Lamarck: Important Theories for the Advancement of Biology

Short Biography

Jean Baptiste Lamarck was born on August 1, 1744 in the city of Bazentin (France) and died in the year 1829 in Paris. He was an important biologist, as his studies contributed greatly to the systematization of the knowledge of Natural History.

It was Lamarck who began to use the term "biology" to designate the science that studies living things. It was this scientist who also founded the paleontology studies of invertebrates.

Lamarck's theories were transformational, meaning that living beings evolve and transform. In this way, the simplest organisms, over time, would become more complex beings, until they reach an ideal and perfect living condition.

Lamarck's Theories

Use and Disuse Theory

He explains that the organs that are little used during the life of an animal will, over time, atrophy and lose their functions until they disappear. On the other hand, the most used organs, whose functions for survival are fundamental, tend to gain strength and develop in proportion to the time used. To explain this theory, Lamarck used the example of giraffes. These animals, needing to get their food from the tops of tall trees, strengthened their necks over time (from generation to generation) and thus had this well-developed body part.

Theory of acquired characteristics

Lamarck claimed that the environment was constantly undergoing modifications and evolutions. Therefore, the body of living beings had the capacity for transformation in order to adapt to changes in the environment. The transformations acquired by a species would be transmitted to their descendants. As generations go by (millions of years), species accumulate transformations, giving rise to new groups of living beings. In short, changes in the environment are “forcing” and generating needs for anatomical, organic and behavioral transformations in species.

Lamarck's theories influenced the evolutionary studies developed by Charles Darwin. In the third edition of Origin of Species, Darwin even praised Lamarck's research.

Research in the areas of genetics and heredity developed in the second half of the twentieth century invalidated Lamarck's theory of acquired characteristics.

Lamarck: observation of giraffes and theory of acquired characters.