Transcript Evidence for Evolution

The Evidence for Evolution
Chapter 22
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Darwin’s Finches
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Peppered Moths and Industrial Melanism
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Selection Against Melanism
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Artificial Selection
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Agriculture
– corn kernel characteristics
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Artificial Selection
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Domestication
– breeds and characteristics of dogs
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Evidence for Evolution
The Fossil Record
Anatomical Record
Molecular Record
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History of Life
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The Evolution of Horses
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Modern members of Equidae (horses, zebras, donkeys) are
descendents of a lineage originating in the Eocene period 55 mya.
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The earliest known members were species in genus Hyracotherium.
 small size
 multiple toes
 small, simple teeth
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The Anatomical Record
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Homology
– structures with different appearances and
functions that all derived from a common
ancestor
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Development
different organisms exhibit similar
embryological forms
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The Anatomical Record
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Vestigial structures
– organs with no apparent modern function,
but resemble ancestral structures
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The Molecular Record
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Distantly related organisms are expected to
accumulate a greater number of evolutionary
differences than closely related species.
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Convergent Evolution
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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
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Convergent Evolution
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Darwin’s Critics
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there are no fossil intermediates
natural selection does not imply evolution
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Summary
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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
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