Tuesday, September 11, 2007

Darwin & Evolution

Today we learned about natural and artificial selection. For hundreds of thousands of years the theory of the gods creating all life on earth had been accepted and people were not as bold as to question this belief until circa 1800's. Contrary to this belief we have fossil records showing creatures that are very similar to present creatures. Also existing are archeopterix which show the link between reptiles and birds.
Here is a link that i found of a recent journal further explaining this subject: Transitional Forms

Charles Darwin came across fossils of extinct armadillos however he found that the living armadillos on the same continent (South America) were very similar and this helped prove his theory of natural selection and that creatures cannot adapt over a lifetime but through reproduction (however he did not come up with the theory of DNA and genes). He concluded that those armadillos who were not born with the favorable trait did not survive and eventually this favorable trait became normal and only this type of armadillo would survive. He found the same situation with the Mylodon (giant ground sloth) and the Modern sloth.

Another scientist who had ideas about evolution was LaMarck. LaMarck understood that adaptations took place, but was a little off in his theory. LaMarck believed that organisms adapted over their lifetime, like in this cartoon that I found.

1 comment:

KB Foglia said...

Good work, Marc. Another good cartoon illustrating misconceptions that are often seen in students' statements about evolution. And a good point that Darwin could not have spoken about genes, since the concept of genes was only being formulated by Mendel in the latter part of Darwin's life and DNA (& its relationship to genes) would not be discovered until many years later. Be sure to keep that in mind in essays!