John Cherwonogrodzky jcherwon at dres.dnd.ca
Tue May 6 09:21:59 EST 1997

Dear Colleagues:
     There was a question on the net posed by a highschool student on whether 
the only driving force in evolution was survival (Darwinian causes). Chris 
Colby replied and gave an informative concise reply that there are several 
forces involved, not just evolution. Just to add my voice to Chris', I also 
believe evolution is complex, fluidic, with several forces blending into each 
other in the creation of a final product: The main ones are:

- Survival. As Darwin postulated, the strongest tend to survive to leave more 

- Nature abhors a vacuum. If an opportunity arises (e.g. an island emerges, a 
land formation occurs) life forms arriving there will adapt and evolve to take 
advantage of the environment.

- Sexual attractiveness, sexual programming. The dominant bird has bright 
plummage to attract the other sex (I forget the example, but where the female 
is dominant she is bightly coloured and the male is drab) and to stake its 
territory from others. Whether its mate is acceptable (song, dances, 
nest-building, etc.) is sometimes arbitrary but the process is essential to 
determine if  its all there, of the correct species, etc.

- Sexual competition. A giraffe has a long neck because 
the males use this and their horns to thrash their opponents. The longer the 
neck, the better it can hits its competitors. I recall reading about an 
extinct "mouse deer from hell" that had fangs, horns, etc. though it was 
vegetarian because the species was trapped on an island and fought itself 
intensely for mates.

- Survival of the weakest. If an animal has a genetic abnormality, i.e. it 
cannot synthesize an essential amino acid, it has less fur to keep warm, 
etc., it may seek a food source to make up for this weakness. It then moves 
into a new niche and evolves lock-step with its weaknesses.

- Translatase? All reactions are reversible, even irreversible reactions are 
simply A->>>>B, A <-B. Is there a process by which one normally has genetic 
material to transcribe to messenger RNA which translates to proteins which 
handles stresses in the environment. Can one reverse the process, or can 
stresses cause a weak feedback by which the genetic structure changes subtely?

- Chance. An asteroid hits the earth, volcanic activity increases, 
temperatures rise, methyl hydrate and carbonate release increases, etc. The 
several stresses are too much for a species, it gets wiped out and the other 
species take advantage of the slack to flourish. 

      I'm sure there are also several other processes, but again, evolution 
appears to be complex...Take care...John   

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