The Common Ancestry Thread

by cantleave 271 Replies latest members adult

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  PSacramento

  Mutations in DNA sequences generally occur through one of two processes, DNA damage from environmental agents such as ultraviolet light (sunshine), nuclear radiation or certain chemicals or mistakes that occur when a cell copies its DNA in preparation for cell division.

  And it's by pure chance that some mutations are in the best interest of the organisim?

  The view that the zub-zero environment of Siberia would cause animals to evolove to deal with that cold is incorrect then?

  They just happened to evolve via pure chance via mutations that had nothing ( or very little) to do with their environment?
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  cantleave

  And it's by pure chance that some mutations are in the best interest of the organisim?

  As cofty said said many DNA mutations are neutral to the organism, some are harmful but a few can be beneficial. These mutations are passed onto the next generation. Interestingly it may two or more mutations to occur before a beneficial result can be seen. This was an observation in the famous Lenski experiment.

  Don't forget what these sequences do, they code for proteins. One class of proteins are enzymes. If a mutation reults in the production of a modified enzyme, which say, has the ability to break down a starch molecule, it may allow the organism to create energy from a food source that organisms without that mutation can not benefit from. This may allow the mutated organism to fill a new niche.
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  jgnat

  Harmful mutations die out before passing on their mutation to their offspring through the harsh sifting of the environment. Neutral and beneficial survive.
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  jgnat

  [Ideal design] Accoring to who? to what? There is no "design", the human eye got to where it was based on either by pure blind chance and random mutation OR because it needed to evolve to the satge it did to help with the surival of the species, either way there was no design NOR can it be viewed as flawed unless it doesn't DO what it is supose to do, right? If the purpose is to see and the eye sees, then where is the "flaw" or lack of "ideal"? - PSacramento Well, I thought the eye was a great example of this. If we were to design receptor rods, wouldn't we put them in facing forward? We are creative beings, and we design lots of things like iPods an so on. I have an e-reader that does some of the functions of an iPod. I curse it every time I use it because the sub-optimal design has the volume and the on-off buttons on the bottom. If I knock it with my knee, it does what I don't expect.
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  cantleave

  The view that the zub-zero environment of Siberia would cause animals to evolove to deal with that cold is incorrect then?

  A hypothetical for you to consider...

  Imagine a species of animal living in a temperate climate in the south of a land mass (group A). These animals have a thin layer of subcutaneus fat and a thin coat of fur making them unable to cope with very cold temperatures. This means they have to confine themslves within a geographical location where the temperature does not get too cold for them to thrive. Now imagine the population grows and its food resources become scarce. Yet there are food sources further north where the climate is too inhospitable. If some individuals possessed a genetic sequence that produced a thicker layer of subcutaneous fat, they could start to colonise the colder regions (group B) and take advantage of the more abundnat food supply. They would also have an advantage if the climate were to become generally colder. This could result in the two groups becoming more isolated from each other until eventually group A and Group B can no longer breed togther. The two groups are now forming two different gene pools.

  This process can continue. Some individuals in group B develop a gene sequence that allows for thicker fur. With the thicker fur and subcutaneous fat layer they can form a group even further north, right up into Siberia and form group C. With time this group becomes isolated from B, it forms yet another gene pool. These isolated groups will continue to evolve along different pathways and eventually form 3 different species living in 3 different climates.
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  PSacramento

  I see what you are getting at cantleave.

  But, why does Group A have a thin layer to begin with? and why would that change just because they moved to an area where its colder?
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  cantleave

  why would that change just because they moved to an area where its colder?

  The genetic change happens first, allowing the animals to exploit the food sources up north.
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  PSacramento

  Ah, really?
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  cantleave

  Have you ever looked at the Lenski experiment Psac?
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  tornapart

  I'm sorry to jump in at this late stage. However I decided to take Cantleave up on his suggestion. I at least want to try and understand where 'evolutionists' are coming from (sorry.. I know you don't like that word!)

  So I'm reading this thread from the beginning (I've only got to page 2 as I want to read it slowly and carefully so I can understand what I'm reading). It is a fascinating subject and I'll leave my own opinions to one side until I've finished the whole thread.

  I wanted to understand a little more about psuedogenes so I looked up a few other articles on it (though not too much.. I don't want to become brain frazzled in 24 hours!)

  I came across this article which I found interesting... though I'm sure you'll have an answer for it! And yes, of course I'll be looking at both sides of the story!

  http://www.evolutionnews.org/2012/08/paper_rebuffs_v063201.html