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paolo
Phoenix
Joined: Aug 13, 2006
Posts: 1081
Location: Italy
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 Posted: Thu Dec 27, 2007 4:01 pm Post subject: Time spans of evolution. |
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How much does is take for species to differentiate from one another? Sometime millions of years. But they still maintain something in common. For example whiskers (vibrissae). Whiskers are present in cats, wolves and other canines, seals, some whales, rats, and many other mammals (not apes and humans). They are very important sensory organs. They are not different versions of a solution to a sensory need. They are the same evolutionary solution to a need which is maintained across the differentiation of species.
A courting bird song and a human love song, are different solutions to some common need (courtship). But, attachment springing from maternal care (imprinting) is the same solution to the need to create social bonds among animals. They are behavioral pieces which are common to different species. They are not analogues, they are the same thing.
Reaction of flight, increased attention, predisposition to attack in presence of a strong noise are common to humans and most other animals.
The magnitude of the time spans required to differentiate and the communality of some of the evolutionary solutions is something that puts our lives in perspective and should reduce the drama of our experiences of suffering. After all we are al part of a huge thing, and our stories are only an eye wink.
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crazyllama
Snowy Owl
Joined: Oct 11, 2007
Posts: 162
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| Posted: Thu Dec 27, 2007 4:16 pm Post subject: |
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Over a hundred years ago, all parakeets in the world were blue. Now they have green, yellow, white, red etc... through breeding. Sometimes evolution happens quickly and other times it takes millions of years.
Crocodiles have been pretty much the same for tens of millions of years. |
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paolo
Phoenix
Joined: Aug 13, 2006
Posts: 1081
Location: Italy
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| Posted: Thu Dec 27, 2007 4:37 pm Post subject: |
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| Yes, but breeding, as genetic engeneering is human manipulation of existing things, is mixing things up, hodgepodge, jumble, medley, miscellany, muddle, pastiche (Roget's synonims) for human short term finalities. |
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EvilKimEvil
zoo-music girl
Joined: Sep 27, 2007
Posts: 3040
Location: highway to hell
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| Posted: Thu Dec 27, 2007 9:19 pm Post subject: |
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Breeding is not evolution. Breeding is a process directly controlled by another species (us). Evolution occurs gradually and is affected by many different factors. The time that it takes for observable changes to transpire should be measured in generations, not years. There is naturally a lot of variety between species and within species in terms of how fast reproduction takes place.
The rate of evolution can also be affected by genetic variables specific to the species, as well as sudden environmental changes (which tend to temporarily speed up the process).
This information comes from an Evolutionary Biology class that I took several years ago. |
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Starr
Phoenix
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Joined: Sep 18, 2006
Posts: 4248
Location: the misty mountain
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| Posted: Fri Dec 28, 2007 4:26 am Post subject: |
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| I often wonder how much consciousness we as a species possess. If it is that which separates us from our ape ancestors, then maybe it is not so much. That, and the ability to kill and control other species. I was going to say, and communicate with each other, but of course other animals also do this but often in a way we cannot understand. If we are the most intelligent species, as scientists tell us, I wonder why our evolutionary path has given us the intelligence to control our environments so much as to effect changes that may one day wipe us off the planet. It doesn't seem to make sense from an evolutionary point of view. We seem to be 'over-evolved' and over-breeding. |
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paolo
Phoenix
Joined: Aug 13, 2006
Posts: 1081
Location: Italy
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| Posted: Fri Dec 28, 2007 5:33 pm Post subject: |
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| We are over breeded certainly. Not overevolved in intelligence, if intelligence is, as I think, something different from the artificial intelligence of computers. Tenderness, intuition, ecstasy do not belong to artificial intelligence. Have you ever seen an ecstatic computer, an affectionate computer, a computer who makes "wild guesses"? In R.U.R by Carol Capek robots (he invented the word) become human when they discover love . But PCs built by men will never discover that thing. |
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Sedaka
Searching For My Catcher in the Rye
Joined: Jul 17, 2006
Age: 26
Posts: 5128
Location: In the recesses of my mind
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| Posted: Fri Dec 28, 2007 7:07 pm Post subject: |
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all breeds of dogs were generated in less than 5K generations... but they are considered one species by most species definitions.
_________________
and yet i'm
still roaming these
empty streets at night
alone again only to find
there are no shelters here;
i must simply resolve
to play in the rain. |
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syzygyish
Dada Dodo
Joined: Feb 04, 2007
Age: 41
Posts: 3988
Location: waiting for IF
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| Posted: Sat Dec 29, 2007 3:01 am Post subject: |
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Evolution occurs in response to environmental pressure.
The most important (i think) are diseases & virus's.
An organism occupying a niche can remain stable (i.e.not evolve) for millenia -e.g.crocodiles
If it goes extinct, new organism's will rapidly evolve into the new niche.
A species that is separated will slowly diverge genetically. |
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Sedaka
Searching For My Catcher in the Rye
Joined: Jul 17, 2006
Age: 26
Posts: 5128
Location: In the recesses of my mind
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| Posted: Sun Dec 30, 2007 4:43 am Post subject: |
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evolution produces diversity... on which environmental pressure select which is most fit.... there's no predicting what that will be... although there is a good base recipe for most things
_________________
and yet i'm
still roaming these
empty streets at night
alone again only to find
there are no shelters here;
i must simply resolve
to play in the rain. |
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