What is the main cause behind mutation in evolution?

Re: evolution

Basically the main cause of mutation is when, during reproduction (either asexual or sexual) the DNA sequence is reproduced incorrectly, causing slight variations in the sequence. If this organism with the new sequence reproduces, it will very well pass the mutation on. Over a long period of time if the mutation is advantageous to the population it will thrive.

 

Transcription - The process by which messenger RNA is synthesized from a DNA template resulting in the transfer of genetic information from the DNA molecule to the messenger RNA.

Translation - The process by which messenger RNA directs the amino acid sequence of a growing polypeptide during protein synthesis.

To explain easier, they are the process by which your DNA is read and the instructions on what is needed to be made in your body, as well as how to make it, are carried out.

For instance let's say your body needs more T-helper cells.

Your DNA will be read and transcribed into RNA. Then the particular portion which contains the instructions on how to make t-helper cells will be taken out, and the instruction will be carried out so more t-helper cells are made.

This has nearly nothing to do with mutations.

 

Re: evolution

http://www.talkorigins.org/faqs/faq-intro-to-biology.html

(there's a secton on muytation about 1/4 the way down)

 

gI thought it was mainly environomental... There's alot of background radiation and that sometimes knocks a peice of DNA out and if that happens to be a germ cell...

 

No, because if an organism dies, it doesn't reproduce anymore. It's only in the offspring of a mutated organism that the mutations will show up.

 

Greetings !

Hmm... I have very little knowledge so please correct me if
I'm wrong, but I think that new generations could be
treated kin'na like rebooting - restarting of the old and
"heavy" program that acquired too many mistakes and possibly
"dead ends".

If one organism exists for a long time it's cells would
mutate and it would get all messed up, so that's why we
don't just live on but rather nature "installed" a mechanism
which makes us get older and eventually die. The new generation
has it's source in a single piece of code - so it's perfect
and with no different mutated cells at the very beginning.

An even simpler and more basic reason is the fact that all
life forms we know of, except humans, were and are part
of some food chain. So a creature that can't reproduce will
be extinct rather quickly - which makes no evolutionary sense.

Examples of near "perfect" creatures are ants and crocodiles,
because they stayed pretty much the same for many many millions
of years. And yet they do reproduce.

Am I close ? Makes sense ?

Live long and prosper.

 

Hmmm...lots to say

Firstly, there is no such thing as a 'perfectly evolved being'. The closest thing that exists to that, is a being which happens to fit into a particular niche exceptionally well. But, over time, the environment changes, the predators around it change, its prey changes...stuff changes, and so too, must the well suited organism.

Umm...well, i guess so. But I wouldn't say that this is the reason why. It is true....but I think death and birth etc have an origin which comes from quite different reasons to this.

Umm..in the begining, this wasn't necessarily true. At some stage, the food was just CO2 and other chemical elements not yet within the 'life cycle'...such as CH4, NH3 and whatever... and originally, there were no predators. Predators had to evolve...

But back to the original question: Mutation is caused by a variety of things. Most common is a result of errors copying DNA, misplacements of DNA, then a variety of mutations caused by things like radiation, chemicals etc.

The misplacements of DNA is probably the one least understood by the public, because people have this view of DNA as a static "This is how I am" sort of molecule. This is basically wrong. DNA is a dynamic molecule which actualy changes around quite a bit (though not oo much...). There are several mechanisms through which similar bits of DNA can be swapped over. Recombination and crossing over are examples of this....but I can't really get into it all without diagramms and a whole bunch more effort than I am willing to put into this at the moment.

But yeah, mutation is almost a natural part of DNA being DNA. It is just a function of the organism to try to stop mutations, in an attempt to maintain the tried and tested functional code of DNA that it has achieved....Of course, nothing is perfect....



einsteinian77, if you really want to get a neat explanation of Transcription and Translation, check this website out:
UCLA MOlecular Biology Tutorials
It has good flash presentations of how it works. Just click on the Gene Expression link....

 

Do you have Flash 5? You may need to download it (there is a link there to get it.) If you have dial up, I guess it may take a long time to download the animations....