E volution Thursday 10/24/13. Charles Darwin influences on his thinking // decent with modification evolution by natural selection overview Evidence of Evolution fossil record biogeography comparative anatomy // embryology molecular biology
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Darwin’s voyage on HMS Beagle 1831-1836
see fig 27.1
Based on observations during his travels and subsequent research/experimentation, Darwin proposed a theory to explain how and why populations change over time:
Wrote manuscript – “Origin of Species” in 1844 – not published until 1858
w/in a decade - widely accept that evolution occurs
Darwin made two main points in The Origin of Species:
(b) A Trinidad tree mantid that mimics dead leaves
(a) A flower mantid in Malaysia
(c) A leaf mantid in Costa Rica
Think about “artificial selection”
Rivers bring sediment to the ocean. Sedimentary rocks containing fossils form on the ocean floor.
Over time, additional strata are added, containing fossils from each time period.
As sea levels change and the seafloor is pushed upward, sedimentary rocks are exposed. Erosion by rivers reveals strata; deeper strata contain older fossils.
Younger stratum with more recent fossils
Older stratum with older fossils
present day South American armadillo
extinct - found in fossil record
see fig 27.7
see fig 27.8
Comparative embryology of vertebrates supports evolutionary theory
relative similarity between CytochromeC structure (protein used in ETC)
Peter and Rosemary Grant
Researchers at Princeton, began studying the finches in the 70’s
Geospiza fortis –
Medium Ground Finch
Medium Ground Finch
Over 20 months 84% disappeared before breeding
Evidence of Evolution
see fig 27.11