His theory, known as Lamarckism, proposed that:
* Use and Disuse: Organisms develop traits during their lifetime based on their use or disuse of certain body parts.
* Inheritance of Acquired Traits: These acquired traits are then passed on to their offspring.
For example, Lamarck believed that giraffes developed their long necks because they stretched to reach leaves high in trees. This stretching, he argued, was then inherited by their offspring.
However, Lamarck's theory has been largely disproven by modern genetics. We now know that acquired traits are generally not passed on to offspring. Changes in a species over time are primarily driven by natural selection acting on genetic variations already present within a population.
