"Eliezer Figueroa"  wrote in
news:blhri0$2in4$1{at}darwin.ediacara.org: 

> I belive in evolution so please do not get my question like an atack.
> I know about all the well known cases of evolution like reptil to
> birds. But I want to know about any evolution registered case in the
> last 7,000 years. I am not looking for small changes like the
> galapagus's birds evolution documented by darwin. I am looking for
> changes in an organ or the formation of new organs or new
> characteristics . I want to know about it even if it only happened in
> one specimen. I am looking for something like for example a rabbit
> that was spawn with 2 hearts for backup and that is able to spawn new 
> baby rabbits with it's caracterisctics. Is there is no case i would
> like a theorie about why not or just a simple "not yet"

7,000 years is a pretty short time from an evolutionary standpoint, so you 
should not expect large changes. Obviously new viral pathogens have 
appeared (SARS and AIDS very recently), but these require only small 
changes in existing genomes. Numerous varieties of domesticated species 
have appeared in the last 7,000 years, but you may not consider the 
Chihuahua as representing a "new characteristic". Note that what you are 
looking for - formation of new organs - is the type of change that would be 
very unlikely to occur in any short period of time, as it would generally 
require changes in a  number of associated organs to produce any benefit to 
the rabbit or other animal involved. The enlargement of the human brain 
relative to that of chimpanzess, our closest animal relative, is considered 
to have taken place very quickly from an evolutionary standpoint, but it 
still took millions of years. Possibly the best documented example of rapid 
evolutionary divergence is the cichlid fishes of Lake Victoria in Africa(my 
recollection is that this still took several hundred thousand years, and 
the speciation is not complete). A web search on this topic should give you 
some good information on maximum rates of evolution.

Yours,

Bill Morse
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