Evolution?

baddog1 wrote:

maporsche wrote:
There is no DNA mutation when you lop off a rat's tail.

Your assertion is not consistent with Buffalo's example.

Please tell me how it's inconsistent?

buffalo wrote:

...but if you cut off the tails of every newborn rat for several generations, they still continue to grow tails?

There is no DNA mutation if someone cuts off a rat's tail after it's been born. Just as if I lose my finger in a rip-sawing accident, my child will still have all 10.

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Do the continuous disrespectful comments somehow make you feel better about yourself fm

I guess its the teacher in me. I dont abide imperious ignorance with anything but impatience . If you wish to continue these types of discussions then youre sure to develop a thick skin.

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I understand natural selection - limb regeneration helps with survival. Is this true?

And is it true that DNA changes are happening all the time?

If true - can DNA mutation happen during natural selection?

If yes, then the mutation could indirectly affect a rat(s) DNA

Limb regeneration assissts in survival modes--yes
DNA changes happen frequently-yes

Where youve fallen off the cart is in the following two lines. You fail to understand . let me try this.
cutting a rats tail has no bearing on its genic complement(Its amounts or types of DNA). Any survival or sexual selection benefit that a short tail provides is merely resultant of the selection of specific individuals whose genetic variability already provides for the DNA expression of a short tail. (vis, ALleghany Cave Rats v Alleghany mountain rats).Nobody cut the rats tails. The expression was alreay there and , as new genes are subsequently formed , new dimensions of genic variability are added.
Short tails may not even have a genic expression, but as the short tailed rats are selected FOR, their sub species can evolve apart further so that the Alleghany cave rat develops a smaller eye and melanin depletion, whereas the Mountain rats develop a thicker coat, smaller pikalike ears and huge eye flaps. All this from a historical founder population that was as recent as less than a thousand years ago. (the Cherokee and Iroquois ate them and made pouches out of their fur) . So we have historical refernces to founder populations and evolved daughters .

Noone cuts any tails and what ros says is the correct answer. There is no "direct" nor "indirect" affects on DNA, unless its convened as a collateral event when another change is made evident. (Fur, ears, tail, eye flaps for wind protection etc).

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A polymorphicexpression of a trait can provide for a whole range of body plans . A normal rats population has individuals with tails that go from very short to very long. The environment can sort out the polymorphic expression and select a tail size best suited to that enviironment.

Does any of this ring a bell from hs biology? Im trying to be as approachable as I can. BUT, somehow I know that Im gonna get my hand bitten sooner or later.

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maporsche wrote:

baddog1 wrote:
maporsche wrote:
There is no DNA mutation when you lop off a rat's tail.

Your assertion is not consistent with Buffalo's example.

Please tell me how it's inconsistent?

buffalo wrote:
...but if you cut off the tails of every newborn rat for several generations, they still continue to grow tails?

There is no DNA mutation if someone cuts off a rat's tail after it's been born. Just as if I lose my finger in a rip-sawing accident, my child will still have all 10.

Member buffalo's example was in consideration of many rats over several generations. Your example was a single incident. Is there no difference?

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farmerman wrote:

I guess its the teacher in me. I dont abide imperious ignorance with anything but impatience . If you wish to continue these types of discussions then youre sure to develop a thick skin.

My lady teaches 5th grade. While I feel sure that would be well beneath your level - I much appreciate that she refuses to participate in the self-importance that you show. Based on the success rate & preparation of her students to advance - I am sure they & their parents agree.

farmerman wrote:

Where youve fallen off the cart is in the following two lines. You fail to understand . let me try this.
cutting a rats tail has no bearing on its genic complement(Its amounts or types of DNA).

I don't believe there was any inference of this.

farmerman wrote:

Any survival or sexual selection benefit that a short tail provides is merely resultant of the selection of specific individuals whose genetic variability already provides for the DNA expression of a short tail. (vis, ALleghany Cave Rats v Alleghany mountain rats).Nobody cut the rats tails. The expression was alreay there and , as new genes are subsequently formed , new dimensions of genic variability are added.

Short tails may not even have a genic expression, but as the short tailed rats are selected FOR, their sub species can evolve apart further so that the Alleghany cave rat develops a smaller eye and melanin depletion, whereas the Mountain rats develop a thicker coat, smaller pikalike ears and huge eye flaps. All this from a historical founder population that was as recent as less than a thousand years ago. (the Cherokee and Iroquois ate them and made pouches out of their fur) . So we have historical refernces to founder populations and evolved daughters .

Noone cuts any tails and what ros says is the correct answer. There is no "direct" nor "indirect" affects on DNA, unless its convened as a collateral event when another change is made evident. (Fur, ears, tail, eye flaps for wind protection etc).

OK for short & long tailed rats. However, to the best of my knowledge - there have been no known instances in history where generations of rats have had their tails removed in order to survive. Had there been - are you suggesting the impossibility of any DNA changing that could affect this?

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But you forget BD, we have had a species were we have repeatedly chopped of the tails for decades if not centuries. Yet those dog breeds that get their tails docked still require it after all this time.

http://www.cdb.org/what_is.htm

But then of course docking doesn't just occur with dogs

Pigs and sheep also often have their tails docked and have had for multiple generations.

We have evidence that cutting off the tails of a mammal does not cause the tail to no longer appear even after multiple generations.

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parados wrote:

We have evidence that cutting off the tails of a mammal does not cause the tail to no longer appear even after multiple generations.

Nor would you expect it too.

This would not be selected for via natual selection because the is NO DNA MUTATION causing it. This is happening outside of any DNA influence.

Unless you were somehow manupliating the DNA in order to breed dogs/rats w/o tails, there is nothing that natual selection would acto upon.

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My lady teaches 5th grade. While I feel sure that would be well beneath your level - I much appreciate that she refuses to participate in the self-importance that you show. Based on the success rate & preparation of her students to advance - I am sure they & their parents agree.

We have great patience with kids atrting out. However, when they pay to be trained to become part of a professional corps, its quite different. We weed em out if they cant keep up. You dont do that in public elementary schools..

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farmerman wrote:

Quote:
My lady teaches 5th grade. While I feel sure that would be well beneath your level - I much appreciate that she refuses to participate in the self-importance that you show. Based on the success rate & preparation of her students to advance - I am sure they & their parents agree.

We have great patience with kids atrting out. However, when they pay to be trained to become part of a professional corps, its quite different. We weed em out if they cant keep up. You dont do that in public elementary schools..

There you go again with wrong assumptions. Did anyone say "public" schools?

BTW: What is "atrting out"?

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parados wrote:

We have evidence that cutting off the tails of a mammal does not cause the tail to no longer appear even after multiple generations.

Why did you change from 'animals' to "mammals"?

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farmerman wrote:

hanno, Darwin , in his 1st edition of "Origins..." devotes several chapters to artificial selection and hybridization, as compared to natural selection. Its worth a read from someone who was as blown away by the mechanism as any interested student.

Also, Id rethink your statement about cutting off the tails of a population of rats.

Alright professor what have you got on me? Maybe a quote instead of an ISBN number.

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You aren't altering a rat's environment by cutting off its tail. And to see a change you have to wait millions of years. Part of the reason people don't believe in evolution is because they can't grasp the age of the earth or the universe. In fact, that's why it's so groundshaking. I mean, try to imagine just one million dollars. Those bills would fill up entire rooms. Who can conceive that much money? Now make that closer to 4 billion. Absolutely mind blowing what can go on in that time. If you cut a rat's tail off and kept doing that for every generation and breeding them together, the rats would eventually develop a new way to balance. It would take millions of years, but they would probably have stubby tails eventually and something else to create balance.

The base of your spine sticks out because, theoretically, human's earliest forms (before it was ever considered human) had a tail. In fact, some people today are still born with them as a sort of passive defect. Same with the ducts in your eyes that people say are tear ducts---they aren't. They're vestigial structures that at one time looked like dog or cat lids, the second one that goes horizontal. Chances are we needed those structures at one point to balance and see under water, but when we stood up and started using tools we no longer needed those things.

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The article linked below refers to a fish that has encountered "DNA alterations that are responsible for causing changes in the regulation ... of different processes, including pituitary development and craniofacial development".

Interesting.

http://www.hhmi.org/news/kingsley3.html

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baddog1 wrote:

The article linked below refers to a fish that has encountered "DNA alterations that are responsible for causing changes in the regulation ... of different processes, including pituitary development and craniofacial development".

Interesting.

http://www.hhmi.org/news/kingsley3.html

This is interesting, but I hope your not suggesting that it supports the "cutting a tail off of a rat" hypothesis that buffalo presented.

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maporsche wrote:

baddog1 wrote:
The article linked below refers to a fish that has encountered "DNA alterations that are responsible for causing changes in the regulation ... of different processes, including pituitary development and craniofacial development".

Interesting.

http://www.hhmi.org/news/kingsley3.html

This is interesting, but I hope your not suggesting that it supports the "cutting a tail off of a rat" hypothesis that buffalo presented.

Oh I don't know - we could probably go on for quite a while with various scenarios. At the very least; I would say that the article could indirectly support the tailless rat hypothesis.

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does indirect support of the tail-less rat hypothesis lead to anything else that can be indirectly supported?

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wandeljw wrote:

does indirect support of the tail-less rat hypothesis lead to anything else that can be indirectly supported?

Hey wandeljw.

Probably, but not my intention. Absolutes have been presented, some of which seem to be inconsistent with my [admittedly limited] knowledge. If you're keeping up with this topic - please offer your further thoughts. The original poster's question presents an interesting scenario.

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baddog1 wrote:

maporsche wrote:
baddog1 wrote:
The article linked below refers to a fish that has encountered "DNA alterations that are responsible for causing changes in the regulation ... of different processes, including pituitary development and craniofacial development".

Interesting.

http://www.hhmi.org/news/kingsley3.html

This is interesting, but I hope your not suggesting that it supports the "cutting a tail off of a rat" hypothesis that buffalo presented.

Oh I don't know - we could probably go on for quite a while with various scenarios. At the very least; I would say that the article could indirectly support the tailless rat hypothesis.

And how can it even "indirectly" support it? You could go on for quite a while with ludicrous scenarios perhaps but nothing that follows any logic.

1. Cutting off tails doesn't change the DNA. (As evidenced by the docking of tails on several animals over multiple generations.)
2. DNA changes led to the changes in the stickleback fish. Their environment changed making the DNA changes advantageous.

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parados wrote:

2. DNA changes led to the changes in the stickleback fish. Their environment changed making the DNA changes advantageous.

How did you reach this conclusion?

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baddog1 wrote:

parados wrote:
2. DNA changes led to the changes in the stickleback fish. Their environment changed making the DNA changes advantageous.

How did you reach this conclusion?

Did you read the link?

Quote:

The researchers were able to determine the DNA sequence of the Pitx1 gene in marine fish with a normal hindfin and in freshwater fish with hindfin reduction. Although no changes were seen in the portions of the gene that code for the Pitx1 protein, comparative expression studies showed that the gene was no longer expressed properly at some locations in the freshwater fish, including the place where hindfins would normally develop.

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