The Science Guys - Theories of Evolution :: essays research papers

Jean-Baptiste Lamarck (1744-1829)Today, the name of Lamarck is associated merely with a discredited theory of heredity, the "inheritance of acquired traits." However, Charles Darwin, Lyell, Haeckel, and other early evolutionists acknowledged him as a great zoologist and as a forerunner of evolution. To be fair to Lamarck, we should mention that since the time of Linnaeus, few naturalists had considered the thornlesss worthy of study. The word "invertebrates" did not even exist at the time Lamarck coined it. The invertebrate collections at the Muse were enormous and rapidly growing, but poorly organized and classified. Although the professors at the Muse were theoretically equal in rank, the chairman of "insects and worms" was definitely the least prestigious. But Lamarck took on the enormous challenge of learning -- and creating -- a new field of biology. The sheer number and diversity of invertebrates proved to be both a challenge and a rich source of know ledge. What Lamarck actually believed was more complex organisms are not passively altered by their environment. Instead, a change in the environment causes changes in the needs of organisms living in that environment, which in turn causes changes in their behavior. Altered behavior leads to greater or lesser use of a given structure or organ use would cause the structure to increase in size over several generations, whereas neglect would cause it to shrink or even disappear. This rule -- that use or disuse causes structures to enlarge or shrink -- Lamarck called the "First Law" in his harbour Philosophie zoologique. Lamarcks "Second Law" stated that all such changes were heritable. The result of these laws was the continuous, gradual change of all organisms, as they became adapted to their environments the physiological needs of organisms, created by their interactions with the environment, read Lamarckian evolution. Carl Linnaeus (1707-1778)Carl Linnaeus, also k nown as Carl von Linn or Carolus Linnaeus, is often called the Father of Taxonomy. His system for naming, ranking, and classifying organisms is still in wide use today (with many changes). Erusmus Darwin      He did discuss ideas that his grandson elaborated on sixty years later, such as how life evolved from a single common ancestor, forming "one living filament". He wrestled with the question of how one species could evolve into another. Although some of his ideas on how evolution might occur are quite close to those of Lamarck, Erasmus Darwin also talked about how competition and sexual selection could cause changes in species