Final answer:
Heritability is a measure of how much phenotypic variation is due to genetic differences in a population, not a fixed value applicable across all environments. It shows the potential for evolutionary change, but does not determine individual development and is not a prediction of an outcome.
Step-by-step explanation:
The statement "heritability is not an absolute measure" means that heritability, which is the fraction of phenotype variation attributable to genetic differences among individuals in a population, does not provide a fixed value that can be applied universally across all environments and contexts. Heritability is a population-specific measure and depends on both genetic variance and environmental variance. Importantly, it indicates the potential for a trait to evolve under selection, but it is not a measure of how much of a trait is caused by genes in any one individual, nor is it an indication that a trait is unchangeable.
In the context of evolution, heritability plays a key role as it signifies the amount of phenotypic variation that can respond to natural selection. However, the concept of relative fitness is also integral as it reflects an individual's reproductive success in comparison with others in the population. No organism is perfect, and natural selection can only work with existing genetic variation and new alleles that arise.
Findings from studies such as the Minnesota Study of Twins Reared Apart have shown that traits like personality can have a significant heritability ratio, suggesting a strong genetic influence. However, these traits result from the intricate interplay of multiple genes and epigenetic factors, not from single genetic determinants.