Ethology - Scala Naturae and Lamarck's Theories

Scala Naturae and Lamarck's Theories

See also: Great Chain of Being

Until the 19th century, the most common theory among scientists was still the concept of scala naturae, proposed by Aristotle. According to this theory, living beings were classified on an ideal pyramid that represented the simplest animals on the lower levels, with complexity increasing progressively toward the top, occupied by human beings. In the Western world of the time, people believed animal species were eternal and immutable, created with a specific purpose, as this seemed the only possible explanation for the incredible variety of living beings and their surprising adaptation to their habitats.

Jean-Baptiste Lamarck (1744 - 1829) was the first biologist to describe a complex theory of evolution. His theory substantially comprised two statements: first, that animal organs and behaviour can change according to the way they are used; and second, that those characteristics can transmit from one generation to the next (the example of the giraffe whose neck becomes longer while trying to reach the upper leaves of a tree is well-known). The second statement is that every living organism, humans included, tends to reach a greater level of perfection. When Charles Darwin went to the Galapagos Islands, he was well aware of Lamarck's theories and was influenced by them.