Survival of the fittest or the battiest?

Survival of the fittest. How can you prove that? Any organism that is either fit enought or lucky enough to survive will become by definition one of the "fittest" that has survived. Can't be proven because it can't be seen until after the fact. You'll never know if they were actually the fittest or just lucky, it does happen. After all the Twins won the World Series a couple of times, I'm a fan but I have to admit that that took plenty of luck!
As far as the missing links in fossils goes, there is one species that has no missing links and that is the bat. Problem is the very first bat is virtually the same as todays bat. They did not require evolution to develop radar over the eons, the very first bat came completely radar equiped same as the bats you'll find out at night today. Maybe that is why when there is a complete record available the Darwinists won't use it, because it disproves their claims.