Fortunately one of the comments was an excellent summary of some the powerful evidence for evolution. Here it is:
What do you mean? Of course, this has been proven. Proof doesn't always come from what you're calling as the "classic scientific method", i.e reproducing the whole thing in the lab. This is a process that happened over hundreds of millions of years over varying geologic/climatic conditions on a global scale. Therefore, it can't be redone in the lab in a short time.
However, the common descent hypothesis makes predictions and these can be tested and verified. So far all these predictions have held true through thorough scrutiny.
For example, all life forms from the simplest of bacterial c
If you examine the fossil record, ancestral forms appear earlier than their descendants. This is supported by the geologic timescale. For example, we always recover human fossils from layers that are younger than those containing ape fossils. We always see fish appearing earlier than any land vertebrate in the fossil record.
We have found many transitional and intermediate fossils linking animal groups, exactly as the tree of life (phylogeny) predicts. There are fossils linking dinosaurs with birds, land mammals with the aquatic whales, fish with all land animals, apes with humans, reptiles with mammals etc etc.
If you look at living animals, they have vestigial organs that have lost their main function, but were fully functional in their ancestors as predicted by phylogeny. Humans have tail bone, appendix, wisdom teeth, ear-moving muscles, hair-raising muscles and many more linking us to animals that used these structures for functions we no longer require!
There's also evidence from embryology. The developing foetus of animals as varied as humans, fish, bird, dolphin and frog look strikingly similar early on. Human foetus develops the same pharyngeal pouches which form gills in fish. Later on they form other structures of the ear and throat in all mammals including us.
We find homologous structures in animals that are predicted to be related even though these structures are used for totally different functions. eg: the human arm, bat wing, horse leg and dolphin flipper have varied functions, yet share the same anatomical structure!
I can go on & on. To cut a long story short, the theory of common descent is supported by all branches of science from genetics to paleontology to biochemistry and even geology. It is due to this overwhelming support that evolution and common descent are considered as facts and not as mere beliefs.