Evidence for Evolution

Evidence for Evolution - SBI4U0 EVIDENCE FOR EVOLUTION 1...

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SBI4U0 1 EVIDENCE FOR EVOLUTION Evidence for evolution shown by geographical distribution of living organisms, including the distribution of placental, marsupial and monotreme mammals. ~ 200 million yrs. ago, all continents were attached. 10 million yrs later, they started to break apart early mammals in existence were small and most likely nocturnal age of the dinosaurs Mammals - constant body temp, hair, mammary glands (provide young with milk) Monotreme - non-placental mammals, lay leathery eggs, eg duck-billed platypus Marsupial - female has ventral pouch surrounding nipples, premature young leave uterus crawl into pouch to complete development eg. Opossum and kangaroo Placental - mammals carry young in uterus until fully developed, placenta ensures efficient nutrition eg. Humans, mice Evidence to support evolution from reptiles to mammals made several times, independently. Evidence suggests marsupial and placental mammals shared a common ancestor Monotremes history unclear - they may have developed separately. Great reptiles disappeared suddenly and number of mammalian species greatly increased. They spread over the area available - marsupials found in S. America and Australia. These continents were attached via Antarctica and separated ~ 55 million years ago. Evidence to support this - fossil marsupial found in Antarctica, but no fossils of other mammals found there. Fossils - any form of preserved remains from a living organism. Examples: mammals frozen in Siberia mummies in acidic swamps in Scandinavia insects in amber (plant resin which became hard) bones in rocks Fossils only formed in a few cases (why fossil record is incomplete) most organisms do
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This note was uploaded on 02/05/2011 for the course PHYS 1010 taught by Professor Tomkirchner during the Spring '11 term at York University.

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Evidence for Evolution - SBI4U0 EVIDENCE FOR EVOLUTION 1...

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