The Mutations (1974)

Students have been going missing from the local college, and the one person who knows what's happened to them is Dr. Nolter (Donald Pleasence), a rogue biologist. Not satisfied with the pace of natural selection in driving evolution, Nolter wants to push things further by creating his own genetically engineered creations. Having already created some amazing specimins by mixing the DNA of plants and animals, the doctor has now set his sights higher, and want to work on modifying humans, as well.