Unit 5 EvolutionUnit 5 EvolutionEvidence of Evolution

Evidence 1Evidence 1

Fossil: impression of dead organism made on a surface

Types:Mold: imprint on surface in shape of

organismCast: mold that has been filled

w/minerals to form a model

AustraliaAustralia

Distribution of FossilsDistribution of Fossils

Law of superposition: layers of materials accumulated on the organism

Bottom layer = oldestTop layer = youngest

Succession of formsSuccession of forms

1. Extinction2. Mass extinction: large population

of species disappear in a short period of time

a. Reasons:

Evidence 2Evidence 2

1. Homologous structures: structures that are similar in different species

a. May have common ancestorb. Different functionsc. Example:

Evidence 2Evidence 2

2. Analogous structures: structures of different species that have same function

a. Look similarb. May not have common ancestorc. Example:

Homologous and Homologous and AnalogousAnalogous

Analogous StructuresAnalogous Structures

Evidence 2Evidence 2

3. Vestigial organ: existing structures used by ancestors but not by current species

a. Example:

Evidence 3Evidence 3

Embryology: a. Embryo: first stage of developing

organismb. All vertebrates show similar

features in embryo stage

Evidence 4Evidence 4

Macromolecules:a. Amino Acid and DNA sequences

are similar for certain species-Common ancestor

Patterns of EvolutionPatterns of Evolution

1. Coevolution: different species adapt over time with one another- can be btwn species of mutualism- Example:

CoevolutionCoevolution

Patterns of EvolutionPatterns of Evolution

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

Patterns of EvolutionPatterns of Evolution

3. Divergent Evolution: 2 or more related species become more different over timea. Different habitatsb. Adaptive radiation: arise from 1

common ancestor1. Example:

c. Artificial selection: diverging due to unnatural occurrences1. Example: