2: Natural selection always works for the good of the species.
Natural selection doesn’t mean perfection; hence we cannot assume that “the best” traits are always the ones that are going to be selected for in a population. Contrarily to the popular misconceptions, the way natural selection works is by producing more of the better genes (although better doesn’t necessarily mean not harmful), in other words, if an organism’s genes are strong enough, or good enough, or fit enough then they’ll survive in the population by being passed on from one generation to the next.
We will inherit what we are given, whether it is a good gene or a bad gene, if a gene manages to survive, we will inherit it. As the article said “Natural selection is the simple result of variation, differential reproduction, and heredity — it is mindless and mechanistic. It has no goals; it's not striving to produce "progress" or a balanced ecosystem.”
Evolution is nothing but gradual genetic changes that came about due to natural selection. One thing we need to understand is that what evolves is not “an …show more content…
Why weren’t they removed from the populations? The answer is because natural selection is a directed evolutionary mechanism which operates by differential reproductive success of individuals. When an organism is more effective than another in producing offspring, over time this organism’s genes will eventually dominate the population’s gene pool. Ultimately, the genotype with fewer offspring will vanish.
The other explanations are very well exposed in the article. Heterozygote advantage is one of them as in the case of sickle cell anemia, mutations, gene flow, not enough time to be able to remove the “bad gene”, or the gene doesn’t reduce fitness so it’s not selected against, even though it may very well be deleterious later in