Unit 5 Evolution Evidence of Evolution

Evidence 1 Fossil: impression of dead organism made on a surface Types: Mold: imprint on surface in shape of organism Cast: mold that has been filled w/minerals to form a model

Australia

Distribution of Fossils Law of superposition: layers of materials accumulated on the organism Bottom layer = oldest Top layer = youngest

Succession of forms 1. Extinction 2. Mass extinction: large population of species disappear in a short period of time Reasons:

Evidence 2 Homologous structures: structures that are similar in different species May have common ancestor Different functions Example:

Evidence 2 Analogous structures: structures of different species that have same function Look similar May not have common ancestor Example:

Homologous and Analogous

Analogous Structures

Evidence 2 Vestigial organ: existing structures used by ancestors but not by current species Example:

Evidence 3 Embryology: Embryo: first stage of developing organism All vertebrates show similar features in embryo stage

Evidence 4 Macromolecules: Amino Acid and DNA sequences are similar for certain species -Common ancestor

Patterns of Evolution Coevolution: different species adapt over time with one another can be btwn species of mutualism Example:

Coevolution

Patterns of Evolution Convergent Evolution: species not closely related adapt similar traits to their environment separately Analogous structures result Phenotypes converge Example:

Patterns of Evolution Divergent Evolution: 2 or more related species become more different over time Different habitats Adaptive radiation: arise from 1 common ancestor Example: Artificial selection: diverging due to unnatural occurrences