the whales evolved the ability to give birth in the sea, removing the necessity to be able to move about on land.

So you have evolution in one part of the animal leading to unexpected evolution in another. It's not always obvious at first sight what has happened and why.

[Strange]

A slightly different perspective: inany population there will be variation - think of your friends, so rare taller and some shorter, some have blue eyes, and some brown, etc. (In the case of the ancestors of whales some would have had more fully developed legs and some less so.)

 

In all these variations, some may be advantageous (in some circumstances) and some disadvantageous (in some circumstances).

 

The traits that are advantageous will tend to help their owners survive and reproduce. They will therefore become more common. (The traits that are disadvantageous will tend to become less frequent for the same reason.)

 

In the case of ncestors of whales, presumably those with less developed legs were faster in the water which helped them feed, survive, reproduce...

 

Repeat over multiple generations (with new variations in each generation).

 

Where does mutation come into this? It is one source of variation (that feeds selection and hence drives evolution) in the population.

[StringJunky]

A slightly different perspective: inany population there will be variation - think of your friends, so rare taller and some shorter, some have blue eyes, and some brown, etc. (In the case of the ancestors of whales some would have had more fully developed legs and some less so.)

 

In all these variations, some may be advantageous (in some circumstances) and some disadvantageous (in some circumstances).

 

The traits that are advantageous will tend to help their owners survive and reproduce. They will therefore become more common. (The traits that are disadvantageous will tend to become less frequent for the same reason.)

 

In the case of ncestors of whales, presumably those with less developed legs were faster in the water which helped them feed, survive, reproduce...

 

Repeat over multiple generations (with new variations in each generation).

 

Where does mutation come into this? It is one source of variation (that feeds selection and hence drives evolution) in the population.

It seems, an example of evolution doubling back on itself; some organisms evolved to live on land from water then variants of them evolved back into the water.

Edited February 4, 2017 by StringJunky

[mistermack]

It seems, an example of evolution doubling back on itself; some organisms evolved to live on land from water then variants of them evolved back into the water.

That's right. Evolution has no intentions, or preferred direction. It simply follows what is advantageous in the present for billions of individuals acting as individuals.

If there's a resource available, something will go for it.

I believe there are bats somewhere in the Pacific that are losing the power of flight, and living on the ground like mice.

(that's a vague memory, but I think it is right).

So after evolving flight, they are dumping it again. Like Ostriches and Penguins did I guess.

It happens because it's a success, at the time and place that it occurs.

[Moontanman]

It should also be noted that the majority of mutations are neutral and have no effect...

[StringJunky]

That's right. Evolution has no intentions, or preferred direction. It simply follows what is advantageous in the present for billions of individuals acting as individuals.

 

It's generally seen as a process of incrementing advantageous factors but if you ask an evolutionary biologist they will say 'it's a change in allele frequency over time' which can mean species decline as well as species success. They are still evolving either way.

Edited February 4, 2017 by StringJunky

[Strange]

It should also be noted that the majority of mutations are neutral and have no effect...

 

 

Although they may add to genetic diversity and hence be selected for (or against) if the environment changes in future.

[mistermack]

It's generally seen as a process of incrementing advantageous factors but if you ask an evolutionary biologist they will say 'it's a change in allele frequency over time' which can mean species decline as well as species success. They are still evolving either way.

That's a good point. But I would suspect that when a species declines, it's usually due to outside factors, rather than the way it's evolved.

 

Unless, I guess, it specialises to such a degree that it's left vulnerable to any new conditions.

Like the Dodo, becoming big and fat and flightless and delicious, because of the lack of predators on Mauritius.

[StringJunky]

That's a good point. But I would suspect that when a species declines, it's usually due to outside factors, rather than the way it's evolved.

 

Unless, I guess, it specialises to such a degree that it's left vulnerable to any new conditions.

Like the Dodo, becoming big and fat and flightless and delicious, because of the lack of predators on Mauritius.

Yes, it's ability to fit in declines and not able, or less able, to exploit the changing/new conditions.

Edited February 4, 2017 by StringJunky

[Obtuse-Venom]

Mutation is random. If it's useful mutation, organism survives, spreading genes to further generations. If it's adverse, organism dies.

What is useful or adverse is typically environment dependent.

I disagree with you that mutation is random. More so it is finite. I will give a very good explanation a bit later when I get past the noobness of this account.

 

But in brief, the DNA of any organism for that matter.

 

Every living organism on this planet is constructed of three dimensional digital coding. Like zip files, pure data with "ZERO" junk code in every single strand. Line for line, which opens up click by click by click , to become a living biological organism. All of it fitting together like a perfect glove. And deeper inside, the genome, the framework of pure biological software, and precision operating systems. File folders containing actual body plans. Digital instructions coordinating every strand,every cell, every part.

Pulling the molecular fabric of every piece together to create a biological masterpiece. Literally written, birthed, into reality itself. From scratch! The intangible controlling the tangible. The living blue print of what you call "you".

 

By the way, so you know. Each DNA generation of a organism cycling down per generation. Losing a bit of DNA from the previous generation. The laws of replication, over and over again.

[Strange]

Every living organism on this planet is constructed of three dimensional digital coding.

 

 

What do you mean by "three dimensional coding"?

 

 

 

By the way, so you know. Each DNA generation of a organism cycling down per generation. Losing a bit of DNA from the previous generation.

 

Some genes may be lost. On the other hand, they may be gained, transposed or changed.

[Obtuse-Venom]

 

 

What do you mean by "three dimensional coding"?

 

 

Some genes may be lost. On the other hand, they may be gained, transposed or changed.

As to the first question, the statement speaks for itself.

As to the second question. Genetic material is only gained/transposed/changed only by a collision with other chemical/genetic material. The organisms original material remains the same unless that happens.

Edited February 6, 2017 by Obtuse-Venom

[Strange]

As to the first question, the statement speaks for itself.

 

 

Obviously not, otherwise I wouldn't have asked the question.

 

 

 

As to the second question. Genetic material is only gained/transposed/changed only by a collision with other genetic material.

 

What do you mean by "a collision with other genetic material"?

 

 

 

The organisms original material remains the same unless that happens.

 

You mean the genome stays the same unless it changes. Err.... yeah.

[Obtuse-Venom]

 

 

Obviously not, otherwise I wouldn't have asked the question.

 

 

What do you mean by "a collision with other genetic material"?

 

 

You mean the genome stays the same unless it changes. Err.... yeah.

Because you are having difficulty. I would recommend reading up on the laws of Entropy as well as read up on Bio-Genesis. Then come back and talk about evolution. As my first statement pertains to both. And no,I am not trying to make you feel bad. Just perhaps a little more information to help you with comprehension. ;-D. It should also give more information pertaining to the original question given above. What causes a species to change over time?. I gave you the answer just in this statement

Edited February 7, 2017 by Obtuse-Venom

[Moontanman]

Because you are having difficulty. I would recommend reading up on the laws of Entropy as well as read up on Bio-Genesis. Then come back and talk about evolution. As my first statement pertains to both. And no,I am not trying to make you feel bad. Just perhaps a little more information to help you with comprehension. ;-D. It should also give more information pertaining to the original question given above. What causes a species to change over time?. I gave you the answer just in this statement

 

 

I am quite well read in the laws of Entropy and abiogenesis. What causes an population of organisms to change over time is random mutations filtered by natural selection...

[Phi for All]

Because you are having difficulty. I would recommend reading up on the laws of Entropy as well as read up on Bio-Genesis. Then come back and talk about evolution. As my first statement pertains to both. And no,I am not trying to make you feel bad. Just perhaps a little more information to help you with comprehension. ;-D. It should also give more information pertaining to the original question given above. What causes a species to change over time?. I gave you the answer just in this statement

 

!

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[Strange]

Because you are having difficulty. I would recommend reading up on the laws of Entropy as well as read up on Bio-Genesis.

 

 

Do you mean "biogenesis"? The hypothesis put forward by Pasteur in opposition to "spontaneous generation".

 

Or is the hype significant, and you are referring to something else?

 

And how is it relevant to the question of evolution?

 

BTW:

 

What do you mean by "three dimensional coding"?

 

What do you mean by "a collision with other genetic material"?

 

When you say, "I gave you the answer just in this statement"; which statement do you mean?

 

[Sensei]

I disagree with you that mutation is random. More so it is finite. I will give a very good explanation a bit later when I get past the noobness of this account.

Substantial part of DNA molecule is Carbon.

 

10^-12 of Carbon is Carbon C-14.

 

Which is unstable isotope and decays via:

 

[math]^{14}_6C \rightarrow ^{14}_7N + e^- + \bar{v}_e + 156.5 keV[/math]

 

with half-life 5730 years +- 40y.

 

If C-14 used to be part of DNA molecule, and decayed to Nitrogen, obviously DNA is damaged. Not severely damaged cell will be able to rebuild.

Now, imagine what will happen, if this happens in the middle of cell division..

Edited February 10, 2017 by Sensei