Anthropology Exam 2 (Anderson)
Primate Phylogenetic tree
-anthropoids: all monkeys, apes, humans -least closely related to us are the platyrrhines or the new world monkeys
primate phylogenetic tree
-biggest primate -then strepsirhines -and then haplorhines: everything else
Sahelanthropus tchadensis
"Sahel Man from Chad" -most famous and best studied -Oldest possible hominin (bipedal ape) -Location: Northern chad, central africa -Age: ~7 Ma Ape or human? Hominoid or hominin? -Intermediate foramen magnum -Small Brain (<400 cc) -Large brow ridges and cranial crests -Flat face and anterior dentition LCA with other apes? Skull became very famous and the femur was hidden from the world (hid the femur bc they thought that the femur showed evidence of it not being bipedal)
Locomotor Modes
- Arboreal quadruped - Terrestrial quadruped -knuckle-walking - Vertical clinger and leaper - Suspensory/Brachiation - Orthograde bidepedalism
Early primate studies
- Comparative primate anatomy - Early behavioral studies ---unsystematic --- studied animals in captivity
Reduced dentition
- Derived dental formulas -We have fewer numbers of teeth in our mouth (also types of teeth) than others
Binocular vision
-Forward facing orbits -More reliance on vision -Both eyes work as a coordinated team -orbital convergence
Hominoids: lesser and great apes
-humans
Ardipithecus: "Ground Ape"
Ardi = Ground
Earlier Hominins Summary
Ardipithecus ancestral to Australopithecus? Au. afarensis likely ancestral to Paranthropus ("Robusts"), Au. Africans and Au. sediba Paranthropus likely NOT ancestral to Homo Au. Afarensis ancestral to Homo?
Which of the following hominid species is NOT found in South Africa?
Australopithecus afarensis
What is the oldest known species within the genus Australopithecus?
Australopithecus anamensis
'Gracile' vs 'Robust'
Australopithecus: "Graciles" -Large anterior dentition -Post-canine dentitions "proportional" -Sagittal crest generally absent -Weak brow ridge -Moderate prognathism Paranthropus: "Robusts" -Small anterior dentition -Post-canine "megadont" -Strong sagittal Crests -Strong brow ridge -Little prognathism
3. Energy Efficiency Model
Climate change--> Dispersed resources Bipedal walking more efficient over long distances -More efficient than most Primate quadrupedalism (exp. knuckle-walking) -Increasingly important with distance
Earlier Hominins Review
Derived Hominin Traits: -Bipedal -non grasping big toe (except Ardipithecus) -More parabolic dental arcade -smaller canines Retained Primitive Traits: -small brain sizes -Small body sizes -large back teeth -relatively long arms
Earlier Hominins Review
Derived Hominin traits: -Bipedal -non grasping big toe (except Ardipithecus) -More parabolic dental arcade -smaller canines Retained Primitive Traits: -Small brains -Small body size -Large molars -Relatively long arms
Why be social?
Disadvantages -Food competition -Predator visibility -mate competition -social tension/violence Advantages -Access to food -Predator defense -Mate access -Assistance in care of young Being social (an evolved strategy) makes sense in certain environments but not in others
2. Temperature Regulation
Environmental change -Forests--> Savanna/grasslands Bipedalism reduces heat stress (leaves you less exposed to solar radiation) Problem: Environmental context -Not savannas but likely woodlands Some support but not known HOW important
Which femur is most likely from a biped?
Femur A
Tarsiers
Gigantic eyes
Australopithecus Sediba "Southern Ape of the Natural Spring"
Hominin traits: -anterior foramen magnum -parabolic dental arcade -closely spaced tooth cusps -wide pelvis? -Shorter fingers/toes Primitive traits: -Small brain (420 cc) -Marked brow ridges -Large molars -Long arms -Fingers more curved -Ape-like thorax and shoulder -Flexible ankle -Homo ancestor?
Tool use?
Homo long thoughts first -Homo habilis = "Handy Man" NOW we know: -oldest stone tools ~3.3 Ma -Cut marked bone ~3.4 Ma Australopithecus and Paranthropus may also have used tools
Important to Consider
How much skeletal variation should we see within a species? What does H. rudolfensis mean for classifying species from fossils? -Classify on as many traits as possible -NEVER consensus -SPECIES ARE HUMAN-CREATED CATEGORIES!!!!
______ accounts for a majority of the mass of the human skeleton
Inorganic materials
Controversial?
Kenyaanthropus platyops -3.5 Ma (k-Ar) -Kenya -flat face -skull has suffered expanding matrix distortion Australopithecus garhi -2.5 ma (K-Ar) -Ethiopia -Au. afarensis or Paranthropus? -associated with stone tools and cut-marked bone Au. deyiremeda -3.5 - 3.3 Ma (K-Ar) -Ethiopia -Au. afarnesis? Au. bahrelghazali -3.5 ma (biostrat) -Koro toro, Sahara, Chad -vertical mandibular symphysis
Reconstructing Diet: Microwear
Leaves vs fruit leave different marks on teeth Disagreement between isotope and micro wear research -"Last Supper" effect Results? -Australopithecus ate more leaves -Paranthropus were hard/tough object feeders
Ardipithecus ramidus conto..
Mosaic of human-like and ape-like features... several distinct from modern great apes facultative bipedalism, plus arboreal quadrupedalism and careful climbing Diet distinct from modern chimps and later hominins Bipedalism may have evolved in more forested environments???
What's in a name?
Most fossil taxa named after combo of: -Where first fossil found -suffix meaning "ape" or "from some place" Example: Australopithecus -Latin Australo: "Southern" -Greek -pithecus: "ape" -So Australopithecus: "Southern ape" Greek -ensis = "originating in" or "from" Greek -anthropus= "man"
Earliest Homo
Oldest possible fossils 2.8 - 2.3 Ma -Very fragmentary -East Africa (South Africa?) Oldest identifiable by ~2.0 Ma How do we distinguish it from the gracile Australopithecids? -
Homo habilis
Olduvai Gorge (OH) 1.9-1.6 Ma, East Africa Famous fossils: -OH 8 foot -OH 24 "Twiggy" -KNM-ER 1813 Derived traits: -Increased brain size (650 cc) -Rounder skull -Dental arcade more parabolic -Short toes/fingers -Shorter arms/legs? Retained Primitive Traits: -Slightly curved fingers/toes -small body size Not a lot of securely associated post crania
Paranthropus "Beside Humans"
Probably not ancestral to modern humans -Descended from Au. afarensis or Africanus? Unique Traits: -sagittal crests -very large teeth very thick tooth enamel Broad, dished faces -flared cheekbones P. robustus= South Africa P.aethiopicus and P. boisei =East Africa
Australopitheid Diets: Isotopes
Some ate C3 plants (leaves, berries, fruits, nuts) and some ate lots C4 (sedges, grass seeds) -most ate a mixed diet Paranthropus NOT hard-object feeders -Lots of C4 plants Modern humans can't digest C4 grasses -Earlier hominins eating more C4 grasses -OR eating animals that eat C4 grasses
Ardipithecus ramidus cont...
Some sites reconstructed as heavily wooded -Colobines and forest bovids -Soil chemistry suggest wooded habitat -Low transport BUT also savanna Other sites reconstructed as wooded grassland
Interpreting the Fossil Record
Taphonomic biases affect what's preserved Collection biases affect what ends up being studied Best for taxonomic analysis -Cranial + dental fossils (craniodental) Ideal for taxonomic analysis: -Craniodental + post crania = "associated" specimens
What about Climate?
Turnover pulse Hypothesis: Significant faunal turnover events coincide with periods of global climatic change Significant shifts @2.5Ma, 1.8Ma, and 900ka -correlation = causation?
Oldowan Tools
Unifacially worked cores -Oldest ~3.3 Ma from Lomekwi, West Turkana, Kenya Bifacial--> Developed Oldowan -Technological stasis 2.6-1.5 Ma Associated with H. Habilis, H. erectus AND P. Boise and P. robustus -Maybe K. platyops and Au. garhi
Field studies Important because:
_ Minimizes human interference and "unnatural behaviors" -Helps us understand: ---Ecology ---Behavioral ecology ---Human-primate cultural relationships
Miocene Environments
_increasingly cooler and drier -Breakup of tropical forests --Expansion of woodlands and grasslands --Increased environmental diversity --Resources more dispersed
All of the following are part of the postcranial skeleton EXCEPT:
a. Patella b. metatarsals c. occipital d. os coxae e. coccyx -Occipital
Which of the following statements about carbon 14 dating is correct?
a. it can only be used on volcanic materials b. it rarely needs to be calibrated with other methods c. it can be used to directly date fossilized remains d. it can be used to date things older than 50,000 years e. it can only be used on organic remains e. it can only be used on organic remains
Ardipithecus ramidus
a. retains an abducted hallux b. is likely directed ancestral to paranthroupus c.has a large brain compared to chimps d. is found exclusively in south africa e. shows no adaptations for bipedalism a.
Prosocial behaviors are best defined as
behaviors that benefit others without rewards for the performer
Paleoecology
ecology key-indicator species -examples: fish, arboreal monkeys taxonomis uniformitarianism Ecological functional morphology
Social group and testes size
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Au. afarensis
- 3.6 ~2.9 Ma, East African --definite biped --small brain --intermediate dentition --possible ancestor to homo -Lived in range of habitats from closed woodland to open grasslands
Our heritage as mammals
- As mammals -Possess modified sweat glands that produce milks -As Eutherian mammals: -placenta: organ that allows exchange of gases, nutrients, and waste elimination during gestation -Other shared derived traits with mammals: -Increased brain size -Enlarged cerebral cortex -Emphasis on quality offspring and socialization -K-selected (quality over quantity)
Link to Humans
- Modern chimp, gorilla and human lineages not established until late Miocene (5ish Ma) - Gap in the fossil record 10-5 Ma - Molecular data now being applied
lesser apes: gibbons and siamangs
-SE Asia -extreme brachiation -"lesser" = smaller
Post-WW2 shift
- Field studies: Studying free-ranging primates in natural habitats using evolutionary perspective
Cercopithecines
- Fossil macaques similar to extant - Baboons ~ late Miocene -modern baboons by Pliocene - Theropithecus -specialized grass seed eaters - dominate fossil assemblages
Functional morphology
- Functional morphology: using skeletal shape to estimate locomotor capabilities - How do you think we can apply this is to fossil record? -comparisons -Qualitative and quantitative analyses
Primitive Primate Traits
- Have shared derived traits with all mammals ---Makes them primitive for primates ---Each primate group in turn has own set of shared derived traits
Non-Human primates
- Help us understand human biology and evolutionary history --- Reconstruct steps ---ID evolutionary forces ---Modern analogues for ancestors
Comparative Method
- Helps us: ---ID adaptations in morphology, physiology, and behavior -Understand evolutionary processes that made us human -example: human brain size -Can help us interpret fossils -Linking anatomy with behavior and ecology
Locomotor trend example
- Intermembral Index (IMI): arm length/leg length -IMI<100 legs longer than arms -vertical clinging/leaping -bipedalism -IMI>100 legs shorter than arms -suspensory/brachiation -IMI = 100 +- 10ish arm and leg similar length -quadrupedalism
Relatively slow life history
- Longer gestation, maturation period, age to reproduction and life span
Humans are Primates
- Non-Human primates are our closest living relatives (many shared served traits) -Last common ancestor (LCA) of humans and chimps/bonobos lived (7ish Ma) -Next closest: gorilla
Haplorhines: dry nosed
- they don't have that wet nose -tarsiers, monkeys, apes, and humans -Greater reliance on sight -Post-orbital bar -post-orbital closure -More pronounced orbital convergence -no tapetum lucidum -Decreased reliance on smell -dry nose (no rhinarium) -reduced snout -larger brain -no dental comb
Ardipithecus ramidus
-"Root of the ground Ape" -4.4 Ma (K-Ar) -Ethiopia -Mosaic of features -Ape or hominin? -
Homo rudolfensis? "Man from Lake Rudolf"
-1.9-1.6 Ma in East Africa Derived Traits: -Larger brain (775 cc) -relatively flat face -small brow ridges -robust jaws -relatively large teeth H. habilis or distinct taxon?
Mammals in context
-1st mammals in mesozoic ---1st Eutherian ~ 160-125 Ma -Undergo adaptive radiation ~65 Ma ---Adaptive radiation: rapid expansion and diversification of life forms into new ecological niches
What Makes us a Great Ape?
-2.1.2.3/2.1.2.3 dental formula with Y-5 -Shoulders for brachiation/suspension -No tail -Large brains relative to body size -why we are a great ape
Australopithecus africanus
-2.5 ~ 2.0 Ma (biostrat, U-Pb) -South Africa -First Australopithecus ever found -Hominin Traits: --Anterior foramen --Human-like teeth --Parabolic dental arcade --Less prognathic --Reduced postorbital constriction --Short/broad pelvis Primitive traits: -small brain -prognathic face -large molars -small body size-similar to au. afarensis Reconstructed habitats open woodland with nearby river and grasslands
Paranthropus aethiopicus "Beside Human of Ethiopia"
-2.7 - 2.3 ma (K-Ar) -Kenya and Ethiopia Traits: -Small brain -Sagittal crest Postorbital constriction Descended from A. Afarensis and ancestral to P. Boisei?
Australopithecus afarensis "Southern Ape of the Afar"
-3.8 ~ 2.9 Ma (K-Ar) -Ethiopia, Kenya, Tanzania -29-45 kg (64-100 lb) -Mosaic of human-like and ape-like features
Australopithecus Anamensis "Southern Ape of the Lake"
-4.2 - 3.9 Ma (K-Ar) -Kenya and Ethiopia -Traits: --Large canines --Thick tooth enamel --Anterior foramen magnum --Human-like elbow --Small brain (~370 cc) -Specimens --Teeth, jaws, post crania, skull!!
Hominidae: great apes
-5 living apes -distinguished by their names
Colobines
-Fossils in Europe and africa -some terrestriality -Fossils larger than extant -up to 40kg (~88 lb) -Diverse compared to extant
Euprimates- Eocene
-Adapoids and Omomyoids by early Eocene (~56 Ma) -primitive dentition -adaptive radiation in the early Eocene -reduced by end of Eocene -extinct in NA by 35 Ma -Evolutionary relationships uncertain -shared derived primate features: -forward facing eyes -greater encephalization -post-orbital bar -nails instead of claws opposable big toe
Propliopithecids
-Aegyptopithecus -arboreal quadruped? -2.1.2.3 dental formula -significant sexual dimorphism -Ancestral to OWM and apes? -Would make them our ancestors!! -primate from egypt -look like monkeys and apes -OWM ape
Affiliative Behaviors
-Affiliative: amicable associations between individuals --hugging, kissing and grooming -reinforce bonds and enhance group stability -relationships crucial to nonhuman primates and can last a lifetime -biological: grooming gets rid of parasites -seem to have friends and maintain a close relationship
Colobus monkey
-Africa -common in zoos -hunted for their skins -long tails, but no grasping ability
Orrorin tugenensis "original man from tugen"
-Age: ~ 6mya -Found in Kenya -Present: femur, teeth/kaw, tibia, metacarpals (don't have a nice skull) Hominin status: (nice femur) -Femoral angle -Femoral neck length -Thick molar enamel APE status: -canines: -long, curved fingers
Macaques (macaca)
-Asia, Middle East, North Africa, and souther europe -20-24 species -most species of old world -most geographically diverse
Communication
-Autonomic: involuntary things (shivering, your hair stand up when feel threatened, fear grin (expose their teeth when threatened) -Deliberate --Displays: repetitive behaviors of emotional state of some kind (ex: gorillas (learning how to beat its chest, standing up and shaking a branch, posturing) --Ritualized behavior: behaviors that are engaged in ( ex: grooming, it has a health benefit but it also is engaged in them not always finding parasites) ( it is a social bond showing that they care)
1. Seed Eating model (Jolly 1970)
-Baboon analogy --Savanna environment --Seed and nut eating requires postural shift --bipedalism---> food acquisition --different postures to get to other resources (upright posture=advantage) Problems: -Environmental context: change since 1970 -reliance on seeds unlikely:very little evidence of hominids eating these foods -little support
Social systems
-Basic social unit among all primates is the female and her infants -relationships maintained throughout life -alloparenting: when individuals other than parents hold, carry and interact with infants
Verraux's sifaka
-Biggest lemur type -Live in trees
Orangutan (pongo)
-Borneo and sumatra -almost completely arboreal (quadrumanual) -solitary, frugivorous -least closely related to humans -3 species of orangutans -tapalui? long arms -different body sizes between males and females -y-5 molars
Origin of Bipedalism: Early models
-Carrying --Objects, weapons, dependent offspring, food -Tool-use -Visual surveillance -Food --Hunting or gathering
Modern Great Apes??
-Chimpanzees -2 published teeth are known from ~509-545 Ka (40Ar/39Ar)
What is hominin?
-Clade of Hominoidea including humans and fossil relatives -Trends: --bipedal locomotion --large brain size --tool making behavior -mosaic evolution: different traits evolve at different rates -the trends that are present now, were not present in the earliest humans -bipedalism: we see it -hominin: all of the human species
Early primates review
-Closest to Dermoptera and Scandentia -Plesiadapiformes 65-55 Ma -Euprimates ~ 56 Ma -adapoids: lemur-like -omomyoids: tarsier-like -Haplorhines ~37-30 Ma -propliopithecids: haplorhines ancestor? -aegyptopithecus -platyrhhines? -Catarrhines ~19 Ma -victoriapithecidae: OWM ancestor? -known as flying lemurs
Primate Cultural Behavior
-Cultural behavior is learned -Makes primates attractive models for early homing behavior -Chimps only nonhuman primate to consistently and habitually make/use tools -Cultural behavior is not an instinct -Primate observed using implements in threat displays, territorial defense and hunting -Attempts made to teach apes human behaviors ---tool manufacture --Language -Anthropocentric: viewing nonhuman phenomena in terms of human experience, capabilities and emotions -They use "weapons" -anthropocentric ex: when I make this facial expression when sad, my dog is sad when it makes the same facial expression (have to be careful of these things)
What makes us human?
-Culture -Language -Technology -Ability to think -Individual personalities -Self-awareness of place in environment -Empathy -Morality -Souls -Reliance on symbolic thought -Consciousness -Scale of environmental impact -Creativity -Social constructs -DNA -Bipedalism -Brains
Australopithecus afarensis
-Derived Hominin traits --smaller molars --Thick tooth enamel --Short, wide pelvis --Anterior foramen magnum --Valgus angle --Jaw shape -Retained primitive traits: --Face prognathic --Strong neck muscle attachments --Curved finges and toes --Relatively long arms --Sexual dimorphism?
Implication of Ardipithecus??
-Directly ancestral to Australopithecus and later forms? (possible ancestor to later hominids and possibly to us) Hominin but not directly ancestral to Australopithecus or later forms? Represents facultatively bipedal non-hominid hominoid? (its a biped but not a hominin) Pan and Gorilla anatomy not primitive for hominis, but extant apes independently specialized
earliest haplorrhines
-Distinguished from strepsirhines: -larger body (earliest only 3 oz) -larger brain -small, frontated brain -postorbital closure -fused mandibles -bilophodont molars- alignment of molar cusps into two ridges -bilophodont molars!! -see these before Y-5 molars
For their own sake
-Diversity of extant and extinct primates -Living primates found in Africa, Asia, South/Central America -Urgency- Now or Never -521 species of living primates, 30% endangered, 713 subspecies, 80 distinct genres within 17 families
How the hell did they get there?!
-Earlier "American" primates gone by ~ 35 Ma -Closest fossil relative from Egypt 30 + Ma -Platyrrhines in Americas by ~ 28 Ma -Rafting? -mangrove forests
Proconsuloids
-Ekembo 20-17 Ma -22 lbs ~ 110 lbs -skeleton monkey-like -probably lacked a tail -Y-5 dental pattern -Afropithecus 17.5 Ma -1st ape-like primate outside Africa -quadrupedal arboreal lifestyle
Oligocene (34-23 Ma)
-El Fayum: late Eocene to Oligocene (37-30 Mya) -more primates in younger deposits -haplorrhines at Fayum: -1. parapithecids -2. Propliopithecids -3. Platyrrhines -Egypt -Most of the Haplorrhines fossils come from this site -Easier to dig due to few vegetations
Chimpanzees (pan troglodytes)
-Equatorial africa -knuckle-walking and brachiation -omnivorous -large communities -most famous -troglodytes: live in caves -reproductive isolated from bonobos -more genetically distinct from each other -live in really large communities compared to others
Miocene hominoids: Asia
-European apes migrate into Asia ~ 15 Ma -Sivapithecus -India ~ 12.2 Ma -Only Miocene ape firmly linked to modern ape -Arboreal quadruped with climbing capabilities -Yuanmoupithecus -possible gibbon/siamang ancestor -9 Ma in China -only one hominoids that people have any firm or definitive to modern apes -looks like an orangutan -may be ancestral to the modern orangutan
Hierarchies
-Factors --sex(biggest) --age(biggest) --aggression --time in group --intelligence --motivation -mother's social position (status, rank) -juveniles often have less status -Dominance hierarchy imposes order within the group --reduces violence --increased reproductive success for some -Young primates learn hierarchical position from mothers -reduces violence because if you know the position of the other group, you avoid them.
Anatomy of bipedalism
-Foramen magnum anteriorly oriented --neck less-developed than apes -big hole at the base of our skull that feeds the spinal column to our brain -where its located -for humans it is right below -if you can't see the foramen magnum if it is not biped -Vertebrae increase in size toward pelvis --4 distinct curvatures --lumbar lordosis, S-shaped -ribs altered for controlled breathing -the further down the vertebrae goes, the larger they get -Limb proportions: --long arms and short legs --> short arms and long legs -fossil evidence on when occurred
Gorillas (Gorilla)
-Forested regions of central africa -knuckle-walkers -herbivorous -2 species of gorilla -4 subspecies -light purple -mostly in forest -some in mountains -get around by walking on all fours -they walk on their knuckles -specifically the middle knuckle -highly endangered
Baboons and mandrills
-Found in most zoos -all live in africa -largest body of OMW
Bipedalism
-From --"Bi" = "two" --"pedal" = "feet" --bipedal = "two feet" -many animals use bipedal stance: --carrying --surveillance --displays --balance -orthograde bipedalism: unique to hominid lineage --predates brain expansion by ~ 2.5 million years --predates tool use by ~1 million years
Miocene Hominoids: Asia (cont)
-Gigantopithecus -~8.5 Ma-300ka -China -largest ape ever -lower jaws and isolated teeth -Overlap with early humans? -less than 2 million years old -relatively young -you can estimate body size by using molar size and different bones of the skeleton -you can't do it with gigantopithecus because they only have teeth and jaws -no evidence of any apes in NA until humans show up
Platyrrhines
-Have: -Platyrrhine dentition -some terrestrial morphology -oldest hard to link to modern platyrrhines -younger more clearly ancestral -1st platyrrhine-like fossils from Egypt~ 30 Ma -South America~ 28 Ma -Africa (oldest platyrrhines)
The Big Picture: Number of Species
-Human evolution is complicated and species-rich
"Human" Taxonomy
-Humans are a species of Great Ape -Superfamiy: Hominoidea (gibbons, siamangs, great apes) -Family: Hominidae (great apes) -subfamily: Hominae (African Great apes) -Family: we share a lot of shared derived characteristics with great ape from any other group
Language capabilities?
-Humans use open or symbolic language (arbitrary) --NOT only species capable of symbolic thought and complex communication -Physiological and genetic restrictions --E.g FOXP2 gene, laryngeal morphology --FOXP2: humans have 3 single nucleotides (when we are born without those 3, we are unable to develop language) Vocals: --the way that humans speak is unique --physiological: shape of our lungs, ribs, larynx, we have more finely developed muscles in our mouth
Patterns of reproduction
-In most primates tied to females' reproductive cycle --estrus -Permanent bonding not common -We have concealed ovulation --probably affected some interesting human behaviors
Strepsirrhines
-Lemurs, lorises, and galagos -Maintain Rhinarium (wet nose) -More Prognathic (projecting faces) -Some reliance on night vision -Tapetum lucidum -Grooming claw and dental comb -Lorises and galagos -Africa and Asia -galagos: bush baby -slow loris: venomous, trafficked, pet trade, endangered -Lemurs -madagascar -geographically restricted -mouse lemur: smallest living primate -different ranges of size
Reduced snout
-Less prognathic than other mammalia -Prognathic: skulls; projecting faces; Human have plat faces
Reduce reliance on olfaction
-Loss of rhinarium in MOST primate groups -Rhinarium: wet nose
Group Type: one female, multimale
-Mating system: polyandry -female has more than one mate
Group type: multi male, multi female
-Mating system: polygynandry -two + males mate with 2+ females
Group Type: one-male/multifemale
-Mating system: polygyny -male has multiple mates -Female philopatric -stay in the group their born into -gyny: female reproduction (many females)
Group type: semi-solitary
-Mating system: polygyny -single male mates with more than one female -rarest
Mating system vs social system
-Mating system: who is mating with who -Social system: composition of the group -DO correlate, BUT same social system can vary in mating system depending on species and vice versa! -Philopatry: remaining in one's natal group upon reaching adulthood
Importance of social environment
-Mother-infant bond important --Harry Harlow Study -Isolated infants: --Couldn't function socially or reproductively -Inspiration for stories of feral children?
Enhanced sense of touch
-Nails instead of claws
Platyrrhines
-New world monkeys -Central and south america -diurnal (except one genus) -Arboreal (no terrestrial species) -Prehensile tails -2.1.3.3/2.1.3.3 dental formula -Most of them active during the day
South African Fossil Woes
-No volcanic tuffs --Can't use MOST radiometric --Biostratigraphy and Ur-Pb BUT cave accumulations gives excellent preservation -"Cradle of Humankind" --Sterkfontein --Swartkrans --Malapa (and others)
Cercopithecoids
-Old world monkeys -the most diverse group of living primates -138 species alive today -2 subfamilies -colobines -cercopithecines Last OWN and NWM shared a common ancestor: 45-55 million years -Traits: Bilophodont molars (OWM) vs Y-5 in apes and humans -they all have the same general number of teeths -old world: have bilophodont molars -Apes: different number of cusps or bumps on their teeth (both have the same dental formula but different shape of molars) -Shared derived trait of cercopithecoid
Catarrhines
-Old world monkeys and apes -cercopithecoids (OWM) and Hominoids (apes) -Dental formula: 2.1.2.3/2.1.2.3 -They have two science division:monkey and apes (major divisions) -easiest to look at: dental formulas
Old world monkeys
-Oldest 'modern' monkeys are the Victoriapithecidae (19 Ma) in africa -derived traits of both extant OMW subfamilies
Ardipithecus kadabba
-Oldest (original one) -"Father of the Ground Ape" -5.8 - 5.5 Ma (K-Ar) -Middkle Awash River, Ethiopia hominin status: -Possibly bipedal (toe bone) -upper canines not sharp MAIN issues: -based on handful of fossils (not a ton of fossils)
Monkeys as Ecological Referents
-Overlap in size, diet and environment with early humans - Locomotor adaptations can tell us about environments
Earliest primate-like things: Plesiadapiformes
-Paleocene (65-55 mya) -Very successful group -most insectivorous but some omnivores and herbivores -size of small-medium rodent -tiny -55ish million -Skeletons primate-like but and teeth very specialized -no postorbital bar -do have shared characteristcs -dont have enclosed eye sockets -earliest primate like mammals
Anatomy of Bipedalism cont...
-Pelvis shorter, broader, and more basin-shaped --ilium wider --pelvis inlet/outlet shape --rearrangement of gluteal muscles --anterior inferior iliac spine (AIIC) -strangest and most derives structure in the human body -(ilium) humans pelvis is short from top to bottom and really wide -(rearrangement of gluteal muscles): humans have more developed gluteal muscles than chimps -(AIIC): having a body is only visible in bipedal muscles -Knees modified for striding gait: --femur angled--valgus or bicondylar angle --accommodates efficient walking and large birth canal -humans slant inwards when walking -Reoriention of foot: --decrease in mobility --increase in stability --digit 1 (hallux) --no longer opposable --longitudinal arch -grasping hands and feet are a characteristic of primates -humans have lost that grasping toe (much shorter) and has increased our stabilities -longitudinal arch: (being born with flat feet can affect walking) it gives us a springboard
earliest apes
-Proconsuloids: ape-like -mostly from east africa -first Y-5 molars and thick enamel -Vary in size and locomotor adaptations -smallest ~6lbs -Micropithecus
Primate infanticide
-Reproductive success increases by killing babies of other males -Usually by new especially dominant males -Seen in some: --Cercopithecoids --Hominoids -killing makes the reproductive success of the mother increases by stress
Mating systems
-Sexual selection: type of natural selection -result of competition for mates -sexual selection leads to sexual dimorphism
Homologous Primate Features
-Shared derived traits of Primates -Grasping hands and feet -Binocuar vision -Reduced reliance on olfaction -Generalized dentition -Reduced dentition -Relatively large brains -Relatively large brains -Relatively slow life history
Eocene Adapoids
-Similar to modern lemurs -diverse adaptations to insects, leaves and omnivore -Has: -reduced nasal area -stereoscopic vision -post-orbital bar -strong leaping adaptations -grasping hands and feet with nails -some have dental combs -Euprimates -some of them have dental combs -adapoids: more lemur like -Darwinius masillae- transition between strepsirrhines and haplorhines? -Probably early lemur-like strepsirrhine -other fossils confirm probably not haplorrhine -awesome fossil -fur imprints and stomach contents, all of the teeth -not directly ancestral to monkeys and apes
Grasping hands and feet
-Slow loris -Tarsier -Macaque -Spider Monkey -Gibbon -Human
Eocene omomyoids
-Tarsier-like: -dental formula -large orbits -small snouts -mostly insectivorous -adaptations for leaping -basal haplorrhines? -tarsier like could make then ancestral to basal haplorrhines
Haplorhines
-Tarsiers -SE Asia -Really hard to study, they live in trees and are very small
Euprimates ("True" primates)
-Two major groups -adapoids and omomyoids
Hominins
-Us and all fossil hominins -mostly terrestrial -complex language -distinctly omnivorous -rely on technology
Bipedal traits?
-anterior foramen magnum -Reduced neck/nuchal muscles -Lumbar lordosis Short, bowel-shaped pelvis -Valgus/bicondylar angle on knee -Non-opposable/adducted big toe -Longitudinal arch on foot
Primate phylogenetic tree
-anthropoids -Tarsiers are the most common to us -they are the most closely related
primate origins
-closest living relative: colugos (Dermoptera) and tree shrews (Scandentia) -shared with primates: -large eyes -mobile hands and feet -Different from primates: -claws instead of nails -lack binocular vision -often used as models for early primates -colugos and tree shrews are the ones closest related to us -we have shared characteristics
Bonobos (pan paniscus)
-found only in DRC south of congo river -omnivorous -matrilineal -live in democratic republic of congo -different behavior than chimpanzees (more boring) -sleep a lot more -1.5ish million years ago (separated) -have a middle part (chimps don't)
Why solitary behavior?
-home range: the areas explored by an animal or social group; usually given for one year or for the entire lifetime of an animal -Solitary foraging -reduced feeding competition -smaller home range -insects are scattered resources, thus more efficiently hunted alone -predator avoidance
Miocene hominoids: Africa
-hominoids back in Africa by ~10Ma -probably multiple dispersals -Evolve into LCA of aces and humans -Modern African apes descended from European apes -Great ape first evolved in Europe
Aye-aye
-lemur -highly endangered
Group type one-male, one-female
-mating system: pair-bonded -rarest
match each bone of the left with its proper classification from the column on the right
-metatarsals---> long bone -vertebrae---> irregular bone -frontal bone ---> flat bone -patella---> short bone
Aggression
-often conflict over resources like food and mates -Certain behaviors resolve conflict without violence -Seen in a lot of animals
Primate altruism?
-prosocial behaviors: benefit others without rewards for the performer -altruistic behaviors: benefit another while involving some risk to the performer --e.g. mothers protecting offspring -We don't know if other primates feel empathy -difference of both behaviors: --one risks to help out the other individual -Chimps routinely come to aid of family and friends --adoptions observed but rare -kin-selection: altruistic acts more likely to be for a relative --biological relatives: adopting when its from one of their siblings. -reciprocal altruism: help another individual today and hope they return the favor
hominoid traits
-shared derived traits -upper body modification for suspension -relatively long arms -allows brachiation -no tail -y-5 molars -enlarged brain -locomotive: brachiation, swing -molars you have to rely on
Group type: fission-fusion
-size and composition group changes over time and animals move throughout the environment -mating systems: polygynandry
"odd-nosed" monkeys
-they all share same dental formula an bio...molars
Body size
-type of social group and mating pattern can correlate with morphology
Canine size
-when dimorphic, males have larger canines than females
Laetoli Footprints
-~3.6 Mya (K-Ar), Tanzania -Most likely two individuals -Fairly modern bipedal gait -Toes relatively long -Adducted hallux
The Australopithecids
-~4.2-1 Ma -Characteristics --Habitual Bipeds --More modern teeth --Large teeth --Brains getting relatively larger -Open woodland and grassland
Origins of Bipedalism: Recent models
1. Seed eating hypothesis (not supported) 2. Temperature regulation 3. Energetic efficiency These models make projections the can be tested and either rejected or supported.
Splitters vs Lumpers
2 categories of humans Lumpers: -Conservative in classifying organisms, Require a lot of differences and evidence -Many fossils as possible and a s many shared derived traits OPPOSITE Splitters: -Less conservative. Require few differences go name different groups -Most people fall in-between A point about incentive: -A lot of factors push some scientists toward being splitters (e.g. "hominin fever")
Paranthropus robustus "Robust Beside Human"
2.0-1.4 Ma (Biostrat, U-Pb) South Africa Traits: -broad, flat face (dished face) -pronounced sagittal crest -Small front teeth -very large back teeth
Paranthropus boisei "Boise's Beside Human"
2.3-1.2 Ma (K-Ar) Olduvai (OH), Tanzania and Koobi Fora (ER), Kenya traits -small brain -sagittal crest -postorbital constriction -Hyper-robust dentition first "Australopith" dated using K-Ar
Hominn Genera
6 genera of hominin known (we belong to genus homo) Earliest hominin: -Sahelanthropus (7-6 mya) -Orrorin (6 mya) -Ardipithecus (5.8-4.4 mya) -Australopithecus (4.2-2.0 may) -Paranthropus (2.5 - 1.2 Ma) -Homo (2.4- present)
Earliest Homo
Ancestor? -A. sediba is about 1.98 Ma -Au, africanus or Au. afarensis? -H. habilis, H. rudolfensis, and H. Erectus by ~1.9 Ma Adaptive radiation of more modern hominins ~2 Ma
Ardipithecus ramidus
Ape-like features -chimp sized (~400 cc) brain (small) -Postorbital constriction (the more constriction the smaller the brain) -Relatively long arms -Grasping big toe -Curved fingers -Long toes Hominin -Small canine -Anterior foramen magnum -Bipedal pelvis- AIIS (key) -Muzzle less prognathic
Diet and Ecology Summary
Both Australopithecus and Paranthropus show evidence for living in woodland and savanna environments Australopithecus more varied diet than Paranthropus Both microwear and isotopic data useful for understanding diet Australopithecus and Paranthropus have different diets than modern humans and later hominins
Reconstructing Diet: Isotopes
Isotopic analysis: Using chemical signature of dentition to study diet Amount 13C Isotope -C3 (leaves, fruit, berries, nuts) OR -C4 (grasses) plants
which of the following statements about fossils is FALSE?
a. teeth, shell and bone are commonly fossilized b. they cannot always be dated using radiometric methods c. they usually preserve organic materials d. objects must be buried quickly to fossilize e. they are rarely random samples of ancient ecosystems -c. they usually preserve organic materials
Marmosets and tamarins
multiple births
