LECTURE 10KEY TERMS- Plesiadapiformes-First primates (near K-T boundary)-Small and arboreal[“squirrel-like” most likely became extinct by rodents]- Prosimians-First true primates (Eocene)-Not monophyletic[Long snout, small brain]- Anthropoids-Larger primates-Diurnal[Most likely switched from a nocturnal to a diurnal predator]- Homo-Homo habilis[Oldest homo]-Homo erectus[lost long finger digits]-East Africa-Intercontinental distribution-Large-Body proportions humanlike-Large brain-Humanlike nose-Small teeth-Homo ergaster[females are larger, less sexually dimorphic, human like, delayed tooth eruption therefore had a longer child stage]-Homo heidelbergensis-Africa and Europe-500,000 – 300,000 years ago-Homo neanderthalensis[larger occipital region, receding forehead, lots of injuries from fighting]-Germany-Stocky-Distinct facial characteristics-Large brain-Strong-Teeth with heavy wear-Stone toolmakers-Societies-Homo sapiens[cave paintings, very competitive]-African origin 100,000 – 200,000 years ago-40,000 years ago -Coincident with extinction of H. neanderthalensis and erectus-Homo floresiensis-Hobbit-Small brain-Stone tools-Flores (Indonesia)- Australopithecus[sexually dimorphic]-Bipedal-Lucy (A. afarensis) [most pre-homo prominent fossil, small but fully grown, growth plates sealed, ape like features, more arboreal]-Still possessed apelike features-Lots of Australopithecus fossils (see Fig. 24-13)-A. garhi “missing link” between Australopithecus and Homo [first to eat meat and use tools]-A. africanus arboreal [latest surviving]-Australopithecus may not be the direct ancestor of Homo-Kenyanthropus [possible close ancestor]- Ardipithecus-Ethiopian specimens-4.4 mya-Primitive-Possibly bipedal[chimp-like characters]NEED TO KNOW1. What are the four social systems of primates?1) Female transfer systems- Females leave the group from which they were born, females not closely related, social group size small (chimps)2) Male transfer systems- Male dispersal from birth place, females closely related, larger group size (baboons)3) Monogamous species- Minimal sexual dimorphism (gibbon)4) Solitary species- Guard territories, resources, and mates (orangutans) 2. What are the three ecological factors that are important in shaping the social systems of primates?1) Distribution of food resources- Whether to defend resources based on how common they are2) Group size- More resources=Larger Group3) Predation- The larger the group, the more defense, but also more predators. Greater number lowers individual’s chance of getting picked off.3. Know the types of social relationships among primates1) Adult-Juvenile Associations- Young are born helpless and dependent on adults-weaning (people)2) Female Kinship Bonds- Several males and females- females will bond together and protect their own kin, and males will join.3) Male-Male Alliances- Common in female transfer systems while females move around4) Male-Female Friendships- Nonrandom association- hangout together but are not mates (baboons)4. Know the three main groups of primatesHominoidea: two groups1. Hominidae (apes and everyone else) 2. Hylobatidae (gibbons)-Humans, chimps, gorillas, orangutans, and gibbons-Asia and Africa-Critically endangered-Diverged from Old World Monkeys ~23 myabrachiate through trees – swing w/ arms – not mobile on ground back legs stubby-Human & chimp split ~5 myaorangutans – sex dimorphic5. Who are the hominoid apes?Refers to all “non-human” hominoids6. Know the major players in human evolution (Homo, Australopithecus, Ardipithecus). Homo sapiensHomo neanderthalensis – hybridization of Neanderthals & humansHomo floresiensisHomo heidelbergensis (ancestor of Neanderthals)Homo erectus – delayed tooth eruption so longer developmental stageHomo habilisAustralopithecusKenyanthropusArdipithecus7. Which genera came first? Be familiar with each species listed in class (characteristics, importance for human evolution)8. Know about human bipedality. When did it evolve? In what setting? What type of evidence/skeletal characteristics are there for bipedality?-Previously thought bipedality evolved in savanna habitats 2-3 mya-Skeletal evidence for bipedality as far back as 7 mya; Evolution of bipedality in forests-Skeletal evidence: S-shaped curvature of the vertebral column, modification of the pelvis and position of the hip socket, and lengthening of leg bones and positioning as vertical columns under the body-Lots of modifications to the feet-Modifications to the trunk as well (waist)-Why bipedal? It couldn’t be from deficiency in locomotion because it is not perfected judging by the lower back and knee problems. It is much more efficientto use four legs than two. 9. Know discussion topics about the origin of a larger brain in humans-Human brain increased in size 3X over ~2.5 million years-Larger prefrontal cortex - personality-Smaller olfactory bulbs-Why? Perhaps increasing ability for social interactions, conceptual complexity, tool use, dealing with rapidly changing ecological conditions, and languages-Brain tissue is metabolically expensive to maintain-May have had an effect on prolonged development both prenatal & postnatal10. Know discussion topics about the origin of speech in humans-Need adaptations for controlled breathing to produce speech-Need change in anatomy of pharynx and vocal tract to produce vowel sounds-Need change in neural capacities-Disadvantages: choking, SIDS-Advantages: breathing in and out of mouth11. Know discussion topics about hair loss and development of skin pigmentation in humans-Nakedness unique-Parasite avoidance-Increase of eccrine sweat glands-Occurred ~1.2 mya-Use parasites to infer clothing use[Skin pigmentation was darker at the equatorial regions where the sun is more