BIOL-3030 Lecture 24: Lecture 24 - Eutherian Evolution
Document Summary
Distinguished by chorioallantoic placenta (vascular connection between mom and young derived from 2 extraembryonic membranes, chorion and allantois) Eyes: good color vision, frontally directed for good depth perception. Primates distinguished by features related to climbing in trees: Opposable thumb for grasping, nails replace claws, >arm mobility. >brain and vision capacity (e. g. frontal eyes w/ overlapping view for 3d vision) Lemurs, lorises, tarsiers - prosimian grade primates (most highly arboreal) lemurs : Very long hind legs, vertical clinger and leaper. Nose no longer damp and glandular; round nostril. Set apart by features related to dealing with stresses of grinding fibrous plants in diet. Platyrrhines - new world monkeys , rafted from africa. Spider and howler monkey"s prehensile tail. Nostrils close together, larger size, lose 3rd premolar. Sinuses (air filled spaces in skull bones) Chest flatter and broader, shoulder blade shifts to back (aids balance in upright. Anatomical features distinguishing hominins (humans and close ancestors) from apes (hominids)
