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From First Primates to First Bipeds
- 1. FROM FIRST PRIMATES TO FIRSTBIPEDS A non-linear and intricate process… don’t be fooled by the image!
- 2. EVOLUTIONARY RELATIONSHIPS Scientists usea system of classification known as TAXONOMY to organize all living things into categories based on similarities and differences. The classification scheme starts with very general similarities Taxonomic levels become more and more specific for inclusion The smallest classification level contains only closely related organisms. KINGDOM PHYLUM CLASS ORDER FAMILY GENUS SPECIES
- 3. HUMAN TAXONOMY KINGDO M PHYLUM CLASS ORDER FAMILY GENUS SPECIES ANIMALS CORDATES MAMMALS PRIMATES HOMINIDS HOMO HOMO SAPIENS Organisms ableto move on their own Animals with a backbone Cordates with fur or hair and milk glands Mammals with collar bones and grasping fingers Primates with relatively flat faces and three- dimensional vision Hominids with upright posture an large brains Members of the genus Homo with a with a heightened forehead and thin skull bones
- 4. EVOLUTION ON AGEOLOGIC TIMESCALE Visual, anatomical, and genetic change (evolution) tends to occur in a pattern of PUNCTUALTED EQUILIBRUM where long periods of stability are punctuated by periods of rapid change. EXAMPLE: dinosaurs roamed the earth for 100 million years until a meteor crashed into earth and caused a global cooling effect that lead to their extinction Mammals begin to proliferate during the mass extinction of dinosaurs 65 million years ago (rapid change) 55 million years ago true primates emerge due to a warming trend in the enviornment
- 5. WHAT DEFINES AMAMMAL? Hair Mammary glands – produces milk Reproductive system – long gestation period Circulatory system – four chambered heart Allows for thermoregulation Neocortex – higher function part of the Spatial relations Reasoning Conscious thought Language/communication Sensory perception (feeling and
- 6. WHAT DEFINES APRIMATE? Skeleton Brain Teeth Sensory Organs Binocular stereoscopic vision (forward facing, 3D, color vision) Opposable thumbs Prehensile(grasping) hands and feet Clavicle (allows for increased arm mobility) Reliance on sight and social behavior Reduced use of olfactory senses Rounded (rather than sharp) molar cusps
- 7. TAXONOMY OF PRIMATES PROSIMIANSANTHROPOIDS MONKEYS APES HUMANS Chimpanzee OrangutansGorillas Bonobo TARSIERSLORESIS Gibbons LEMURS
- 8. PRIMATOLOGY A sub-fieldof Biological/Physical Anthropology that studies non-human primates In the past (fossils) and the present (living animals) Primatologists study the behavior and social life of their subjects by looking at HOMOLOGIES, which are similarities inherited from a common ancestor
- 9. BECOMING BIPEDAL Walkingupright on two legs is unique to humans Other primates are QUADRAPEDAL (walk on all four limbs) Or BRANCHIATE (swing from branch to branch) as a means of locomotion Becoming BIPEDAL required anatomical changes that took place over a span of more than 50 million years…
- 10. ANATOMICAL CHANGES PELVIS– adjusted iliac crest from a posterior to a lateral position to allow for upright locomotion FORAMEN MAGNUM – the hole at the base of the skull adjusts to support an upright position to balance the skull atop the spine ARMS – shorter in length for increased movement TEETH – overall structure changes to accommodate varied diet BRAIN – becomes larger in capacity
- 11. HUMAN ANCESTORY 1. Sahelanthropus Tchadensis(Toumai) 2. Orronin Tugensis 3. Ardipithecus Ramidus Australopithecines 4. A Anamensis (4.2-3.9 mya) 5. A. Afarensis (3.8-3 mya) 6. A. Africanus (3-2 mya) 7. A. Garhi (2.5 mya) 8. A. Robustus (2-1 mya) 9. A. Boisei (2.6-1.2 mya) 10. A. Sediba (1.9-1.7 mya) Homo 11. H. Rudolfensis 12. H. Habilis 13. H. Erectus 14. H. Sapiens 14a. Archaic Homo Sapiens 14b. Neandertals 14c. Anatomically Modern Humans (AMH)
- 12. HUMAN ANCESTORY BREAKDOWN Homoniod(family) 1. Sahelanthropus Tchadensis (Toumai) Hominin (subfamily) 2. Orronin Tugensis 3. Ardipithecus Ramidus Australopithecines (genus) 1. 3.
- 13. HUMAN ANCESTORY BREAKDOWN Australopithecines(genus) 4. A Anamensis (4.2-3.9 mya) 5. A. Afarensis (3.8-3 mya) 6. A. Africanus (3-2 mya) 7. A. Garhi (2.5 mya) 8. A. Robustus (2-1 mya) 9. A. Boisei (2.6-1.2 mya) 10. A. Sediba (1.9-1.7 mya) Homo (genus) 5. 5. 5. Lucy Letoli Footprints (LF) LF
- 14. HUMAN ANCESTORY BREAKDOWN Homo(genus) 11. H. Rudolfensis 12. H. Habilis 13. H. Erectus 14. H. Sapiens 14a. Archaic Homo Sapiens 14b. Neandertals 14c. Anatomically Modern Humans (AMH) 12. 14b.
- 15. REMEMBER… Humans areclassified on their OWN BRANCH of evolutionary history Humans DIVERGED from apes and monkeys however, we all SHARE a common ancestor Evolutionary forces that caused humans to branch from other primates: MUTATION – random changes in genes that introduce new variation GENETIC DRIFT – fluctuations in the gene pool that influence survival (i.e unique or catastrophic events) GENE FLOW – the introduction of new alleles from nearby populations NATURAL SELECTION – adaptative change for survival
- 16. REMEMBER… New findingsare constantly changing the evolutionary timeline Evolutionary relationships are controversial Some scholars prefer to “’lump” similarities into an existing species category Some scholars prefer to “split” differences into a new species category
- 17. TIMELINE REVIEW 65 mya –environment cools, dinosaurs go extinct, mammals radiate across the globe 55 mya – environment warms, mammals slight demise, proliferation of primates 6-7mya – first signs of bipedal locomotion 2.6 mya – first signs of tool use and the genus Homo 150,000 ya – emergence of language