Exam 3 COPY Flashcards
biocultural evolution
- confers the notion that biology makes culture possible
- developing culture further influences the direction of biological evolution
what have biocultural interactions caused in humans?
- anatomical, biological, and behavioral changes
worldview
cultural perspective shared by the members of a society
what are humans the result of?
the long-term interactions between biology and culture
what are fossils?
- traces or remnants of organisms found in geological beds on the earth’s surface
- can include once-living forms as animals, plants, insects, and algae
trace fossils
related to an organisms way of life, its behavior, not necessarily the remains of the animal itself
who studies fossils?
paleontologists
paleontology
the study of fossil remains, their context and their evolution
- subfield of geology
geology
the study of earth’s physical characteristics and their formation
what are fossils good for?
fossils tell us about otherwise unknown totally extinct species
- phylogeny
- paleoecology
- paleoenvironment
what do fossils tells us when dated?
when dated, fossils allow us to add a time scale to a phylogenetic tree, and the evolutionary events it depicts
- phylogeny
paleoecology
the settings in which the fossils lived
paleoenvironment
reconstruct the ancient events of evolution and how it occurred and what transpired
teeth and jaws
- ready made fossils
- highly heritable (phylogenetic info)
- sensitive to selection (functional info)
homology
the same organ in different animals under every variety of form and function
- similarities between organisms based on descent from a common ancestor
richard owen
father of homology
analogies (homoplasy)
- similarities between organisms based strictly on common function with no assumed common evolutionary descent
- convergent evolution
taphonomy
- bias in the fossil record is unavoidable
- there will always be a loss of information from the present to the past
plesiadapiformes
- stem primates who split off the tree before the last common ancestor of euprimates
carpolestes
- late paleocene and early eocene
- distribution: north america europe, and asia
- body size: small
- evidence: abundant, nearly entire skeleton known
- divergent, opposable hallux with a nail instead of a claw
- 3.1.3.3. dental formula
- highly aboreal
where in the fossil record is hominid fossil material poor?
- late miocene (12-7 mya) in sub-saharan africa
- but a key time period to explore divergence between humans and our closest cousins, the african apes
molecular clocks
- best when used with the fossil record
divergence estimates between humans and chimpanzees
5-6 mya
divergence estimates between humans and gorillas
6-8 mya
the last common ancestor
- africa
- molecular clock dates 9-5 mya
mosaic evolution
the piece by piece emergence of a new form
- interested in becoming human
- the tinkering nature of the evolutionary process adds and removes and this is how modern humans emerged
east african rift valley
- geologically very young and active
- one of three volcanos that are part of mt. kilimanjaro
- divergent boundary of land where african plate and indian plate are moving apart due to mid-oceanic ridge in the indian ocean
australopiths
- east africa
- 2 genera = australopithecus and paranthropus
- ca. 4.2 - 1 mya
- all bipedal
- large teeth, thick enamel, big chewing structures
- chimp-sized brains
- key countries: ethiopia, kenya, and tanzania
hadar, ethiopia
- 1973 discovery
- ca 3.4 mya
- key features: valgus, femoral condyles modified, and patellar notch raised
- finding of “Lucy”
Lucy
- 1974 discovery
- ca. 40% complete (47/207)
- single adult individual, about 1 m tall
- AL 288-1
A.L.
afar locality and specimen number
laetoli, tanzania
- 1978 discovery of footprints
- 3.6 mya
- fossils similar to hadar finds
encephalization
- hominin brain enlargement beginning with H. habilis and culminating with H. heidelbergensis is the fastest percentage growth of any organ in the history of life
stone tools
- stone tools confer an advantage to gaining access to difficult to get to places (bone marrow)
what is a nutrient rich food that is thought to have attributed to encaphilization?
bone marrow
Paranthropus boisei
- discovery in 1959 by Mary Leakey
- robust australopith first named zinjanthropus boisei
- very large cheek teeth
- small anterior dentition
- a human cuisinart
hominini
taxonomic group that contains humans and closely related extinct species
- more closely related to humans than any other primate group
- everything that is descended of the unknown last common ancestor of modern humans and chimps
what are the two families of the superfamily hominoidea?
hylobatidae and hominidae
hylobatidae
- lesser apes
- gibbons
- siamangs
hominidae
- great apes and humans
- orangutans
- gorillas
- chimps
- bonobos
- humans
if we treat the age of the earth as 12 hours how old are primates? humans?
- 10 min, 48 secs
- 22 seconds
K-T boundary
- explosive adaptive radiation of mammals after the KT boundary as they adapted to inhabit niches left unoccupied after the mass extinction
- primate diversity as most mammalian diversity exploded here
when did primates emerge?
- eocene and paleocene
- 56.5 * 65 mya
synapomorphies
- shared, derived characters of a taxonomic unit that distinguishes members of that taxonomic unit from others
what are the adaptions of bipedalism?
- foramen magnum position
- pelvis shape - lumbar lordosis
- femoral head/neck shape
- valgus knee
- some features in the foot
what is the shape of the human pelvis in comparison to chimps?
- in humans the wings of the ilium extend from either side of the pelvis
- in chimps, the tall narrow wings of the ilium extend from the back of the pelvic ring
- humans have a short ischium, chimps have long ones
what features in the foot do humans have the chimps do not?
- enlarged calcaneus
- curved arch
- convergent big toe
suspensory traits
- curved phalanges, funnel shaped thorax, relatively short hindlimb, cranially oriented shoulder joint, and large pisifirm
- early hominins retain but are lost in the genus homo as the brain size increases
hominin synapomorphies
- flatter face
- bigger brains relative to body size
- thick enamel and large molar size
- smaller canines
hominin evolution
- timing and geography
- brain expansion, then bipedalism or bidepalism then brain expansion?
- europe, asia, or africa?
piltdown man
- large brain
-ape-like jaws and teeth - missing foramen magnum
- found in europe
- hoax exposed in 1953
taung child
- au. africanus
- raymond dart
- south africa
- small brain
- bipedal
- 3 myo
- ignored for many years
- discovered bipedalism then brain expansion occurred in africa
early miocene
warm and wet
late miocene - early pliocene
begin to cool and dry
early hominins
- very ap-like but share synapomorphies with later hominins that are clearly part of the human lineage
early hominin localities: sahelanthropus tchadensis
central africa - koro toro, chad
- 6-7 mya
early hominin localities: east africa
- Orrorin tugenensis
- Ardipithecus kadabba
- Ardipithecus ramidus
what are the bipedal features in the femur of Ororrin tugenensis?
thick cortex on inferior part of the femoral neck
- enlarged femoral head
robust group of austrolipithecus
- 3 - 1 mya
- P. boisei
- P. robustus
- P. aethiopicus
gracile groups of austrolipithecus
- 4 - 2 mya
- A. africanus
- A. afarensis
- A. garhi
- A. bahrelghazali
- A. anamensis
what are the two gracile genera of the australopiths?
- australipithecus
- Kenyanthropus
what are the two robust genera of the australopiths?
- paranthropus
east african gracile australopiths
- Australopithecus anamensis
- Australopithecus afarensis
- Kenyanthropus platyops
- Australopithecus deyiremeda
central african gracile australopiths
- Australopithecus bahrelghazali
southern african gracile australopiths
- Australopithecus africanus
- Australopithecus sediba
Australopithecus afarensis
- 3.8-3.0 mya
- hadar, ethipia
- laetoli, tanzania
- discovered in 1974
what is the evidence of bipedalism in a. afarensis?
- valgus knee and human-like pelvis
what are the oldest tools?
- 3.3 mya
- lomekwi kenya
- “lomekwian tools later oldowan tools associated with homo
Australopithecus africanus
- 3.0 - 2.0 mya
- many sites in south africa
- taung child
- small brain
- bipedal
- first authralopith described
east african robust australopiths
- Paranthropus aethiopicus
- Paranthropus boisei
southern african robust australopith
Paranthropus robustus
Paranthropus boisei features related to heavy chewing
- massive molars with hyper-thick enamel
- huge, thick mandible
What did Paranthropus eat?
- hard foods - seeds and nuts
- tough foods - grasses and sedges
striations
- tough foods
- grasses and sedges
pits
- hard foods
- seeds and nuts
enamel chipping
- high bite forces associated with large enamel chips in living primates species
- many australopiths show high frequency of chips
when were the australopiths named and by who?
- 1920s
- by Raymond Dart
what traits separate homo and the australopiths?
- tool use - precision grip
- dental and facial reduction
- larger brains - encephalization
- connected by the expensive tissue hypothesis
cerebral rubicon
a treshhold established by Sir Arthur Keith at 750cc designating the species which could be placed into the genus homo
- although was a major supporter of piltdown man
piltdown man
- england in 1912
- encephalization vs. bipedalism
- uncovered as a hoax officially in 1953
Johnny’s child
- olduvai gorge and turkana basin, tanzania by the Leakeys in 1960s
- 1.75 mya (2-1.4 mya)
- highly fragmentary - partial madnible, parietal bones, and pieces of the hand
- designated homo habilis as the handy man
- associated with stone tools, reduced facial anatomy, and slightly larger brains
did homo habilis use tools?
- stone tools were found in the area, and were consistent with the daring
- the bones of the hand suggested that they had the ability for a precision grip (seen as necessary for tool use)
did homo habilis have dental and facial reduction?
- the jaw suggested reduced prognathism and the molars and premolars were reduced as compared to p. boisei because that was the only species in the area
did homo habilis have larger brains?
- because the skull is not complete and because it is a juvenile (likely in the 12-13 range) cranial capacity estimates range from 590-710 cc
what are the three kinds of oldowan tools?
- hammer stones
- stone cores
- stone flakes
hammer stones
- these show signs of percussion damage and were likely used to smash into other rocks
stone cores
- these are stones with flake scares around them forming a sharp edge on one side
stone flakes
- these are sharp flakes off of stone cores for fine cutting
did oldowan tools appear prior to the first known homo habilis?
- yes
- 2.6 mya in east africa
- 2 mya in south africa
- 1.8 mya in east asia and middle east
- .8 mya in europe
what are the cranio-dental differences from the australopiths to homo
- similar incisors and canines but reduced molars and premolars
- M3 smaller than M2
- no sagittal crests
- slight post-orbital constriction
when did the modern shape to the dental arcade first appear?
homo habilis
what do postcranial remains of homo habilis show?
- hand bones are robust, but also with fine grip capabilities
- stout, adducted big toe
- hand and forelimbs indicate some climbing was still available
what is the re-definition of the genus homo according to Leakey that disrupts the cerebral rubicon?
- pelvic and hind-limb indicative of obligate bipedality
- upper limb shorter than lower limb
- grasping thumb with precision grip abilities
- cranial capacity ranging from 600-1,600 cc
- overlaps with the australopiths**
KNM ER 1813
- found on koobi fora, kenya in 1973
- dated 1.9 mya
- adult, all teeth erupted, but very small at 510 cc
OH24 - twiggy
- found in olduvai gorge in 1968
- originally crushed flat so there was significant distortion even after reconstruction
- dated 1.8 mya
- young adult based on lack of wear in M3
- 590-600 cc
what disrupted the idea that homo habilis washe clear link between early hominins and later homo?
- KNM-ER 1470
- dated to 1.9-1.8 MYA
what are the features of KNM-ER 1470?
- larger flatter face
- larger brain at 775 cc
- larger molars and premolars
- other than the teeth, this is clearly trending towards modern humans**
single species hypothesis
- proposed by C. loring brace and milford wolpoff
- humans and our close ancestors (everything in the genus homo) occupy such a comprehensive niche that only one species can exist at a time
- therefore all variation seen in fossil taxa from the same time period must be intraspecific variation
lumpers
- fewer species
- intraspecific
splitters
- more species
- interspecific
is H. rudolfensis a male H. habilis?
- lumper v splitter debate
- under the single species hypothesis some argued this
- more than 100 cc in brain size differences between the sexes?
- H. rudolfensis has more gracile facial features (other than teeth)
H. rudolfensis v H. habilis
- the fossils exist, suggesting two morphologies
- dating shows that KNM-ER 1470 was alive at the same time as H. habilis
- fossil KNM-ER is homo rudolfensis and a separate species
- homo habilis is the ancestor of modern humans
so who made stone tools in east africa?
- stone tools are present in east afica by 2.6 mya
- at least one hominin with a slightly larger brain and reduced dentition and face is present in east africa (along with other australopiths) by 2.0 mya
- this hominin(s?) may or may not be the maker of the tools and may or may not be the ancestor of later homo erectus
why focus on the three traits, specifically why the face and tooth size?
- because big teeth suggest a tough diet and as teeth get smaller, so does the jaw and therefore the face
- brains become larger through human lineage
- proportion of body mass dedicated to digestive function is reduced in humans
- possible because tool use allows higher-quality diet
- proportion of body mass dedicated to digestive function in humans appears unreduced in australopiths
expensive tissue hypothesis
- redefined by leslie aiello and peter wheeler as an attempt to explain the co-occurrence of larger brains and tools in a bio-cultural evolutionary context
- brains are metabolically expensive
how much basil metabolic rate and glucose does the human brain use?
- only 2% of your body mass but use 16% of your resting BMR and 30% o your glucose
what significant changes occurred in early homo lineage after 2 mya?
- anatomical changes
- geographical distribution
- evidence of culture
- multiple fossils known, for which taxonomic classification is debated**
what is the geographic distribution of homo erectus?
- homo erectus and contemporaries are found all over the old world, including:
- africa
- georgia
- asia
- western europe
ER 3733
- found at east lake turkana (east africa)
- dated to 1.7 mya
- 848 cm3 cranial capacity
- no longer the “oldest” h. erectus speci,em found, but the oldest from africa
WT 15000
- from nariokotome kenya (east africa)
- dated to 1.6 mya
- nariokotome boy
- juvenile
- the most complete h. erectus specimen yet found
what major sites are homo erectus found in and what are they characterized by?
- china
- zhoukoudian
- indonesia
- sangiran
- characterized by thick skull and pronounced brow ridges
zhoukoudian
- cave site in china
- .7 - .04 mya (recent)
- lots of material recovered
- remains of more than 40 adults and children
- large browridge,sagittal keel, nuchal torus
- thick skull bones
- protruding face, broad near bottom
- site was occupied for 250k years
java sites
- includes type specimen of homo erectus
- dubois worked 1980-1900
- sites: trinil (solo river)
- brain case, mandible, limb bones
- .9 mya
modjokerto and sangiran
- java sites
- von koenigswald worked 1936-1941
- several “new” species all now h. erectis
- 1.7-1.0 mya
what sites are homo erectus found in western europe?
- atapuerca (sima del elefante and gran dolina)
- ceprano
ceprano
- western europe
- .9 - .8 mya
- this one may be h. heidelbergensis
what is the assumption of the anatomic changes of homo erectus?
- associated with behaviors related to emigration from africa and appearance at all these sites
what is the evidence of culture in homo erectus?
- tool use - transition from olduwan to achulean
- hunting debate exists
- controlled fire debate exists
- clothing debate exists
- social structure with groups assumed and sexual dimorphism
