What population? Perhaps you mean if there were no variation for natural selection to select from.
Natural selection acts on variation by picking out from a population's gene pool those that are more fit to survive. More variation leads to more natural selection. For example, currently endangered cheetas are found out to have less genetic variation than other animals. As a result, if a disatrouous event occured, there are no genes that could help the cheetas survived. Thus, natural selection prevent the cheetas from reproducing as a population and they become extinct.
Genetic variation in itself does not 'support' natural selection: it is what natural selection acts upon.
There must be genetic variation, the variation must be heritable, and there must be differential reproduction (due to competition).
when there is competition
No, natural selection works on that genetic variation presented to it.
no there is no genetic variation for natural selection to act upon
No, there is no genetic variation upon which natural selection can operate.
What population? Perhaps you mean if there were no variation for natural selection to select from.
Genetic Variation is a measure of the genetic differences there are within populations or species. For example, a population with many different alleles at a locus may be said to have a lot of genetic variation at that locus. Genetic variation is essential for natural selection to operate since natural selection can only increase or decrease frequency of alleles already in the population
Natural selection requires variation in traits within a population, heritability of those traits, and differential reproductive success based on those traits. Without these components, natural selection cannot act on a population.
Natural selection can only work on genetic variation that already exists. So mutation comes first, then natural selection.
Without variation there is nothing to select from.
Evolution by natural selection actually relies on variation within a population. Without variation, there would be no genetic differences for natural selection to act upon, leading to no evolution. Variation provides the raw material for natural selection to work with, allowing beneficial traits to be favored and passed on to future generations.
Natural selection acts on variation by picking out from a population's gene pool those that are more fit to survive. More variation leads to more natural selection. For example, currently endangered cheetas are found out to have less genetic variation than other animals. As a result, if a disatrouous event occured, there are no genes that could help the cheetas survived. Thus, natural selection prevent the cheetas from reproducing as a population and they become extinct.
Genetic variation in itself does not 'support' natural selection: it is what natural selection acts upon.
The trait is the same for all organisms.