Evolution and the fossil record?

In evolutionary time a "short period of time" can be thousands of generations, and we can't always know what these generations went through that others didn't. the accelerated change could have been a time of selective breeding within the population, or dietary preference from predators, we can't always know. Only a small ratio of animals are "lucky" enough to be fossilized. There is no guarantee that transitional forms can ever be found, even if they existed. This makes it a challenging science. Whatever fossils the earth gives us are the ones we have to work with.