Answer:
Darwin and Lamarck's theory is different but they were also very similar. Both of them thought that the organism changed, and they are very helpful for the organism to survive. These characteristics are also passed to their young generation.
Darwin theory state that an organism gets the helpful variation before the changes in the environment, Lamarck's theory said that organism gets variation after the change in the environment.
Lamarck's stated that giraffe got long neck when the food on the ground ran out. In order to get the food they stretch out their neck to get food. Darwin thought organism changed by chance, at the time when they are born and before the change in the environment.
