According to kagmi on yahoo these are three lines of evidence that support the theory of evolution.
The fossil record shows the existence of billions of extinct species. It also shows a clear progression from one species to the next; there are many "transitional fossils," such as the archeoptryx (probably spelled that wrong, lol) which is clearly an intermediate in the evolution of dinosaurs into birds.
Biogeography shows the distribution of species, providing further support that different species can and do evolve from common ancestors. Australia has many species of marsupials not found on other continents, for example; this implies that these species may have shared a common ancestor which lived on Australia when it was separated from the other continents by continental drift.
Molecular biology allows us to analyze genes and proteins down to the very molecules that make them up. This reveals many similarities and differences between organisms not readily apparent to the naked eye. We can see, for example, that humans share the vast majority of their DNA with all mammals; slightly less with reptiles; slightly less with amphibians, and so on. We find that species' DNA sequences match up well with the fossil record in terms of how closely related the species are.
