Human Evolution - Lecture notes 1-8 PDF

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Human Evolution Did you descend from the apes on your grandmother’s or your grandfather’s side Numerous non-scientific explanations about human origins  These will not be dealt with in the next three lectures Only scientific facts, theories and hypothesis will be covered Theroies: closest thing we have to a statement of fact – in science we cannt prove things we can only disprove things Hypothesis – is an opinion about an explanation on something Numerous non-scientific expalantions about human origins Intelligent diesign currently popular magical thinking in non –scientific circles Summary of the scienttic explanation Dawn of humans-homo argaster-homospaiens Own from trees- bigger brain- developed tools The details will take a bit longer to elucidate

The topic has been much debated Origin of species (darwin 1859) – sciene Racial caricatures- the cartoon from Puck clearly illustrates English Victorian era views about lesser races in the case of the Irish Social Darwinism: has been used repeatedly to justify one ethnic grou’s abuse or domination of another- such attitude involve incorrect assumptions about human evolution Huxle vs Wilberforce At the 30 Junes 186 british association meeting, Tomas Henry Huxlet a friend of Dawrin, debate the origin of species with Bishop Samuel Wilberforce ,mouth piece of anti-evolutionist Sir Richard Owen

Human evolution: the science  Where do humans fall in general classification?  When did humans/hominid/hominin lineage diverge from other great apes?  How diverse is the human lineage through time?  When and where did homo sapiens first appear in the fossil record?  How many races of Homo Sapiens have Evolved? – can we dvide races into taxonomical useful groups Phylogeny of Mammals  Mammals- female produce ilks ton ourish development lung, have air  3 kinds of mammals o Monotremes- egg laying o Marsupials-pouch maturation- developing fetus is born very immature, crawls into puch and latches onto milk gland and continues development into the pouch o Placental Mammals- specialized embryonic organ attached to the wall of the uterus Phylogeny of Eutherians  Afrotheria- aardvark, elephant, manateem hyrax  Xxenarthra- armadillo, sloth, anteater  Euarchontoglires tree shrews, lemurs, monkeys, great apes, squirrels, mice, rabbits  Laurasiatheria – Primates and people-important dates  Primates are one of many groups beling to Euracrontoglires (mid cretaceous 90-85 mya)  Great apes appear in the fossil record about 20 million years ago  Hominids appear between 5-8 million years ago  The genus homo is about 2.8 mllion years old  Modern humans appear in the fossil record about (3000,000 ybp) Moroccco o Very recent evolutionarily Hominid phylogeny  Some details of geat ape evolution are shown in this diagram

Taxonomics can be divided into 2 gorup- Lumpers vs splitters  Lumpers like fewer categories  Splitters- like smaller units  Taxonomists fall somewhere on the contrime of extree lumers to extreme splitters  This means that there are different opinions on how many specis, genera and familes if great apes should be recognized  This makes reading about human evolution confusing….same name but different applications Changes in the numbero f taxa - Re 1965 there were far fewe fossils known but many of them were placed into different spcies in different genera…splitters were active - Then lumpers sorted through much of what was known and the phylogeny became rather simply Hominid Phylogeny (earlier brances) - The first great apes, “dryopithecines” lasted from 20-10 mybp; they gave rose to 2 branches: one African and Asian - Asian- dpongidate-orangutan - African-panina hominae Dryopithecines: dryopithecus - Dryopithecus and related genera were the first great apes - The oldest appear in the fossil record about 20 mybp - They were small arboreal primates about the size of a big cat or a dog o Little more htan a money without a tail - Drypithecines: the first great apes o Tryopithecin Pongids: earlier brances - The Dryopithecine Ramapithecus- were first thought to be in direct line to humans - Additional data places it in the pongid line (orangutans) Hominid Phylogeny: the fossil gap - There was a gap in fossil record for 9-4.5 mya - Before the gap only dryopithecines and pongids are known - the gap is being filled in with early recent finds of early hominid fossils increasing numvwwe od doaail dinsa - mant importat fossils have been ound onl in the last 35 years some in the last 18 years - pre 1900- we knew about neanderthalenesis and homo erectus - 19240 australopithecus africanus - your life span- sahelanthropus, tchandeis, - the oldest hominids have bee nfound most recently - 1944: graecopithecus freybergi – in 2017 someone figures out it was a hominid

hominid Phyloheeny: Bi pedal locomotion - an important parto of human origins was the evolution of bipedal locomotion o gorillas knuckle walk o chimpanzees can stand and walk on 2 legs but are not really evolved to do so efficiently- prefer to knucle walk- really aren’t designed for bipedal locomotion o all hominids stand and walk on 2 legs although with varying degrees of efficiency - Bi pedal locomotion is not as efficient or as fast as quadrupedal locomotion – why did it evolve Human phylogeny: where - All early hominid fossils come from the right Valley of East Africa- Gorillas and chimpanzees come fro mcentral and west African forests Why did the African Dryopithecine line split - Chimps and corrilas stayed in the forrest -> east Africa dried out over multiple mllions of years ago- continuous forrest dried into smaller and passages close to the rivers with vast lsavannah and grasslands - Changing habitat in the Rift Valley o Arberiousral great ape- as it dried out you get open spaces between the treesecomes necessary for great apes to move across the bucn hof trees to another Changing selection pressures in the Rift Valley - Changing selection pressures in the rift valley - Changing habitat resulted in new selection pressure that favoured bipedal locomotion which in turn allowed new sills and traits to evolve - Changing habittalt result in new selectio nrpessures that favoures bpedal locomotion which in turn allowed new skills and traisl to evolved which in turn End Result - A different habitiat for a geat hape - A different kind of great ape - A standard pattern in evolution

Who did I evolve from? - Early human phylogeny: australopithecines- early hominids are placed in the genera Australopithecus and ardopithecus - Hominins include us homo and our ancestr Australopithecus and its ancestor ardipithecus - Some 5-10 species existed from ca. 4.9-1.5 mya - They were all +/- bipedal and had small brains Australopitecus: diversity in time and space - Boisei, ROoustus

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The fossil record is a chance discovery of rmain or evidence of some organism that lived in the past- the vast majortyiof organisms tat never lived never became a fossil 2nd lecture starts here Australopithecines- Diversity in Time and Space Easly Australopithecines - East Africa- 4.4-2.9 mya o Bipeideal, small, chimp-like in features - Adipthecus ramidus 4.4 mya (Australopithecus ramidus) - Australopithecus anamensis - 4.2-3.9 mya (jaw partial femur and partial humerus) - Australopithecus afaresis 3.9-2.9 mya- best known of the 3 species Ardipithecus ramidus (“Ardi”- adult female) - A partial skeleton from the Ethiopia in east Africa- dated at 4.4 mybp Australopithecus Afarensis “Lucy” - A 40% complete skeleton from the Hadar region, Ethopia in East Africa - Dated at 3.18 mybp - Discovered in 1975 Bipedal locomotion: Laetoli footprints - Fossilized footprints of Australopithecus afarensis from Laetoi, Tanzania are 3.5-3.8 mya - 3 sets of tracks occur ,the midsized set within a larger set Bipedal locomotion and standing - the weight of the body is borne differently in chimps, australopithecines and humans - on one leg we balance our weight over one knew with the upper leg angled inward - the hip and femur neck are a fulcrum Bipedal locomotion - bipeadal locomotion is the result of any changes in bones and muscles - the gluteus maximum is a small muscle in chimps that became the largest muscle in humans - the big toe shifted to face forward and no longer was good for grasping lie the thumb Bipedal locomotion: walking - walking involved inefficient use of muscles and nearly fully extended joints - walking is the fine art of controlled falling over Bipedal locomotion: sprinters start - sprinters crouch to get more power - joints are bent for reater muscle action om movement:

Changes in Pelvis Bone - the orientation and shape of the pelvis shifted considerably from chimps to australopithecines to modern humans Consequences of bipedalism and a bigger head on giving birth - it is much more difficult for human babies to pass through the birth canal than for chimps - the big head must rotates twice as it moves through the birth canal - Ouch!!! Bipedalism and a big head: evolutionary compromises - Contrasting selection pressures o long femur neck and narrow hips and birth canal selected for in evolution of bipedalism o wide birth canal is selected for in evolution of bigger head, but too wide makes walking and standing more difficult ( the fulcrum problem) - Solution; a compromise between ideal hips for walking and ideal hips for birthing o Human babies are born 3 moths “premature” Later Australopithecus - Eastern and Southern Africa – 2.9-1.2 mya - Bipedal or arboreal-bipedal, small to robust and less chimp like in some features - Aust. Africanus, aust. Robustus, aus. Boisei and other comnemporary with early Homo Origins of Homo - The genus Homo evolved in East Africa from an australopithecine ca. 2.8-3 mya - Transitional fossils have been placed in Homo (usually) or by some in Kenyapithecus Homo habilis - The oldest member of our genus - Fossils have been found in east Africa in deposits ca 2.8 -1.9 mi yeard old - A slighltly bigger brai than in australopithecines - The name means “handy” man; stone tools appear, but it is found even before Homo’s - Crude stone tools appeared ; but it is found even before Homo’s - Conemporary with several species of Australopithecus - Early fossils palced in Homo rudolfensis Homo habilis: fleshing out of the face - Forensic reconstruction of the face based on known and assumed points of muscle attachment Homo Naledi: a stunning discovery - Berget et al. (2015) described the new species base on 1550 hominin bones and fragments found in a single chamber of a cave in South Africa Homo naledia: were they buried

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Berget et al. (2014) and the accompanying geology paper (Dirks et al. 2015) on the Dinaledi Chamber n the Rising Star Cave syste m found the mostly undisturbed remains of at least 15 individuals who appear o have ben deliberated placed a different times in the chamber located far back in the cave system in a completely dark area - No evidence of having been placed there by a predator were they deliberately placed in that location? Homo naledi: Dinaledi Chamber - Dirs. Et al (2017) 236-335 K old - Deep in the dark zone - The bones were found in a chamber named dinaledi chamber of stars acceissibly only through a narrow chute, almost a hundred yards from the cave entrance. How they got there is a mystery. The most plausible answer so far: bodies were dropped in from above Homo a bgger brain - The genus Homo shows a significantly different endocranial to body weight ration than Australopithecus Homo: a tool maker – butchering an elephant with stone cutters ad scrapers Tools and culture - The use of stool tools changed how hominids made hteir living - Large game could be butchered and the pieces more conveniently transported Homo habisis: stone too lmaler (Oldowan culture, east Africa) probabl began with austalopithecines Homoerectus (broad sense) – made tools and used fire (Archeulian culture, variations in geography nad time) Homo neanderthalensis had a more complex culture (Mousterian culture, Europe and adjacent areas) Homo sapiens build compters, rocket ships and museums Next: Homo ergaster or homo erectus - Who came after H. Habilis, depends on whether you are a lumper or splitter- neither is wrong Distribution of homo erectus group - members of the H. erectus group left Africa some 1.8 mya (out of Africa) Homo ergaster - homo ergaster includes the Afrcan members of the Homo erectus complex ca 1.8-1.0 mybp; oldest of the complex - turkana boy 1.6 mya Ethipopia Homo erectus: “Peking Man” “Java man” - homo erectus (narrow sense) incudes the asin members of the H. erectus complex ca 1.8-005(?) mybp - cranial capcities as high as 1100 c - relatively crude stone tools associated with Asian sepcies of hominin - post crania skeleton to H. sapiens

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cranial and cultural differences distinguish the younger forms of the species from African and European forms Homo erectus complex :stone tools - homo ergaster/erectus associated with stone tools of the archeulian culture (1.4-0.5 mybo) - found in Africa (earliest) ,Europe western and soutehr Asian bust absent in East Asian - Why not in East Asian? o Tradition o Bamboo tools o Archeulian tools developed after migration o Two species? Homo florensiensis”hobbit man, flores man” - Homo florensiesnsi, recently discovered reative of H. erectus native to the Indonesian island of flores - Ca 180000 [1 mill (?)- 12,0000} ybp - Cranial capcity in range of himpanzee 390-410 cc - Less than 1 m tall Homo florensiensis “hobbit man, flores man” The history goers are complicated - If the splitters are right then the post H. ergaster history is complex with at least six descendant species: four in Africa, Europe and Western Asia - Lumpers recognize just two species Homo antecessor and H. heidelbergensis - Fossils (ca 1.2-0.16 mya) often treated as archaic homo sapiens have been placed by some in the past 20 or so into 1-2 (or more) separate species - All are transitional between erggaster/erectus types and Neanderthal and modern human types - Contemporary with H. sapiens in Africa Homo eanderthalensis “Neanderthals” - Early Neanderthal – 300,000-1000,000 ybp - Classic late neuonderthal-75 thousand-c forty thousand ypb o 13000-1650 cc brain o 1500 cc mean…bigger than H. sapiens - the species is the “cave man” f movies and stories - often is treated as H. sapeinds neanderthalensis - reent DNa data indicated no that close to H sapiens Homo neandertaelnsis” cave men and women”

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Neanderthals live in Europe and western Asian up until around the time modern man arrived from Africa- the 2 species overlapped in time if not in space Homo neandertalensis: skeleton - Late neandertals were shorter and thicker than modern humans (note the rub cage) - If dressed in a suti and put on a supway car in New York you probably would stare - Not as mucl like us as some people hypothesized in the last 30 years Homo neandertalensis: classic skulls - Late neandertals had a l Facial comparison: homo neandertalensis and homo sapiens - Not us but close in many ways and not so close in others - A form of the gene MC1R would have endowed its carreirs with red hair and pail skin - Neanderthals carried a version of the FOXP2 gene associated with language and biity Homo neandertlalensis distribution - 250,000-45,000 years ago - Neanderthals before he arrival of modern humans in Eurasia - The greatest number of fossils have been found in souther france - A nature (2014) paper redated to 40,000 y.a. Homo neandertalenss (how close) - 500,000 year apart based on DNA - 99.5% similar - molecular phylogensit Svante Paabo Homo neandertalensis: What Happened? - Wy did they go extinct - The regional continuity hypothesis argues that they were genetically assimilated by modern humans as the later migrated to Europe over secera thusand years - The out of Africa hypothesis treats them as genetically isolated from modern humans and were replaced by a better kind of hominin - A very recent molecular data indicates something else - Some modern humans (Caucasians and asians) have 1-4% of their genome acquired from Neanderthals The leaky Replacement Hypothesis - 2 separate interspecific hybridisation events - multiple interspecific hybridizatio vents - analysis of human sequence date receals two - pulses of archaic denisovan admixture Wy did they go eist? - No clear reason yet but 2recent hypothesis suggests they were - 1. Forest edge “ambush hunters” hwo dies out as the forests changed to tundra with the advance of Wurn Glaciation 30-35 ybp

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2. A sharpt freece a 350000 yr ago was to severe f themresulting in reduction nin numbers to unsustainably low levels Homo spens: modern man and woman - skull: cro – magnon 1 - found: 1868 - site: cro-magnon, France - ca. 30,000+ yr old - ca. 300,000 ypb – to present - 1000-2000 cc brain (1400 cc mean) - all humans alive otday belond in one species o fossil and bpchemical evidence indicate that modern humans evolved from H. HeidelbergesisH. Anctecessor in East Africa at least 300,000 years ago (Morocco) known from middle east about 90,000 yrs ago Homo sapiens: early artifacts - flakes, stone points, scrapers, bone needle, anler harpoon head - stone tools of modern man, even the oldest are more aritstc and some tiems more delicate than Neanderthal tools - stone tools show atleast 4 levels in less than 30,000 years, a pace of change unprecedented in the archeological record homo sapiens early art - 30,000 y old dave paintings from Lascaux, France - Paleolithic art has been found all over the world - 39,000-40,0000 years old cave paintingso n the island of Sulawesi, Indonesia Homo sapcies: early art - fertility figures from Ice Age Europe - (35,000-20,000 year old) - the purpose of these figures is speculative - art? - Religious sympols - Paleo prn Homo sapiens, 2 hypothesis on origin - 2 very different hypothesis on the origin of . sapiens have been proposed and debated in the last 30 years - regional continuity and single origin recent out of Africa - molecular data strongly supports out of Africa hypothesis Homo Sapiens: migration nof Africa - for some reason, H. sapiens migrated out of Africa about 60,00-65,000 years ago (supported by fossil and genetic data) e are all derived fro ma small found population of as few as 10,000 indivduals… a botel neck

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recent nw evidence indicated that H. sapiens migrated out of Africa much earlier 8sipported by fossil and genetic data) and possibly multiple times e.x. H sapiens DNA in H. neandertalensis not H. densiova, 120,000 ya modern H. Sapeins

Some DNA polymirousms show regional patterns - dna analyses and gene frequenc studies show that some geneti information follows geographic patterns- the greatest diversity in sounds in African language

Great Human expansion - expansion included serial foudners effect events - African population was large enough to allow build up and tretention of substantial genetic diversity Phylogeny of languages - Have we migrated language teded to become simpler- Polynesians and ha Homo sapciens, a polymorphic species - We can all recognize members of different geo-ethnic groups Homo Sapiens: migration out of Africa - for osme reason H. sapiens igrated out of A...