Early Ideas on Early Ideas on Evolution Evolution

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Evolutionary TimelineEvolutionary Timeline

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Carolus Linnaeus – first to group similar organisms and assign them Latin names (taxonomic classification system)

Two word name (Genus species)

Known as binomial nomenclature

Originally believed all organisms were fixed and did not change; did not believe that living species could evolve from a common ancestor 3

James Hutton - Scottish geologist

Described the geological forces that have changed life on Earth over millions of years (erosion, earthquakes, volcanoes, mountain building)Changes in Earth’s crust due to slow continuous processesIdea known as GradualismThese changes caused certain species of life to become extinct.

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Thomas Malthus – economist who said that, in nature, plants and animals produce far more offspring than can survive

Poverty, famine, disease result from overpopulation

Darwin would eventually use this idea to help explain natural selection and survival of the fittest 5

Jean-Baptiste Lamarck – French naturalist that proposed that all organisms evolved toward complexity and perfection

Stated that changes are adaptations to environment acquired in an organism’s lifetime

Said acquired changes were passed to offspring

Example – bird ancestors desired to fly so they tried until wings developed 6

Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution Inheritance of Acquired Characteristics

Proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime.

Those traits could then be passed on to their offspring.

Over time, this leads to new species.

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Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution

Use & Disuse - Organisms Could Change The Size Or Shape Of Organs By Using Them Or Not Using Them

Giraffe’s neck got longer from stretching

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Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolutionInheritance Of Acquired Traits◦Traits Acquired During Ones Lifetime Would Be Passed To Offspring

10Clipped ears of dogs could be passed to offspring!

Lamarck’s MistakesLamarck’s MistakesLamarck Did NOT Know how traits were inherited (Traits are passed through genes)

Genes Are NOT Changed By Activities In Life.

Change Through Mutation Occurs Before An Organism Is Born.

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Charles Lyell – geologist; published Principles of Geology which advanced and popularized ideas of Hutton

Proposed theory of Uniformitarianism

Geological processes occuring at a uniform rate were responsible for building & wearing down Earth’s crust

Proposed that the Earth was millions of years instead of a few thousand years old

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Georges Buffon – studied fossils to propose that species shared ancestors instead of arising separately

Species were created, but were not perfectly adapted and gradually changed over generations by “degenerating” from the forms given to them by God

Had no suggestion for how these changes occurred 13

Alfred Russel Wallace -if an animal has some trait that helps it to withstand the elements or to breed more successfully, it may leave more offspring behind than others; the trait will become more common in the following generation, and the generation after that (natural selection)

Considered Darwin’s “co-discoverer” of evolution by natural selection

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