EVOLUTION- a change
in the gene frequency of a population
It's reasonable to suppose that the genes
that best increase their chances of being passed on to future generations,
tend to become more common in future generations.
What factors have we studied that influence
the chance (probability) of an organism passing on its genes?
Which then is the basis of the definition
of Natural Selection: Differential
survival and reproduction of traits controlled by genes.
| Pre-industrial | Post-industrial |
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More simply, the more copies of the blueprint passed on by one type of individual, the more prevalent those blueprints become in the future generations.
"Natural selection is not an active agent
with physical properties, much less a mind. It is no more than a
statisical measure of the difference in survival and reproduction among
entities that differ in one or more characteristics. Selection is not caused
be differential survival and reproduction; it is differential survival
and reproduction, and no more"
Richard Dawkins - "The Blind Wacthmaker"
Two important consequences
of evolution via natural selection for ecology (the first is important
for understanding life history patterns, the second for understanding of
population interactions)
1. Natural selection is both a function of survival and reproduction.
If a gene causes an individual to have superman-like survival abilities, will it become more common in future generations?2. Individuals only 'cooperate' with other member of their population or with other species only if the genes that promote such interactions are more likely to be pass on. The consequence of this is that there is no inherent "balance" that develops with a community. Instead a community is a collection of individuals evolving to take advantage of available resources resulting in a dynamic "balance of power"
In a very general sense, what determines survivorship and reproduction?
How reproduction and survivorship are optimized for a given population in a given environment is the central question of 'life history' studies.
Why? Because genes are not shared between populations (by definition), and individuals that pass on genes more successfully to future generations increase the likelihood that their kind will remain a part of that ecosystem.
It's every individual for itself, and so populations and ecosystems are composed of a collection of individuals with different evolutionary histories, each adapted to "make a living" in a way that maximizes their own survival and reproduction within their environment.
When cooperation is seen in nature, is this unexplanable based on natural selection?
Through out the semester, the dynamic nature of ecological systems will be made apparent.
Side note:
Just because the living world is structured by natural selection, does not imply that this should be the basis of human ethical and moral belief systems.
