How did Lamarck contribute to the theory of evolution?

Flexi Says:
In early 1800s, the French naturalist Jean-Baptiste Lamarck proposed the idea that species change over time. He argued that organisms could intentionally make changes to adapt to their environment, and pass those changes to the next generation. For example, if a giraffe stretched its neck to reach higher leaves, its offspring would be born with longer necks as well. He believed this allowed species to evolve from simple to complex forms by acquiring new adaptations over time. Darwin's observations during the voyage of the Beagle led him to agree with Lamarck that species could change, and had done so during Earth's history. However, he disagreed with Lamarck on how this happened. Darwin proposed the mechanism of natural selection, where offspring are born with a variety of traits, and those with beneficial adaptations living longer and reproduce more, passing those traits to following generations.