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
offspring.
- 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
