ANT 350 Lecture Notes - Lecture 7: Most Recent Common Ancestor, Ape, Dryopithecus
Document Summary
Homology: similarity of structure in tissues, organs, or skeletal elements. Charles darwin: used homology to identify ancestry, homology reflects ancestry, shared traits with the same structure are traceable to a common ancestor. Taxon (taxa): formally recognized classificatory group: pan troglodytes (chimpanzee, gorilla gorilla (gorilla, australopithecus boisei (east african robust australopithecine, 2. 2-1. 2 mya, australopithecus afarensis (east africa: 4. 4-2. 9 mya) Homoplasy: similar traits that emerge not because of common ancestry, but due to parallelism (same niche) independent adaption to similar demands. Mandibular molar morphology: y-5 (dryopithecus) pattern: cusp: major elevation on the occlusal (chewing) surface of molars and premolars (posterior teeth, present in all four target taxa, plus proconsul and all other miocene apes. Homology linking all 4 taxa: superfamily: hominoidea, ontogeny: same development; deciduous teeth also show pattern. Week 4, lecture 7: a. afarensis no (but intermediate: remnant distal cutting blade) evolutionary sequence, ontogeny: same development; deciduous canines same.
