Transcript ppt on Evidence for Evolution

• Darwin found convincing evidence for his ideas
in the results of artificial selection
–
The selective breeding of domesticated
plants and animals
Hundreds to thousands
of years of breeding
(artificial selection)
Ancestral dog (wolf)
Figure 13.2A
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Figure 13.2B
• Darwin proposed that living species
– Are descended from earlier life forms
and that natural selection is the
mechanism of evolution
African wild dog
Coyote
Wolf
Thousands to
millions of years
of natural selection
Figure 13.2C
Ancestral canine
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Fox
Jackal
Evidence for Evolution
How can we show that species have changed
through time?
How can we observe natural selection?
Fossil Record
Biogeography
Comparative Anatomy- Homologous
Structures & Analogous Structure
Comparative Embryology
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Fossil Record has strong evidence for evolution
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Fossil Record
Many fossils link early extinct species with current species
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Biogeography
• Biogeography, the geographic distribution of
species
– Suggested to Darwin that organisms
evolve from common ancestors
• Darwin noted that Galápagos animals
– Resembled species of the South
American mainland more than animals
on similar but distant islands
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Comparative Anatomy
Analogous & Homologous Structures
• Comparative anatomy
–
Is the comparison of body structures in different
species
–
May show common ancestry despite different
morphology (arm & fin)
• Homology
–
Is the similarity in characteristics that result from
common ancestry
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• Homologous structures
– Are features that often have different
functions but are structurally similar
because of common ancestry
Figure 13.4A
Human
Cat
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Whale
Bat
Comparative Embryology
• Comparative embryology
– Is the comparison of early stages of
development among different organisms
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Comparative Embryology
Many vertebrates
–
Have common embryonic structures
Pharyngeal
pouches
Post-anal
tail
Human embryo
Chick embryo
Figure 13.4B
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Molecular Biology as Evidence for Evolution
• Comparisons of DNA and amino acid sequences between different
organisms
• Reveal evolutionary relationships (common ancestry)
• homology has come to mean any similarity between characters
that is due to their shared ancestry (DNA seq., Protein seq.,etc.)
Amino Acid Sequence for
Human Insulin
malwmrllpl lallalwgpd paaafvnqhl
cgshlvealy lvcgergffy tpktrreaed
lqvgqvelgg gpgagslqpl alegslqkrg
iveqcctsic slyqlenycn
NCBI link
Table 13.4
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Development of pesticide resistance in insects
Chromosome with gene
conferring resistance
to pesticide
Pesticide application
Survivor
Additional
applications of the
same pesticide will
be less effective, and
the frequency of
resistant insects in
the population
will grow
Figure 13.5B
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings