Final answer:
The statement about the dependency of a new variant's relative fitness on immediate selective conditions is true, as environmental factors heavily influence the survival and reproduction success tied to specific mutations. Beneficial mutations can confer an advantage in certain environments, while the same mutations can be deleterious in others.
Step-by-step explanation:
The statement that the relative fitness of a new variant depends on the immediate selective condition is true. A mutation that may be beneficial in one population may indeed be deleterious in another. This is because relative fitness is an individual's ability to survive and reproduce in comparison to the rest of the population, and it can be influenced by various environmental factors such as the availability of food, the presence of predators, or other selective pressures. These environmental factors determine the effectiveness of the organism's traits for survival and reproduction.
Beneficial mutations increase an organism's fitness by giving it a competitive edge in its environment. This can lead to more offspring with the favorable trait. However, when environmental conditions change, what was once beneficial can become neutral or even detrimental to the organism's survival and reproduction, demonstrating the dynamic nature of natural selection.
On the contrary, deleterious mutations generally decrease an organism's fitness by negatively affecting its survival or reproduction. Under certain conditions, some deleterious traits can persist in a population, such as when they confer some advantage in specific scenarios, or due to genetic drift or inbreeding.
The variability of environments thus illustrates why more fit individuals are more likely to have more offspring, as their traits better serve the immediate selective conditions.