Final answer:
Lamarck proposed the theory of inheritance of acquired characteristics, suggesting that traits acquired by individuals can be passed on to their offspring. However, this theory was later disproven by scientific evidence.
Step-by-step explanation:
Lamarck proposed the theory of inheritance of acquired characteristics, which suggests that traits acquired by individuals through use or disuse could be passed on to their offspring, leading to evolutionary change in the population. According to Lamarck, individuals more fit to their environment would be more likely to survive, reproduce, and pass on their genes.
His theory suggested that as organisms used different parts of their body or underwent changes due to the environment, those changes would be passed down to the next generation. For example, Lamarck believed that the long neck of a giraffe resulted from generations of giraffes continually stretching their necks to reach leaves at the tops of trees.
However, it is important to note that Lamarck's theory was later disproven by scientific evidence, and the theory of evolution was further developed by Charles Darwin through natural selection.