Human Evolution 03 Flashcards
Modern Human vs primitive features
• short humerus | long forearm, stable elbow
• lumbar lordosis | funnel shaped thorax, small vertebrae
• wide sacrum | small hip joint
• long femoral neck, valgus knee | short femur
• adducted hallux | long curved toes
Humans vs. Australopitecines
still used upper limb for climbing, strong lower limb for bipedal locomotion
How did Lucy probably die?
Many complex fractures indicate fall from high hight => tree => climbing
What do Laetoli footprints suggest?
Footprint deeper on outside
Rotation in hip joints rather than in lumbar region
Footprint size => estimate stature of them according to Lucy’s body/foot size => slightly larger
Male and female or diff. species? not clear, but large stature of hominins at beginning
What has been discovered in the Olduvai gorge?
• Stone tools
• evidence of early homo => skull of paranthropus boisei
But might not have been toolmaker
• Homo habilis (handy man)
Homo habilis
1.8 Ma
skull suggests larger brain size
Mandible with smaller teeth, compressed and elongated => human like
Foot suggests bipedalism
Strong finger bones (stone tools, climbing?)
Longer humerus than Lucy, otherwise similar morphology
Early homo from Ethiopia
2.8 Ma
narrow, elongated molar teeth, third molar smaller than second
shape of mandible is Australopithecine like
Stone tools before homo?
Cut marks => butchering
Stone tools => 3.3 Ma suggests Australopithecines made them
Brain size
Humans defined by large brain size
Homo habilis smaller => similar to Australopithecines
Threshold is outdated
Was Lucy more human-like than Homo habilis?
Limb proportions (humerus length & circumference) of Lucy human-like, Homo habilis great-ape-like (but gorillas and chimps and too small a sample size (few small))
If accounted for these: both fall into humans, lower limb of homo habilis could have been more human like
So NO => but we need more fossils
Homo rudolfensis
2 Ma
Large brain size (human)
Flat face (paranthropus)
Different morph/species from h. habilis?
teeth/mandible suggest diff. species
Which 4 species of human-like great apes lived at the same time (ca. 1.9 Ma)
• Paranthropus boisei
• Homo rudolfensis
• Homo habilis
• Homo erectus
Homo erectus
flat skull cap
small brain size
fully upright
very human like femur
no chin => receding mental symphysis
marked superorbital ridge/torus
sulcus behind superorbital ridge
occipital torus, runs to ear
torus on saggital region
=> flat and thik/robust skull
engarvings on shells => symbolic behavior
teeth from china (dragon teeth) => sinanthropus => fossils lost in WWII
very diverse geographic distribution
few postcranial fossils
KNM-WT 15000
~ 1.5 Ma
skeleton of boy
ca. 1.40 m => adults could have diff. stature (1.80 or 1.60)
flat, asymmetric ribs => but maybe just juvenile, so normal, also new rip fragments found => no longer asymmetric
=> scolliosis => no scolliosis
vertebrae => disc herneation
asymmetric pelvis => reconstruction: not asymmetric, more primitive, broader
rare genetic disorder?
When did body stature of modern himans evolve? What does it suggest for Homo erectus
Quite late, diff from H. erectus
=> modern humans shorter legs
suggests H. erectus were endurance runners? & follow migrating animals out of Africa
Explain out-of-Africa migration
Longer legs => followed migrating animals for meat
Europe very recent
Asia 2.1 Ma (but very fragmentary)
What was found in a Dmanisi Monastery (in Georgia)
5 H. erectus skeletons
Align to other H. erectus skulls, but show primitive morphology and small brain size
=> large cranial variation
What is the implication of large cranial variation?
Maybe all the diff species form one single evolving lineage just with phylogeographic variability
But maybe with more fossils there is greater variance => bias bc. of narrow picture of evolution
What is special about Homo erectus?
first to leave africa?
first to use fire?
stone tools => but older ones
smaller teeth: meat & varied diet=> but chimps also eat meat
Was H. erectus predator or prey?
Some fell prey to predators, but in general rather not
No weapons, but stones might have been used to throw at animals
Trends in body mass
Trend is increasing
Larger in H. erectus, but variation
Dimorphism in species or sexual?
Sexual dimorphism reduced recently
=> changed with h. floresiensis
H. floresiensis
Island of flores
900 - 30 ka => quite recent
Island environment led to small stature?
stature of Lucy but at time of modern humans
small brain size
pathological? But too many individuals for it to be statistically true
derived from earlier forms?
shape of skull similar to h. erectus
long feet => almost length of tibia => similar to tibia
humerus ratio similar to Lucy
carpal morphology similar to great ape
Why stone tools later in Europe than in Asia?
Ice age glaciers blocked way to Europe
Homo antecessor
Different from Neanderthals and H. erectus
Homo heidelbergensis
In germany
Also diff from neanderthals and h. erectus
Neanderthals
In europe
Different skull morphology from humans
nose shape is oval (not triangualr) => larger nasal cavity = adaption to cold?
Superorbital ridges divided
Elongated and compressed shape of skull (like bread loaf 🍞)
mandible shape is diff, more robust, stronger muscles?
broader trunks and hips
Earliest spears
Neanderthals in germany => jagdverhalten
Cut marks on bear bones indicate skinning
Why did forests largely disappear in germany
Activity of Neanderthals => first to change environment drastically
Homo sapiens
Same time as Neanderthals (315 ka)
in Morocco
Same area in israel => interbreeding?
Out of Africa
Modern humans about 200’000 years ago
Denisovans
Only fragmentary record
Ghost lineages
Lineages that are thought to have existed, but no fossils
Through interbreeding => complex pattern of genetic ancestry => also Neanderthals (recent interbreeding)
Why did Neanderthals disappear?
• assimilated into modern human species
• climatic and environmental deterioration (later humans look very different from earliest ones in Europe)
• competition with modern humans
=> reduction of genepool
Cave Art
Neanderthals
