Anthropology

Hypotheses for bipedalism

carrying, thermoregulation, long distance traveling, foraging, visual surveillance, provisioning, aquatic ape

Body and trace fossils

body fossils reveal body structures while trace fossils reveal behaviors (Laetoli footprints)

Eugene Dubois

found Java man, Homo erectus/ first to intentionally look for fossil hominins and went to Asia rather than Europe

Red queen hypothesis

shifting to a dryer and more variable climate forces change in hominoids/ we are evolving in response to the environment just to stay in place and not get left behind—evolution is keeping up to survive now, not getting ahead

Why did hominins evolve???

exploit new environments?/ competition drive adaptations?/ shifting resource availability?

Pre-Australopithecines

earliest hominin ancestors/ Sahelanthropus, Orrorin tugenensis, Ardipithecus ramidus

Sahelanthropus

earliest hominin ancestor/ intermediate foramen magnum and a flat face/ hominin status somewhat debated

Orrorin tugenensis

early and firmly established hominin/ hindlimbs and femoral ends start to show bipedal tendencies

Ardipithecus ramidus

many biped features (smaller canines, broader pelvis, platform talus) but still had arboreal features like a divergent hallux and long limbs meaning it was a habitual biped in a patchy forest and woodland environment/ “Ardi” is the most complete early hominin skeleton

Australopithecines

longest enduring category suggesting a more stable environment (successful because of rivers and lakes—less arid, still seasonal shifts leading different species to evolve, adapted to resources and diet)/ Anamensis, Afarensis, and Africanus

A. Anamensis

earliest australopithecus/ concurrent with afarensis

A. Afarensis

most widely found and studied/ found in East Africa/ mixed terrestrial and arboreal features/ strong candidate for ancestor to all later hominins/ Lucy, Salem, Laetoli footprints

Lucy

Afarensis/ clear bipedal features like medially angled femurs and bowl-shaped pelvis with a small brain and some arboreal features still, showing that bipedalism drove evolution—not brain size/ found by Donald Johanson

Selam

Afarensis/ a 3 year old individual important for understanding the still short but slowing life history pattern based on baby teeth and smaller brain size

Laetoli footprints

Afarensis/ trace fossil created with volcanic ash with a minimum number of individuals (MNI) of 2 indicating bipedalism/ found my Mary Leaky

A. Africanus

found in South Africa/ more adapted bipeds with less prognathism and more gracile features/ Taung Child and Mrs. Ples

Taung Child

Africanus/ was the first found in Africa and controversially proved evolution started in Africa, not Europe/ found by Raymond Dart

Mrs. Ples

Africanus/ used for research and cranial comparisons and shows that walking upright evolved before a larger brain size

A. Sediba

2 individuals found still with small stature and brain size, but more derived features closure to an obligate biped (mosaic evolution)/ had stone tools/ potential link to Homo

Paranthropus

Robust Australopithecus/ ⍉ more robust, more prognathism, larger teeth, sagittal crest, evolutionary dead end due to being too specialized for heavy mastication/ three types: robustus < aethiopicus < boisei

Kenyanthropus platyops

another genus or possible Austraopithecus or Homo/ unknown ancestry/ concurrent with afarensis

Lice and body hair reduction with Australopithecus

the evolutionary split between head and body louse with australopithecines suggests the development of clothing sparked by less body hair/ public lice was already separate from head lice and similarities to Gorilla louse suggests hominins rested in gorilla nests

Genus Homo

extraordinary diversity/ cycling climates with migration during warm and wet interglacial periods and restricted movement during cold and dry glacial periods/ evolutionary trends include smaller teeth, less prognathism, brain expansion, and increased culture

H. habilis

first member of the genus Homo and was found with Oldowan tools (not first tool user)/ loss of arboreal features/ ⍉ short stature and legs, short stride, and habitual bipedalism like Australapithecus/ ⍉ smaller chewing muscles and teeth, larger brain, and tool use like Homo

H. rudolfensis

some say it's a different species than Homo habilis while others say its normal and slightly primitive or robust variation of it

Oldowan tools

H. habilis/ single-face core tool/ scavenging

H. erectus

first obligate biped, first to leave Africa, and first to use fire/ widespread dispersal (except Americas) with varied geographic climate adaptations/ more complex culture with Achulian tools and increasing intelligence/ ⍉ taller stature with longer legs, larger brain, increase in body size, and less robust with smaller teeth compared to Homo habilis/ life history pattern slows/ cranial changes/ Java Man, Peking Man, Turkana Boy

Achulian tools

H. erectus/ bifacial core tool/ scavenging

Cranial changes with H. erectus

larger brain size, longer and lower brain case (widest area is low parietals), large brow ridge (supraorbital sulcus), thick cranium wall bones, post-orbital constriction, sagittal keel in Asian forms

Java Man

H. erectus/ first Homo erectus discovered—in Indonesia Asia/ showed widespread bipedal evolution/ compared to later Homo erectus finds/ found by Eugene Dubois

Peking man

H. erectus/ evolution and variation in China

Turkana boy/ Nariokotome

H. erectus/ long bone fusion and dental measurements inform an intermediate life history pattern/ most complete hominin skeleton found in Africa

Dmanisi Man

H. erectus in the Near East or its own species Homo georgicus

Homo antecessor

oldest H. erectus in Europe or its own species

Migration of H. erectus

First seen in Africa, soon in Near East, then in Asia and South Africa, then China and Indonesia (Java), lastly Europe

Use of fire with H. erectus

tenderizes food > smaller and teeth/ breaks down food > easier nutrient extraction and a smaller gut/ less energy for digestion > larger brain and body size/ provided warmth may contribute to loss of body hair/ provided protection which allowed for sleeping on the ground and lost arboreal traits/ associated with social gathering and language development/ associated with Homo erectus leaving Africa

Biocultural evolution cycle

better nutrition > larger brain > complex tools > better nutrition

Short answer question: Describe the importance of each bipedal feature determining obligate or habitual bipedalism—biped features include central foramen magnum, non-divergent hallux, bowl-shaped pelvis, S-shaped spine, medially angled femurs, platform-like talus, robust calcaneus

The central foramen magnum allows the skull to balance on top of the spine and easily maintain an upright posture necessary for bipedalism. A sigmoidal, S-shaped, spine is also important for centering weight above the legs. The bowl-shaped pelvis bears weight, positions two legs directly underneath the torso, and allows for greater supporting muscle attachments of the legs. Medially angled femurs keep weight supported and centered along the body’s midline. A platform-like talus means supported body weight and limited ankle movement to prevent dislocation or falling. A robust calcaneus provides stability and balance when shifting weight. Lastly, a non-divergent big toe allows for increased balance, forward momentum, and keeping weight in line when walking bipedally. In general, all of these features are important for bipedalism because they increase balance, support, and energy efficiency.

H. heidelbergensis

diagnostic feature is a discontinuous brow ridge/ uncertain how it fits into human evolution/ first hunting species/ Mousterian tools with Levallois technique/ Bodo, Atapuerca pit of bones, Dali, Jinniushan

Bodo

H. heidelbergensis/ mixed features in Africa and oldest evidence of cannibalism (cuts to skull)

Atapuerca pit of bones

H. heidelbergensis/ largest fossil collection—intentional disposal of dead

Dali and Jinniushan

H. heidelbergensis/ most complete in Asia with mixed and more derived features

H. Neanderthalensis

diagnostic feature is an occipital bun/ larger brain size than modern Homo sapiens/ adaptations to cold weather: midfacial prognathism (very large nose and sinuses), very robust with powerful muscles, larger and more stocky bodies, barrel-chested, 5-6 inches shorter, uses furs or hides for clothing/ Mousterian tools with Levallois technique/ La Chapelle-aux-Saints, Moula-Guercy Cave, Vindija, Shanidar Cave

La Chapelle-aux-Saints

Neanderthals/ missing teeth and broken bones indicate caring for the elderly

Moula-Guercy Cave

Neanderthals/ processed skeletons—best evidence for cannibalism

Vindija

Neanderthals/ slight chin suggesting a link to H. sapiens

Shanidar Cave

Neanderthals/ intentional burials

Mousterian tools with Levallois technique

Neanderthals and H. heidelbergensis/ more refined and intentional carvings where chipped pieces can be used for hunting

Denisovans

only few bones found in Siberia and Tibet/ mtDNA shows they are distinct from Neanderthals and H. sapiens, but, there’s overlap in nuclear DNA with Neanderthals and H. sapiens

H. Floresiensis

on island of Flores in Indonesia/ same time as Homo erectus and sapiens with similar proportions, but had a much smaller body size (3-4 ft)/ some suggested a degenerative disease, but it is likely a case of island dwarfism with H. erectus (species shrinks when getting on an island to adapt to fewer resources)

H. naledi

in caves of South Africa (Lesesi Chamber and Dinaledi Chamber)/ like H. floresiensis, contemporaneous with H. sapiens and obligate biped but small brain

H. sapiens

expanded geographic distribution into America with regional variations and very complex culture/ defining feature is a chin–mental eminence/ Modern humans: high vertical forehead and brain orientation, widest part of skull is high parietals, no post-orbital constriction, smaller brow ridges, smaller, flat (orthognathic) face, small teeth, and overall more gracile/ Magdalenian tools/ Omo Kibish and Herto, Skhūl Cave

Omo Kibish and Herto

H. sapiens/ in Ethiopia have mixed features supporting African origin

Skhūl Cave

H. sapiens/ in Israel with Neanderthal overlap and interbreeding

Magdalenian tools

H. sapiens/ longer, thinner, more delicate and precise/ projectile weapons/ specialized tools not just for hunting—aesthetic and ritual reasons tool

Domestication

changing something from it’s wild form/ animals typically get smaller and plants get bigger with certain features selected for/ dogs are the first domesticated/ earliest agriculture in the Jordan Valley Fertile Crescent

Short answer question: Explain why agriculture would have persisted among H. sapiens despite the negatives—sedentary population, city development, close living and disease spreading, less diverse diet, more interpersonal violence, trade, specialized jobs, decreased interbirth interval, less nutrients, smaller and less robust teeth and facial bones, dental problems

The agricultural revolution began because of a shift to a warmer, wetter, and more stable climate suited for growing crops or because of the need for more food due to increasing population. Agriculture developed independently with some native plants in 7 different locations and the idea spread. The agricultural revolution had many dietary, behavioral, cultural, and biological influences which influence each other. Relying on what one place can grow means their diet was much less varied and they were missing vitamins and nutrients which is reflected in the skeleton. There were more tooth defects like cavities and calculus because of starchy foods. Tooth size, height, and bone mass decreased because individuals didn’t have to work as hard. Drinking cow milk lead to lactose tolerance. Their new stationary lifestyle meant more permanent houses and larger cities with specialized jobs, trade of luxury items, and social hierarchies. This close-quarter living also contributed to spread of disease, competition for resources, and interpersonal violence. Despite all of these negative effects, agriculture persists because it increases the evolutionary fitness of the species. Agriculture drastically decreased the interbirth interval and increased fertility because stable food production can support a much larger population. The ability to reproduce and have grandchildren is what drives evolution.

Stressors

things in environment that disrupt homeostasis

Plasticity

ability to adapt to stressor and maintain homeostasis

Franz Boas

his cephalic index proved raced wasn’t a biological concept

Bergman (body)/ Allen (limbs) rule

long slender body in warm environment to release heat and short stocky body in cold environments to retain heat

Physiological adaptations

acclimation are short-term quick changes and acclimatization takes days or months for the change to occur/ body responses to the environment that can occur at any time, aren't inherited, and reversible/ Ex. sweating, shivering, sunburning and tanning, generating more red blood cells for oxygen adapting to altitude sickness

Developmental adaptations

ontogenetic periods of growth that aren’t reversible/ related to Boas cephalic index and Bergman and Allen rules

Genetic adaptations

nonreversible microevolutionary adaptations are small, inheritable changes that happen when a population is in the same environment for many generations/ Ex. skin color, sickle-cell

Cultural adaptations

behavioral adaptations like clothing, shelter, and diet are dictated by the environment's resources

How adaptations are interconnected

Adaptations are not mutually exclusive--one can influence another

Sunburns (acclimation) > tanning (acclimatization) > change in melanin production (genetic) > clothing or sunscreen (cultural)

Lactose intolerance, a cultural adaptation leads to the genetic adaptation of lactose persistence

Vitamin D hypothesis, UV radiation, and melanin production

Skin color and melanin production is an adaptation for high levels of solar radiation. Dark skin is associated with high UV exposure near the equator and light skin is associated with low UV exposure away from the equator.

UV radiation is associated with Vitamin D required for healthy bone growth. Rickets, deficiency in Vitamin D and warping bones, has the greatest impact on northern regions.

Vitamin D hypothesis- light skin absorbs more UV radiation and Vitamin D/ natural selection in northern regions favors alleles with light skin while darker skin disrupts proper absorption and isn't advantageous in these regions

Life history

an adaptation that is highly variable and diverse--what natural selection acts upon/ primarily genetically based with some flexibility within species/ humans have a slow life history pattern despite not being arboreal due to cultural adaptations like fire/ (Factors: Age of weaning, Age at reproduction, Average life expectancy at birth, Life expectancy at maturity, Birth rates, Infant sex ratios, Litter sizes, Longevity, Brain to body size at birth, Rates of reproduction at each age)

Race

Race- biologically a subspecies/ a social construct—not a biological one because: 1. Humans represent a biological continuum (clines) 2. Not every population fits into a neat category 3. Groups of traits used to define race don't always appear together 4. The environment influences many characteristics which are used to determine races 5. Interbreeding between races is common 6. Genetics and inheritance are complicated 7. Racial categories change with time and culture/ still has real cultural, historical, and emotional values

Four goals of forensic anthropology

1. Provide positive identification—estimate age, sex, ancestry, associated material culture, etc.

2. Determine cause of death—timing, manner, and cause of death

3. Provide accurate physical evidence to be used by legal authorities—based on ID and cause of death

4. Be a reliable witness—not biased

Finds and excavation

Recovering remains first requires assessing the situation, environment, and soil (archaeology)/ Look for animal trails and scattered remains/ Flag surface finds/ Excavate if necessary/ Locate, reference, describe, and photograph everything because excavation is a destructive technique that can’t be undone

Four post-mortem stages of death

1. Pallor mortis (15-30 minutes)—paleness of skin

2. Algor mortis (12-18 hours)—no energy and cold to the touch

3. Rigor mortis (starts 2 hours post-mortem and peaks at 12 hours)—stiffening of muscles lasts for 24-48 hours and ends as the body starts to decompose

4. Livor mortis (starts 2 hours post-mortem and is fixed at about 8 hours)—fat congeals and blood pools

What influences decomposition

Climate specific—slower in cold weather and quicker in warm weather

Clothed parts of the body decompose more slowly

Burning accelerates decomposition

Short answer question: How to positively identify a body using various features in a lab setting—stature, age, sex, ancestry, cause of death

In a forensic anthropology lab setting, it is important to ask “is it bone,” “is it human or faunal,” “is it contemporary or non-contemporary,” and “what is the minimum number of individuals.” If bones are human and contemporary, it is important to first lay them out in standard anatomical position. During the analysis to positively identify an individual, stature can be estimated using long bone formulas. To determine age, dental development can be used for children, and the degree of suture fusion, epiphyseal fusion, or pubic synthesis can be used for adults. Features like the mandible, forehead, and pelvic bones indicate sex—males have more robust cranial features while females have a wider pelvic inlet. Additionally, genetic testing in combination with specific dental, cranial, and postcranial features can inform ancestry. However, guesses about ancestry have no biological basis because of continuous geographic variation, but it can narrow down the search. Lastly, determining the cause of death involves thinking about the timing and types of trauma. Signs of healing indicate an antemortem injury, clean breaks mean a perimortem injury, and jagged breaks are postmortem injuries. Injuries can also appear to be caused by blunt force trauma (round indentation), sharp force trauma (cutting edge or point), or projectile trauma (often bullet holes).

Parry fracture

defensive bone break of the forearm

Blunt force trauma

caused by a forceful impact with a dull object or fall

Sharp force trauma

caused by a cutting edge or pointed end

Projectile trauma

causes by high velocity impacts, often bullets, which have a clean entrance, jagged exit, and secondary injury

Antemortem

before death/ signs of bone healing

Perimortem

at or around time of death/ clean break, no signs of healing

Post-mortem

after death/ jagged breaks and discoloration