Evolution

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Slide 80

Evidence for Evolution – Evolution Observed

Slide 81

Evidence for Evolution – Evolution Observed

Selection against small guppies results in an increase in average size

Slide 82

Evolutionary Time Scales

Macroevolution: Long time scale events that create and destroy species.

Slide 83

Microevolution:

Short time scale events (generation-to-generation) that change the genotypes and phenotypes of populations

Evolutionary Time Scales

Slide 84

Evidence of Evolution

Key Concept

Darwin Argued That Living Things Have Been Evolving On Earth For Millions of Years. Evidence For This Process Could Be Found In:

The Fossil Record

The Geographical Distribution of Living Species

Homologous Structures of Living Organisms

Similarities In Early Development

Slide 85

Fossil Record

Earth is Billions of Years Old

Fossils In Different Layers of Rock (sedimentary Rock Strata) Showed Evidence Of Gradual Change Over Time

Slide 86

Geographic Distribution of Living Species

Different Animals On Different Continents But Similar Adaptations To Shared Environments

Slide 87

Homologous Body Structures

Scientists Noticed Animals With Backbones (Vertebrates) Had Similar Bone Structure

May Differ In Form or Function

Limb Bones Develop In Similar Patterns

Arms, Wings, Legs, Flippers

Slide 88

Homologous Body Structures

Structures That Have Different Mature Forms But Develop From The Same Embryonic Tissues

Strong Evidence That All Four-Limbed Animals With Backbones Descended, With Modification, From A Common Ancestor

Help Scientist Group Animals

Slide 89

Homologous Body Structures

Slide 90

Homologous Body Structures

Not All Serve Important Functions

Vestigial Organs

Appendix In Man

Legs On Skinks

Slide 91

Similarities In Early Development