When Darwin published On the Origin of Species he knew he didn´t know everything about evolution and his theory had some gaps. He believed and relied on future scientists that would complete his theory and prove it.
For him, all diversity was a product of evolution. As species try to survive and struggle for existence they change in order to survive and adapt more easily to nature.
Professor Armand Marie Leroi, evolutionary biologist tries to understand Darwins thoughts and ideas. He believes that with the new science of evolutionary developmental biology it will be possible to revise and complete Darwins´s work. If the past can be explainded, scientists might be able to predict the future