Evolution Introduction https www youtube comwatch vYg Hrn
Evolution Introduction https: //www. youtube. com/watch? v=Yg. Hrn 2 VFbvo
Varieties of life forms Figure 1. 4 C-F
Clown, Fool, or Well Adapted? • 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 through water at high speeds
• A streamlined shape, large tail, and nostrils that close are useful for diving – Specialized salt-secreting glands manage salt intake while at sea
Evolution explains the unity and diversity of life • Charles Darwin synthesized the Theory of Evolution by natural selection • Theory vs hypothesis • Evolution is the core theme of biology
The voyage of the Beagle Great Britain Europe North America Pacific Ocean Atlantic Ocean Africa Galápagos Islands South America Equator Andes Cape of Good Hope Australia Tierra del Fuego Cape Horn New Zealand Tasmania
Prevalent ideas at Darwin’s time • species are fixed • Earth is about 6, 000 yrs old
New ideas proposed Georges Cuvier: Fossils indicated the earth was very old
New ideas proposed Charles Lyell: Lyell, a geologist, argued that land forms changed constantly.
New ideas proposed Jean Baptiste Lamarck: 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
Darwin proposed natural selection as the mechanism of evolution • Darwin observed that: • organisms produce more offspring than the environment can support • organisms vary in many characteristics • these variations can be inherited
• Alfred Wallace Man with beard • Charles Darwin, 1874 Man with longer beard
• Darwin cartoon
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
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