Bio Anthro Exam 2
Orrorin tugenensis
"Original Man" 6 MYA, found by Senut Kenya Femur → similar to the human femur, suggesting bipedalism, gluteal muscles were also attached, which increased bipedal movement (with hips) Hand Phalanx Teeth for the most part are closer to chimpanzees and predecessors Thicker enamel was similar to humans Senut vs White Debate
Mutational "birth" / "path" to the Homo Genus from the Paranthropus
**Frameshift mutation in myosin gene ~2.4 mya and species branching off and rise to genus Homo. Mutation in humans (no monkeys) and less of a protein → gives weaker jaws relative to apes and primates without mutation strapped with massive jaw muscles (masseter) that limit other skull morphological changes. This smaller jaw muscle in humans allowed more evolutionary changes to occur over time
Know details about Dikika child (aka Lucy's baby aka Salam) (Australopithecus afarensis) (any more?) ****
-3.3 MYA -Died at roughly 3 years old -Possessed a hyoid bone, giving the ability to speak; but the hyoid bone and tongue gave it the characteristics of ape-like speech as human-like speech -Due to brain size relative to the adults (and when in comparison with chimps), it was likely that the Australopithecus Afarensis developed into adulthood slower than the chimpanzees and predecessors -Brain is roughly 300CC (3 years old remember) -Tooth eruption rate also sheds light on the slower development than chimps
Australopithecus anamensis, general features, where found.
-4MYA -Kenya (Lake Turkana) -Found by Meave Leakey -Larger canines than the hominins (hominoid trait) -Parallel tooth row, as opposed to the parabola which humans have (hominoid trait) -Was bipedal, as evidenced by the tibia and femur structure; at the knee socket (hominin) → they are attached at an angle, which is a characteristic of humans, but not of chimpanzees
Australopithecus afarensis (details about "Lucy" and who found her)
-Hadar, Ethiopia in dried up lakebed -Discovered by Don Johanson -Likely from about 3.5 MYA -3.5 Feet Tall -25-30 years at time of death -40% intact -Softball-sized head with cranial capacity of 400-450cc -Oldest, most complete best-preserved skeleton of erect-walking human ancestor that has ever been found -She was a girl, based on the pelvic structure, which was large and round; as well as the subpelvic concavity, required for childbirth
What does Ardipithecus ramidus tell us about human origins? *****
-Modern apes evolved distinct social/locomotive behaviors in parallel. Ex. Knuckle-walking was a derived trait. -Our last common ancestor with chimps was more primitive than we initially thought, and probably had more of a monkey-like foot -Bipedalism could not have evolved in the Savannah. -There is no modern ape that is a proxy for our common ancestor. The common ancestor is important, but as we go along the ape line, they are very different, as well have derived traits.
"Fossils of Apelike Creature still Stir Lineage Debate". What is the debate regarding Sehalanthropus tchadensis?
-Some researchers said that the skull was too ape-like to be a hominid -Size of Toumai (Sehalanthropus tchandensis) was similar to that of a chimp's, but its face, teeth, and brow ridge were more in the direction of other hominids -Another reconstruction said that tchadensis is most definitely a hominid, and is not closely related to apes
How can researchers identify bipedalism in the fossil record?
-The foramen magnum (hole at the bottom of the skull, where skeleton connects to vertebrae), apes will have it further back; humans (bipeds) is more centered, the pelvis shape -Pelvis (ilium is shorter) and the hamstring is longer -Thicker femur -The tibia -Patella Shape
Why else bipedalism was selected for?
1. Effective locomotion; also, bigger brains need more energy, and thus more nutritious food sources (especially meat), which is what might have went hand with bipedalism; expend much less energy walking upright; the early hominid environments were oftentimes very spread out, which would required this more efficient traveling; good focus more energy on reproducing; also climate change reduced the amount of food available 2. Thermocooling - cool body more effectively, since less surface exposure (as a quadruped) 3. Standing upright allows access to more food sources as well 4. Can harvest vegetation easier with free hands 5. Can carry resources with their free hands 6. Can carry weapons to defend themselves with free hands 7. Can look ahead of oneself and scan the landscape for nearby predators
Pleistocene
1.8 MYA - 500 KYA. First hominins to leave Africa (pre-Ergaster). Major fluctuations in temp, culminating in massive warming.
Homo Habilis (general details) (Handy Man)
2.3-1.5 MYA Kenya, Tanzania, possibly South Africa 500-650 cc (maybe even some up to 800) Discovered by the Leakeys as well as Don Johanson and Tim White (Richard and Meave Leakey were the first) Was the first to make and use stone aldowan tools → shows recognition of situations and high cognitive ability Debate of whether it was closer to humans or to Australopithecus (Lucy) Not much larger cranial capacity than Lucy Overall: traits were not super "homo" Much longer arms than actual humans Less post orbital constriction than the Australopithecines More modern teeth Smaller face and brain than Rudolfensis
When do stone tools begin to appear in East Africa?
2.5 MYA
Know details about Taung Child (Africanus) (and who found it) ***
3-2.2 MYA South Africa Discovered by Raymond Dart Based on dentition, it was likely 3-5 years old Found a facial portion, mandible & teeth, and the endocardium
Know the general traits of Australopithecus afarensis:
3.9-2.8 mya Mostly in East Africa, especially Chad Roughly 300 individual samples Prognathic = ape-like Post-orbital constriction (narrowing of cranium behind eyes) → small brain, especially lack in the frontal lobe area Likely the successor to Australopithecus Anamensis
Know the general traits of Australopithecus afarensis
3.9-2.8 mya Mostly in East Africa, especially Chad Roughly 300 individual samples Prognathic = ape-like; subnasal Prognathism (front of face below nose is pushed out) Post-orbital constriction (narrowing of cranium behind eyes) → small brain, especially lack in the frontal lobe area Likely the successor to Australopithecus Anamensis 450cc cranial capacity - like that of a chimpanzee Rather sexually dimorphic (also in canine size) Bipedal Arched foot with non-opposable toe Pelvis is short and wide, femur slants inwards Possessed a diastema like the chimpanzees, as opposed to humans Sexually dimorphic in canine size
Pliocene
5-1.7 MYA. Likely the start of the hominins (may have been at the end of the miocene though). Temperature was generally cooling throughout.
Ramidus (the morphology) ("ardi")
5.8-4.4 MYA, Kenya, Tim White ~4 ft. tall -Was not a knuckle walker -Had a less specialized foot -Was a ridged foot, that allowed for easy push offs by the heal as well as stabilization -Had a mosaic of ape and australopithecine features -Ape sized brain of 300-350cc -Prognathism was similar to chimpanzees -More thick enamel (as well as cusps), general reduction in size and extent of sexual dimorphism (less sexual aggression and specialized diets between the sexes), -Pelvis allows for bipedal upright walking -Palms and fingers shorter, while the thumbs are longer → human
Ardipithecus Kadabba
5.8-5.2 MYA Middle Awash Valley of Ethiopia Yohannes Halie-Selassie was the discover Possesses a mosaic of human and ape traits Canines sharpen against 1st premolar = hominoid Likely bipedal - hominin One toe bone suggests bipedal motion Thicker enamel than chimps and hominoids
Late Miocene / Miocene
7 MYA - 5 MYA. We see the arrival of the hominoids.
Why might others label them as one species (H. erectus)? (****find this out)
A Daka cranium from Ethiopia appears to be an intermediate form of H. Erectus and Ergaster, so it may just be one species with a lot of variability
What kinds of stone tools are associated with H. ergaster/African H. erectus? (add more ****)
Achulean tools, such as the biface, hand ax, cleaver, and pick → more complex overall
Dating Methods: Relative Dating
Age of a fossil relative to another fossil --> Law of Superposition, Biostratigraphy, and Fluorine Dating
Scavenger Theory
Ancestors were scavenging meat from carcasses, such as bone marrow This was a way to have a nutritious and caloric diet We picked up after larger predators The early tool marks were used to cut up bones, not to physically kill the prey Evidence: We can analyze puncture wounds to determine which came first: the larger predator's teeth almost always came before the ancient man's cut marks; so we were just scavenging The killer ape theory was the refutation Utilized a Scanning Electron Microscope to analyze teeth marks; further proof
When did the hominins start to migrate out of Africa? What is the evidence for this? (hint: read about the fossils from the Republic of Georgia, and read the article, Stranger in a New Land.)
At around 1.8 MYA, Hominins began to reach Dmanisi, Georgia, where the lower jaw of a hominin was found, along with many Oldowan tools. These were going to be the descendants of the African Homo Erectus/ Homo Ergaster.
Homo heidelbergensis / pre-neanderthal fossils from Sima de los Huesos, Atapuerca, Spain Description of site; General demographic distribution; Health status of these ancient hominids
Atapuera, Spain From 300 KYA European hominins had most definitely diverged from those in Africa Demography of the 28 skeletons: 3 were older than 35 7 were between 20 and 35 16 were teens between 13 and 19 2 were children under 12 8:12 Male to Female ratio, but was actually equal The cave was very deep underground, and required many years of digging to find Was about 43 feet underground Was called the "pit of bones" with so many full skeletons Interestingly enough, these Homo Heidelbergensis, based on DNA, were more closely related to Siberian Denisovans than to Neanderthals The largest cranial capacity was at 1390cc They had occipital buns and no chin (primitive features) Marks on Cranium could show signs of fighting and aggression between them; earliest known intra-group violence Did show signs of dental abscesses, but there were no cavities-so diet may have been low in sugar Some of the cranial depressions may have been the result of disease as opposed to head trauma → Cribra Orbitalia appeared to be present in just the adult Homos, but this is caused by an iron deficiency, and consequently leads to an eye orbital problem It was speculated to be a burial site, because some pink quartzite, not local to the region, was found, which may have some spiritual significance.
Which species are candidates as the makers of those Oldowan tools?
Australopithecus Afarensis, Australopithecus Garhi, and Homo Habilis/ Rudolfensis, and later Homo Erectus (the Asian version)
Man the Hunted Theory
Australopithecus and Early Homo were not hunting but were actually the hunted Evidence for: primates still were actively hunting us, as well as tigers in India Taung Child was clearly killed by a large bird Teeth marks in Taung Child and many other skulls The killer ape theory, with all the caves, but this was clearly work done by leopards and porcupines Australopithecus was primarily a vegetarian Homo was primarily a scavenger Both were the size to be potential prey, and evidence of these marks
"Evolution of Human Birth" Why is human childbirth riskier than in other primates?
Backward facing birth, canal navigation
Homo Rudolfensis (general details)
Best example was found at Lake Turkana Discovered by Richard and Meave Leakey Rudolfensis had a greater cranial capacity than Habilis Larger jaw and body Larger brain at 600-800cc Similar brain and masticatory process to Habilis Coexisted in East Africa with Habilis from 2-1.5MYA Larger Molar and Premolar teeth than Habilis (which are actually Australopithecus features)
What suite of traits and behaviors may have been needed for ergaster/erectus to migrate out of Africa?
Big Brain - with a bigger brain = ability to make more creative tools, plan ahead more, and adapt to environmental changes when they move into Europe Body shape - Had a bigger and more robust body than its predecessors. The body was very human like in terms of proportions, and even taller than Homo habilis. Those like Turkana boy had strong muscles to survive migration Good Achulean tool set and ability to control fire Diet and early homos → complex tool kit, which opened up scavenging and other foods (cooking tubers); so could exploit environmental niches Were inclined to follow game animals/ game carcasses
Australopithecines in General
Bipedalism, yet also tree climbers Brains the size of modern apes (340-500cc) Mosaic of ancestral and derived dentition: Smaller canines and incisors, but Bigger molars and premolars with thicker enamel than chimps Smaller than modern humans in terms of weight Sexually dimorphic body size
Theories as to why hairlessness may have evolved in Homo
Bodies with less hair were more effective at cooling during times of strong heat and heavy exertion We avoid heat exhaustion and are more effective hunters and scavengers Lived on the savanna full time Hunting Advantage, Clothing, Sex related, sexual selection, aquatic apes, neoteny, ectoparasites
Homo habilis / Homo rudolfensis (one species or two? How do they differ?)
Both used Oldowan Tools Found around same time Contained many of the same primitive features (arguably more similar to Australopithecus) Share a masticatory process, and have only a little different-sized brain (so may have shared the same thought processes) Obviously shared the time in which they were around Different in that Rudolpfensis was much stronger Larger jaw, body, brain, and also molars/premolars Debate Rages on as to whether they are one or two species
Brunet vs. Wolpoff debate regarding the Sahelanthropus Tchadensis
Brunet says the definitive first Hominin Obligative Bipedalism (forced to be a biped) Direct ancestor to the Homo Genus Wolpoff says it was still a hominoid (ancestral ape) It had facultative bipedalism (had the option/ anatomy to be a biped, but oftentimes just to remain a quadruped) Was ancestral to the apes or species that may have went extinct
Potassium Argon Dating
Can work for much older remains; Potassium (K) has a half-life of 1.3 billion years (very slow), and the best samples will be over 200,000 years old. One measures the actual rock that the fossil rests in, not the fossils themselves.
Describe the morphology of Homo erectus from Asia. (might need more)
China/Indonesia 1.1 MYA -300 KYA Not a full frontal lobe yet Cranial Capacity large than the African one at 1000-1250cc No Frontal Lobe Yet Thick brow ridge and cranial structure, relative to the Africa Homo Ergaster Shovel shaped incisors Sagittal keel had V-shaped ridge Shorter and Stockier body than African Homo Erectus The occipital torus/ bun was more pronounced than in African version
"Evolution of Human Birth" Explain the relationship between the pelvis/birth canal and brain size (and how one constrained the other).
Conflict with bipedal pelvis and having a big-brained child (conflict in evolution) Need hip in certain place for efficient bipedal walking, but this pushed it in the way of the birth canal, which was required to be wide, for humans came out of the uterus head-first and had larger and larger brains As big-brained as possible was adapted for, so that the baby could still fit through the birth canal Babies then would twist and turn out of the canal, to allow the mom to survive, with assistance Parallel evolution is the presence of assisted birth Therefore, human babies often have to be born premature, and have a shorter gestation period, so there will be more brain development outside of the womb
Describe their (Paranthropus') morphology and what that tells us about behavior. (** ASK ABOUT THE BEHAVIOR)
Cranial Capacity of 500-550 cc Bipedal locomotion Pronounced sagittal crest (connected with chewing) and masticatory apparatus; gives more room for the temporalis muscle to be attached Large and powerful teeth, especially the molars Good masticatory apparatus including a large and powerful jaw→entire skull was designed for it Quite sexually dimorphic like its predecessor Afarensis Similar postcranial anatomy to Afarensis Broad zygomatics; cheekbones were flared outwards to make more room for the temporalis muscle Also had a strong masseter muscle for chewing chewy things So - Matured at an early age, shorter period in which they were raised, could have a more diverse diet Led an ape like lifestyle Pronounced sexual dimorphism (4.5ft vs. 3.5ft)
What is the evidence that suggests A. afarensis spent a bit of time in the trees (ie., had a somewhat arboreal lifestyle)? ****
Curved fingers = grasping qualities to grab onto trees
Java Man and Eugene Dubois
Dubois decided to stop teaching in order to start fossil hunting in the late 1800s This was the first Homo Erectus to be found in Indonesia in 1891 Java was a disgusting place to do work It appeared to be a link/intermediary between the old apes and modern humans For many years into the 1900s, he hid the fossil to study just for himself Eventually, many more H. Erectus like Java Man were found in Indonesia Between 1 MYA to 700 KYA
African Countries (North to South)
EKTZ Ethiopia Kenya Tanzania Zambia
Man the Hunted. You've read Chps 1&2 from the book, "Man the Hunted" and should have ascertained the overall argument of the book. What is it? (i.e., What's the thesis?)
Early humans were actually hunted by other predators and not the big vicious hunters we had previously thought. To get meat, we were just scavengers - hunting may have began around Erectus or Heidelbergensis. Humans were not hunters; rather predators including leopards and hyenas hunted them.
Homo ergaster (African Homo erectus) Description
East and South Africa 1.8 MYA - 500 KYA Cranial Capacity increased by a great deal: 700-1000cc Made Acheulean tools, which were more advanced and thus required a greater thought process External Nose (nostrils facing downwards) Ancestral Traits = some post-orbital constriction, receding forehead, no chin, large browridges Derived Traits = Less prognathic, taller skull, smaller jaw & post canine teeth, may have had hairless skin Thick Cranium Humanlike limb proportions (shorter arms, longer legs)
"Evolution of Human Birth" What argument do the authors make RE assisted childbirth?
Ever since bipedalism started, the birth canal became complicated. Therefore, assisted childbirth was likely not limited to humans, but also our ancestral hominins, who would have needed to use the same tactics.
Killer Ape Theory
Evidence: Possible tools for killing found in South African caves by Raymond Dart, along with bones and teeth "Violence is innate in hominoid ancestry" Dart proposed the idea of an Osteodontokeratic Culture→ we were bloodthirsty psychopaths (Australopithecines in particular) Refute: leopards eat and drop bones, then porcupines gather the remains; these sites were likely the product of other animals' doing
Describe the morphology of Homo erectus from Africa (a.k.a the Ergaster)
External nose with nostrils facing downwards (unlike previously) ⇒ can keep air moist and neutralize air temperature before entering the lungs Ancestral traits: some postorbital construction, receding forehead, no chin, not fully developed frontal lobe Derived traits: less Prognathism (smaller face), taller skull, smaller jaw and post canine teeth Had humanlike proportions Humanlike gait (walking pattern) → found Kenyan footprints from 1.5 MYA which show strides like humans and not like Lucy
What was its form of locomotion of Ardipitehcus? How do we know?
Facultative biped (arboreal clamberer); foot bones and features walk bipedally and based on placement of the spinal cord
This is a comparison between Homo Habilis on the Left and Homo Rudolfensis on the right. Differences: Rudolfensis has a greater cranial capacity, and a much thicker skull, and is more built up in the body as a whole. It has a thicker jaw, as well as larger molars and premolars (which are actually australopithecine characteristics)
Figure 12.2 What are the differences between these two fossils? What are their genus and species names? (This image was also shown in lecture.)
What evidence supports their argument? Give two specific pieces of evidence (for the Man the Hunted thesis)
Fossil evidence: skull holes fit exactly that of tooth patterns of living African carnivores, especially jungle cats Living primate evidence: hunting is common throughout the primate family, therefore it is not true that humans were the only ones that use hunting to survive, and this does not make us distinct from relatives. Also possible: humans did not necessarily receive that many nutrients from meat at this point in time (without proper cooking)
In what kind of ecological context might bipedalism have evolved?
From heavily forested to the savanna climate, in which it was easy to spot things, the climate was drier, and food sources and shelter was further apart. Free hands were very important, to carry things and reach up into the few trees. This was a time of climate change.
Paranthropus (aka, the more robust australopithecines) (broad information) (do we need to know the three 3 species?)**
Genus with 3 different species, lasted from 2.5-1 MYA, found in Kenya/Tanzania, by Alan Walker at Lake Turkana
General lifestyle of Homo erectus (tools, fire, compassion, etc).
Had the ability to make and control fire With the fire, they could cook, to detoxify and tenderize meat, as well as make certain tubers edible They were migratory people Utilized Achulean tools (in Africa), and Oldowan tools in Asia - which showed a complex thought process Likely had social interactions Could teach and share information Cared for members of their group—showed compassion Fire gave warmth, protection, and cooking Likely a very good endurance runner Likely not much control over spoken language Developed into an adult at a slower than Australopithecus, but faster than humans Learning was not necessarily an important part of their life Were definitely meat eaters (Vitamin A residue on bones, obtained from livers of prey) Teeth well suited for shredding meat Many more tapeworms also suggest meat eaters Cut marks on elephant bones from Achulean tools (although could have been scavenging)
Describe "Turkana Boy" (H. ergaster/African H. erectus). (Be able to give three specific details about him.)
He was tall at roughly 5'4'', but would have reached about 6 feet, based on→ Some of his growth plates (such as the humerus) hadn't fully fused, his bone epiphyses were not fully fused He was lean, muscular, and tall He possessed the new nose, which would be beneficial during daytime He was 12 by looking at the dentition, and amount of secreted enamel Strong gluteus Maximus probably led to advanced running ability.
From which hominin did H. floresiensis evolve?
Homo Erectus
According to lecture, which species had controlled use of fire? Why was this important?
Homo Erectus in Africa was the first to have complete controlled use of fire. This allowed for cooking benefits Killing bacteria, bringing about more nutrients (tuber), increasing taste Fire brought warmth Fire brought protection from predators Fire may have even had a cultural significance It could have allowed the development of new tools (with stone).
Which may have been the first hairless hominin?
Homo Ergaster / African Homo Erectus was likely the first body fully hairless hominin (with the exception of head hair)
How do researchers know that Taung Child (Africanus) was 3-5 yrs old?
Human teeth erupt (especially molars) at an expected rate, which correlates with puberty, and helps to determine age along with the enamel formation →, which showed that there was a faster growth pattern for Taung Child Deciduous teeth formed in Utero (unlike humans) 6 months enamel begins to show (start of teeth growth) At 2 years →teeth are more prominent and the first molar begins to form At 6 years, the first molar is completely erupted, while the second molar is coming up The Taung child's faster growing teeth illustrate a shorter dependency period, as well as a faster infant growth rate, more resembling Chimps
Homo ergaster or African Homo erectus. Why might some researchers split H. ergaster and H. erectus into two species?
In Asian Homo Erectus, the brow ridge and the cranial structure are slightly larger than the African Homo Erectus Cranial morphology and capacity are different The African Erectus/Ergaster used Achulean tools; the Asian Homo Erectus used Oldowan tools (in Indonesia), which were primarily what the H. Habilis and H. Rudolfensis had used Times do not completely overlap
For Homo Floresiensis: Where? Dates of existence. Why are these dates so surprising?
Island of Flores 95-13 KYA Homo Sapiens may have overlapped with them. They likely speciated from Homo Erectus. Discovered in 2003 By Mike Morwood and his colleagues
Some scholars think H. Floresiensis is so tiny simply because it is a diseased human. What evidence do they highlight in order to support their interpretation? Others disagree—what evidence do they site? (*** more evidence for diseased human?)
It was 3 feet tall 380 cc - like a chimp Believed to be Microcephaly The facial morphology was different than Homo sapiens, and it still possessed some archaic features It did share some human resemblances, but not that many Counter point: the brain was so small, that the microcephaly Had rather complex tools, more so than H. Erectus
Homo heidelbergensis (from Zambia and Greece). What did H. heidelbergensis likely give rise to in Europe? In Africa?
Its predecessor was likely Homo Ergaster (African Homo Erectus) Was found in Kabwe, Zambia from 800-500 KYA Overall, Heidelbergensis lasted from 900-130 KYA Was rather primitive in its morphology Heavy brow ridge, no steep forehead, no chin Face was large and prognathic Looks much like Homo Ergaster → with a larger cranium at 1280cc and rounded occipital (which allowed for larger brain) The frontal lobe was jutting out, and there was a higher forehead Culture: had a refined set of Achulean tools → shows intelligence Also, found wooden spears that somehow lasted, which shows that they were very advanced hunters In Africa, Homo Heidelbergensis likely gave rise to Homo Sapiens THEN Homo Heidelbergensis migrated to Greece From 400-200 KYA Called the "European Version" Cranium was slightly smaller at 1220 cc Found remains also in Germany, with evidence of wooden spear hunting and processing of bones at 400 KYA Also, found wooden spears that somehow lasted, which shows that they were very advanced hunters (in Germany from 400 KYA Strong evidence also of hunting at the Island of Jersey In Europe, Homo Heidelbergensis likely gave rise to Neanderthals Therefore, this was possibly the common ancestor to both Homo Sapiens and Neanderthals (if it wasn't convergent evolution!)
Turkana Boy (How did researchers determine that he was 9-12 yrs. old?)
Lake Turkana, Kenya 1.6 MYA Richard Leakey Still room for growth plates of the humerus, which hadn't fully fused Also, can measure by the dentition and secreted layers of enamel He was 5'4'', but likely would have reached 6 feet tall Lean, muscular, tall Physically active during the heat of the day (aided by new nose) Probably lost body hair No climbing arboreal abilities Lived in Savanna full time Bone epiphyses fuse with age, and those like the Humerus had yet to do so
What's the approximate sample size of the number of individuals of Ardipitehcus ramidus?
Large sample size at 36 individuals!
Figure 10.9:
Less sexually dimorphic as time goes alone.
Dr. Dan Lieberman's explanation in detail of why bipedalism was selected for.
Lieberman → humans developed the ability, through their bipedalism and other features, to run long distances at a constant rate, while preserving energy and not overheating -Long legs, -Narrow hips -Barrel-shaped chest (for lung capacity) -The human's fully arched foot, -Fully attached Achilles tendon. -The attachments of the hip/gluts to the spine have many more muscles in the humans than the Australopithecus -Shoulders are only loosely connected to the spine, to allow for more arm movement; and they can rotate the opposite way from the hips -This also prevents the head from bobbing (canals in the Ear); elastic ligament from skull to base of neck
Dating Methods: Absolute Dating
Like name suggests, finding the specific age --> radiocarbon dating, potassium argon dating
Figure 11.25. Some researchers have argued that the stone and bone accumulations at this Olduvai site are either a home base or a workplace for processing carcasses. If you were an archaeologist how would you go about testing these ideas? Think about the kinds of data you would need to collect to examine the merits of each hypothesis. (find this out***)
Look for Homo Habilis remains More likely a butcher site Permanent site would be too dangerous Look for attacks on human remains Look at tools
Breakthrough of the Year: Ardipthecus ramidus: The team that discovered Ardi suggest that there was less male-male aggression. On what evidence do they base this claim? (see p. 1599).
Males of the Ardi species lack the large, sharp, dagger like upper canines seen previously in chimps - and were thus less aggressive between on another
What discoveries (and re-analysis) made the scientific community accept Dart's general ideas about Taung Child/Africanus?*****
Many more adult skulls and postcranial bones of the Australopithecus Africanus began to show up in South Africa The hipbones, pelvis, ribs and vertebrate found were awfully similar to Afarensis, which was clearly bipedal
Sahelanthropus Tchadensis ("Toumai")
May be the oldest hominin; but still might be just hominoid 7-6 MYA Found in Chad Brain was 320-350cc Smaller canines and thicker enamel than apes Massive brow ridge Brunet vs. Wolpoff debate
What might have been advantageous about increased meat eating for evolution of Homo?
Meat has more proteins than a purely Vegetarian diet, which in turn gives the brain more energy and power to complete complex thoughts A larger brain required meat intake
How do the paranthropines differ from those in the genus Homo?
Paranthropus was not much bigger than Australopithecus, but was more robust overall Still, had a smaller brain capacity (450/500 - 550 cc), compared to Homo Larger prognathic faces (more Prognathism or jutting out of the chin) Post cranium still allowed for some ape-like climbing, even though was a biped Larger posterior (molars and premolars) teeth than Homo Large temporalis muscle (also the masseter?) Lived more like apes overall → faster growth and shorter juvenile period, sexual maturity earlier, and a shorter lifespan of less than 45 years
Know the general traits of Australopithecus africanus
Rather sexually dimorphic Males = 4'6'' Females = 3'9'' Postcranial features were nearly identical to predecessor in Australopithecus afarensis Bigger chewing molars than modern humans Less prognathic than Afarensis Smaller canines than Afarensis Brain capacity = 460cc, so slightly bigger than Afarensis Faster maturation rate than Homo sapiens
What are some examples showing how science does not always operate in a vacuum, but is sometimes influenced by social and political circumstances?
Raymond Dart's ideas were largely ignored for a while, due to racism, since he was South African and researched in South Africa, and Europeans believed that Europe had to be the birthplace of humanity - social Darwinism - Asia was second to Europe, in terms of "importance" Also, in Indonesia, Eugene Dubois went there because it was a Dutch colony, and he would have complete access to it the island and its people We have holes in Middle East because politics make it hard to get there
Senut vs White Debate
Senut - declares they were bipedal, and would thus bump the Australopithecus off the hominin line, and did not end up giving rise to humans/homo/hominins White - declares that they were bipedal, and shared enough morphological features with us to keep the Australopithecus on a track to humans
Australopithecus Afarensis: Laetoli footprints. Why are these footprints so important?
Tanzania 3.6 MYA Mary Leakey Footprints of Australopithecus Afarensis They looked to be more human than ape-like, with no divergent big toe Spacing and heel to toe ratio and no palm prints from walking on hands → may not have had as long of a stride, but was definitely bipedal
What did R. Dart propose based on this find of the the Taung Child (Africanus)
That the Taung Child was bipedal → based on the placement of the foramen magnum Also, that this was an intermediary between humans and apes, which originated in Africa but these were rejected in the late 1920s
How do the finds in the Republic of Georgia place doubt on that interpretation (noted above)? What species might those Republic of Georgia hominids belong to?
The Georgia Hominin had been in Georgia much earlier than expected → 1.8 MYA Much more primitive tools that the Ergaster's Achulean tools We had previously believed that the only method to travel this far was with larger brains and advanced tools These remains had much smaller brains than expected May have been the intermediary between Homo habilis and Homo Ergaster They had small brains and were short in stature At this time, climate change was shifting the grasslands northwards
What are two derived traits in H. ergaster (African H. erectus) that are shared with modern humans? (p.294-297 and see lecture)
The Homo Ergaster's nostrils would face downwards, and the nose projected out → therefore, Ergaster's nose could maintain moisture during periods of physical exertion in a dry environment, thus keeping cool and hydrated and high stamina. Homo Ergaster developed hairless skin, which allowed it to more effectively cool itself through efficient sweating, like us. It had similar body proportions to the modern human, with long legs, shorter arms, a barreled chest (for increased lung capacity), which contributed to strength at long distance endurance running, which we also possess. The face also featured a reduction in Prognathism, with a taller skull, smaller jaws and post canine teeth, and a reduction in the number of roots for upper molars.
What is another explanation as to why H. floresiensis is so small (cite the more widely accepted explanation, according to lecture)?
The Island effect→ there was a serious advantage to being a smaller animal on this small island, with few predators. Therefore, one could stay small and rely on fewer calories per day. Dwarfism was favored in this environment; no reason to be huge
Peking Man and site of Zhoukoudian (where; site description; time period)
The Zhoukoudian cave is located near Beijing 800-400 KYA Deposits are 40 M deep Cave had 51 individuals No massive frontal lobe, huge brow ridge Hundreds of stone tools → also animal/faunal bones that were burned while fresh with intentional cut marks - evidence of either hunting or scavenging Theory of cannibalism with the fractured skulls, but was defunct. The marks were probably from hyenas.
How do we know if it (Australopithecus Africanus) grew quickly or slowly relative to modern humans?
The enamel layer formation developed much faster than humans, and closer to the enamel formation in apes (even a little faster). Growth patterns were more rapid and closer to the apes than humans.
Briefly describe the ~1.8 million year old fossils and tools found in the Republic of Georgia.
The fossils were much more primitive than anticipated Smaller brains Used Oldowan Tools So likely an earlier migration Small cranial size, with nearly identical size to Ergaster for some We did not need big complex brains to leave Africa
Radiocarbon Dating
The ratio of Carbon 12 remains during any organism's lifetime and post-death. However, the ratio of Carbon 14 (an isotope) will begin to decline after the death of an organism, at a half-life rate of 5,730 years. The number of half-lives passed is used to calculate age! 50:100 after 5,730 years, etc. → works up to 40-50KYA (with an accelerator mass spectrometry, can last up to 55-60KYA)
What is the evidence for meat eating among H. ergaster / erectus?
There were stone tools (specifically the Achulean), as well as butcher marks on animal bones, and a large amount of diseased bones with an extensive buildup of Vitamin A, due to the consumption of the livers of prey. Also, the incisors and canines were sharper than previous, and the molars were not as large, which signaled how the mouth was becoming efficient at shredding meat, as opposed to grinding on hard plants.
Why might selection favor larger brains, prolonged juvenile period, and longer life span?
These traits make it easier to learn the complex foraging method (collecting foods, extracting foods, and hunting foods) → learning takes time, and complex thinking would also require a larger brain; selection thus favors a longer life, because it allows people to fully utilize foraging methods, which would be best taught during a prolonged juvenile period.
Did A. africanus mature quickly like chimps, or slowly like apes? Why is this information important? (see Boyd & Silk).
They developed quickly, as evidenced by the many layers of teeth enamel; quickly like an ape/chimp ** The secretion of enamel from the teeth shows how the teeth began to erupt at 6 months, and the first molar erupted at 2 years, growing in at 6, with the next molar on the way Therefore, the Africanus babies did not have as long of a dependency on their parents as human children do Consequently, many of the societal requirements for humans (which are taught to the young of a society) were likely not possible: Home bases Sexual division of labor Extensive food sharing
Were R. Dart's ideas rejected or accepted about Taung Child/ Africanus? Why or why not?
They were not for 3 reasons: -Scientists had then believed that large brains (which the Africanus lacked), were required before the evolution of bipedalism -There were no postcranial (bones besides the skull), to further support the bipedalism assertion, which relied solely on the position of the foramen magnum -Scientists believed that the species in Asia were the connection to modern humans
Were Oldowan toolmakers right or left handed? How do we know? (Box 11.1)
They were right handed → right handers hold hammer in their right hand and hold the stone to be flanked in the left, which they then rotate to strike in a clockwise circle. They were quite variable in size and shape, but were relatively effective in the time period. They had a good edge to them, which could serve multiple purposes (cutting, maybe even hunting)
What ideas have been posited to explain why African Homo erectus has thick cranial bones and a large brow ridge?
Thick cranium protects the larger brain, which is also more important as Erectus/Ergaster had developed the idea of Achuelean tools Thick cranium also might have illustrated that violence was first becoming a serious problem Thick brow ridge may have been protective during fights Also, thick brow ridge might have developed in order to keep hair out of eyes
Figure 10.27. Know how to interpret this graph.
This graph shows the enamel secretion rate of six australopiths in comparison to the African Apes, which is about the same rate, showing that it is about the same growth rate. Additionally, it shows that the enamel growth rates for humans is much slower, proving how humans develop slower than Australopithecines.
Man the Hunter Theory
Tools were used for hunting animals, which gave essential nutrients In 1966, man the Hunter Conference The Activity of Hunting for Large animals was unique to the hominin culture, and distinguished us from our hominoids predecessors Stone tools, fire, and bipedalism were essential to this theory However, it ignored how many ancient men were capable of sustaining on an omnivorous diet Refutation: Robert Sussman sought to disprove the theory Hunting only contributed relatively few calories to diet because meals were not consistent Biased because only half of the story Australopithecus Afarensis likely couldn't even consume the meat, with its set of teeth Evidence for hunting might have only been random occurrences, as opposed to planned out endeavors
What is the best explanation as to why they (Homo Floresiensis) went extinct?
Volcanoes
Drawing from Boyd & Silk, the Nova video, class lecture, and Man the Hunted excerpt, do researchers think that australopithecines and early Homo were hunters or scavengers? What's the evidence to support this?
We were scavengers. Through use of a scanning electron microscope, scientists have been able to identify that the cut marks by human Achulean and Oldowan tools came after the kill marks from larger animals (sometimes teeth marks). Also, the cut marks on bones did not indicate fatal kills, rather just cutting off meat. As further evidence, the kill marks in the caves were most certainly those of a leopard. Also, it has been proven that early humans could survive on a purely vegetarian diet. Finally, it did not help that humans were oftentimes prey as well, as evidence by kill marks on Australopithecine skills by actual apes and other cats.
Describe Ardipitehcus ramidus lifeways.
Woodland-to-forest habitat (many trees)
Was A. afarensis sexually dimorphic in body size?
Yes, it was sexually dimorphic. The males were roughly 5 feet tall, while the females were roughly 3.5 feet tall. When averaged out, the afarensis is sexually dimorphic, including the extremes on both ends. It was just one species
Molecular Dating
how to use the molecular clock to infer the date of TMRCA (like example in lecture) Often relies on mitochondrial DNA. This is based on the idea that any molecular differences among taxa are neutral mutations that accumulate at a constant rate, on average. Shared genetic makeup between different branches of the taxa is corollary to the time between the most recent common ancestor. (TMRCA)
Thermoluminescence Dating
this relies on heated objects accumulating trapped electrons; it shows when the object was initially heated at high temperatures, and works up to 1,000,000 years. One relies on the ratio of radition being emitted.
