Jean-Baptiste Lamarck proposed that organisms have the ability to inherit acquired characteristics. This means that changes an organism develops during its lifetime, due to its environment or use/disuse of certain organs, could be passed on to its offspring.

This theory, known as Lamarckism, is no longer considered scientifically valid. While we now know that acquired characteristics are not inherited, Lamarck's ideas paved the way for the development of the theory of evolution by natural selection.