Interestingly enough, Mettrie has quite a few quotes on the subject, decades before Darwin. "The first generations must have been very imperfect. Here the esophagus will have been lacking; there the stomach, the vulva, the intestines, & so on. Obviously the only animals that will have have been able to live, conserve, & perpetuate their species, will have been those who have been provided with all the parts necessary for reproduction, & which in a word no essential part will not have been missed…