Lamarck was a French naturalist and author of a theory of evolution based on the inheritance of acquired characteristics. He argued, for example, that giraffes have long necks because their ancestors stretched their necks to reach the leaves on the highest branches of trees, resulting in offspring with longer necks.

We now know that giraffes have long necks because of the process of natural selection. Giraffes with longer necks had a reproductive advantage over giraffes with shorter necks. The latter did not produce as many offspring and eventually disappeared from the population. According to Lamarck’s theory, a bodybuilder would have a baby with more developed muscles than the average baby.

Darwin was the first to contradict Lamarck’s theory and thus explain how evolution actually works. We now understand that acquired traits are not passed on to future generations. Lamarck proposed that physical changes acquired by an individual over a lifetime could somehow impact its genes. Biologists have learned that genes determine the production of proteins and affect the physical changes in an individual, not the other way around. This is known as the Central Dogma of Biology.