CHAPTER 15 Tracing Evolutionary History

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CHAPTER 15Tracing Evolutionary History

• Modules 15.1 15.14

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The fossil record chronicles macroevolution
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The actual ages of rocks and fossils mark
geologic time
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The Study of Fossils is Very Important Evidence
for Evolution
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Some examples of Fossils
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How do we know this?

• age of earth confirmed by radiometric dating

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Plate Tectonics
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• This movement has influenced the distribution of
  organisms and greatly affected the history of life

CENOZOIC
Eurasia
North America
Africa
India
SouthAmerica
Australia
Antarctica
Laurasia
Millions of years ago
MESOZOIC
Gondwana
Pangaea
PALEOZOIC
Figure 15.3B
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Mass extinctions opened up new niches
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• Continental drift explains the distribution of
  lungfishes

Figure 15.3C
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• The movements of Earths crustal plates, are also
  associated with volcanoes and earthquakes -

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Mass extinctions were followed by diversification
of life-forms
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• Every mass extinction reduced the diversity of
  life

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Key adaptations may enable species to
proliferate after mass extinctions
Figure 15.6
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Evo-devo Genes that control development play a
major role in evolution
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• Paedomorphosis,

Chimpanzee fetus
Chimpanzee adult
Figure 15.7A, B
Human fetus
Human adult
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• Stephen Jay Gould argued that there was a
  connection between our juvenile physical traits
  and our long period of dependency

Figure 15.7C
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Evolutionary trends do not mean that evolution is
directed toward a goal
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Classical systematics

• Systematics has a long history it predates
  Darwin

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Phylogeny
Systematists classify organisms by phylogeny
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Hierarchy of organization
Specific epithet
Species Felis catus
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• Taxonomists often debate

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Feliscatus(domesticcat)
Mephitismephitis(stripedskunk)
Lutralutra(Europeanotter)
Canisfamiliaris(domesticdog)
Canislupus(wolf)
SPECIES
GENUS
Felis
Mephitis
Lutra
Canis
FAMILY
Canidae
Mustelidae
Felidae
ORDER
Carnivora
Figure 15.10
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Homology indicates common ancestry, but analogy
does not
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Homology
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Figure 15.11
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Phylogenetic classification
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Cladistics
Cladogram
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In Cladistics

• The importance of different traits or
  characteristics depends on which evolved earlier

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• Cladistic analysis is often a search for the
  simplest hypotheses about phylogeny

Lizards
Snakes
Crocodiles
Birds
Lizards
Snakes
Crocodiles
Birds
Figure 15.13B, C
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Molecular biology and systematics
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Arranging life into kingdoms is a work in
progress
MONERA
PROTISTA
PLANTAE
FUNGI
ANIMALIA
Earliestorganisms
Figure 15.14A
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• A newer system recognizes two basically
  distinctive groups of prokaryotes

BACTERIA
ARCHAEA
EUKARYA
Earliestorganisms
Figure 15.14B