–varieties of life forms figure 1.4c-f. all organisms have evolutionary adaptations –inherited...
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– Varieties of life forms
Figure 1.4C-F
• All organisms have evolutionary adaptations– Inherited characteristics that enhance their
ability to survive and reproduce
• blue-footed booby
• Large, webbed feet help propel the bird throughwater at high speeds
Clown, Fool, or Well Adapted?
– A streamlined shape, large tail, and nostrils that close are useful for diving
– Specialized salt-secreting glands manage salt intake while at sea
• Charles Darwin synthesized the Theory of Evolution by natural selection– Theory vs hypothesis
• Evolution is the core theme of biology
Evolution explains the unity and diversity of
life
Figure 1.6A
• The voyage of the Beagle
Figure 13.1B
NorthAmerica
Great Britain Europe
Africa
Equator
Australia
Tasmania
NewZealand
Cape ofGood Hope
SouthAmerica
An
des
Cape Horn
Tierra del Fuego
GalápagosIslands
PacificOcean
AtlanticOcean
• species are fixed• Earth is about 6,ooo yrs old
Prevalent ideas at Darwin’s time
New ideas proposed• Fossils indicated the earth was very old
• Lyell, a geologist, argued that land forms changed constantly.
• Lamarck proposed that organisms changed and these changes were passed to progeny.
• Darwin became convinced that the Earth was old and continually changing
– He concluded that living things also change, or evolve over generations
– He also stated that living species descended from earlier life-forms: descent with modification
• Mex. marine snail shells on high mtns
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Darwin observed that
– organisms produce more offspring than the environment can support
– organisms vary in many characteristics
– these variations can be inherited
Darwin proposed natural selection as the mechanism of evolution
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Darwin concluded that individuals best suited for an environment are more likely to survive and reproduce than those less well adapted– As a result, the proportion of individuals with favorable characteristics increases
– Populations gradually change in response to the environment
• natural selection explains the mechanism of evolution
Figure 1.6B
(1) Population with varied inherited traits
(2) Elimination of individuals with certain traits
(3) Reproduction of survivors
Pesticide-resistant insects
Antibiotic-resistant bacteria
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Charles Darwin, 1874
Figure 13.1x2
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Alfred Wallace
Figure 13.1x6
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Darwin cartoon
Figure 13.1x3
• Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the reproductive success of some individuals over others–Natural selection is the editing mechanism
–Evolution is based on adaptations
Figure 1.6C
– Hominid skull
Fossils provide strong evidence for evolution
Figure 13.2A, B
– Petrified trees
– Ammonite casts
– Fossilized organic matter in a leaf
Figure 13.2C, D
– Scorpion in amber
– “Ice Man”– acid bogs
Figure 13.2E, F
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Mammoth tusks
Figure 13.2x4
• fossils show that organisms have appeared in a historical sequence
• Many fossils link early extinct species with species living today– hind leg bones of
fossil whales
Figure 13.2G, H
– Biogeography– Comparative
anatomy– Comparative
embryology
Other evidence for evolution
Figure 13.3A
Human Cat Whale Bat
– Molecular biology - protein “clocks”
Figure 13.3B
Human Rhesus monkey Mouse Chicken Frog Lamprey
Last commonancestor lived26 million yearsago (MYA),based onfossil evidence
80 MYA
275 MYA
330 MYA
450 MYA
Figure 15.8
No predestined goal of evolution