Lamarckism

Lamarckism (or Lamarckian inheritance) is the hypothesis that an organism can pass on characteristics that it has acquired through use or disuse during its lifetime to its offspring. It is also known as the inheritance of acquired characteristics or soft inheritance. It is inaccurately named after the French biologist Jean-Baptiste Lamarck (1744–1829), who incorporated the action of soft inheritance into his evolutionary theories as a supplement to his concept of orthogenesis, a drive towards complexity.

The theory is cited in textbooks and popular works to contrast with Darwinism since the late 19th century. Many researchers from the 1860s onwards attempted to find evidence for Lamarckian inheritance, but these have been explained as being misunderstood or misrepresented.

History

Lamarckism was named after the French biologist Jean-Baptiste Lamarck, who in his 1809 work Philosophie Zoologique proposed that an organism could pass on characteristics that it had acquired during its lifetime to its offspring, also known as heritability of acquired characteristics or soft inheritance. He incorporated this mechanism into his theories of evolution, as a supplement to his concept of orthogenesis, a perceived inherent drive in organisms towards increasing complexity and perfection.

Lamarck's Theory

Lamarck's theory of evolution consists of two main ideas. The first is the idea that body parts used more often become stronger and larger, while those not used slowly waste away and disappear. The second is the idea that changes acquired or lost during the life of an organism are passed on to the offspring.

Criticism and Decline

Lamarck's theories were largely ignored or criticized during his lifetime, and they were subsequently overshadowed by Darwin's theory of natural selection. The idea of inheritance of acquired characteristics has been shown to be incorrect in the light of modern genetic theory.

Modern Views

Modern views in epigenetics, genetics and evolutionary developmental biology have sparked renewed interest in Lamarckism. Some, such as Eva Jablonka and Marion J. Lamb, argue that there must be some sort of Lamarckian mechanism in cells due to the apparent inheritance of acquired traits, but this is a controversial view.

See Also

• Epigenetics
• Orthogenesis
• Darwinism
• Evolution

References

Lamarckism Resources
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