Transcript for:
Exploring Human Evolution Through Fossils

Paleoanthropology Study of the immediate ancestors of humans (homininis) * Relies on fossils * Geographically specific * East and South Africa * East Asia * Middle East Process of Fossilization Fossilization is rare * Less than 10% of species are represented * 95% of fossils are marine animals Taphonomy * Study of decomposition * Process may be arrested by * Dry * Cold * Wet (anaerobic environments) Fossils Fossilisation: * Rare process * Conditions must be just right Types of fossils: * Sedimentary rock * Volcanic activity Dating Fossils How old is old? Relative Dating: * Give a relative assessment * Does not give a specific date * One strata is younger or older Absolute Dating: * Give a range of dates * More accurate than relative dating Law of Superposition: the further down you go down, the farther back you go in time. Index Fossils Certain fossils used to date strata * Changes in fossil organisms can reflect changes in paleoenvironments * Useful in paleontology and economic growth Relative Dating - Fluorine Fluorine is an element found in soil * Leaches into bones * Amount of fluorine gives a relative age * The more you have in the bones, the older it is * Amount of fluorine depends on the soil * There is a limit Relative Dating - Cultural Dating Common in archeological contexts * Based on the Excavation of a site * Analyze the change in artifact styles over time * Putting the artifacts in order → noting the changes in styles → you are able to replicate a timeline. Absolute Dating - Dendrochronology * The first absolute dating method that was developed. * Based upon some archeological sites in the midwest Principles of Cross Dating: comparing different trees to find the ring patterns; this allows us to assign exact dates to each ring Absolute Dating - Radiocarbon * Based upon the decay of unstable isotopes * Takes 5,730 years for half of the carbon 14 to decay * 1950 is consider present * When you get passed 50,000 years you can’t use carbon dating because the carbon 14 is gone. Absolute Dating - Chemical Dating Techniques This is how a lot of fossils are dated * Rely on half-lives of radioactive elements * Potassium-argon (K-Ar) dating * Half-life: 1,250,000,000 years * You are not dating the fossil directly, you have to bracket it. * Uranium Series (fission track) dating * Half-life: 4,500,000,0000 years * Areas where you do not have volcanic ash * Composes into lead * The ranges of dates are not as precise as potassium-argon dating Archeological Recovery Used on paleoanthropological context “To dig is to destroy” * Mapping of fossil-rich areas * Recording of strata/geology * Measuring spatial distributions in 3D space Bipedalism This occurred 1st Upright walking Facultative Bipedalism: not their main method of locomotion. * Some primates * It's not their preferred but they can do it Habitual Bipedalism: our main way of getting around, locomotion * Birds * Macropods (kangaroos) * Dinosaurs (T-Rex) * Homo sapiens (humans) Hypothesis of Bipedalism Why did it arise? Hunting (no longer believed): * Darwin believed we are bideds because we are hunters; we use our hands. * proposed that the caves and sinkholes were the early sites of the hominins. * Osteodontokeratic technology: bone, tooth, horn. * To go out and kill other animals to bring back to their home base. * Raymond Dart: * Involvement in the 1924 discovery of the first fossil found of Australopithecus africanus. * Said they are not using modified stone tools, but unmodified items are weapons to kill things. * The horn of an antelope Seed eating hypothesis: * Proposed by Clifford Jolly * He thought the early hominids were inhabited in an open grassland environment. * Efficient for gathering seeds * Can see predators more easily * Maybe it helps with survival. Thermoregulation * Radiator hypothesis * Better cooling for the body; you are on two legs and the sun is only beating down on the top of your head vs your back. * Dean Falk Patchy Forest Hypothesis: * Peter Rodman and Henry McHenry * African Forests became fragmented * Bipedalism may have begun in the trees (gibbons) * Used to walk between patches of food resources Male provisioning: * Owen Lovejoy * Monogamous pair bonding * Males assisted w/ child-learning * Provided for defense Chimpanzee hypothesis: * Andrienne Zihlman * Early homininis did not form pair bonds Traits in Fossil Record Traits: * Primitive: a trait that was possessed by a last common ancestor; ex: opposable thumb * Derived: specific to a species or a group of species; ex: bipedalism Convergent evolution: * Convergence of traits in dissimilar creatures Parallel evolution: * Parallel development in two environments * Two different environments, yet the plants and animals mirror each other. Ex: australia. Homologous traits: (homology) * Similar due to a shared ancestry * Ex: frogs, horse, human. (single bone humerus, radius, ulna and metacarpals) Homoplastic traits: (homoplasty) * Similarity but no common ancestor Anatomy of Bipedalism Derived traits of bipedalism * Position of foramen magnum * The more center it is, the more biped they are. * Shape of pelvis * Arched foot * In line big toe (hallux) * Limb proportions * Musculature Born to Run? * Hypothesis that humans are designed for long distance running. * Takes evidence from several American Indian tribes and physiology/anatomy. Other Human-Like Traits * Reduced canine * Masticatory muscles * Enlarged brain (cranial capacity) * Enamel thickness * Nonhoning canines The First Hominins Miocene Epoch (23-5 mya) * Large expanses of tropical and subtropical forests * First biped fossils * Prob time of the split between humans and chimps Early Hominins Sahlenthropus Tchadensis: * 7-6 mya * Discovered in 2001 by M. Brunet in France * Found in Chad * 350 cc cranial capacity * Ape like * Massive brow ridge * Non-honing chewing complex * Forest environment * Possible knuckle-walker? * Likely not a biped * Femur morphology * Ulna morphology * Ulna consistent w/ quadrupedalism Orrorin Tugenesis: * Discovered in Tugen Hills, Kenya * 6 mya * Mostly postcranial elements * Mandible fragments * Suggestive that it is a biped * Chimpanzee-like teeth * Lived in dry forest environment Ardipithecus Kadabba: * Discovered in Middle Awash, Ethiopia * Fossils include postcranial bones and teeth * Not a whole lot to go off of to piece a body together * 5.8 - 5.2 mya * Lived in mixed woodland environment * Big toe is broad and flat * Indicates push off by big toe in locomotion similar to humans afrdipithecus Ramidus: * Found in Ethiopia * 5.5 - 4.5 mya * Bipedal? * Opposable hallux * Not flexible * Many primitive ape-like characteristics * Ancestral * Thin enamel * Forward foramen magnum These are called pre australopithecus Pliocene Epoch Environment * Cooler and drier than the Miocene * Expansion of the grasslands in Africa * Appearance of large grazing animals * Megafauna Australopithecines (4 -1 mya) Their brain size is the same as modern apes Genus: Australopithecus * Paranthropus? * “Robust” australopithecines” cranial anatomy, highly specialized in what they are eating. Like gorillas. * “Gracile” australopithecines; not as robust. * Bipeds * Ape-like body proportions * arm/leg ratio * Ape-like brain size * Geography Australopithecus anamensis Earliest australopithecine *** Oldest one * Ethiopia * Ape-like characteristics * Large canines * Parallel tooth rows * Bipedal femur Australopithecus afarensis Found in early 1970s * Donald Johanson * Found 40% of the skeleton “lucy” * After the Beatles song, “Lucy in the Sky” * Many ape-like characteristics * True biped * Primitive Characteristics: * Teeth * <500 cm brain (small brain) * Ape-like face proportions * Curved phalanges * Long arms Australopithecus africanus Discovered in 1925 “The Taung Baby” Raymound Dart * Not immediately accepted as a hominin. For 2 reasons: * It's a child; who knows what it would have looked like as an adult * They already exhibited a fossil that was a good candidate and was accepted by the other anthropologists “Piltdown Man” Found in south africa Characteristics: * Ape-like face * Ape-like body proportions * Omnivores * Relatively long arms/ shorter legs * Anatomy is more gracile Australopithecus (Kenyanthropus) platyops 3.5 mya 400 - 500 cm^3 cranial capacity * Derived characteristics * Flat faced (platyops) * Small molars Australopithecus garhi 2.5 mya * Small brain 450 cc * Some features indicate it may be ancestral to early homo * Gracile features * Smaller teeth * Used tools? * If we used tools, chimps used tools, very possible that our latest ancestor also used tools. (modified stone) Australopithecus sebida Discovered in 2008 One of the later australopithecus Characteristics: * Smaller teeth * Pelvis similar to homo * arm/leg like australopithecines. Robust Australopithecines: (Paranthropus) 3-1 mya Characteristics: * 410-530 cranial capacity * Sagittal crest * Very large teeth * Dish-faced Three members of Genus: * A. Boisei * A. Aethiopicus * A. Robustus Australopithecus aethiopicus The “black skull” 2.5 mya Flattened cranial base * Small brain: * Very large teeth * Perhaps ancestral to boisei Australopithecus robustus Behavior: * Lived in large groups * Specialized diet: seeds, nuts, tubers * Robustus australopithecines thought to be an evolutionary “side branch” * Disappeared about 1 mya Australopithecus boisei * Zinj (name that was given by Louis L who discovered it) * Large molars but small canines * Sagittal crest * Large jaw Pleistocene Epoch Begins when homo habilis shows up 2.6 mya - 11,700 ya * One of the earlier cooling periods on earth (the last great ice age) * Glacials * Interglacials * Sea level 130 meter (145 feet) lower than today Early Homo 2.5 - 1.8 mya East Africa * East Turkana * Hadar * Olduvai Gorge South Africa Homo Habilis * 550 - 800 cc cranial; larger (631 cc average) * Sexual dimorphism * Greater than homo sapiens * Human-like dentition * Reduced face Homo habilis - OH 62 Found in 1980s - Olduvai Gorge Australopithecine-like postcranial remains * Skull can not be reconstructed * Short legs, relatively long arms * From the neck down it is very australopithecine Australopithecus habilis? OH 24 Bernard Wood and Mark Collard * Homo habilis very different from later homo * Primitive face * Primitive limb proportions * Should be considered an australopithecine Two Species? KNM ER 1470 * Really big cranium * Teeth are bigger * Larger body size * Found in Kenya * Sometimes considered homo rudolfensis Stone tools - the Oldowan Complex Olduvai Gorge, Tanzania * Louis Leakey * Until you find a homo habilis with tools in their hand, you don’t know who is making these * Stone tools at same level as homo habilis and late australopithecines * Simple stone tools * Simple reduction process * Take one rock against another rock, shaking off flakes. Creating cutting implements. Oldowan Tools Commonly used obsidian - volcanic glass; very sharp Hammer stone → core stone → flakes Homo Habilis - precision grip Flexor pollicis longus * Precision grip * Originates along the radius * Inserts on the ventral surface of the 1st terminal phalanx Homo Habilis the Scavenger Scavenger hypothesis: “homo habilis is starting to eat more meat than the australopithecines did” * Pat Shipman came up with the hypothesis * Groups of H. habilis began to eat meat * Opportunistic scavenging * Oldowan tools * Based on cut marks of animal bones * Something had taken a sharp tool, and cut away the meat Early Homo and Meat Eating Advantages * Increase in calories * Rich in vitamins and nutrients * Reduced digestive system * Expansion of the brain * Early weaning of offspring * Aids childhood growth and development South African Homo Habilis SK 847 (total number of fossils period) * Evidence for early homo in south africa * Homo ergaster? Other fossils present * Mostly small pieces and teeth Homo naledi Discovered in 2013 by Lee Berger in Rising Star Cave 336 - 236 kya (thousand years ago) * Longer arm/leg ratio * Skull features: * Small brain * Sagittal keel * Relict population? Group of organisms that has persisted in a restricted area after being more widespread in the past Homo erectus Asian form First discovered in 1891 in Java * Eugene Dubois * Skull cap and a femur * Later dated to 1.6 mya * Named it “Pithecanthropus erectus” Homo ergaster Found in East Africa Early homo erectus * 1.8 - 0.3 mya * 900 cc cranial capacity * Human-like limb proportions * Human-like teeth (smaller molars) * Less sexually dimorphic Homo erectus (ergaster) “The Nariokotome Boy” WT15000 * West Turkana * Aged about 15 at death * 5’3 tall (taller as an adult) * 880 cc cranial capacity Ileret, Kenya Erectus 1.51 - 1.53 mya * Anatomy almost identical to homo sapiens * Features an in-line hallux and an arch * Reveals truly human form of bipedalism Acheulean Technology * The tool is flaked on both sides to create a cutting edge * They vary in size * You have a point, cutting edge, then a chopper on the bottom (3 tools in 1) Homo Erectus: Out of Africa Dmanisi, Georgia (6 individuals were found at the site) * Found in 1990s * 1.7 mya * Relatively small brain * Evidence homo erectus left africa early in evolutionary history Asian Homo Erectus * Physiology * Characteristics: * Greater robusticity * 850 - 1100cc cranial capacity * Heavy browridges * Low forehead * Sagittal keel * Nuchal torus Zhoukoudian, China Erectus “Peking Man” * 1929 - Pei Wenshong * 1930s - Franz Weidenreich * He described the fossils * Cave site * Dates to 670,000 to 410,000 ya * At least 14 individuals * Cultural debris (some tools and ancient hyenas) * The 1st site to have evidence of fire * Hunting * They had heavy clothing Homo Erectus Culture * Acheulean technology * Africa, Europe * East Asia? - chopper/chopping tool complex * Tool differentiation in later H. erectus sites * Tools found on indonesian islands * H. erectus embraced culture as a survival strategy * The islands present suggested that there were use of rafts for them to cross the water Homo Erectus and Fire Direct evidence: * The earliest site is the Daughters of Jacob Bridge Site in Israel * There were traces of ash * 1 mya Indirect evidence: * Geography - living in cold places (you would need fire to survive that climate * Cooking - when did that show up? Cooking Richard Wragham (he thinks it began with homo erectus) Advantages: * Releases nutrients (helps breaking down the rough wall of the food) * Easier to digest * Led to longer life span * Implications for societal formation * You can wean offspring sooner with softer foods * Birth rate increases Late African H. Erectus Bodo, Ethiopia * John Kalb * 600 kya * Very robust * 1250 cc cranial capacity * Uncertain technology * Cutmarks? * Was he butchered * Eaten * Or evidences of symbolic sacrifices Homo Erectus (1.8 may 0 300,000 ya) Interpretations: * 1st to leave Africa * Efficient bipedalism * Human-like body size * hunting /cooking/ butchering animals * Relying on clothing * 1st biocultural creature * Which has caused speculation of early homo sapiens Homo Heidelbergensis Homo erectus populations begin to differentiate Probably represents multiple species * Retain many H. erectus characters Derived Characteristics: traits that have evolved in a lineage and are distinct from ancestral traits * Increased brain size * More rounded brain case * Dental reduction * Less angled occipital Atapuerca, Spain 28 Hominins were found in this site Gran Dolina * Discovered in railway cut * 850 - 780 kya * “Homo antecessor” original name given; not used much anymore * 1000cc cranium * Homo erectus-like morphology * Occipital bun * Human-like body size Africa Kabwe (Broken hill), Zambia * 600 - 15 kya * Erectus-like browridge (very large prominent) * Low vault * Large occipital torus * Modern cranial base/ thinner cranial bones * 1300cc cranial capacity Asia Also display a suite of primitive and derived characteristics Dali, China * 230 - 180 * 1120 cc Jinniushan, China * 200 kya * 1260cc * Modern homo sapiens-like braincase Europe Arago, France * Prominent brow ridges Steinheim, Germany * Large braincase * Round occipital * Flat face * Cranial base is broken Middle Pleistocene 780 - 125 kya The Ice Age * Glacials (big glaciers and expansion of ice caps) * Interglacials (warm periods, desert areas expand and ice retreats) * Restricted or encouraged hominin migrations * Sea level drops during glacials * Food resources change *** Need to know: Conversion of Evolution and parallel evolution. Schoningen Spears Set of wooden spruce spears * Made out of ash, no stone tips * Found in lignite coal mine * Date to 380,000 - 400,000 kya * 6 - 7.5 ft long Neanderthals “Late Archaic Homo Sapiens” in the txtbook Found from Spain all the way to Middle East and Central Asia Skull is larger than homo sapiens; larger jaw and larger cranial space They have derived characteristics: * Projective midface * Large nose * Large cranial capacity (1500cc) * Occipital bun Derived characteristics not shared with us (Primitive): * No chin * Large brow ridge * Low forehead *Almost all neanderthals that were found had some sort of injury to them 300 - 30 kya Europe and Middle East Pleistocene of Europe: Homo neanderthalensis 1856 - Neander Valley, Germany * Limestone quarry * Neanderthals started to be appreciated for what they were 1829 - Engis, Belgium * Some neanderthals found 1848 - Forbes Quarry, Gibraltar * Some neanderthals found 1908 - La Chapelle, France Site 60,000 ya * Was buried * Flexed (same position at birth) * Severely arthritic * Led to interpretation of “brutishness” * Compassion? * 1620 cubic cm brain - one of the largest brains ever found Sanidar, Iraq Site Shanidar Cave 45 - 35,000 ya Shanidar 1 * Hints at the neanderthals took care of their groups * Healed cranial fracture on left side; but impaired vision * Lost the use of his right arm through injury * 1600 cc * 5’7” Teshik-Tash, Uzbekistan Site A single 9 year old child was found * 70,000 ya * Intentionally buried * Ibex horns placed around the grave Neanderthal Culture Mousterian tool technology: * Central core * Flakes driven off core * Produced more cutting edge * Much more efficient * Levallois technique: Subsistence: * Big game hunting * Lived in sub-arctic conditions * Did hunt big animals * Had handheld spears; used close-proximity spears Neanderthal Culture Cont: * Burials * Wore more form fitting clothing * Evidence for symbolic behavior * Site in Switzerland shows the remains of their culture practices * Artwork dated to 43,000 ya Neanderthal Genetics Series of studies * Diverged from other hominins around 550 kya * Less genetic diversity = small population * Evidence of inbreeding Homo sapien genome * Evidence in inbreeding * 1-4% of DNA is neanderthal * No neanderthal mtDNA lineages in modern humans What does Neanderthal DNA mean for homo sapiens? * Advantages: * Toleration of low oxygen * Improved blood coagulation * Fewer miscarriages * Freckling, skin pigmentation * Disadvantages: * Allergies * Depression * Skin cancers * Blood clots, strokes Homo Denisova “The Denisovans” * Discovered in 2008, in Altai Mtns * DNA differs from humans by 385 bases * Equally distant from homo sapiens and neanderthals The “Dragon Man” Skull * Found in China, 1930s * 138,000 - 309,000 ya * Morphology more like homo sapiens than neanderthals * DNA not recovered Penghu, Taiwan * 130,000 - 190,000 ya * Male mandible * Genetics = confirms distinct species from homo sapiens and neanderthals * That it was denisovan Denisovan DNA 1 - 4% of dna of modern humans * Highest percentage in Tibetans, Melanseians, and Australian Aborgines (3-5%) Advantages: * High altitude adaptations Homo Florensiensis “The Hobbit” Flores, Indonesia * Discovered in 2003, several were found * Dated from 80 to 18,000 ya * Small stature * 3.5 ft A dwarf species Island Dwarfism Large animals get smaller over time * When you isolated large animals on an island, they tend to get smaller; a smaller body needs smaller food (think of Journey Mysterious Island) * Genetics: possible inbreeding * Examples: mammoths * Island gigantism: small animals get bigger Early Homo Sapiens Fossils African Sites * Earliest dates * 300 kya Unique Homo sapiens morphology: * High forehead * Reduced brow ridge * Chin rounded cranium * Less robust Homo Sapiens sapiens Africa Jebel Irhoud, Morocco (oldest specimen found there) * Dates: 300,000 ya * Discovered in 1961, redacted in 2017 * Neanderthal-like tool technology Herto, Ethiopia * Dates: 160,000 ya * Modern homo sapiens morphology Klasies River Mouth, South Africa * Dates: 110,000 ya * Mandible w/ chin * Relatively thin cranial bone thickness Middle East Skhul V * Location: Mt. Carmel, Israel * Dates: 120,000 - 80,000 ya * Contemporaneous w/ neanderthals Qafzeh, Israel * Dates: 100,000 ya * 5 individuals * Qafzeh 11 ( 13 years old, buried with red deer antler inclusion) Asia Tam Pa Ling, Laos * Dates: 63,000 - 43,000 ya * Oldest homo sapiens fossils in SE Asia * No artifacts recovered Europe Oase, Romania * Dates: 39,000 - 41,000 ya * Multiple individuals found in cave * Cave bear remains were placed around cave Cro-Magnon, France * Dates: 32,000 - 30,000 ya * Rockshelter * 5 individuals were found and had some kind of trauma on their skelton Australia Lake Mungo * Dates: 40 - 68 kya * 2 individuals were found * Fully modern homo sapiens * Simple inhumation (male) * Cremation (female) North America * First humans arrive * Dates: 13,500 ya * Different interpretations * Original : people migrated from siberia/alaska down into north america due to the ice age * Sea faring hypothesis: Instead of walking and following herds, instead they sailed along the coast. * Different timing? * Different sources? * Clovis Technology: (oldest recognisable technology) * Clovis, New Mexico (1st found) * Designed for big game hunting (mammoths among other animals) * Anzick 1 (Montana) * 12,700 BP (Before Present) * DNA; indicated that paleolinians are the primary ancestors to modern native americans Intermixing? Lagar Velho, Portugal * Dates: 24.5 kya * Has a mix of homo sapiens and neanderthals traits * Modern features: chin * Neanderthal features: robust; short limbs Oase, Romania * Dates: 40,000 kya * Genetic analysis: 6-9% of DNA derived from neanderthals The Upper Paleolithic (homo sapiens) * Cultural period began in Europe about 40,000 ya * Industries based on sophisticated tool technologies * Fine, thin blades are produced * Atl-atl: way to increase the velocity of a spear throw Chauvet Cave Discovered in 1990s * Oldest cave art in Europe * Dates: 30,000 ya * Horses, cave lions, and rhinos were represented on the walls * They are using the uneven cave surfaces of the wall to create a 3D effect North America First humans arrived about 13,500 years ago * Differing interpretations * Different timings? * Different sources? Clovis Technology * Clovis, New Mexico * Anzick 1 (montana) * Dna