Biological Evidence of Evolution Ch 6 Sect 3

Evidence of Evolution Evolution of a population does not occur in a straight line. Living species that are closely related share a common ancestor.

Comparative Anatomy Is the study of similarities and differences among structures of living species. Homologous Structures are body parts of organisms that are similar in structure and position but different in function. Homologous structures suggest that different species are related.

Analogous Structures Analogous Structures are body parts that perform a similar function but differ in structure.

Vestigial Structures A vestigial structure is a body part that has lost its original function through evolution.

Developmental Biology Embryology is the science of the development of embryos from fertilization to birth. Studying embryos can also provide evidence that species are related. Ex. Pharyngeal Pouches

Molecular Biology Is the study of gene structure and function. Mutations in genes are the source of variations upon which natural selection acts. All organisms have DNA, this supports the idea that all organisms are related. Scientists study the proteins and genes to determine if organisms are related. Use molecular clock to estimate when species have diverged from common ancestors.

Study of Evolution Today Scientists differ on the rate at which natural selection produces new species. Diversity shows that genes can be reorganized and give rise to drastic changes in organisms.