| Subject: |
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I guess it's not too HARD to figure it out |
| Name: |
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akg41470 |
| Date Posted: |
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Feb 25, 08 - 10:30 PM |
| IP Address: |
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75.72.23.70 |
| Email: |
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eolcott@triplo.com |
| Message: |
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"If mutations are random, explain in detail how and why novel or more complex traits evolve in unison with their diverged counterparts when exposed to similar environments"
1. You can't assume they happened "in unison". They could have evolved the traits millions of years apart. It just so happened to be the same trait.
2. Just because something is random does not mean it is unique. It IS possible to "roll the lucky number" more than once.
3. Similar environmental pressures will influence useful traits being passed on, subjecting them to the same natural selection. It's certainly a lot less "random" than you're leading on.
"explain in detail why placental and marsupial mammals evolved a different mechanism for reproduction if they had similar environmental pressures?"
Because both of the reproductive systems worked just fine in the given environment. "Similar" is not "exactly the same". It would be possible that the marsupial reproduction system was a better system in that environment as opposed to the mammalian in a subtle way... but I'm only guessing.
Conversely, we don't know that the marsupial reproductive system wouldn't have evolved in the mammalian environment, either... that's just the way the mutations led!
"be specific and explain exactly how much environments must match for convergent evolution to occur"
That kind of answer is impossible. It's like asking exactly where marshmallow #13 is going to end up in my cup of cocoa after I stir it with this spoon. Too many variables are in that equation.
"Since the first series of changes after the placental/marsupial split must have been completely different for each organism (otherwise, how would they have ‘diverged’?), that would mean that the subsequent molecular changes didn’t just change equally, but one miraculously evolved into accordance with its counterpart."
You're assuming WAY too much symmetry, not only in sequence but in the time the traits showed up. Convergent evolution doesn't say that the traits showed up *at the same time* and *in the same order*, simply that they appeared AFTER the speciation event, independently of one another.
"Since you believe that evolution is still occurring, please provide an example of just ONE novel or more complex trait that is beginning to appear in an existing population."
I'll give you a great example as a result of a recent environmental pressure, global warming:
Canadian squirrels are evolving to take advantage of an earlier spring and are breeding sooner, which allows them to hoard more pinecones for winter survival and next year's reproduction. Squirrels with genes for earlier breeding are more successful than squirrels with genes for later breeding.
The "complex trait"? Earlier breeding cycles. It may be small, but it's notable and "novel", especially when continued over many years. |
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