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Lamarck and the Pre-Darwin Evolution Theory

Explore Jean Lamarck's evolutionary theory before Darwin's time, focusing on inherited acquired characteristics, illustrated by the salamander's evolution into snakes. Learn about the early understanding of homologous and vestigial structures and the search for a unifying explanation of evolution.

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Lamarck and the Pre-Darwin Evolution Theory

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  1. Theory of Evolution

  2. Before Darwin • At the beginning of the 1800s, scientists knew of some kinds of fossils and were aware of homologous and vestigial structures • Many scientists suspected some type of evolution had given rise to living things around them, but they had no unifying theory to explain how it happened • Before Charles Darwin, Jean Lamarck presented the first theory of evolution

  3. Jean Lamarck • In 1809, French scientist Jean Lamarck put forth the first systematic presentation of evolution • Lamarck described a mechanism by which he believed evolution could occur • The mechanism was known as “the inheritance of acquired characteristics”

  4. Lamarck argued that salamanders living in grasslands had a hard time walking due to short legs not being able to trample tall grass/reach the ground • Over time, the salamanders began to slither on their bellies and their leg muscles wasted away from disuse and legs became small • Lamarck’s theory said the trait was passed on to the offspring and in time, salamanders legs became so rarely used that they disappeared • Legless salamanders (snakes) evolved from salamanders by inheriting the acquired characteristic of having no legs • Lamarck’s theory failed to catch on because he presented no experimental evidence or observations

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