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37 Cards in this Set

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1. What do we mean by “context” in describing fossils and artifacts? What are the differences between primary and secondary contexts?
Context refers to fossils and artifacts which have been preserved within the same archaeological record (ie. same stratigraphic level). Something that is in its primary context has not been disturbed from its placement and stratigraphic layer after having been originally deposited. If there had been a disturbance in the placement of a fossil or artifact, then it is considered to be in its secondary context. For example, if a bone from a pre-human hominin is found packed into well-stratified clay, and the positioning of the object does not suggest it have been shifted through geologic processes, then it would be in it’s primary context. If on the other hand, the bone was found on the top on the top of a sandy plane in the middle of the Great Rift Valley, it would be in it’s secondary context, since it had been moved or distrubed from it’s original stratigraphic placement.
2. What is so unique about Homo floresiensis? Where and when did the hominin occur? What is its significance in regard to human evolution? Why is there a controversy?
(1). INFO: Time: 95,000-17,000 yo. Where: Island Flores, Indonesia. Nickname: Hobbit(3’6’’), so they are short.
• Tiny brain, large teeth for their size. Large feet relatively to their short feet. Use stone tool.
• WHAT: Their diminutive stature and small brain may be resulted from island dwarfism, which leads to long term isolation.
(2). WHEN/WHERE: 6-7 mya, Great Rift Valley of East Africa.
(3). Significance: The suggestion is now that this might represent an even earlier stage of human evolution, one that's closer to Homo habilis or even to Australopithecus (rather than homo erectus, despite going extinct only 17 kya when homo erectus dominated the planet), creatures that lived two million years ago or more in Africa. What is significant is that it survived, or potentially could have just been a pygmy homo erectus. Regardless, shows variation and complicated human evolutionary timeline.
• Although we've got no evidence of it happening yet, the argument is that one of those more primitive forms got out of Africa more than two million years ago, somehow found its way over to Southeast Asia, and survived in isolation on the island of Flores until 17,000 years ago, when it went extinct. That would be an even more extraordinary story than a Homo erectus getting there and dwarfing, that you've actually got a relic of an earlier stage of human evolution that got all the way over there.
(4). Controversy: The argument was that this was a dwarfed Homo erectus, explaining the smaller body and brain size. However, some researchers refused to accept that. They felt that this was such a bizarre find, under bizarre circumstances, and they actually favored the view that they were some kind of pathological modern human, perhaps suffering from cretinism, microcephaly or something called Laron Syndrome. Some would argue florensis is not a distinct species, it is microcephaly
3. What is mosaic evolution? Give two concrete examples found in human evolution that is to say, name two hominin species and explain why these two species are referred in discussing mosaic evolution.
Mosaic Evolution Definition: Evolutionary pattern in which physiological and behavioral systems evolve at different rates.

All the anatomical changes we’ve discussed occurred like the construction of a mosaic, with interlocking pieces driven by natural selection in every generation. Natural selection drove the evolution of bipedalism because in each subsequent generation once the shift began, each transitional stage conferred survival and reproductive benefits on individuals. The mental image of a shuffling prehominin that was neither an efficient quadruped nor biped is certainly wrong. Instead, in each generation the emerging biped must have been very good at surviving and reproducing, or else natural selection would not have pushed the process further.
Two different species: Homo Sapien was the product of mosaic evolution. H. Erectus and H. Neanderthals. Erectus was the first hominin who went out of African, and then we found Neanderthals broadly in Europe. Erectus ate meat, so they got more nutrition which led to larger brain in Neanderthals (1450 cc). Overall, Mosaic evolution is a step by step process.
4. Discuss the process of human evolution from the earliest Australopithecines to anatomically modern Homo sapiens. What are the trends that are evident in the morphology of human fossils during the last 4 million years? Indicate the geographical locations and geological time periods of major hominin fossils that were found and dated. Furthermore, discuss significant behavioral and cultural changes that took place in the hominins.

Earliest hominin Fossils found in E. and S. Africa
- Earliest hominin fossils found in E. and S. Africa
- “Lucy” (Au. afarensis) found in Ethiopia; cranium and teeth intermediate in appearance between living ape and modern human; cranial capacity small but larger than apes/earlier hominins (350-500 cc); biped; long arms in comparison with modern humans; more curved phalanges; some degree of arboreality; high level of sexual dimorphism
- Au. garhi: more modern limb proportions between arms and legs; prognathic face, large canines and cheek teeth, sagittal crest; used tools
- Au. africanus: Taung child found in S. Africa; followed a growth pattern similar to an ape’s; more derived than Au. afarensis; larger braincase (450-550 cc), no cranial crests, less prognathic face, small anterior teeth but large anterior teeth
- Robust au. (Paranthropus): postorbital constriction, flared zygomatic arches, dished face, massive molars/premolars, tiny anterior teeth, sagittal crest, large chewing muscles
4 PART II Earliest Hominin Fossils found in E. and S. Africa
- Au. generally small brained, small bodied, biped African apes with both derived and primitive features
Genus Homo: larger braincase; smaller, less projecting face; smaller teeth; larger body and more efficient bipedalism. Shift to more animal-based diet, greater ranging and greater food processing through tool use
- Homo habilis found by the Leakeys in Tanzania; used stone, Oldowan tools
- Types of hunting/scavenging: hunting, confrontational scavenging and passive scavenging
- Homo erectus: extremely successful species that left Africa and went to Europe/Asia; larger brain and body; thick, pentagonal brain case; massive brow; sagittal keel; avg brain size is 900 cc; shovel shaped incisors; robustly proportioned and tall (5’6”-6 ft); could possibly sweat
- First H. erectus fossil found in Indonesia in 1891
- More H. erectus found in China in 1930s
- H. erectus used Acheulean tools (hand axes); known as Lower Paleolithic/Early Stone Age
Archaic H. Sapiens V. Modern H. Sapiens
Archaic H. sapiens v. modern H. sapiens
- Modern H. sapiens: larger brain (1350 cc), bulbous and gracile skull, small brows, round occipital region, no occipital bun, no occipital torus, vertical forehead, parietal maximum skull breadth, poorly developed wisdom teeth, small face, no prognathism, canine fossa, chin, straight limb bones, and lower limbs are much longer than upper
- Archaic H. sapiens exhibits mosaic between H. erectus and H. sapiens features
- First European archaic H. sapiens found in Germany (H. heidelbergensis)
- Mousterian tools: indicates forethought and abstract thinking
- Used biodegradable tools
- Big game hunting
4 PART IV Neanderthals
- large cranium (1600 cc in males), robust, double arched brows, large nose, shovel-shaped incisors, no canine fossa, midfacial projection, long and low vault, occipital bun, retromolar gap, prognathism
- large skeleton but shorter on average, barrel-shaped chest, body designed to conserve heat in cold climate, indicates physically demanding lifestyle
- Middle Paleolithic tools, and some Upper Paleolithic
- anterior teeth were large and heavily worn, used in a viselike manner
- mobile people seasonally occupying sites for short periods of time
- ate a lot of meat
- may have buried their dead
- Upper Paleolithic: cave art, burials, microliths,
4 PART V summing up
We've got the lineage of the hobbit, 'Homo floresiensis' (in quotation marks because its human status in not yet clear), perhaps diverging more than two million years ago, evolving in isolation in southeast Asia, and apparently going extinct about 17,000 years ago.
We've got Homo erectus, most likely originating in Africa, giving rise to lineages which continue in the Far East in China and Java, but which eventually go extinct. In Europe, it perhaps gave rise to the species Homo antecessor, "Pioneer Man," known from the site of Atapuerca in Spain. Again, going extinct.
In the western part of the Old World, we get the development of a new species, Homo heidelbergensis, present in Europe, Asia and Africa. We knew heidelbergensis had gone two ways, to modern humans and the Neanderthals. But we now know because of the Denisovans that actually heidelbergensis went three ways—in fact the Denisovans seem to represent an off-shoot of the Neanderthal lineage.
4 PART VI summing up
North of the Mediterranean, heidelbergensis gave rise to the Neanderthals, over in the Far East, it gave rise to the Denisovans. In Africa heidelbergensis evolved into modern humans, who eventually spread from Africa about 60,000 years ago, but as I mentioned, there's evidence that heidelbergensis populations carried on in Africa for a period of time. But we now know that the Neanderthals and the Denisovans did not go genetically extinct. They went physically extinct, but their genes were input into modern humans, perhaps in western Asia in the case of the Neanderthals. And then a smaller group of modern humans picked up DNA from the Denisovans in south east Asia.
5. Describe three different hypotheses that attempt to explain the origin of anatomically modern Homo sapiens and how it has become a cosmopolitan species in the last 200,000 years or so. What kinds of evidence are there to support or refute the hypotheses? Discuss starting from about 2 million years ago.
Three major theories are the African Origins & Replacement Model, of which there is the theory of complete replacement and also partial replacement. The other Major theory is multi-regionalism. The third theory is the one that had been disproved entirely by the scientific community and that is the candelabra theory.
5 PART II Evolutionary Timeline
Evolutionary Timeframe
homo habilis 2.3 mya→ homo erectus→ homo ergaster & homo erectus leave Africa 1.3-1.8 mya→ homo heidelbergensis Homo rhodesiensis homo antecessor 50,000-100,000 ya (replacement theory) → homo sapien → homo sapien sapien modern humans
5 PART III evoutionary timeline expanded
The earliest documented members of the genus Homo are Homo habilis which evolved around 2.3 million years ago; the earliest species for which there is positive evidence of use of stone tools. During the next million years a process of encephalization began, and with the arrival of Homo erectus in the fossil record, cranial capacity had doubled to 850 cm3. Homo erectus and Homo ergaster were the first of the hominin to leave Africa, and these species spread through Africa, Asia, and Europe between 1.3 to 1.8 million years ago. It is believed that these species were the first to use fire and complex tools. According to the Recent African Ancestry theory, modern humans evolved in Africa possibly from Homo heidelbergensis, Homo rhodesiensis or Homo antecessor and migrated out of the continent some 50,000 to 100,000 years ago, replacing local populations of Homo erectus, Homo denisova, Homo floresiensis and Homo neanderthalensis
5 PART IV Modern Human Origins Debate
Modern Human Origins Debate
African Origins, Replacement Model (syn. Out of Africa, OOA, Eve Replacement, Single Origins, Recent African Origins, RAO)
• These are the two large scale ideas out there that compete about origins in Africa
Complete Replacement Model
• The origin of Homo Sapien Sapiens is found at only one place at one time--so at about 200,000 ya from the stock of homo heidelbergensis spread all over and replaced any existing humans at that time
• Somewhere about 60,000 ya there was some population Crash, but then became very successful and became cosmopolitan
• While we spread out, we displaced everyone else
5 PART V Partial Replacement Theory
Partial Replacement Model
• The earliest dates for African modern Homo Sapiens at over 110 kya
• Initial dispersal of homo sapiens sapiens from Africa was influenced by Environmental conditions
• Moving into Eurasia, Modern humans hybridized with resident groups, eventually replacing them.
• The disappearance of archaic humans was due to hybridization and replacement
• If this is the case--you'd have to find evidence of homo heidelbergensis or homo erectus in humans. This is true, there is molecular evidence that there was interbreeding all collectively, but not as much as you would expect (small traces)
5 PART VI Multiregionalism
Multiregionalism (Regional Continuity): Milford Wolpoff, John Relethford, Alan Templeton, John Hawks
• Variation to these ideas
• Populations in Europe, Asia & Africa continued to evolve from archiac Homo sapiens to AMH.
• Humans arose in Africa 2 million years ago
• Gene Flow kept the populations from speciating
• Chinese Anthropologists support this, modern Chinese sometimes do have sagittal keel-- evolved separately in China
• Indonesian Anthropologists support this idea as well, as there are traits from modern to early homo sapiens
• No genetic evidence to support this theory!!
• Not enough genetic diversity between us in order to actually make this claim
• We have the smallest level of genetic variation compared to Chimps or Gorillas, etc.
5 PART VII Candalabra & conclusion
Candelabra Model
• is not supported by any evidence at all
o shows no exchange between people, that everyone developed entirely separate.
• This candle model shows the molecular exchange

• Partial replacement theory makes the most sense
o Some individuals in Asia will also Nisenbaum caves in Siberia have unearthed some teeth and bones that show genetic affinity of homo heidelbergensis-- indicates that there had to have been interbreeding between species to some degree
6. Discuss what Neanderthal is. When did they appear in the fossil record? How long did they live on the earth? Where did they occur? How did they live? In what kind of environment did they live? What types of evidence exist that indicates what they ate? What are their morphological characteristics? Did they speak? What are some of the hypotheses regarding their extinction? What is their genetic relationship with anatomically modern humans?

Neanderthals are later Pleistocene hominins that occupied the earth from roughly 400,000 years ago to roughly 25,000 years ago. This was a time period in which extreme oscillations in temperature occurred as a result of strong glacial and interglacial cycles. Geographically speaking, the largest numbers of Neanderthal sites are found in Western Europe, but their range extends into parts of Eastern Europe, the Middle East, and central Asia. Some evidence also points to Neanderthal occupation as far north as Siberia. Evidence indicates that many Neanderthals lived in caves. There is evidence that Neanderthals migrated based on the seasons, but they did not go far enough to avoid the cold all together.
Stable isotope ratios of carbon and nitrogen indicate that Neanderthals ate a lot of meat and not a lot of vegetables. Their use of tools and injuries found in the skeletons support the idea that they were hunting large game.
6 PART II Summary
The bones of prey also had burn marks that indicate that Neanderthals were cooking their food. There is also evidence based on skeletal remains with cut and burn marks that indicate that Neanderthals may have engaged in cannibalism.
Scientists believe that Neanderthals represent a unique scientific trajectory because they have features that are not present in anatomically modern humans or archaic H. sapiens.
6 PART III- Morphology
• Larger craniums than Homo sapiens females had an average cranial capacity of around 1300cc, and males had roughly 1600 cc. Scientists believe that their large brains were a result of large body size and an adaptation to cold environments.
• Cranium is widest in the temporal region rather than the upper parietal region that is seen in human skulls.
• Presence of an occipital bun at the back of the skull
• Faces exhibit midfacial prognathism , large noses, and no chin.
• Strong brow ridges
• Large eye sockets
• Presence of a retro molar gap (no wisdom teeth)
• Curved, shovel-shaped incisors
• No canine fossa
• Extra cusps on molar teeth
Post-cranial Skeleton-
• Craniums were much larger than those of humans
• Shorter in height (on average 5’3” to 5’6”) and weighed less (110-145lbs)
• Barrel-shaped chests
• short, robust limbs with large joints
• Body design is consistent with a body designed to conserve heat in a cold climate.
• Their skeletons also show evidence of h
6 PART IV- Morphology Adaptation to cold weather, Hypotheses for why they disappeared, similarities with anatomically modern humans
• The shape of Neanderthal hyoid bone is similar to ours, which indicates that they probably spoke, but there is little evidence to what extent that they understood symbolic behavior.
Adaptation to cold weather-
• Large infraorbital foramma (large blood vessels to warm the face)
• Large nasal aperture (cold air is warmed before entering the lungs
• Broad trunk (torso)à surface to volume ratio is low
• Short limbe/fingers (long femur/short tibia shows adaptation to sloped, hilly terrain)
• Fat deposits around vital organs
• adjustment of blood flow
Hypotheses for why they disappeared are:
•Outcompeted by Homo sapiens (ecological niche displacement and active competition).
• Extinction by climate change that caused a scarcity of food.
• Lack of division of labor between sexes
• Assimilated by Homo sapiens or evolved into Homo sapiens (not supported by genetic evidence)
Similarities with anatomically modern humans-
• same dental development rates as humans, similar growth
7. Explain why there is a plethora of ambiguous terms that designate different groups of hominin species. For example, why is there a variation in taxonomic designation of neandertals (Homo sapiens neandertalensis vs., Homo neandertalensis)? Furthermore, explain why paleoanthropologists often disagree on how they interpret the diversity of hominin fossils.
Essentially, the taxonomic distiction for all of these hominids is dependent upon our definition of species and on the phylogenetic model for the emergence of anatomically modern H. sapiens. (textbook pg. 389)
Hominin fossils often share certain morphological characteristics, but then differ in other ways. It is unclear whether or not they are all completely different species, or just had subtle differences.
For Neanderthals, scientists disagree as to whether Neandethals should be considered a species within the genus Homo (H. neanderthalensis) or a subspecies within H. sapiens (H. sapien neanderthalensis). There is much disagreement as to whether or not anatomical differences mean that Neanderthals are a separate species or simply a geographic variant of modern humans.
8. During which geological time period(s) did Homo erectus live and how did they make a living? When and where did they migrate out of Africa and why? What are some of its morphological characteristics and diversities of fossils? How are the morphological diversities of hominin fossils from these geological periods interpreted by paleoanthropologists? What tools did these hominins use? How was their growth and development? In light of what Richard Wrangham proposed about the importance of cooking and what Daniel Lieberman said about this species, what are some of the significant aspects of Homo erectus (and Homo ergaster)?
(1).H. erectus appeared in Africa about 1.8-1.9 million years ago. Their body and brain size increased and their tooth size decreased. it may due to their adaptive to food and new environment and climate. They used very sophisticated stone tools(Acheulean tools) to do active hunting. And they can cook!
(2).They probably left African continent around 1.7 or 1.8 million years ago. But recent fossil records indicate a later date: 1 million years ago. (But DEF earlier than that) The reason why they left Africa maybe the result of multiple movements of small groups of hominins into new territories.
(3).Some morphological features: low frontal; enlarged brain in angular vault, occipital torus, angular torus, sagittal keel, bar-like supraorbital torus(HUGE browridge), thick boned and robust, Pentagon is the widest part. Thick bones strengthen the increase of brain size.
Dental Feature: shovel-shaped insicor(anterior teeth which on their lingual surface are concave with two raised edges that make them look like tiny shovels)
(4). The beginning of modern human body plan, larger body size and less funnel-shaped thorax than early hominins and apes. BRAIN SIZE: 640-1200cc or more! Average: 900.
(5). Body size and shape: platymeric femur: a bone that is flattened from front to back; platycnemic tibia: a bone that is flattened from side to side. Body proportion is long and linear, adaptive to tropical environments. They tend to be like modern humans.
(6). Significance:
9. What types of anatomical changes in human skeletons have taken place when hominin ancestors became bipeds? Thoroughly discuss the anatomical evidence that is observable in human fossil record as well as in comparing the anatomy with the great apes.
Anatomical changes that have taken place when hominin ancestors became bipeds include how the foramen magnum shifted from the back to the skull to the bottom of the skull, the gluteal muscles are repositioned to aid with balance and support, the change in the vertebral column from a C-shape to an S-shape, a decrease in the intermembral index (Short arms, long legs), the human vertebral column is not parallel to the ground like the great apes, the human big toe is convergent with the other toes while the big toe of the great apes is divergent from the other toes, the great apes were flat footed while humans have a curved foot to absorb the shock of bipedal walking, the human pelvis is shorter and wider compared to the pelvises of the great apes, and also how the human femur is angled inward while in the great ape it is straighter.
10. Describe different types of dating methods.
o Relative dating techniques
§ All techniques relate one site with others
§ Lithostraitgraphy
§ Using rocks to date, uses rock layers
§ Biostraitgraphy- faunal successions (index fossils)
§ Tephrostraitigraphy
§ Means volcanic ash
§ Each volcanic eruption differs in chemical property
o Paleomagnetism: Calibrated Dating
§ Geological record of Earth's magnetic field
§ Rocks contain iron-oxide (aligned with magnetic field when rock is formed)
§ Plio-pleistocecne geomagnetic polarity time-scale:
o Chronometric dating techniques
§ Annual growth rings in trees
§ Glacial retreat
§ Used more before global warming and glaciers began melting, no longer a viable form of dating
§ Radiometric Dating (next slide)
o Radiometric dating methods
§ Uses decay of radioactive atoms
§ Radiocardbon dating
§ Potassium argon dating
§ The heat of volcanic eruptions drive off all AR gasses, and therefore, newly formed volcanic sediments only have 40k
§ Argon-argon dating
§ Uranium-series dating
o Radiocarbon dating
§ Carbon has different isotopes
§ Theres both stable and unstable isotopes
§ Carbon 12 and 13 are both stable and have six neutrons
§ Carbon 14 however, is unstable and has an extra neutron
12. How can you tell whether hominins practiced active hunting, passive scavenging or active (or confrontational) scavenging?
• How did they obtain meat?
o Olduvai Gorge
o Olorgesailie Butchering site
o Early Homo carried stone tools for short distance
o We used to considered them the first species to make and use Oldowan tools
o It was assumed that they brought these tools a short distance with a basket or bag made of twine
o The question is whether or not their obtained meat by scavenging or by hunting
 starring under a microscope you can view the layers of activities, a hunter's teeth or tools are visible first, these layers determine the type of Scavenging or Hunting
 Passive Scavenging - A scavenger would have tooth marks of the animal first and then cut marks.
 Active Scavenging- Maybe they scared away a leopard after it killed the carcass. There would still be tooth marks on the first layers, but there would be more tool marks.
 Active Hunting- they would go before lions, throwing stone tools killing lion. Maybe tooth marks but they are very few. Mostly tool marks and cut marks
12 PART II- Persistence Hunting
o Persistence hunting (Liebermann 2000)
 Homo erectus became such an adaptive species in terms of sweating, they obtain meat by active hunting
 This hypothesis was featured in the Becoming Human movie
o Confrontational scavenging hypothesis (Bunn & Kroll 1986, Bunn & Ezzo 1993)
o Passive Scavenging hypothesis (Blumenschine 1988, Shipman 1986, Potts 1988)- experimental work by Dominiguez-Rodrigo and other provide countering evidence
o Cultural vvariation hypothesis: Some were hunters, other wre scavengers- inferred from Chimapnzee cultural variations.
• Persistence hunting- sweating facilitates this
o Bushman know that animals rest in the midday sun-- best time to hunt when predators are resting
o Strategy is simple, run the animal to exhaustion
o Animal becomes immobilized by heat stroke
• Homo erectus hunt was simple-yet effective
o The meat they gained fed their growing brains and the complexity of early human society
o Only cooking can explain the magnitude of this cha
o Evidence of meat eating in H. erectus
 Cut marks
 Hypervitaminosis of vitamin A
 Even contemporary human societies, if someone is eating a lot of mea and not a lot of vegetables, a person has a lot of vitamin A
 Human and hyena tapeworm divergence at about 1.8 mya
 If humans have done some scavenging it means that we would exchange tapeworm with hyena at some point
 When youre looking at molar cusps, H. erectus has deeper cusps
o Homo erectus behavior
 The presence of many cut and fractured animal bones at localities (eg Zhoukoudian, Koobi For a) indicates that H erectus was perhaps a good hunter (& gatherer)
 No concrete evidence that indicates that h. erectus was controlling fire until 400k years ago
 It also indicates that this species ate a significant amount of meat (contrary view h erectus as a scavenger)
 Use of fire 1mya (Berna et al 2012)
 Making fire (terra Amata, 750 kya)
 Opinions divided-- did H erectus have full use of fire?
PART IV How did they obtain meat?
• How did they obtain meat?
o Homo erectus had no claws and no defense
• The ancestors of homo erectus were built to run
o They lost their thick hair that helped sweating and cooling
o Examining louse help to understand these changes
o When we lost our body hair, the original human louse originated to our heads
o When our ancestors had contact with gorillas the gorilla louse colonized their pubic region
o Eventually it evolved to the human public louse
o Human public louse and gorilla louse diverged from a common ancestor 3 mya
o Turkana boy was mostly hairless like humans
o Most animals are at a disadvantage in the midday sun, but homo erectus sweats and so they did not overheat
o Quadrapeds can gallop for 10-15 minutes then they overheat
• Persistence hunting- sweating facilitates this
o Bushman know that animals rest in the midday sun-- best time to hunt when predators are resting
o Strategy is simple, run the animal to exhaustion
o Animal becomes immobilized by heat
13. What evidence is there regarding the emergence of modern Homo sapiens-like life history patterns in ancestral hominins? What methods are used to discern growth and development in hominins? Give two example species and describe the methods and the study results.
Quickly: looking at teeth to determine age--especially those of children. H. habilis (Turkana Boy) and I think H. erectus
14. How can one study the diets of hominins? What methods are used to discern what the hominins ate? Give two example species and describe the methods and the study results.
Evidence of meat eating can include cut/slice marks on the bones of animals found near the bones of early hominins, which indicate cutting meat from the bones, or breaking them to extract the marrow. In the Homo-lineage, especially in Homo erectus, that we see biological features often linked to meat-eating, such as a decrease in tooth and gut size and an increase in body and brain size. Carnivorous animals also have stable isotope ratios of carbon and nitrogen (shown in Neanderthals).
Also looking at the facial features of hominins can yield what types of food they eat. Robust australopithecines have prominent brow ridges, nuchal crest, sagittal crest, and wide zygomatic flare. These indicate that it had large chewing muscles, and was therefore chewing hard food. Gracile australopithecines do not have these characteristics, and therefore were chewing less hard food.
15. What are paleoanthropologists interested in studying and learning about out ancestral species and what methods are used? How do paleoanthropologists study about the climates and environments they lived?
Paleoanthropologists are interested in studying and learning how Homo sapiens emerged, how many species of Hominins were there, how large was their geographic distribution, morphological changes, dietary information, how old they were, causes of mortality, and growth and development rates. Some methods that paleoanthropologists use, but are not limited to, Taphonomy (Primary and Secondary), Stratigraphy, relative dating techniques (lithostratigraphy, biostratigraphy, tephrostratigraphy), Calibrated dating techniques, and chromatic dating techniques (Radiometric dating-radiocarbon, potassium-argon, argon-argon, Uranium-series dating). Paleoanthropologists study the climates and environments in which they lived through detecting the amount of oxygen isotopes there is in a fossil. They can also try to detect the amount of stable carbon isotopes there are in the teeth, bones, soil, and fecal matter of our ancestors.
16. When did our ancestors lose hair and when did our ancestors begin wearing
The origins of when we lost our hair and started wearing clothing can be found by studying three different types of lice: head lice, pubic lice, and clothing lice. When our ancestors had full body hair, lice were able to travel all over the body, but when we lost our fur, pubic lice and head lice were separated from one another. Head lice and clothing lice are the same species, as clothing lice evolve from head lice in certain situations. These two types of lice are a completely different species from pubic lice. Pubic lice lived on archaic gorillas, but switched hosts from archaic gorillas to hominins approximately 3–4 mya. The loss or reduction of body hair as well as the development of pubic hair would have facilitated the success of this host switch and therefore suggest that human hair loss and the gain of pubic hair had occurred by 3–4 mya.
Because clothing lice live exclusively in the clothing, they are thought to have evolved only after humans began to wear clothes, and it has long been proposed that dating the origin of clothing lice could give us a date by which H. sapiens must have been wearing clothing. Recent molecular evidence from clothing lice suggests that clothing use originated between 83,000 and 170,000 years ago, and suggests that clothing use by H. sapiens likely originated before they moved out of Africa.