Evolution by Atrophy in Biology and Sociology

abdominal adaptation to arboreal adaptation to leaping adult ancestral animals apical leaves appendages aquatic Archeopteryx assimilative Astacus atrophy basilar leaves become belonging biology bipinnated blade branches calcaneum cells characters chlorophyll claw collective property colony completely condition consists Crustacea custom degenerative evolution digits disappeared distal Dollo Echinoderms Edition endopodite epipod exhibited existence exopodite ex female fins five-toed flowers foliage leaves foot formed fourth function Heterocephalus Huxley hypopod individual instance institutions joint land larvæ larval leaf leaflets limbs male mammals marriage maxillipede membrane ment mesonephros metameres metatarsals modification muscles normal original pairs petiole phalanges pineal eye plants podite primitive progressive pronephros prothallus protopodite pr reduced regarded remain represented result retracing rods Rosa rugosa rudimentary organs segment slow-worm social societies sociology species stage stamens stem stipules stomata structure survival tarsius terrestrial thalamencephalon tion transformation useless vertebral column vertebrates vestiges