How is Natural selection a mechanism?

In species that are not monogamous, this mutational spread (or genetic drift) increases

In population genetics 'genetic drift' is something quite specific, I think the way you are using it here is confusing especially when you go on to essentially conflate selection with 'genetic drift'.

TTFN,

WK

'Genetic drift' refers to the changes in allele frequency between one generation and the next in a population which can be attributed to random factors. What you describe, natural random variation in mating success, could be one such factor. Being hit by a tree falling over clearly does curtail an organisms chances of reproductive success.

Your monogamy issue is pretty abstruse though, and certainly not considered a particularly important element of genetic drift as far as I know.

TTFN,

WK

Coyote writes: Kevin123 writes: What slowed evolution down? Perhaps successful adaptation to niches and slower changes in environment.

The obvious answer to my mind is that generation times vary greatly. A small mammal like the mouse has a generation time of 10 weeks from being born to being able to give birth. In primates it is much longer, for chimps and human it is around 15-20 years. I can certainly see how that could slow evolution down, by a factor of about 78, and the difference compared to a very primitive multicellular life form should be larger again. Brine shrimp for example have a generation time of 3 weeks giving a factor of 260.

This makes sense to me at least.

TTFN,

WK