One example that could support Lamarck's theory of evolution is the concept of giraffe's long neck. According to Lamarck's theory, giraffes elongated their necks over time in order to reach higher leaves from tall trees. Whatever changes an organism makes in its lifetime, is inherited by its offspring which results in the evolution of species. Therefore, the giraffes with longer necks survived and passed on their traits to their offspring which eventually led to the evolution of giraffes with long necks. Although this idea has since been disproven, it was widely accepted in Lamarck's time and the concept of giraffe's long neck is still often used as an example of Lamarckian evolution.
