It's hard to disprove a negative. Anyway it depends on what you mean by species. People with Downs Syndrome have a different number of chromosomes. Most changes in species are negative and don't get carried on, but occasionally a deformity could be an advantage. Pandas for example do not have opposable thumbs, but a deformed finger serves the same purpose.
Sorry not to let you have the last post, but evolution is generally considered proven by scientists. Many laypersons consider it "just" a theory, but theories are not something scientists make up at a late night party. They spend a lot of time researching and testing different explanations. I'm not saying we came from monkeys. That's absurd and no scientist believes it, but we are related to the other hominoids and share well over 90% of our DNA with most of them.
Opinions in this post are solely that of Luigison. Facts, on the other hand, are facts.
Edit: Sorry for my arrogance. I never thought of it this way: "Simply because they cannot be proven wrong, does not make them right." - Scott Berkun
Edited by - Luigison on 5/29/2005 9:27:16 AM