Why Study Primates (Biologically)
Biologically, primates are our closest living
relatives and provide a biological standard of
reference to compare ourselves.
Why Study Primates (Behaviorally)
Primates provide comparative behavioral
information to use in reconstructing early human
behavior.
Prosimians vs. Anthropoids
Prosimians-Small cute little mammals
Anthropoids-Old and new world monkeys and apes
Prosimians
One claw, rest nails
Nocturnal
Smaller
Smaller, less complex brains
Anthropoids
Nails,
Diurnal,
Larger,
Larger, more complex brains
complex social systems (parental care)
2123 Dentition
Anthropoids have this -
2 incisors, 1 canine, 2 premolars, 3 molars
Evolutionary Relationships (what does DNA/biochemistry tell us about this?)
Humans, bonobos, and chimpanzees are between 98
and 99% identical.
Chromosome? (23 pair = 46)
Gene? (20,000-25,000)
DNA/base pairs?
> 3 billion in the human genome
Humans vary from each other on the order of 0.1%
Apes and Humans
- Apes are human's closest living relative
- Evolutionary relationship of apes and humans
- DNA/Biochemistry: bonobos, chimpanzees, and
gorillas are closer to humans
than they are to orangutans,
gibbons, and siamangs.
Who is Jane Goodall?
Primatologist, UN messenger of peace, runs a place for chimps to have nice home.
Jane Goodall Institute and Chimp Eden, South Africa
Chimp Eden was established in 2006 and is the first and only chimpanzee sanctuary in South Africa. This JGI chimpanzee sanctuary brings the world of chimpanzees closer to humanity through education end eco-tourism.
Overall mission of Chimp Eden
The goal of the chimpanzee sanctuary is to rescue chimpanzees that have survived the bush meat trade, been orphaned, traded in the illegal pet market, or rescued from being traumatized for entertainment in circuses, beach resorts and night clubs.
Milestones in human evolution - which is first?
Bipedalism - using two legs for walking
Late Miocene and changing climate
- Appearance likely driven by climate change, led to dietary change (reduced forest, open savannah)
- Contemporaneous change in dentition
Miocene epoch�Planet of the Apes
The Miocene (23 - 5 mya): Planet of the apes
� Possibly 50-100 species of apes
� Ape/Human ancestors widespread by 8 mya
Bipedalism and early hominid characteristics
-Dental arcade and dentition: wide dental arcade, thick tooth enamel, smaller canines, larger molars.
- Bipedal Locomotion & hypothesis: energy efficient, favors carrying food, babies, and weapons, and also reduces heat stress
- Bipedalism and environment
Advantages and Disadvantages of Bipedalism
Disadvantages: predators can see you on two feet, underbelly exposed, harder to change directions, lower back problems.
Advantages: keeps brain from overheating,
can hold objects in general and while running, bigger field of view, minimal use of energy
Crania vs post-crania
crania - everything above neck
post-crania - everything below the neck (and the neck)
Skeletal indicators of bipedalism
1) Foramen Magnum - hole in the head for spinal cord
2) Pelvis - shorter (top to bottom), broader (more bowl-like), different muscle attachments
3) Femoral Structure - long, angled femoral neck, asymmetrical knee
4) Knee -
5) Foot - Loss of grasping toe,
Earliest potential hominids
1) Sahelanthropus tchadensis - Chad, 7-6 mya, Face & teeth like hominid, Rear of skull like chimp ancestor, Small cranial capacity
2) Orrorin tugenesis - Kenya, 6 mya, Post-crania: habitual biped, Upper limbs = climbing, Teeth/post crania, different indiv
Ardipithecus ramidus "Ardi
- Ethiopia about 4.4mya
- Environment: woodlands
- Skeletal Morphology: chimp like teeth, but bipedal pelvis, opposable big toe, but adapted for bipedalism
- Importance: showed bipedal hominid
Fact and theory in human evolution
Bones are a fact! (location and time in space), but the interpretation of these bones are a theory (a working model; relationship between fossils and between changes and environment)
First certain bipeds (Australopithecines)
Genus: Australopithecus, 4.2 to 1 mya
Hands capable of tool use, human-like from waist down, fully adapted for bipedalism, chimpanzee-like brain.
A. Afarensis
My girl, Lucy
Laetoli Footprints
Mary Leakey and colleagues uncovered a 75 foot-long, 3.5 mya old trail of footprints made by 3 individuals at Laetoli.
Gracile Australopithecines
� General appearance resembled ape-like human.
� Chewed food like humans.
� Size and outward appearance of brain suggest intelligence, similar to a modern bonobo,
chimpanzee, or gorilla.
Robust Australopithecines
Shared most traits with Graciles
� Cranial bones were thick with prominent markings where muscles attached.
� Simian-like sagittal crest.
Sagittal Crest
(in many mammals) a bony ridge on the top of the skull to which the jaw muscles are attached.
Australopithecines (Gracile, e.g.,)
A. africanus
� South Africa, 3.5-2 mya
� Small brain size
� Arm longer than leg
� Big toe mobility
Australopithecines (Robust, e.g.,)
A. boisei (or Paranthropus boisei)
� East Africa, 2.5-1 mya
� Bipedal
� Huge sagittal crest
� Large back teeth & "Hyper-robust" chewing adaptation
� Post-orbital constriction�smaller, chimp-like brain
Various proposed species of Australopithecus�What is special about ~2.5 mya?
-A. anamensis, 4.2-3.9 mya
-Kenyanthropus platyops, 3.5-3.2 mya
-A. afarensis, 3.9-2.5 mya ("Lucy")
-A. africanus, 2.5-2 mya (gracile)
-A. robustus, 2-1 mya (robust)
-A. boisei, 2.5-1.3 mya (robust)
-A. ghari, 2.5-2 mya (gracile)
2.5mya - Homo genus
Olduvai Gorge
Tanzania
� Louis and Mary Leakey, 1959
� Stone tools
Homo habilis
handy-man"
�East Africa and South Africa
�No bony crests on the skull (gracile)
Milestones in human evolution (2nd)
Encephalization and tool manufacture
Homo habilis vs. Australopithecus
1) Encephalization: Larger brain; organized differently than Australopithecus & 650-752 cc (cubic centimeters) at
Olduvai
2) human-like hands and feet, and post-crania similar to gracile Australopithecines like A. garhi
3) smaller teeth relative to skull
Late Pliocene Trends (3 - 1.8 mya):
SKELETAL MORPHOLOGY
Fully bipedal Australopithecus and Homo, Encephalization, prolonged infant dependency, female pelvis, relative reduction in face / jaw / teeth
Taxonomy, paleospecies, and early hominids�classification
classifying species
Oldowan tool industry and E. Africa
- Earliest identifiable ~2.5 mya
- No A. afarensis fossils have been found
in association with stone tools.
- Other tools would not fossilize
Oldowan tool industry and H. habilis
- Not weapons, probably used for food preparation
- Percussion flaking ( the shaping of a stone implement by striking or chipping off flakes with another stone or a piece of wood, bone, or antler)
- Flakes: used for cutting/scraping
- Cores: used for chop
H. habilis culture/behavior
-Hunting/scavenging meat more important
-Concentrations (sites) of stone tools and animal bones
-indicative of early family groups or home bases
-Learning through shared interaction = CULTURE
Experimental Archaeology found...
-Microscopic scratches = cutting meat,
cutting/whittling wood, cutting plant
stems
-Polishing = cutting meat
Geographic distribution of early hominids, up to about 1.8 mya
We were all turning up under the sun strictly in Africa!!!!!
8-6 mya
probable common ancestor of chimps and humans
4 mya
emergence of first australopithecines: definite bipeds, gracile/robust variation
2.5 mya
emergence of first proposed Homo species, H. habilis-Associated with encephalization and first tools (Oldowan tradition)
1.8 mya
emergence of H. erectus/ergaster in Africa, first hominids outside of Africa (H. erectus)-Acheulean tools, likely controlled fire
400 kya
Archaic humans in Africa, Europe, and Asia
130 kya - 30 kya
Classic Neandertals in Europe and SW Asia
200 - 100 kya
Anatomically modern humans first appear in Africa
45kya
Anatomically modern humans appear in Europe
Late Miocene possible ancestors (possible bipeds), 7-6 mya
Sahelanthropus tchadensis
Orrorin tugenesis
Early Pliocene biped, 4.4 mya
Ardipithecus ramidus
Genus Australopithecus: 4.2 mya � 1 mya
A. anamensis
A. afarensis (species to which Lucy belongs)
A. africanus
A. boisei (also known as Paranthropus boisei)
A. robustus
Genus Homo: 2.5 mya � present
H. habilis (2.5-1.6 mya)
H. ergaster/erectus (1.8mya-400kya)
H. heidelbergensis
H. neanderthalensis (~130 kya - 30 kya)
H. sapiens
Emergence of Homo erectus
1.8mya-400kya
What made Homo erectus different?
a. skeletal morphology
b. tool forms / technology
c. behavior
Geographic distribution
First to spread out of South + East Africa
- Europe, 780 kya - 400 kya, Germany
- Georgia, India: Mix of African and Asian characteristics; what does this mean for spread of hominids?
- China, 500 kya, "Peking man" found in Zhoukoudian
H. erectus: general morphological characteristics (crania and post crania)
-post-crania: very similar to modern humans
-short birth canal -> immature birth
-larger body than H. habilis
-nearly modern brain size (late H. erectus): 780-1225 cc; avg. ~960 cc
-endocasts indicate brain organized similar to those of modern humans - he
What is special about "Turkana Boy"?
�Lake Turkana, Kenya
�Discovered in 1984 by Richard Leakey
�Most complete skeleton of human ancestor
�~1.5 mya
Encephalization (h. erectus)
Increased by A LOT! and over the course of the homo erectus' life
H. Erectus tools
Acheulean tool industry
Oldowan vs Acheulean tool industries
Oldowan - H. Habilis, core and flakes
Acheulean tools - finer hand axes, H. erectus
Why do we think H. erectus used Acheulean tools?
-Stratigraphic deposits, H. erectus fossils associated with Acheulean hand axes
-970 to 900 kya
Acheulean hand axe function
Large animal butchery?
� Digging?
� Bark stripping?
� Hunting?
� Flake "dispensers"?
---
Experimental and microwear analyses are consistent with the large butchery hypothesis.
� Flake dispensers
H. erectus: hunters or scavengers? How do we know?
Olorgesaile, a H. erectus/ergaster site in Kenya:
� elephant skeleton with stone tool cut marks
� no carnivore tooth marks on bone
Increasing importance of meat in diet**
...food?
Evidence for fire?
-Warmth, hunting drives, protection from
predators, cooking (makes many plants/
animals more safely digestible)
-No conclusive evidence for early periods,
but...Higher latitudes, temperate climates, marked seasonality
Evidence for shelter?
�Terra Amata site, France
�Lower Paleolithic shelter, ~400 kya
�Central hearth
�Hunting (small and large game), fishing, shellfish
�Tool debris
culture as adaptive behavior
�Tool complexity
�Shelter
�Fire (likely controlled)
�Social interaction
�Commitment to group living
Geographic distribution of hominids
� up to about 1.8 mya --> Africa only
� after about 1.8 mya --> Africa and Eurasia
Ancestor Traits
a trait is 'ancestral' when it is found in an organism, and in a recent ancestor of an organism --> Something old
Derived Traits
a trait is 'derived' when it is found in an organism, but not in a recent ancestor -->Something new
Archaic humans, H. heidelbergensis
- Ancestral Features
� Thick cranial bones
� Receded chin
� Large brow ridges
~600 kya - 400 kya
- Derived Features
� Larger Brains (1100 -1400 cc)
� Slightly higher forehead
� More rounded occipital area
Geographic distribution of archaic humans
� Skeletons indicate habitual bipeds
� Crania reflect large brains, with mean cranial capacity calculated at more than 85% of the modern human mean of about 1,450 cc.
--> they're all over the old world...
Homo neanderthalensis and classic Neandertals
�1856, Neander Valley, Germany
� Skull cap and partial post-crania
Europe & SW Asia
�127,000-30,000 years ago
perceptions of the Neandertal
cave man...robust, hairy, and dumb
geography of Neandertal
all over europe and asia
skeletal anatomy of Neandertal
Derived Features
� Large Brains (~1480 cc)
� Occipital Bun & more rounded crania
� Large, slightly prognathic face
� Small cheek teeth, large front teeth
-Heavily muscled, robust bodies
-Adaptation to a cold environment
Bergmann & Allen's Rules (and relationship to Neandertal studies)
Animals in colder regions are larger and have shorter extremities
*Cold: Low ratio of Surface Area/Volume, conserve heat
*Hot: High ratio of Surface Area/Volume, shed heat
Anatomically modern humans (derived features)
1. brain/rounded skull
2. high forehead
3. Little to no brow ridges
4. Small flat face
5. small teeth and jaws
6. projecting chin
Neandertals and Middle Paleolithic culture
1)tools
2)teeth
3)subsistence, hunting, shelter
Mousterian tools
*More tool types--Scrapers, points and hand axes
*More efficient use of raw material
*More variation between locations
teeth as tools (Neandertal)
found in several Neandertal's skulls that teeth were worn out and were used as teeth.
subsistence, hunting, shelter (Neandertal)
Archaeological evidence of large prey butchering and possible large game hunting
�Meat takes on greater
importance in cold climates
�Evidence of organized camps or shelters is rare
�They survived in frigid Europe for > 100,000 yrs
�Cave sites
compassion? symbolic behavior? (Neandertal)
*Evidence in the archaeological record
suggests frequent burials by Neandertals : Symbolic Capacity
Neandertals, modern humans, and the Upper Paleolithic in Europe
1. Elaborate tool kits (stone, antler, ivory, bone)
2. Long distance transport of raw materials
3. Elaborate shelters
4. Symbolic expression, art, ritual burial
-->Replacement by a new species from Africa (H. sapiens)?? Or, cultural/biological change and
Models that explain the emergence and spread of modern humans (2)
1) Multiregional
2) and Replacement
Multiregional Model
The view that anatomically modern H. Sapiens evolced from premodern humans evolve from premodern humans in several regions simultaneously.
H. heidelbergensis & Neandertals evolved into
modern humans gradually.
� Homo has always been composed of one specie
Replacement Model
The view that anatomically modern H. Sapiens evolved from premodern humans in one place at one time and spread out from that point of origin, replacing premodern humans beings as they encountered them especially in Asia and Europe.
A new species arose in
What would be our relationship to Neandertals in each of these two models?
Multiregional -
Replacement -
Modern human and Neandertal admixture
The Neandertal Genome (2008)
Max-Planck Institute for Evolutionary Anthropology
�mtDNA
�38,000 year old sample
�Neandertal mtDNA fell outside the
variation found in humans
�Did not support admixture
�Suggested common ancestor about 520k - 800k yrs ago
The
DNA evidence (humans, Neandertals, chimps)
We are more closely related to Neandertals than to chimps...
Genetic variation among modern humans and founder effects
only ~ 3% of human genetic variation exists between continental regions
� most variation is in Africa
Leaky Replacement Model (concept and timing)
�Did our ancestors interbreed with other populations and subspecies?
*Limited gene flow (admixture) from Neandertals to modern humans
*Subsequent limited gene flow (admixture) w/ archaic Denisovans
*Denisovan admixture reflected in Melanesian genome (migr
Best fit model?
Leaky Replacement!
�95% of our genome is inherited from African ancestors
who replaced archaic people on other continents
�Interbreeding, possibly only around the margins, with
some archaic populations