7.2 - Charles Darwin

artificial selection

humans selectively breed plants/animals for desired traits

provided Darwin with analogy for natty selection

charles Darwin

english naturalist - evolutionary theory

joined 5 yr voyage on HMS Beagle

voyage on HMS Beagle

read Lyell’s Principles of Geology - influenced uniformitarianism

studied fossils and noted small differences between species

galapagos finches different beak shapes for food sources

post voyage insights

respected scientist

read Lamarck, Malthus, and Erasmus Darwin

natural variation - size, color, etc

artifical selection ←→natural selection

Malthus influence

struggle for existence due to limited resources

concept traits that aid survival are passed on, less beneficial ones diminish

tree of life

1837 darwin diagrammed life history as a tree

different from lamarck’s ladder

species split into new species with enviornmental changes and natural selection

alfred Russel Wallace

independently developed similar ideas on natural selection

1858 shared theories with public - Collab w Darwin

early scientific challenges

limited knowledge of genetics, biochemistry, molecular bio

August weismann (1893) germ-plasm theory - inheritence via repro cells

disproved lamarck’s idea of aquired traits inherited

gregor mendel (1866)

laws of inheritance

thomas hunt morgan (1933)

chroms as base of inheritance

modern synthesis

unified darwin’s natty selection with genetics

random mutation, natty selection, common descent

random mutation

variation in species occurs via DNa mutations

common descent

all life is related through evolutionary processes over time