1. Ch. 23: Evolution Evolutionary Changes

2. Types Fossil Record Biogeography Convergent Evolution Selective Breeding Homologies Anatomical Developmental Molecular

3. Fossil Record Shows timeline of successive evolutionary change Transitional fossils Intermediate states Exhibit characteristics of ancestors as well as descendants

5. Biogeography Geographic distribution of species Extinct and living Reveal patterns of evolution Endemic Species Found only in a particular location Isolated

6. Convergent Evolution Organisms with similar characteristics that are not evolutionarily related Similar environments with similar adaptive pressures. Suggests adaptation as an evolutionary force Similar features are termed analogous structures (convergent traits)

7. Selective Breeding Human Controlled Called “artificial selection” Human breeders determine reproduction Surviving traits are human-desired Augmentation of already present genetic variation

8. Homologies Similar traits between two species Descent from a common ancestor Featured observed Anatomical Homologies Developmental Homologies Molecular Homologies

9. Anatomical Homologies Observations of anatomical structures between species Similar patterns exhibited within features Homologous Structures Same traits may be modified for different functions in successive species

10. Vestigial Structures Structures resembling those of a species’ ancestors but lacking a function in the species itself. Evolutionary relics Structures were functional in ancestral species, but lost function as the species changed lifestyle Structure does not disappear but is degenerated by mutations

11. Developmental Homologies Species that appear very differently as adults can bear striking similarities in the embryonic stage Similarities are temporary and are lost during development. Traits indicate evolutionary ancestors

12. Molecular Homologies Observations of features at the molecular level All organisms use DNA as genetic material RNA carries information for proteins as functional products Certain biochemical pathways are universal These features arose very early in the history of life Analysis of genetic sequences reveals evolutionary relatedness Closest relatives have higher percentage of identical sequences