1

The Evidence for Evolution

Chapter 22

2

Darwin’s Finches

3

Peppered Moths and Industrial Melanism

4

Selection Against Melanism

5

Artificial Selection

• Agriculture– corn kernel characteristics

6

Artificial Selection

• Domestication– breeds and characteristics of dogs

7

Evidence for Evolution

The Fossil Record

Anatomical Record

Molecular Record

8

History of Life

9

The Evolution of Horses

• Modern members of Equidae (horses, zebras, donkeys) are descendents of a lineage originating in the Eocene period 55 mya.

– The earliest known members were species in genus Hyracotherium. small size multiple toes small, simple teeth

10

The Anatomical Record

• Homology– structures with different appearances and

functions that all derived from a common ancestor

– Development– different organisms exhibit similar

embryological forms

11

The Anatomical Record

• Vestigial structures– organs with no apparent modern function,

but resemble ancestral structures

12

The Molecular Record

• Distantly related organisms are expected to accumulate a greater number of evolutionary differences than closely related species.

13

Convergent Evolution

• Convergent evolution - selection that favors changes making two or more groups more similar

– similar solutions to similar problems

• Divergent evolution - selection that favors changes making two or more groups less similar

– exposure to different selective pressures

14

Convergent Evolution

15

Darwin’s Critics

• there are no fossil intermediates• natural selection does not imply evolution

16

Summary

• Beaks of Darwin’s Finches• Peppered Moths and Industrial Melanism• Artificial Selection• The Fossil Record• The Anatomical Record• The Molecular Record• Convergent and Divergent Evolution