Who is jean-baptist lamarck and what was his hypothesis about evolution?

Jean-Baptiste Lamarck was a French naturalist best known for his early theory of evolution, which he proposed in the early 19th century. He suggested that organisms evolve through the inheritance of acquired characteristics, meaning that traits developed during an organism's lifetime could be passed on to its offspring. For example, he believed that if a giraffe stretched its neck to reach higher leaves, its descendants would inherit longer necks. Although Lamarck's ideas were largely replaced by Darwinian natural selection, he is considered a pioneer in the study of evolution.