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Evolution

MicroEvolution:• Change in allele

frequency • Hardy Weinberg

MacroEvolution: • Large scale change

among families • Speciation

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Phylogenetic Tree Galapagos Finches

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Evidence for MacroEvolution1.Fossils

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Fossil Missing Links

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Fossils Radioactive Carbon Dating

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Relative Dating

Can determine

Is performed by

Drawbacks

Absolute Dating

Comparing Relative and Absolute Dating of Fossils

Imprecision and limitations of age data

Difficulty of radioassay laboratory methods

Comparing depth of a fossil’s source stratum to the position of a reference fossil or rock

Determining the relative amounts of a radioactive isotope and nonradioactive isotope in a specimen

Age of fossil with respect to another rock or fossil (that is, older or younger)

Age of a fossil in years

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Evidence for MacroEvolution2. Comparative Anatomy

Homologous Structures and Divergent Evolution

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Vestigial Organs

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Evidence for MacroEvolution3. Comparative Embryology

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Evidence of MacroEvolution4. Comparative Biochemistry

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5 Agents of Evolutionary ChangeMutation

Gene FlowGenetic Drift

Selection Non-random mating

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Mechanism of MicroEvolution:1. Mutations

Might be harmful, neutral or beneficial; rate at which mutations arise at single loci is usually so low that mutations only result in very small deviations from Hardy Weinberg.

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Artificial Selection

2005-2006

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Darwin’s Theory on Evolution:2. Natural Selection

1.

2.

3.

4.

5.

6.

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Natural Selection in Action #1

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Natural Selection in Action #2

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Mechanism of MicroEvolution3. Sexual Selection

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Mechanisms of MicroEvolution4a. Genetic Drift (founder effect)

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Genetic Drift (founder effect)Blood Type Example

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Mechanism of MicroEvolution 4b. Genetic Drift (bottle neck effect)

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Mechanism of MicroEvolution5. Gene Flow

• immigrants• emigrants

Can decrease the genetic differences between populations counter acts natural selection and genetic drift

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Order of Evolution of Life on EarthEarly Earth was hot; atmosphere contained poisonous gases.

Earth cooled and oceans condensed.

Simple organic molecules may have formed in the oceans.

Small sequences of RNA may have formed and replicated.

First prokaryotes may have formed when RNA or DNA was enclosed.

Later prokaryotes were photosynthetic and produced oxygen.

An oxygenated atmosphere capped by the ozone layer.

First eukaryotes may have been communities of prokaryotes.

Multicellular eukaryotes evolved.

Sexual reproduction increased genetic variability, hastening evolution.

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Endosymbiosis Theory

Aerobic bacteria

Ancient Prokaryotes

Ancient Anaerobic Prokaryote

Primitive Aerobic Eukaryote

Primitive Photosynthetic Eukaryote

Chloroplast

Photosynthetic bacteria

Nuclear envelope evolving Mitochondrion

Plants and plantlike protists

Animals, fungi, and non-plantlike protists

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Graph of Free Oxygen

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