Lamarck vs. Darwin: Understanding Evolutionary Theories

Lamarck's Theory of Transformism

The first explicit theory of species evolution was developed by Jean-Baptiste Lamarck, known as the theory of transformism. According to Lamarck, nature is a continuum where species evolve towards more perfect forms. He explained evolution through species adapting to their environment by developing suitable organs. A classic example he used was the giraffe's neck, which he believed elongated over generations due to stretching to reach higher leaves.

While Lamarck's theory contained erroneous points, he correctly emphasized the important role of environmental influence. He also posited that "classes" and "species" are divisions in our minds without real existence, and that all species are interrelated.

Charles Darwin's Theory of Evolution

Charles Darwin's definitive and comprehensive theory of evolution, presented in his seminal work On the Origin of Species (1859), built upon and ultimately superseded earlier ideas. Its main theses are:

Common Origin of Species

The great variety of known species are interrelated, and all species come from simple, primitive forms.

Struggle for Survival

All species tend to overpopulate their habitat through reproduction. As food resources become scarce, a struggle for survival begins, impacting most individuals.

Theory of Natural Selection

Only the fittest individuals, those best able to obtain resources in a particular environment, tend to survive and successfully reproduce. Thus, biological evolution is explained by a process of natural selection.

Defining "The Fittest"

It is crucial to understand that the concept of "the fittest" does not imply being smarter, stronger, or of a superior culture, nor does it support any racist or ethnocentric considerations. Instead, the most suitable individual is one who possesses a more favorable genetic mutation specifically adapted to a change that has occurred in their environment.

Inheritance and Adaptation

Survivors transmit advantageous genetic changes to their descendants. These descendants will gradually become better adapted to their environment. This is the essence of natural selection.

Randomness in Nature

Nature acts randomly and blindly: variations arise by chance. Being "the fittest" is not a pre-determined goal for a living organism; rather, the most apt animals are those that happen to suit their environment. In conclusion, for Darwin, there is no finalism, set order, or directed purpose in nature.