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topic3-evidence for Evolution

Time scientific evidence supports two modes of

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Unformatted text preview: humans -scare of polar bears Silver Do other species change over time? •  Scientific evidence supports two modes of evolution: –  Microevolution: small evolutionary changes within species or populations –  Macroevolution: referring to larger phenotypic changes sufficient to place an organism in a different higher level taxon (eg phylum). Over time, microevolution results in macroevolutionary differences Evidence for Descent with Modification, Direct Observation of Change: Soapberry Bugs those collected form the flat tree grew short beaks regardless of what plants they were reared on -confirms evolution sibling species host shift in the 1920s and as a result the soapberry bugs have a much shorter "beak" Text pages 40 and 41 -not a basis for evolutionary GENETIC change -simple environmental variation Direct Observation: House Sparrows •  Introduced into North America from Europe in 1852 •  Rapidly Spread Across North America •  Populations have evolved differences in body size and coloration since that time Example: House sparrow Evidence for Descent with Modification: Vestigial Structures and Organs rudimentary useless structures (BUT can have a use in other closely related species) -flightless bird but has vestigial wings Rubber Boa: Vestigial Limbs Apteryx mantelli: a flightless bird Evidence for Descent with Modification: Vestigial Structures and Organs still give us goosebumps Human Coccyx: Vestigial Tailbone Treating Evolution as a...
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