However, Darwin's theory addressed many of the problems present in Lamarck's laws. Both Lamarck and Darwin fully understood the importance of variation, and it is their understanding of variation that fundamentally separates these two evolutionary theorists. However, Darwin actually had relatively little to say about the sources of variation and this was a continuing source of frustration for him. In the absence of a model of variation, his attention was mainly focused on selection mechanisms, which influence the traits found within a population (Gilady, Hoffmann., 2013). Darwin's natural selection suggests that biological information is passed on to subsequent generations simply through DNA sequence and leaves no room for heritable phenotypic variation acquired during an organism's lifetime, which contrasts with Lamarck's views of evolutionary change ( THORÉ.,2015). Lamarck's example of the giraffe's neck can easily be used to demonstrate the correctness of Darwin's theory. Although Lamarck's model is incorrect, the question of how giraffes developed such long necks has remained an important question within the topic of evolution; however it can be explained using the study of DNA and Darwin's theory of evolution. According to this theory, giraffes with longer necks are able to eat more leaves, making them healthier and more likely to produce offspring. The genes, or DNA, that encode this long neck are inherited by their offspring, causing their descendants to also have longer necks. Over the years, the number of children with “long neck” genes exceeds that of children with “normal neck” genes. Eventually, the “normal neck” genes are wiped out because they are unable to reach taller trees and obtain adequate nutrition, making it difficult for them to survive and