Anth Midterm 2

What percentage of primates are endangered? Which ones are most endangered?

60%, 98% of lemurs

What is intrinsic value?

the worth of something independent of its effects on others

What is the ecological value of NHPs?

seed dispersers, pollinators, predators/ prey

What is the economic value of primates?

ecotourism, up to $1500 per hour to see rwandan gorillas

How many people live in proximity to gorillas?

5.2 billion

What is the phylogenetic value of primates?

they help us understand ourselves

What are some threats to primates?

Habitat loss/ fragmentation/ degradation, hunting, pet trade, climate change, disease

What are some examples of human illnesses that can affect primates?

Ebola, Covid, RSV

How are primates affected by habitat loss?

90% of primates are tropical species and can lose their habitats to logging, agriculture, fires and cattle ranching

How does forest fragmentation affect primates?

living in smaller, more isolated areas makes them at a higher extinction risk and less likely to receive help, the edge effect causes ecological changes

What is forest degradation?

when primary forest is replaced with secondary forest

What factors affect fossilization?

geological, temporal and biological factors

What is taphonomy?

the study of the processes affecting biological organisms after death

What causes differential preservation?

High rates of decay in forests, erosion in mountains, issue with chimp and gorilla lineages

Where are primate fossils found?

volcanic deposits, lake/ river sediments, caves

What is replacement fossilization?

when organic material is replaced by soil materials

What is cast+ mold fossilization?

When organism is buried in sediment, decays leaving a cavity as a 3 dimensional model of the organism

What are impressions?

Imprints in clay/ silt with no organic material present

What is provenance?

the precise location/ source of the fossil, necessary for dating methods, context of the specimen

What are relative dating methods?

Dating methods that give the time as being older/ younger than another

What is chronometric/ absolute dating?

Exact date, ± error margin

What is statigraphic dating

Dating based on the geologic principle of superposition of layers (older= deeper)

What is biostatigraphy?

the use of reference fossils of other species that only lived in a specific time period

What is fluorine analysis?

a measure of the amount of fluorine in a sample based on the fact that fluorine enters bones from trapped groundwater continuously until recovery

What is Paleomagnetism dating?

As lava cools iron particles orient themselves towards magnetic north (position of magnetic north changes over time)

What is radiometric dating?

the sue of the decay of radioactive isotopes to determine age. Ratio of parent/ daughter atoms is related to time elapsed.

Radiocarbon dating is best for younger specimens, potassium argon is best for older

What is palynology?

pollen analysis, helps to understand plant communities around time of deathWhat

What was significant about the paleocene?

A very geologically active time where NA , Eur and asia were intermittently connected, climate was cool (warmer than today) and the first primates appeared

What were the plesiadapoforms?

Paleocene primate like mammals with a petrosal bulla (!), oldest recognised modern primate falls into this category, best candidate for ancestor of all euprimates also in this category

What is the oldest recognised modern primate?

the Purgitorius, genus purgitoridae

rat sized with primitive molars

What is the best candidate for the common ancestor of all euprimates?

Carpilestidae:

plesaiadaptiforms that are mouse- rat sized, have the dentition to eat vegetation and had a divergent,opposable toe with a nail

What are the Euprimates?

the “true primates”

Why is the classification of hominoids onto 3 families no longer preferred?

because it doesn’t account for the fact that genetic analysis shows chimps are more closely related to humans

What is the significance of the eocene?

tropical forests, primate expansion (adapidae and omomyidae)

What are the Adapoids?

lemur like, potentially more specialised than current lemurs, have sexually dimorphic canines

What are the omomyoids?

found in NA, Eur, As, resemble modern tarsiers

What is significant about the Telihardina?

Omomyoid that provided evidence about the rapid dispersal of euprimates

What was significant about the eocene and oligocene?

Most anthropoid evidence occured

What is significant about Fayum, Egypt?

Was a flooded forest, now site of discovery of about 1000 specimens

What are the true anthropoids? What is significant about each?

oligopithecid: post orbital enclosure

parapithecid: new world monkey dental formula (shows new world monkeys probably didn’t evolve in the new world)

Propliopithecid: size of a howler monkey, fruit eating

What factor messed up the classification of the hominoidea?

the fact that both chimps and gorillas knuckle walk

How did early platyrrhines end up in south america?

originated in egypt, moved to south america via rafting/ island hopping

What is the significance of the Miocene?

• “planet of the apes”

• diversification of primates

• dissapearance of the tail, appearance of large skulls in ape like monkeys

What was the first catarrhine to leave africa?

The pliopithecoidea

When did the true apes emerge?

mid miocene

What are the 2 original diagnostic characteristics of hominins?

habitual bipedalism, large brain size- toolmaking behaviour

What is the problem with bipedalism being a diagnostic feature of hominins?

even great apes have bipedal locomotion sometimes (facultative bipeds, only hominins are habitually)

What is the problem with large brain size as a diagnostic characteristic of hominins?

Large brain size occured only recently, early hominins ahd brains smaller than chimps

When was the LCA of chimps and humans alive?

7-5 MYA

What are some advantages of bipedal locomotion?

• Less heat absorption

• More efficient running

• Use hands

• Able to see better/ more

• Carrying infants

What is the savannah hypothesis?

Bipedalism became more common bc humans were moving in tall grasses between tree patches (ecological changes were affecting savannah habitats and reducing trees)

these changes forced them to walk further to find food, deal with more heat, and made them more vulnerable to predators

What is the problem with the savannah hypothesis?

the earliest accepted hominin lived in wet forests and woodlands but were already bipedal

In what circumstance is bipedalism more efficient?

when walking longer distances

What are some physical adaptations for bipedalism?

• foramen magnum positioned more under the skull

• spine has sigmoid (s) shape to keep trunk and weight centered over pelvis

• pelvis shaped like a basin/ bowl with shorter, broader iliac blades to stabilize weight transmission

• elongation of lower limbs compared to upper limbs compared to apes

• femur angled inward so balance is always in the middle, allowing for standing on one leg

• enlarged big toe in line with other toes

• distinctive arch to help with shock absorption, forward propulsion

What is the general consensus about early hominin bipedalism and brain size?

early hominins were habitual bipeds, retained climbing adaptations, likely spent lots of time in trees

early ancestors had small brain size, walked upright, didn’t see increase in brain size until homo genius

What is mosaic evolution?

an evolutionary pattern in which different traits evolve at different rates

What are the 3 candidates for the first hominin?

Orrorin tunegensis, Sahelanthropus tchadensis, Ardepithecus Ramidus

What about the Sahelanthropus Tchadensis makes it a candidate for the first hominin?

anterior foramen magnum

What about the Orrorin Tunegenesis (millenium man) suggests it could be the earliest hominin?

femur suggests bipedality

found in kenya

What is the main candidate for the earliest hominin species?

Ardepithecus Ramidus

What are the traits of the ardepithecus ramidus?

• found in ethiopia

• large anterior dentition and thin enamel

• some evidence of bipedalism

• primitive pelvis (both bipedal and climbing features)

• opposable toe

What are the australopithecines?

“southern apes”

• diverse range of robust to gracile forms

What is the significance of Australopithecus anamensis??

the oldest australopithecus, found in lake turkana, has a mix of primitive and derived features

What is significant about the Australopithecus afarensis?

• lucy’s species

• found in Hadar, ethiopia

• bipedal (not as much as us)

• small

• strong sexual dimorphism

• primitive traits like small brain, square dental arcade

What species made the laetoli footprints?

Australopithecus Afarensis

What is the difference between the australopithecus afarensis and anamensis?

anamensis has smaller canines and bigger molars

What is the ‘“first family”?

13 australopithecus afarensis skeletons found, 4 were infants

What are the robust australopithecines?

Aethiopithecus, Boisei, Robustus

What are the gracile australopithecines?

all except Aeithiopithecus, Boisei, Robustus

What are gracile Australopithecines like compared to homo?

large teeth, prognathic faces

What is controversial about Australopithecus africanus?

Some think it is the ancestor of homo because it has a larger brain than afarensis

What is significant about Australopithecus Garhi?

Has large teeth, maybe used tools. Some think ancestor of Homo

What is important about Australopithecus sediba?

Has a mix of primitive and derived traits that make some people think indicate a transition from partial arboreality to full bipedality

What seperates the robust australopithecines from the gracile?

sagittal crest, extreme post orbital constriction, flared zygomatic arches

What australopithecine is thought to be the ancestor of later robust forms?

Australopithecus Aethiopius

What is significant about Australopithecus robustus?

has the same isotopic signature of an aardvark- may have eaten termites

What is the honing mechanism?

3rd clear diagnostic feature of hominins- upper canine is sharpened by lower canine and premolar

When did the genus Homo emerge?

2.5 MYA in the pliocene

What are the defining features of the genus homo?

• large brain case

• less projecting, smaller face

• smaller teeth

• more efficient bipedalism

• reliance on culture? stone tools?

What was the environment like during the pliocene?

• high climate variability, high extinction rates

• changes in ocean levels forcing migration

• tool use allowing animal consumption

• extreme variability

What was the first of the genus Homo?

Homo habilis

What were the traits of Homo habilis?

Small brain, somewhat prognathic, no canine fossa, no crests/ keels on skull, used tools

What kind of tools did homo erectus use?

Oldowan choppers, oldest tool industry

Who was the “Handy man”?

Homo Habilis

What are the traits of Homo naledi?

• small brain

• more dexterous than australopithecines

• mix of australopithecine and Homo characteristics

When was Homo naledi thought to live?

250 kya

What is significant about homo erectus?

• 1st species to venture out of africs

• developed acheulean tool tech

• used fire

What is Homo ergaster?

The name sometimes used in reclassifying african Homo erectus

What suggests that asian and african homo erectus should be grouped together?

They have many shared traits

How was the environment changing during the pleistocene?

• glaciation in north/ south broad savannahs and forests in Africa during glacial periods

• habitat fragmentation and deserts during interglacial periods

• sea levels dopped and ice sheets expanded during glacial periods, passage between areas was blocked by glaciers

When did homo erectus leave africa?

about 1.8 mya

When were transitional forms between H. erectus and sapiens found in new areas?

600-200 kya

What were the traits of archaic hominins?

Increased brain size, increased parietal breadth, smaller molars, smaller cranial and post cranial robusticity

Was the transition to homo sapiens all at once?

No, very heterogenous

What were the transitional homo sapiens called?

Some call them archaic homo sapiens, others refer to them as Homo heidelbergensis

What are the 4 (possibly 5) archaic homos?

heidelbergensis, rhodesiensis, antecessor, neanderthalensis, possibly denisovans

What do many people consider the best candidate to be the ancestor of neanderthals and homo sapiens?

Homo heidelbergensis

What is the difference between homo erectus and homo sapiens skulls?

Homo erectus skulls are widest at the bottom, Homo sapiens more globular, more vaulted (wider at the top)

What fossil was found in Dali (asia)

a near complete skull with a mixture of homo erectus and homo sapiens traits

What is the significance of the Atapuerca Gran Dolina fossils?

Found fossils of several individuals who lived the re about 780 kya

evidence of cannibalism