[MD] Oneness, Dualism & Intellect

[Horse]

Hi Platt

pholden at davtv.com wrote:
> Quoting Horse <horse at darkstar.uk.net>:
> 
>> Hi Platt
>>
>> More from Wikipedia:
>>
>> "Evolution is change in populations of organisms over generations. 
>> Offspring differ from their parents in various ways. When these 
>> differences are helpful, the offspring have a greater chance of 
>> surviving and reproducing, making the differences more common in the 
>> next generation. In this way, differences can accumulate over time, 
>> leading to major changes in a population.
>> Evolution occurs through changes in genes, the "recipe" for constructing 
>> the organism. When an organism reproduces, small random changes in the 
>> genes make the offspring different from the parent. Sometimes these 
>> changes help the offspring survive to reproduce. When this happens, the 
>> genes for the beneficial traits are passed on to the organism's own 
>> offspring, becoming more common in the next generation. Genes that do 
>> not help organisms reproduce may become rarer or be completely 
>> eliminated from the population. This is called natural selection, a 
>> major part of evolution. Through natural selection, populations of 
>> organisms slowly change over time as they adapt to changes in their 
>> environments."
>>
>> So evolution is not just about creating new species.
> 
> Isn't a major change in a population the same as creating a new species? 

I don't think so. But it depends on what sort of life we're talking 
about. For a major change in life that reproduces sexually the new, 
"improved" form may be compatible with the earlier form although with 
significant differences. Whereas a new species is generally incompatible 
   with a related species even though they have a common ancestor.

> If not, what constitutes creating a new species? 

I suppose that depends on what definition of species you want to use. 
Have a look at the Wikipedia page on species to see what I mean. An 
interesting quote from this page relating to species classifications is:

"....the differences between them are more a matter of emphasis than of 
outright contradiction. Nevertheless, no species concept yet proposed is 
entirely objective, or can be applied in all cases without resorting to 
judgement. Given the complexity of life, some have argued that such an 
objective definition is in all likelihood impossible, and biologists 
should settle for the most practical definition."

> And, are any major changes in populations being observed today? Thanks.

Again, what sort of populations are you thinking of. Going back to what 
I said a while ago about bacteria, they are seen to be changing all the 
time and given that there are about 5 X 10^35 (5 with 35 zero's added) 
bacteria on the planet and around 10 million species of the little 
buggers it would be almost impossible for them not to be subject to 
major changes over time. Another interesting group is fungi which is, I 
think, the second most common form of life on earth.


Horse