Lamarckian inheritance

Lamarckian inheritance (or Lamarckism) was a theory developed by the French scientist Jean-Baptiste Lamarck in 1809 that stated the idea that the characteristics developed during an organisms lifetime could be passed onto their offspring by inheritance.

Lamarck created two laws to support his theory which were:

• The law of use and disuse
• The law that acquired traits are passed down by inheritance.

His “law of use and disuse” caused him debate the idea that organisms and life itself continued to grow and change continuously. Lamarck believed that as a habitat changed the organisms who lived there also adapted in order to survive in the new habitat. This theory supported the idea that if an organism began to use organs etc. that it usually never used then the organ would become larger and stronger over its lifetime. Similarly if an organism stopped using organs etc. as much as it used to then they would weaken and decrease in size before disappearing in the end. He even believed that organisms could make new organs or change an organ’s role within its body.

Lamarck's law of acquired traits stated that organisms started off simply and due to them having to changed due to differences in their environment they eventually evolved into more varigated organisms.

The example Lamarck used most often was giraffe's necks. He believed that as giraffe’s stretched their necks to reach leaves higher up on trees it caused their necks to lengthen. This was then inherited by their offspring, who continued to stretch their necks to reach leaves causing their necks to lengthen even more. This lengthening of a giraffe’s neck was, as before then carried on from generation to generation, with each extension of the giraffe’s neck being passed down to its offspring until you get the modern day giraffe with its long neck.

Study conducted in 2009 provides the experimental support forLamarckian theory of evolution was proposed by Larry A. Feig. In this research scientists focused on Long-Term Potential in mice, mechanism by which the connections between neuronal cells increases in strength and therefore improves the memory. During the experiment researchers intentionally produced genetically engineered mice with memory defect, this mice was raised up in an Enriched Environment that contained social interaction and different king of exercises. Enriched Environment affected the mice development and improved its memory. Second part of experiment involved the return of mice into ordinary conditions and mating it, to produce offspring. Results of study showed that second generation of mice had improved memory, despite the fact that it had a defect.