User:Pbarnes/fixity of species

Fixity of species is a term which means all species remained unchanged throughout the history of the earth. This belief is generally not accepted by the majority in present times because of the vast amount of evidence supporting evolution.

History
Prior to Charles Darwin's work on evolution theory, the current accepted theory for species diversity, the majority of the western world believed all the species remained fixed in their present anatomical state.

Many well-known scientist prior to Charles Darwin publications on evolutionary theory have, at one point in their lives believed this view, including Darwin himself. Darwin was raised in a religious family and was a clergyman early in his life. Prior to his studies, he believed the traditional religious view that God created all the species specifically for their environments. After his studies on the Galápagos Islands in which he observed many examples of species which did not remain unchanged as his religious belief suggested. He rejected this view along with religion all together.

Carolus Linnaeus, founding father of our current taxonomic system, began his study believing this concept, but later rejected it after observing interbreeding between various species. For this reason this belief is sometimes referred to as the "Linnaean Lawn", a metaphor relating which is primarily used in comparison with a phylogenetic tree and a "creationist orchard".

Other, more stern believers of fixity of species included Louis Agassiz, a zoologist and geologist known primarily for his work on the an ice age hypothesis, and Georges Cuvier, French naturalist and zoologist.

Variations of Belief
Fixity of the species doesn't make claims as to how the species originally came into existence. Generally, a creator is associated with the belief such as God or other intelligent designers. In progressive creationism, the species do change but this change is caused by God and therefore is still considered fixity of the species by many progressive creationist.