What did lamarck propose the species evolve?

Jean-Baptiste Lamarck proposed that species evolve through the inheritance of acquired characteristics, a concept known as Lamarckism. He suggested that organisms adapt to their environments during their lifetimes and that these adaptations could be passed on to their offspring. For example, he believed that a giraffe's neck became longer because ancestral giraffes stretched to reach higher leaves, and this trait was then inherited by future generations. Although Lamarck's ideas were later overshadowed by Darwin's theory of natural selection, they played a significant role in the early development of evolutionary thought.