Historical Influences on Charles Darwin

I believe that Jean-Baptiste Lamarck  had the most influence over Darwin's development of his theory of Natural Selection. Lamarck positively aided in Darwin creating his theory in several ways. Lamarck introduced the idea of a relationship between species and the environment around it. For example, "if the external environment changed, an animal's activity would also change to accommodate the new circumstances" (Introduction to Physical Anthropology).  At first, "Darwin was influenced by Lamarck's writings early on while studying medicine at Edinburgh University" but after more studying, "Darwin did not agree with Lamarck that species evolve in an upward manner from lower to more advanced forms. By the 1840's Darwin disagreed with nearly all of Lamarck's theories, except for the ones regarding acquired traits" (http://www.aboutdarwin.com/people/people_01.html). The reason for Darwin to disagree with his idol's ideas was because of Lamarck's example with giraffe's and how they must stretch their necks to reach leaves on the tree, and then those stretched necks could be passed on to their children helped give the basic foundation to Natural Selection. Darwin states that genetics does not work in a way that a stretched neck could be passed down. Darwin suggests that if a giraffe has a short neck, then it would have a hard time surviving in a habitat with taller trees, therefore dying off, making way for giraffes with longer necks. Darwin went on to point out that the giraffes with the longer necks lived because they had better access to the limited sources, such as the leaves higher up on the trees. A significant point was that organisms with better access to resources will be more successful in their reproductive efforts. If a giraffe with a short neck lived in a habitat with tall trees, it would be hard for the giraffe to feed itself, let alone its offspring. If these shorter necked giraffes cannot get enough leaves to feed themselves, then that population dies off. If that population of short necked giraffes die off, then natural selection does not occur because reproduction hasn't occurred. Lamarck believes that giraffes who stretch their necks can pass that through their offspring, however that is not how genetics works. The shorter necked giraffes would reproduce and give birth to more shorter necked giraffes. Through these points, Darwin demonstrated that Lamarck's ideas were wrong and that they did not explain natural selection properly. Darwin could not have developed his theory of natural selection without Lamarck's ideas, however, because if he did not question them, and just believed them to be the truth, then natural selection would not have a proper definition. The attitude of the church affected Darwin mostly because of how afraid everyone was to speak up with their own ideas. He was forced to publish his book, however, because Alfred Russel Wallace had individually created his own idea of evolution, and Darwin had to compete to be the first to publish it and get credit for the theory. This led to the publication of his book On the Origin of Species.