5-6 BIOL 1001 Intro Evolution Hist Evolnary Thought (Jan. 16 18) post-lecture

Heredity inference 3 dierences in survival reproduc2on

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Unformatted text preview: Principle of PopulaAon Struggle for existence… •  Popula2ons grow geometrically •  Food supplies grow arithme6cally How evolu2on occurs…Darwin’s ‘Eureka!’ (Populations) (Food supplies) Compe22on for resources The same principle applies to all species!!! The same principle applies to all species!!! Charles Darwin Alfred Russel Wallace Compe22on for resources Not or resources Compe22on f everyone survives  ­ so who does? Not everyone survives  ­ so who does? In struggle for existence, survival & reproduc2on not pure chance. Those with favourable traits fare beGer 34 Observa6on 1: Popula2ons have the poten2al to increase exponen2ally BUT Observa6on 2: Popula2ons generally remain stable once they reach a certain size AND Observa6on 3: Natural resources are limited Darwin’s Inferences & Observa2ons (compiled by Mayr) Inference 1: Not all offspring that are produced survive & reproduce, b/c of a struggle for resources. Ecology AND Observa6on 4: Individuals in a popula2on are not iden2cal; they vary in many characteris2cs AND Observa6on 5: Many characteris2cs are heritable (i.e., are passed on from parent to offspring) Inference 2: Some individuals are more likely to survive & reproduce than others b/c of their heritable traits. Heredity Inference 3: Differences in survival & reproduc2on among individuals are non ­random, with some traits being passed on at a higher ra2o than others & increasing in propor2on in the popula2on from one genera2on to the next. Evolu6on by natural selec6on! Taken from Gregory (2009) Evolu2on as Darwin saw it… Paoern component of theory of evolu...
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This note was uploaded on 03/03/2013 for the course BIOL 1001 taught by Professor Dr.kelly during the Spring '13 term at York University.

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