ISS 210 1st Edition Lecture 5 Outline of Last Lecture I The Basics II Evolution III Malthus and Population IV Natural Selection V Origins of Genetic Variation VI Chimps and Humans VII Chimp Human Differences VIII Genomic Change IX Genetic Drif X Founder Effect XI Natural Selection 2 XII Malarial Resistance in Nepal XIII Sickle Cell Anemia XIV A africanus STS XV Paranthropus Vegetarian Extraordinaire XVI Paranthropus Robusts XVII Horn Core Tool from Swartkrans South Africa Outline of Current Lecture I P aethiopicus Black Skull II The Panglossian Paradigm or the Calvin Effect III Systematics IV Phylogenetic Trees V Necrolemur and Tarsier Tarsi VI Distinctive Features Monkey VII Distinctive Features Ape VIII Chimpanzee Bipedal Movement Current Lecture I P aethiopicus Black Skull A hyper robust for that lef no descendants but Richard Leaky thinks some tools behind Extreme development of sagittal crest and massive cheekbones II The Panglossian Paradigm or the Calvin Effect The modern synthesis resulted in too many just so stories Imaginative and ofen satisfying explanations of evolutionary adaptations Hominids did this because Do not provide a means to rigidly test hypotheses about adaptation Traits may exist because theyre useful or become of random mutation and genetic drif Exaptation s traits or novelties that may persist for generations and become useful only at a later date forces adaptive or otherwise altering the shape of the vocal tract Once they become useful however the tendency is to understand their appearance in terms their more recent function speech a capitalized post hoc afer the fact on these changes Important not to see our evolution as a process of steady fine toning over eons within a single lineage 89 III Systematics Because all organisms on the plant have a single common ancestor and evolved through descent with modification the pattern can be depicted as a tree The Tree of Life has branches representing all organisms living and extent evolving from simple to complex but all on the same evolutionary plane The Scala Naturae ladder of life established by Linnaus is a top down rigid ranking of living forms In the 1960s system atics was not rigorous evolutionary taxonomies were pronounced by understanding of the diversity of organisms were nothing more than untested and untestable hypotheses Alternate methods require to create testable phylogenetic trees IV Phylogenetic Trees Classification based on similarities organisms were classified together if they were more similar to each other than to other organisms Cladistics based on raw information from individual attributes of organisms If a particular characteristic is confined to a pair of species it is taken as evidence of inheritance from a common ancestor The Rule of Parasimony Ocean s Razor is used to prone the interpretation All things being equal the simplest explanation tends to be the correct one The root of the tree is the last common ancestor the branching shows whether particular traits evolved or were present all along in the tree V Necrolemur and Tarsier Tarsi Binocular vision Supra orbital Ridges Mobil forelimbs and elongated rear limbs for verticals clinging and leaping Grasping Hands Nails instead of claws Snout VI Distinctive Features Monkey Quadrapedal 4 feet 4 Molars Tails New world prehensile grasping tails Noses Platyrrhini flat nosed new world Catarrhini narrow nosed old world Fully opposable thumbs VII Distinctive Features Ape Knuckle walking 5 molars Tailless Brachiators Knuckle walking gorilla Long narrow pelvis Long forearms Bone in the wrist limiting forward motion of the hand to support body weight Opposable big toe Curved shape of back VIII Chimpanzee Bipedal Movement Used to cover from side to side Use of hands to carry objects Arms used for balance Knuckle walking and walking on 2 legs are equally inefficient Bipedalism walking on 2 feet vs knuckle walking Energy efficiency is determined by length of stride and amount of muscle activated in each stride Humans use only 25 of the energy apes use whether knuckle walking or walking upright