For natural selection to occur, adaptive traits must be inheritable. This means that change occurs at the level of DNA. Answer the following question with this in mind

Question

a. How do new traits develop?
b. How may the genetic changes contribute to evolution by natural selection?
c. How can the degree of similarity in DNA or protein sequence be used to infer the degree of relatedness between species?

Answer 1

a. New traits develop through the process of gene mutations. When a mutation occurs, it may result in an adaptive allele. Genes that are not conserved are the basis of major phenotypic differences that define species.
b. When a mutation occurs that results in an adaptive trait, this contributes to natural selection with the adaptive allele being passed on to future generations. As stated in Table 16.1: A certain form of a shared trait may make its bearer better able to survive and individuals of a population that are better able to survive tend to leave more offspring. Thus, an allele associated with an adaptive trait tends to become more
common in a population over time.
c. The more recently two lineages diverged, the less time there has been for unique mutations to accumulate in the DNA of each one. That is why the genomes of closely related species tend to be more similar than those of distantly related ones—a general rule that can be used to estimate relative times of divergence.