Human Origins Study Notes

Geological Time Scale:The organization of earth history into eras, periods and epochs; commonly used by geologists and paleoanthropologists. (Focusing on Cenozoic era, and the series and epochs in that one.)Paleocene: 65-54 mya 1st primate-like mammals Plesiadapiformes, purgatorius Eocene: POMA (primates of modern aspect) Prosimian-like Adapids and Omomyids Oligocene: 34-23 mya Begin to see the ancestors of modern hominoids (apes, humans and our ancestors) Aegyptopithecus (Found in Egypt) Miocene 23-5 mya Origin of hominids (modern or extinct bipedal primates of the family Hominidae) (Origin of the homo genes) Golden Age of the Apes Proconsul Pliocene 5-1.7 mya Adaptive radiation of hominids Origin of the genus Homo Pleistocene: 1.7-10,000 “Ice Age” Evolution of the genus Homo Holocene10,000-presentContinental Drift: The movements of the continents on sliding plates of the earth’s surface. As a result, the positions of large land masses have severely shifted during time. Late Paleozoic: continents came together and formed one large landmass called Pangea Early Mesozoic: Gondwanaland (southern) Laurasia (northern) Late Mesozoic: continents began to assume their current positions, animals became isolated Mammalian Evolution Mesozoic: dominated by reptiles The Cenozoic: “The Age of the mammals” Why such rapid succes? Larger brains Internal development (long-term) Variation of dentition (heterodont dentition) Maintenance of a constant internal body temperature PALEOCENE: 65-54 mya Sub-tropical climate near the equator Worldwide warm temperatures 1st primate-like mammals Plesiadapiforms (families): they resemble a lot of our modern strepsirhines Plesiadapidae Carpolestidae Purgatorius EOCENE: 54-34 mya Ida: considered to be the missing link between the haplorhines and strepsirrhines. Thought to be an arboreal quadruped. Has an opposable toe, the same as chimps. Supposedly 47 mya POMA: Primates of Modern Aspect Euprimates: Adapidae (adapids): Notharctus (2:1:4:3) and Teilhardina The “Big Cut” Massive Extinction in marine and land animals Tropical climate ---> Dry climates 10 million years forest changed to plains OLIGOCENE: Aegyptopithecus: Arboreal quadruped: bridges the gap between eocene fossils and the miocene fossils. Comparison of Bilophodont Molars: bilophodont molars as found in cercopithecoids and Y-5 molars as seen in hominoids MIOCENE Golden age of hominoids (apes) Divided into 3 periods: Early: 25-20 mya Mid: 19-11 mya Late: 10-5 mya Major changes in climate Proconsul: belongs to the early Miocene (2:1:2:3)--arboreal quadruped. Considered to be the ancestor of apes and humans Different from Aegyptopithecus: Proconsul is new world monkeys and Aegyptopithecus is Old world monkeys Kenyapithecus: belongs to mid Miocene likely ancestral to modern apes Sivapithecus: Late Miocene Gigantopithecus: Largest known apes that ever lived (10 ft tall) (transition from Miocene to the Pleistocene. LANEY’S NOTES FROM 3/1/16HOMININ EVOLUTION Iwww.becomoinghuman.orgIs there a missing link? Missing Link: a fossil that exhibits traits common to both an ancestral group and its derived descendants Example: fossil linking modern humans to a primate ancestor THERE IS NO MISSING LINK! It would be a constantly moving target. It is dependent upon currently existing forms. We DO have Last common ancestors Terminology: Distinctive hominid characteristics include: Bipedal locomotion Large Brain size Tool making behavior (later in time) Mosaic Evolution: A pattern of evolution in which the rates of evolution in one functional system vary from those around it. Paleoanthropology: The study of early humansIt is a diverse multidisciplinary pursuit seeking to reconstruct every bit of information possible concerning the dating, anatomy, behavior, and ecology of our hominid ancestors. ----------------------------------The Messinian Crisis: Occurs during the Miocene around 5.9 mya Cooling and drying trend The Mediterranean Sea went to nearly complete desiccation and became a salt basin What African apes made it through the Miocene? Kenyapithecus likely ancestor to African apes Why did the monkeys survive? They are small, their diet is much more efficient. (rely on less food) Gorillas made it through: Large body size Eat leaves, foliage, Metabolism is lower, can subsist on lower quality food Chimpanzees Diverse Diet (50% of diet is fruit, Benefit of Suspension) Humans Thicker Enamel (thicker than Kenyapithecus) Adapted to eating terrestrial hard foods Bipedalism Why become a biped? Cool breezes High off the ground Bipedalism: Many anatomical adaptations: Feet (non divergent toe, aligned with the rest of our toes) Lower Limbs (valgus knee): your knee is fully extendable Pelvis Spine Skull Upper limbs Facultative Bipedalism vs. Obligate Bipedalism Facultative: Using Bipedalism with other types of locomotion Obligate Bipedalism: Using Bipedalism only because it prefers it. 4-8 mya Gap LUkeino molar (KNM-LU335)--6 mya, lower M1 or M2 Kanapoi (KNM-KP271) --Partial distal humerus Lothagam--5.5 mya, Right portion of mandible Tabarin (KNM-TH13150)--5 mya -Mandible (2 complete molars) Pre-Australopiths:MID-90’S, more fossils **MUST REMEMBER THESE** Australopithecus ramidus → Ardipithecus ramidus 17 fossils 4.4mya Middle Awash region in Ethiopia (East Africa) 110 Specimens: 36 individuals Ardi: Had thin enamel Was a Facultative LCA of apes and hominids? Pre-australopith Other Possible LCA (pre-australopiths) Orrorin tugenensis Discovered in 2002 6 mya 13 fossils (minimum of 5 individuals) Postcrania looks more hominin than ape Sahelanthropus tchadensis Discovered in 2002 6-7 mya Djurab desert (modern day Chad) Australopiths Anatomically similar to modern humans, but their heads were significantly different from ours Adult brain size was about ⅓ that of people today Widest part of their skull was below the brain Big teeth, thick enamel, large jaws, and powerful jaw muscles Early hominid faces were concave or dish-shaped 6 species of Australopiths Australopithecines are put into two groups: 1. Gracile (“slender”) 2. Robust (muscular) Main differences are found in the dental anatomy. Robust forms: bigger grinding teeth, more robust jaws, more bulky chewing muscles and muscle attachments. Australopithecus anamensis (Early Gracile) May have been the earliest australopithecine species 4.2-3.9 mya in East Africa Due to the scarcity of fossils and because they are highly fragmentary, little is known about them Australopithecus Afarensis: 2 major sites: Hadar, Ethiopia AL 288-1 (Lucy) Discovered in 1973 3.18 mya Laetoli, Tanzania LH4 (single mandible; 3.4-3.76 mya) Lucy, AL 288-1 Discovered in 1971 40% complete skeleton 3.2 million Years old Transitional species 2 hypotheses concerning locomotion: Obligate, Terrestrial Biped: proposed by Lovejoy and Latimer Short Pelvis Valgus Knee Flare of hips (smaller outlet) Biped, retained arboreality: proposed by Stern, Susman and Jungers Bent-Hip, Bent-knee biped that retained significant arboreality Who is right? Ward (2002) Compared humeral-femoral index to 18 pygmies and bonobos (chimp) Humurs/femur X100 Bonobos h-f index: 97.8 Pygmies h-f index 73.7 Lucy h-f index: 85 Australopithecus afarensis (Early Gracile) slender curved fingers (grasping) Canine teeth were large and pointed Small brain size (375-500 cc) Valgus knee Short, curved ilium Posterior sagittal crest Flat cranial base Parallel tooth rows Australopithecus africanus 3-2.5 mya South African Australopithecine Dates using biostratigraphy Pig used as a marker fossil 1st Australopithecine The Taung child Discovered in 1924 in S. Africa 2.5 mya Raymond Dart found it. Raymond Dart claimed: 1925: Nature; Dart claimed fossil represented missing link between human and ape Australopithecus africanus Immediate criticism Eoanthropus dawsonii (1912)--was a fraud Australopithecus africanus had reduced proganthism Crowding in front teeth Reduction in canine size Parallel teeth rows Australopithecus aethiopicus (Robust) The late australopithecines (robust) had larger jaws accompanied by pronounced sagittal crests Called the black skull (KNM-WT 17000) Discovered in 1985 2.5 mya Only found in East AFrica Thought to be a transitional form from one of the gracile species that came before Primitive vs. Derived traits in Robust forms: Large incisors (derived) Sagittal crest (derived) Broad face (Derived) Prognathism (Ancestral) Small brain (400cc) (Ancestral) Australopithecus robustus (Robust)Molarization of premolars = reduction in anterior teeth (this is unique to robustus)Australopithecus boisei Super-robust East AFrican species 2-1 mya OH 5 Male number: KNM-ER 406 Female: KNM-ER 732 (still very small brains) The ice age Glaciations enveloped huge areas of europe, asia, and North America Divided into three species Pleistocene fossils Middle pleistocene: H. heidelbergensis (or archaic H. Sapiens) Late Pleistocene: H. Neanderthalensis African H. Heidelbergensis (middle Pleistocene) Kabwe, zambia 200 kya Complete crania European h. Heidelbergensis Atapuerca 5 Spain 300 kya 1125 cc Low, sloping forehead Early evidence of neandertal ancestry Big nose Asian h. Heidelbergensis Primitive and derived traits The dali skull 230-180 k China Most complete skull of middle or late pleistocene fossils in china 1120 cc Pronounced brow ridge is primitive Wide nasal opening is derived Neandertals 1st d. In 1829 “Neander” “Thal” (neander valley Neanderthal vs. neandertal LA Chappelle Aux Saints D. in 1908 La Chappelle, France Approximately 40 at age of death 1620 cc Marcellin Boule 1st described fossil La Ferasie Teeth worn out, could be using teeth to crack things, use them as tools Neandertal morphology Average brain size = 1400 cc Occipital bun Pre-lambdoid flattening shoveled incisors Low, sloping forehead Neandertal morphology Very robust Thick cortical bone Males: 5.5 feet, Females: 5 feet Broad chested (barrel Shaped) stocky More area to volume=much heat loss Less area to volume Mousterian technology Associated with archaic H. sapiens (H. heidelbergensis) and Neandertals Levallois technique Involved specially preparing a core in order to remove fakes of a predetermined size and shape Appears first during the later archaic stages but it's the neandertals that improve the levallois technique Subsistence Hunting has become a critically important part of the diet High levels of carbons and nitrogen in neandertal bone confirms that up to 85% of their diet was meat Cooperative hunting Origins of modern homo sapiens 2 hypotheses Replacement hypothesis: “out of africa”. Recent speciation event constrained in time and space. No interbreeding occurred Multiregional hypothesis: modern humans at least in part descended from their archaic regional predecessors in the OW. interbreeding occurred Lagar velho skeleton (portugal 4 year old Chin No H-O foramen thick , arctic-like bones Problems? Only 1 skeleton MTDNA evidence Krings et al. (1997): 1st isolated mtDNA from neandertal MISMATCHES=25 Krings et al. (1999) MISMATCHES between subspecies of chimps Green et al. (2010) 1-4% admixture in europeans and asians Upper paleolithic revolution Amh first emerged=100000 years ago, but no change in lifestyle for 60,000 years Upper paleolithic revolution (40,000) New materials (bone ivory, and antler) Aesthetic appreciation? Most advanced state is the magdalenian tools: Spear throwers (atlatl) Barbed harpoons (spears for fish) Bow and arrow Symbolic representations (art) become more prominent: Cave paintings sculptures Engravings Venus figurines Upper Paleolithic No question of “purposeful” burials AMH vs. Archaic and Neandertal skulls Small faces with the first appearance of chins Smaller teeth and jaws Rounded skulls with vertical foreheads Human variation and adaptation Adaptation: one way that humans meet the challenges of the environment (aka natural selection) According to environmental stresses, humans can go through physiological and growth adjustments (essentially adapting) How do we study genes that govern adaptive traits? Human genome: 2003 SNPs or Single nucleotide polymorphisms Homeostasis: a condition of balance (stability); maintained by physiological mechanisms that compensate for changes Sweating Pigmented skin Acclimatization: physiological responses to changes in the environment that occur during an individual's lifetime. Short term, long term, or permanent Example: tanning Developmental acclimatization: irreversible physiological changes that occur during growth and development due to an environmental challenge Historical views First physical difference of humans to be explained was skin color 1350 b.c.: ancient egyptians classified humans according to skin color Linnaeus’ taxonomic classification Blumenbach’s taxonomic classification Biological determinism: the concept that phenomena, including various aspects of behavior are governed by biological factors Who was proposing these ideas? Eugenics: the philosophy of “race improvement” through the forced sterilization of members of some groups and increased reproduction among others Biological determinism and eugenics lasted until the 1930’s when darwin’s theory was combined with genetics Anthropologists began to view human variation according to darwin’s theory of natural selection Race: refers to geographically patterned phenotypic variation within a species Is a race a biological (genetically based) entity? Richard lewontin Variation within a population Variation between populations “The amount of genetic variation accounted for by differences between groups is vastly exceeded by the variation that exists within groups” Skin color Hemoglobin Carotene Melanin pigment A granular substance produced by specialized cells (melanocytes) found in the epidermis A tan is a temporary increase in melanin production (acclimatization) Evolution of skin color Jablonski & Chaplin, 2000 Skin + ultraviolet light + vitamins 2 mya early members of genus homo started moving from cool forests to open plains to find food Individuals born with less hair had a survival advantage Moving to a sunnier environment meant great exposure to UV light Melanin shields folate from the effects of UV light Folate: B vitamin produced in the dermis and epidermis, can be replenished through diet: important for proper cell division, key for proper growth in utero, and during infancy. In children and adults is important to produce healthy red blood cells and to prevent anemia Vitamin D: is made naturally in the body when UV sunlight hits the skin. Vitamin D is key for building strong bones, for a strong immune system, for cell proliferation and for an adequate functioning of the brain, heart and pancreas Those with less melanin could still produce vitamin D in environments with less sunlight. This is also safe in areas of high altitude because UV light is not strong enough to damage folate. problem=when they live in tropical areas with high exposure to sunlight. Skin cancer (b/c folate helps to prevent it) Skin color is a simple adaptation to 2 conflicting selective forces: Protection from overexposure to UV rays Adequate UV exposure Adaptation to altitude Mechanisms that have evolved to maintain homeostasis evolved at lower altitudes High altitude environment = stress on the body Hypoxia: body is deprived of adequate oxygen supply People of tibet Live at 12,000 + feet 7,000-25,000 years of occupation at these altitudes Proof that natural selection (given enough time) will increase frequency of advantageous traits Just for comparison: knoxville (886 ft) Antimicrobial resistance Since the 20th century, antimicrobial products reduced the threat posed by infectious diseases These “wonder drugs” (combined with improvements in sanitation, housing, and nutrition) has decreased deaths from diseases that were previously widespread, untreatable, and frequently fatal Conclusions Genetics bring about human variation: gene flow, mutation environment /culture brings about human variation: sickle-cell anemia and antimicrobial resistance geography/physiological stresses bring about human variation: skin pigmentation, developmental acclimitization in high altitudes 5 April 2016 The Human Life Course Introduction Genetics will always prevail over cultural influences Some genetically determined things can be influenced by culture Stature weight Key terms Growth: increase in mass or number of cells Can be a type of development Development: differentiation of cells into types of tissues and their maturation Examples of development Molar development, cells formed for vision purposes, epiphyses fuse in long bones All of these examples occur because of cell differentiation Growth Begins at conception and ends in early 20’s 3 crucial growth periods: 1. First 6 months in utero., 2. From birth to 4 years of age., 3. Puberty Adolescent growth spurt Differs between girls and boys Growth and development Brain development occurs in stages: 0-10 months (neurons develop) Birth to 6 years (voluntary movement, reasoning perception, frontal lobes development) 7 to 22 years (brain at 95% full brain size, prefrontal cortex or impulses and decision making development) Most mammalian species: at least 50% of its adult brain size prior to birth Why? (Rosenberg and Trevathan, 2001) Factors that influence growth and development: Nutrition (most important) Genetics (polygenic traits) Hormones Environmental factors Nutrition Nutrition is the most important factor in healthy growth and development In utero nutrition (most important for 2 reasons) Our evolutionary history contributed to our nutritional requirements Because of culture, our evolutionary advantages are now becoming disadvantages Our ability to store fat Type 2 diabetes In the past, it only occurred in older individuals living in the developed world By 2025, predicted that 70% of cases will be in developing nations (WHO) Also affecting the younger people Hormones 2 important hormones for growth and development: 1). Growth hormone: promotes growth and affects all other body cells 2). Insulin: affects metabolism and glucose levels. Helps Environment Altitude and climate can impact growth and development Exposure to sunlight: vitamin D is necessary for proper skeletal growth (rickets) Infectious disease: if during childhood it can often delay growth Feral Children Genie: found in 1970, 13 years old, 59 pounds and 54 inches tall Many case studies conducted on the growth and development of feral children Pregnancy birth and infancy Pregnancy is different according to cultural influences Who can get pregnant, when, and with whom? Once pregnant, what should the women eat, what should she do or not do? Infancy is the period when nursing takes place (4 years of nursing is the norm) What is the evolutionary advantage to breastfeeding? (protects their immune system, less likely to ovulate) ChildhoodChildhood: the time between weaning and puberty when the brain is completing its growth and the acquisition of technical and social

¨Australopithecus Sediba (This species predates early homo) ¨ ¨Homo habilis vs. Homo rudolfensis (study date ranges & epochs) ¨Physical characteristics of: ¤Homo habilis ¤Homo rudolfensis ¤Homo erectus¨Turkana boy ¨Tool technology and cultural evidence (H. habilis & H. erectus) (study date ranges & epochs) ¨Homo floresiensis ¤Hypotheses concerning its ancestors¨Morphology of H. heidelbergensis & Neandertals ¨Technology & Social organization ¨Modern human origins ¤2 hypotheses & evidence¨Anatomically modern humans ¤Cultural evidence ¤Morphology ¨Evolution of skin color. Watch video again if needed: http://www.ted.com/talks/nina_jablonski_breaks_the_illusion_of_skin_color ¨ ¨Examples of acclimatization ¨How did the lab relate to our discussion of race?¨Courses of the human life ¨What effects growth and development? ¨Success of humans as a species

Australopithecus SedibaLocation: South Africa (Pliocene)When: 1.977-1.98 Mya Skeleton resembled from early australopithecus and early hom Upper chest, teeth, and length of arms/legs close to closest to austra Lower chest, cranial, pelvis, facial features, premolars and molars closest to homo Showed signs of bipedalism, began evolution of upright walking A.S. was partially arboreal and partial bipedal Long arms and small bodies Difference in dentition→ change in diet Homo HabilisLocation: Eastern and Southern Africa (Pliocene)When: 2.4-1.4 mya Larger cranium, smaller face, visible prognathic brow Stronger jaw muscles could eat tougher foods Early stone tools Survived bc they could eat food that wasn’t in season Homo Hab and Homo Rudolf coexisted Homo RudolfensisLocation: Eastern Africa (Northern Kenya/ Tanzania) (Pliocene)When: 1.9-1.8mya Larger braincase, longer face (Homo features) vs Larger molars and premolars (Austra features) Powerful chewing Homo ErectusLocation: Eastern, North, and South Africa; West, East Asia (Pleistocene)When: 1.89-143,000 m/kya Human like proportions- longer legs than arms compared to the torso Capacity to walk and eventually run long distances Expanded braincase vs face Turkana Boy (can someone add info?) Acheulean Technology Tool TechnologyOldowan Stone Tool2.6 mya-hammer stones, stone cores, sharp stone flakesAcheulean Stone Tools1.76 mya-hand axes, large cutting toolsMousterian Technology(H.Sapiens, H. Heidy, Nean)Levallois Technology -made to shape stone coresCulture EvidenceStone tools, hearths, social interaction, signs of eventually caring for the weak and oldHomo Floresiensis (Pleistocene)Where: AsiaWhen: 100-50 kya 3’6, tiny brains, large teeth (in comparison to size), forward shrugged shoulders, no chin, forward head, large feet→ short legs Used stone tools Hunted, maybe used fire Dwarfism→ pigmy elephants as prime food source Hypothesis: may represent modern human w/ diseas or growth disorder. Scientist still trying to figure out Flor and other homo connectionsHomo Heidelbergensis (Pleistocene)Where: Europe, Asia, South and East AfricaWhen: 700-200 kya Large brow ridges, large braincase, flat face, short wide bodies that conserve heat, wide nose, big naval opening Used fireplaces as social hangouts, heat sources, sharing food, ward off predators 1st sign of natural shelters Homo Neanderthalensis (Pleistocene)Where: Europe, South Western to Central AsiaWhen: 400-40 kya Closest extinct human relative Large middle part of face, angled cheek, huge nose for humidifying and warming cold, dry air Short, stocky body→ helps adapt to cold environments Improved levallois technology Big as or bigger brain than ours 2 Hypothesis Replacement Hypothesis: “out of Africa” recent speciation event constrained in time and space. No breeding occurred. Multiregional hypothesis: Modern humans at least in part descended from their archaic regional predecessors in the Old World. Anatomically Modern Humans (Pleistocene)Where:When: 100 kya Small faces Chins!!! Smaller teeth and jaws Round skulls w/ vertical foreheads Cultural Evidence Spear throwers Barbed harpoons Bow and arrows Symbolic representations; i.e. cave paintings, engravings, venus figurines Evolution of Skin ColorApproximately 2 million years ago, early genus homo began migrating to cooler and open plains to find food. If you lived in a sunnier environment, you were exposed to UV light. Your skin adapted to that light by having a darker melanin which protected your folate. When the UV light hits you, Vitamin D is naturally being made. Any melanin type can produce Vitamin D. Those who did not live in an environment closest to the sun’s rays had less melanin bc their skin didn’t have to adapt to protect themselves. They also should stay around less sunlight/UV rays so that folate can prevent skin cancer.Extra info- those born with less hair had a survival advantage- folate is Vitamin B in the dermis and epidermis and is important for cell division, cell division, growth in utero, and during infancy-Vitamin D is good for strong bones, immune systems, cell proliferation, adequate functions of brain, heart, and pancreasSimple adaptations to 2 conflict selective forces Protection from overexposure to UV rays Adequate UV exposure Example of AcclimatizationTanning- short, long, or permanent(definition: physiological responses to changes in the environment that occur during an individual's lifetime)How did our Lab relate to our discussion about race?Idk if I can answer this effectivelyCourses of the Human Life (Holocene)Key termsGrowth: increase in mass or number of cellsCan be a type of developmentDevelopment: differentiation of cells into types of tissues and their maturationExamples of development Molar development, cells formed for vision purposes, epiphyses fuse in long bones All of these examples occur because of cell differentiation Growth Begins at conception and ends in early 20’s 3 crucial growth periods: 1. First 6 months in utero., 2. From birth to 4 years of age., 3. Puberty Adolescent growth spurt Differs between girls and boysGrowth and developmentBrain development occurs in stages: 0-10 months (neurons develop) Birth to 6 years (voluntary movement, reasoning perception, frontal lobes development) 7 to 22 years (brain at 95% full brain size, prefrontal cortex or impulses and decision making development) Most mammalian species: at least 50% of its adult brain size prior to birthWhy? (Rosenberg and Trevathan, 2001)Factors that influence growth and development: Nutrition (most important) Genetics (polygenic traits) Hormones Environmental factors Nutrition Nutrition is the most important factor in healthy growth and development In utero nutrition (most important for 2 reasons) Our evolutionary history contributed to our nutritional requirements Because of culture, our evolutionary advantages are now becoming disadvantages Our ability to store fat Type 2 diabetes In the past, it only occurred in older individuals living in the developed world By 2025, predicted that 70% of cases will be in developing nations (WHO) Also affecting the younger people Hormones 2 important hormones for growth and development: 1). Growth hormone: promotes growth and affects all other body cells 2). Insulin: affects metabolism and glucose levels. Helps EnvironmentAltitude and climate can impact growth and development Exposure to sunlight: vitamin D is necessary for proper skeletal growth (rickets) Infectious disease: if during childhood it can often delay growth Feral ChildrenGenie: found in 1970, 13 years old, 59 pounds and 54 inches tallMany case studies conducted on the growth and development of feral childrenPregnancy birth and infancyPregnancy is different according to cultural influences Who can get pregnant, when, and with whom? Once pregnant, what should the women eat, what should she do or not do? Infancy is the period when nursing takes place (4 years of nursing is the norm) What is the evolutionary advantage to breastfeeding? (protects their immune system, less likely to ovulate) ChildhoodChildhood: the time between weaning and puberty when the brain is completing its growth and the acquisition of technical and social Success of Humans as a Species - speech- advanced technology(please add more)