BioAnthro Final Flashcards
Locomotion
Bicondylar Angle
In humans, the femur angles inward, keeping the legs more directly under the body.
Locomotion
Human foot
- No deposable first toe
- Calcaneus much bigger tan in chimps
- Weight distributed on 2 feet constantly
Calcaneus: The large bone forming the heel of the foot
Bipedalism
How old and present in which oldest human ancestor?
- Currently is 6 - 7 mya
- Defining characteristic for hominins
- Earliest bipeds not “fully” bipedal
- Present in the australpithecous skeletons from Africa, the oldest species that we are for certain had bipedalism.
Bipedalism
Why are we bipedal?
This is a trick question, while we have theories on why, we actually don’t know
Locales
South Africa
- Different from the rest of Africa (in terms of preserving fossils)
- Has different variations of plants and animals
-Hominins from S. Africa don’t necessarily fit into human evolution - Dominated by limestone (caves, nooks, and crannies, crevasses)
- Brits colonize S. Africa and blow shit up ⟾ fossils come out
People
Raymond Dart
- 1925: the 1st discovery of human ancestors in Africa
- Solidified the idea that bipedalism didn’t come from big brains
Human Ancestor
Taung Child
- Taung (gracile Australopithecus)
- Skull, mandible, endocast, teeth
- Biped with a really small brain and large teeth for its age
The Foramen magnum position indicates bipedalism
Discovered by Raymond Dart
Human Ancestor
Robust Australopithecus
- Lived during the Pliestocene: 2.5 - 1 mya
- East Africa on West side of Lake Turkana
- “Chunkier”
- Thicker mandibles
- Large chewing muscles
- Very large teeth: Post canine megadontia with small canines and incisors
- Crests - Sagittal, Nuchal
- Post-orbital constriction
- Differences are only in craniums, not in bodies
Human Ancestor
Australopithecus aethiopicus
- West Turkana
- 2.5 Ma
- 410 cc
- lived in closed habitats in Eastern Africa
- Incredibly sloped face (dished)
- Foramen Magnum points inferiorly
- Large zygomatic bones and arches
- Largest posterior sagittal crest in human evolution
- Ate tough foods; chewed a lot
- Stripper hypothesis
- Displays cases of evolution to eat fall-back food
- Sexual dimorphism?
“The Black Skull” - KNM-WT 17000
Human Ancestor
Australopithecus boisei
- Found in Lake Turkana, Kenya,
- Lived during the Pliestocene between 2.5 - 1 mya
- Average cc: 450-550 cc
- Lived in open grasslands and woodlands
- Sagittal crest is smaller and more superior
- Suggests they are not stripping
- Grinding their food
- Tubers; USOs in the savanna. They contain a lot of sugar. They store water. Extracting them from the ground with digging sticks.
- *Molarized premolars (Post-Canine megadontia) *
- Reduced anterior teeth distinguishes them from Au. afarensis
- Sexual Dimorphism
- Skull shape is similar but size is different
- Diamond-shaped face; smaller sagittal crest
- Descendants are a topic of debate
Human Ancestor
Australopithecus robustus
- Lived during the Pliestocene between 2.5 and 1 mya
- Swartkrans Cave, Africa
- Avg cc: 530 cc
- Molarized premolars, Very small incisors, Body of mandible is very thick
- Dietary plasticity - Possibly eating termites (which contain fat)
- Open grasslands and woodlands in Sourthern Africa
- Unsure of descendants but is sometimes considered to be descended from other Robust Aus.
Human Ancestor
Homo habilis
- Lived between 1.5 - 2.3 million years ago
- Tanzania and Kenya
- They were bipedal
- 612 cc
- They are believed to have been the first hominid species to use stone tools
- Compared to A. boisei: differences in premolar size and morphology clearly showed a transition to Homo
- ~ 4ft tall; weighted about 80-90 lbs
- show precision and power grip
- More vertical forehead
Tools
Benefits of Stone Tools
Wider resource exploitation
- increased meat consumption
- more processing of vegetable material
Hominins
Hominin-Evolution
Human evolution post-chimps
- Displays bipedalism leads smaller canines, larger brains, and tool use
Bipedalism
Knuckle-Walking vs Bipedalism
Significant changes in the hip, knee, and ankle joints
* Bipedalism = longer legs, shorter arms, pelvis orientation, skull orientation on vertebrae w/ foramen magnum pointly inferiorly
* Knuckle-Walking = ape curve spine, posterior-facing foramen magnum, torque produced by body weight, simple stabalization
Bipedalism
Frankfurt Horizontal head aligment
Human: foramen magnum points down (inferior)
Apes: foramen magnum points posteriorly
Bipedalism
Pelvic orientation
- Apes: Torque produced by body weight, gluteal muscles are extensors to help them project forward quadrapedally or simple stablization
- Hominins: Torque from abductor muscles for balancing, muscles working to keep us upright are gluteal muscles - bring leg and pelvis closer causing a flaring iliac blade of pelvis in hominins
Bipedalism
Types of Bipedalism
- Occasional Bipedalism
- Habitual Bipedalism
- Obligate Bipedalism
- Random Bipedalism
Types fo Bipedalism
Occasional Bipedalism
Incorporating it into routine but it is not the only way of movement
Homo (2.3 mya - today)
Autapomorphy: uniquely derived trait
Types of Bipedalism
Habitual Bipedalism
- Using it very frequently, on ground
- However, still can hang out in trees
Australopithicus (4.4 mya- 2 mya)
Types of Bipedalism
Obligate Bipedalism
Have to be bipedal to move affectively
Early hominins (7.6 mya - 4.4 mya)
Types of Bipedalism
Random Bipedalism
Walking on 2 legs but not as a daily use of locomotion
Early Hominins
Sahelanthropus tehadensis
- Found in Chad, Central Africa
- 7.2 - 6.8 Ma (Miocene 23 Ma - 5 Ma)
- 350 cc
- Evidence of occasional bipedalism from a transitional foramen magnum that begins to point inferiorly
- smaller canines
- largest brow ridge in hominin evolution
- possible sexual dimorphism but only one specimen has been found
- lived in mostly forests and possibly grasslands
- suggests that it lived close to the time of the chimpanzee-human divergence, and was possibly related to Orrorin
Early Hominin
Orrorin tugenensis
Orrorin: “dawn child”
- 6.0 mya
- 2001: 13 fossils of at least 5 individuals found in the Tugen Hills of Kenya
- femur used to determine its a human ancestor using Wolff’s Law to determine
- neck of femur has high density cordical bone uniformly around the circumference but inferior edge of femur is thicker then top
- Curved phalange/carpal bones suggests they were still using trees
- No skulls have been found (therefore no cc average)
- Lived in woodlands/forest environments
- Possibly related to Sahelanthropus
Early Hominin
Ardipithecus ramidus
Tim White and Lovejoy
- 4.4 Ma- 4 Ma
- Aramis, Middle Awash, Ethiopia
- 300 - 400 cc
- Shows signs of bipedalism but has opposable 1st digit on feet
- bicondylar angle but no condyle or neck of femur
- Long arms and hands with a bowing radius (suggests climbing)
- No sexual dimorphism (no male-male competition)
- lived in wooded environment
Lovejoy proposes Provisioning Hypo in 2010 based on this
Early Hominin
Savanna Hypothesis
Debunked
- All Early Hominins are coded to have lived in more forest areas
- Zambia to Botswana - River system with outlining trees
- No clues to bipedalism because of savannas therefore they are most likely occassional bipdals
Australopithecus
Australopithecus anamensis
Gracile
- 365 - 370 cc
- Kanapoi and Allia Bay, Kenya
- 4.4 -3.8 Ma
- U-shaped palate
- Large, overlapping canines
- Biped with tree climbing abilities
Australopithecus
Australopithecus afarensis
- Hadar, Ethipoia + Laetoli, Tanzania
- 3.9 - 3.0 Ma
- cc: 375-550 (avg: 435 cc)
- Hominin Traits: evidence of bicondylar angle, pelvic orientation
- Large, overlapping canines and large molars + small anterior teeth
- Prognathic
- U-shaped palate
- Still living in forests / using trees
- In most cranial features, Au. afarensis shares more features with chimpanzees than modern humans
AL 288-1 “Lucy”
Australopithecus afarensis
AL 288-1 “Lucy”
- We have from the neck down
- the bicondylar angle in Lucy falls within the human range (Apes average ~90 degrees but humans are much more than 90 degrees)
- Pelvis: flaring iliac, oval birth canal
- Avg. height: 3.5 ft tall, maybe 4 ft
- still using trees
The Plio- Pleistocene Transitions
Pliocene = Lots of forests in Africa
Pleistocene transition included lots of drying and huge shift to grasslands in Africa
Environment
Mid-Pleistocene Europe
- Very cold
- Upper Europe covered in glaciers around a mile deep
Human Ancestor
Homo neanderthalensis
- Cold Adapted
- Lived mostly in Europe, but some members of made it to Central Asia
- Shorter Limbs to stay warmer
- Shorter in general to stay warmer (averaging 5’0 - 5’6)
- Brain size: around 1500cc. A bigger brain meant it stayed warmer but did not equal additional intelligence
- Used spears that were heated up to last longer
- Sowed clothes: Evidence of bone needles at neadertal sites
Bipedalism
In what environment did bipedalism evolve?
The continent and locale
It evolved in Africa and likely evolved in forests, then possibly sped up by the transistion to drier environments (savanas).
Evolution
How did height change throughout human evolution?
Height increased as the homin evolve over millions of years.
Evolution
How did brain size change throughout human evolution?
As homins evolved, there brain size increased as there head sized increased and as they begun making tools.
Behavior
In what species do we see evidence of care, such as purposful burial?
We see evidence of this in Homo neanderthalensis
Behavior
Who is the first species to leave Africa?
Homo erectus
We know this from remains that have been found in Georgia and Java that date from 1.8 mya to 300ka. We have found no evidence of any other species leaving Africa around this time.
Human evolution
Which species has the largest supraorbital torus we have ever seen?
The supraorbital torus is the brow ridges
Sahelanthropus tehadensis
We know this from skull evidence and no other species we have seen has brow ridges of that size.
Human Evolution
Who is the first species to live in a really cold environment?
Homo neanderthalensis
We know this from finding their remains, which come from Pleistocene Era Europe.
What do all the species in the genus Australopithecus have in common?
- Prognathic
- Large chewing muscles
- Average cc of around 550
- Habitual bipedalism
What do all the species in the genus Homo have in common?
- Larger brain cc
- Presison grip
- Opposable thumbs
- Tool making
- More dietary plastisity
- More of a forehead
- Taller (5’5 - 6’0)
- First to leave Africa
How do tooth proportions change from Australopithecus to Homo?
They started to present smaller canines in relations to apes. Which suggested that they were not using their canines for male to male competition.
In Austra. they had big teeth compared to homo. They got smaller overtime.
Change in Au. boisei. They hhad post canine megadontia, molarized premolars, and reduced anterior teeth.
Then Au. robustus displayed very small incisors
Homo - lange anterior teeth and smaller molars because of tool use.
What are the arguments for putting Au. aethiopicus, Au. robustus and Au. boisei in a different genus?
Because of their very varing features from the rest of Au. such as more dished skulls, larger cranial capacity, larger acending ramus, and thicker and bigger teeth, anthropologists argue that they should be put in their own genus to reflect that transition.
Australopithecus
Australopithecus africanus
- lived in Southern Africa, specifically in South Africa
- 3.3 to 2.1 million years ago
- average : 420-510 cc
- Compared to Au. afarensis, Au. africanus had a rounder cranium housing a larger cranial capacity and smaller teeth
- strongly sloping face with a pronounced jaw
*The pelvis, femur (upper leg), and foot bones of Au. africanus indicate that it walked bipedally, but its shoulder and hand bones indicate they were also adapted for climbing - diet consisted of fruit, plants, nuts, seeds, roots
- It is unclear how A. africanus relates to other hominins, being variously placed as ancestral to Homo and Robust Anthro
What species definition would we use to split these species into Paranthropus?
By analyzing traits of currentlly robust anthropithecus, researchers could determine which traits are shared specifically by the members, creating the genus Parathhropus.
Did Denisovans interbreed?
Yes
Classification and interbreeding
How does this effect what species definition we could use to define these groups? How would that species definition propagate into earlier species?
If we know that different hominin species are interbreeding, that makes their traits more difficult to define. And if we’re having to apply this knowledge to homo, that means that we would also have to consider this for earlier hominins.
What is important about the Plio-Pleistocene transition, and how did hominins deal with those changes?
It became drier, which forced hominins to leave the forests and fall back on fall back foods, which led to the development of stone tools.
Homo
Homo erectus
- Lived between 1.8 million and 143,000 years ago
- Lived in Africa, Asia, and Turkey
- They were bipedal
- cranial capacity of around 700-1250 cc
- first hominid species to leave Africa
- Lived in warm, tropical climates; closed grasslands
- height possibly between 5’9” - 6 ft
- Homo erectus gave rise to Denisovans, Neaderthals, and early modern human beings
- Evidence of spear use
Denisovans
*Denisovans lived in Europe and Asia
* distantly related to each other and to modern humans
* They may have interbred with both modern humans and each other
* Went extinct before Neanderthals
Homo sapiens
- Lived from around 300,000 years ago to the present day
- They are bipedal
- Average cc: 1349 cc
- They are known for their large brain size and complex culture
- Live everywhere!
- Interbred with Neanderthals
