Lamrack’s HypothesisUse and Disuse

Inheritance and Acquired characteristics

ByBo No.22Lita No.24MEP 611

Lamarck started his scientific career as a botanist, but in 1793 he became one of the founding professors of the Musee National d'Histoire Naturelle as an expert on invertebrates. His work on classifying worms, spiders, molluscs, and other boneless creatures was far ahead of his time.

Use and Disuse• He proposed that if an organ is used a lot it will

develop and strengthen • If it is not used it will atrophy• He called this the law of use and disuse

Inheritance and acquired characteristics

• if an organism developed a characteristic feature through adapting to a new way of life during its lifetime, it would pass this on to its offspring

• The classic example given is that of the giraffe’s neck• As the giraffe’s ancestors searched for a richer food

supply they stretched to reach higher branches in trees

• Thus their stretched bodies were passed onto their offspring

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