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Author Topic:   What is missing from the theory of evolution
jasonlang
Member (Idle past 2638 days)
Posts: 51
From: Australia
Joined: 07-14-2005


Message 14 of 68 (684480)
12-17-2012 4:45 PM
Reply to: Message 13 by dayalanand roy
12-12-2012 9:51 AM


Re: re- something missing
@OP: Maybe the piece of the puzzle you're not seeing is sexual reproduction.

With asexual reproduction, you'd be relying on serial mutations or random chance gene swaps, if one organism had gene A and and another had gene B, that were good separately, but together were even better, they'd more or less have to both develop the entire other gene all over again (constantly re-inventing the wheel) to get the benefit of both. And it's true with axesual mutation / reproduction that the child's DNA will only be a couple of letters different from the parent (barring things like copying errors).

Yes, linear mutations are perhaps too slow to produce all the variations and complexity we see today within the given time-frame, but that's not taking into account the "parallel processing" that's enabled by sexual reproduction.

Different lines of inheritance can develop improvements separately, each of which is marginally better than the old version, and these can be recombined into new variants which can benefit from both sets of genes. And huge chunks of DNA can be swapped back and forth within a single generation, because of splitting and random recombination, the child's DNA with sexual reproduction will be an entirely novel sequence, not just 1 or 2 letters different from either parent as in asexual reproduction.

So, if the genome was a book, asexual reproduction would be like copying the entire book, and changing a single letter here and there, whilst sexual reproduction is like taking 2 books, splicing entire words, paragraphs and chapters together picking at random from corresponding chapters of either book (and also switching the odd letter here and there).

So, with sexual reproduction, organisms can inherit entire structures from each parent, and they get jammed together in completely novel ways. Now, this can obviously fail very badly, but it can also lead to great successes that can leapfrog the need to add letter by letter (which might lead to an evolutionary "valley" which doesn't work). The risks come with the rewards.

Edited by jasonlang, : No reason given.

Edited by jasonlang, : No reason given.


This message is a reply to:
 Message 13 by dayalanand roy, posted 12-12-2012 9:51 AM dayalanand roy has seen this message

  
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