Perspective on Lonely Earth

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Perspective on Lonely Earth gt 100 billion
galaxies Each, including the Milky Way Galaxy,
with gt 100 billion stars Our solar system is on
the periphery of our galaxy
Origin condensation Hypothesis Time of origin
estimated At 4.56 Bya. Substantiated by ages of
meteorites and moon rocks. Solar
nebula Planetary system
Solid rock
Frozen gases
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Solid
Rock
Fluid
Lithosphere rigid plates rocky crust upper
mantle Asthenosphere mantle layer
below Lithosphere Plastic permits movement of
plates
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Crust thickness varies
A section of Earth's crust
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Relative dating of fossils
Nineteenth century illustration of a table of
stratified rocks
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Know the eons
Geological ages and associated organic events
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Radiometric (absolute) dating of fossils
Radioactive isotopes used in dating
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Immune from environmental changes
Theoretical relationship between duration of time
in millions of years and the proportion of the
original 238U isotope that remains in a rock
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Continental drift and evolution Alfred
Wagener 1912-1930 Not accepted until 1960s
Evidence matched fit between the offshore
continental shelves
(From Eicher, D.L., and A.L. McAlester, 1980.
History of the Earth. Reprinted by permission of
Prentice Hall.)
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Distribution of various fossil plants and animals
throughout Gondwanan continents.
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The force new ocean floor emerging from
mid-oceanic ridges
Diagrammatic sections through an oceanic ridge
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Continental drift
Lungfishes gt 400 mya
Triassic Period
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Jurassic Period
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Cretaceous Period
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Tertiary Period
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The major geological plates and their boundaries
(From Cosmos, Earth and Man A Short History of
the Universe by P. Cloud, 1978, Fig. 11, p. 82.
Reprinted by permission.)
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Plate collisions
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Plate tectonics and mammalian evolution
Prototheria (monotremes)
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Metatheria (marsupials)
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Eutheria (placentals)
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Effect of continental drift on the dispersion and
isolation of major lineages of mammals.