We have not found the "missing links"
Every species of life is one step on the ladder of the evolution of consciousness. The soul in every species of life is equal in quality and quantity with the others, it is only due to the consciousness of a particular living entity that he takes a higher or lower body. If I ask the real questions one is meant to in this human form of life, which are: "Who am I? What is the purpose of life? What is spirit? Who is God?" then I am bound to be elevated to a higher platform of consciousness in the next life.
The scientists don't know about this "backward" evolution. They are heading backwards in the evolution of consciousness because they are using their God-given intelligence for facilitating the animal propensities in an advanced, scientific way instead of using it for advancing spiritually. As a result of their misuse of their intelligence they are going backwards on the evolutionary path and will find themselves in the bodies of monkeys in their next lives.