Natural Selection Mechanism

B

Barry Flannery

Registered Member
I found most of the literature over detailed for this one line answer question so I thought that I'd ask here.

What is the mechanism of Natural Selection?

Is it basically just that good traits tend to increase survivability which in turn perpetuates the trait?

Barry
 
Basically yes - if you want full marks I would say something like this:

Populations contain genetic variability - this variability is hereditable.

There is often an inequality between the availability of resources, and the number of organisms competing for those resources.
Therefore physical and biological components of an organism's environment act as selection pressures.

Individuals that are best adapted to these selection pressures leave the most offspring.

Any questions?
 
It works on the level of the gene. If a gene codes for something that makes it more common, the gene proliferates.
 
Natural selection IS the mechanism. It is the mechanism for evolution. Populations are the unit of measure that evolves. After all, evolution is a change in the frequency of a trait over successive generations. An individual cannot change the frequency of its trait.

Fitness is the measure of success for an individual/trait in a particular environment. The individual with the most offspring will have more of its DNA in the next generation (assuming survivability) and so is the most "fit". Natural selection is not selecting "for" a trait. It is often better to remember that fitness is relative and the successful adaptation is not always the "best" in that environment. There are just too many random influences outside of the laboratory to assume that the fittest in one generation is necessarily the one that will, generation after generation, continue to be the fittest.

Natural selection basically poses that there is variability in organisms and variability in reproduction. Some of the variability in reproduction is due to the variability of the organisms. The interaction of the two is how the frequency of traits can change from one generation to the next.

To get to evolution, that variability has to work in favor of a trait in repeated, successive generations.
 
linscomb said:
Natural selection IS the mechanism. It is the mechanism for evolution. Populations are the unit of measure that evolves. After all, evolution is a change in the frequency of a trait over successive generations. An individual cannot change the frequency of its trait.

Fitness is the measure of success for an individual/trait in a particular environment. The individual with the most offspring will have more of its DNA in the next generation (assuming survivability) and so is the most "fit". Natural selection is not selecting "for" a trait. It is often better to remember that fitness is relative and the successful adaptation is not always the "best" in that environment. There are just too many random influences outside of the laboratory to assume that the fittest in one generation is necessarily the one that will, generation after generation, continue to be the fittest.

Natural selection basically poses that there is variability in organisms and variability in reproduction. Some of the variability in reproduction is due to the variability of the organisms. The interaction of the two is how the frequency of traits can change from one generation to the next.

To get to evolution, that variability has to work in favor of a trait in repeated, successive generations.
Click to expand...

Yes - but that's not really an answer to the question - the question is related to what drives natural selection.
That is essentially the competition for resources and the biotic and abiotic environment acting upon variations in a population, and the inequalities in reproductive success that arise from that.
 
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