Natural Selection Life’s diversity and connections

Evolution A change over a period of time A collection of facts, observations and hypotheses about the history of life

Diversity What scientific process accounts for: –The millions of species alive on earth now –The hundreds of millions of species that are extinct –No two individuals are exactly alike (with few exceptions) –The molecular instructions for life are the same

Answer started in December 1831 The voyage of the Beagle its five year mission to boldly go where no man has gone (sorry). It was a surveying trip Naturalist on board: Charles Darwin

Evidence of diversity Darwin made collections everywhere they stopped Identified a few specimens on board, but sent most back to England for experts to identify Collected many fossils everywhere they stopped if possible

Evidence of diversity Noticed that traits and behavior together help organisms adapt to where they live Individuals must be able to survive and reproduce to be successful

Evidence of diversity Technical terms for all this: living diversity (the variety of living things), fossil diversity (the variety of fossilized creatures), ADAPTATION (the physical and behavioral traits that enable organisms to survive), FITNESS ( the ability of an individual to survive and pass on genes to its offspring)

The Galapagos Islands Last stop before the long trip across the Pacific (see map page 451) Darwin attempts to reconcile: –Believe vs. observation –Evidence of diversity vs. genesis –Evidence of fossils and geology vs. constant earth –Malthus’s evidence of reproductive success –Anatomy evidence of homologous structures and vestigial structures

Others thinking about change Hutton and Lyell –Geology Lamarck –Biology Malthus –Biology