Human Evolution Flashcards
LCA of Pan and Homo
6-8 MYA
core adaptations (4)
bipedality and canine reduction
tool use - megadonty
striding
symbolism - art - “culture”
Raymond Dart: found? (two names) where? 2 features? scientific reaction?
Taung child; Australopithecus africanus (juvenile)
Taung Site (Africa)
endocast more human than ape like
foramen magnum placed forward = evidence for bipedalism
rejected this
Piltdown man:
characteristics (2)
catch?
ape like face; human like brain
it was a hoax: chimera made of modern human bits and modern orangutan bits
Robert Broom:
Site?
Name (3)?
Characteristics (2)?
Sterkfontein
Adult Au. africanus cranium (“Mrs. Ples”); STS5
like chimp: small brain and prognathic (projecting jaws)
over the course of evolution size and robusticity of facial skeleton ______ and brain size ______
decreases
increases
post-cranial remains of Au. africanus shows
bipedalism
post-cranial remains of Au. africanus shows _________ with Homo
pelvis and lumbar spine show clear functionally significant synapomorphies with Homo
3 characteristics of spine and pelvis for bipedalism
lumbar lordosis (lower back curves in) short ilium laterally directed ilium (curved around)
Understanding Bipedalism:
back adaptation?
lordosis shifts the upper body over the feet which shifts the center of gravity
Understanding Bipedalism:
pelvis adaptation/shape? (3)
pelvis in quadruped is a different shape
in pan - oriented dorso ventrally
in Homo - laterally oriented
General idea about bipedal adaptations
change anatomy of a site where a muscle attaches to a bone, change action of muscle
Understanding Bipedalism:
lesser gluteal muscles (2)
primitive function is to extend leg at hip during quadrupedalism
derived: modified in Au. Africanus and modern humans to maintain balance during bipedalism
in sum: Au. africanus (2)
which means?
primitive ape-like cranium
bipedal like modern humans
bipedalism is the first major adaptive shift in becoming human
Taxonomy (scientific and common):
Family =
Hominidae -> African hominoids
Taxonomy (scientific and common):
Subfamily (3)
Gorillinae -> Gorilla
Paninae -> Pan
Homininae
Taxonomy (scientific and common):
Tribes (2)
Australopithecini -> early fossil hominins
Hominini -> living and fossil Homo
4 early hominin adaptations
and their classifications
habitual bipedal locomotion
thick enamel
reduced canines
large molars (relative to anterior teeth)
first three derived; last one derived and different from Homo
Where did the 4 early hominin adaptations occur?
Africa
At Lake Chad:
Name?
6 characteristics
Sahelanthropus tchadnesis
massive thick supraorbital bones (like gorilla)
very small endocranial volume
small molars
not like most Australopithecines
intermediate enamel thickness
intermediate canine size with apical wear
About canines:
Chimps and other apes (2)
Modern humans (2)
sharp projecting canines; hones
canines incisiform; apical
Sahelanthropus tchadnesis is…
earliest biped anthroped
East African Rift Valley (1)
Ardipithecus ramidus
Ardipithecus ramidus:
5 traits
1 other name
foramean magnum shifted foward very primitive cranium small brain had arboreal climbing adaptations bipedal when on ground (not knuckle walking)
Ardi
First core of Early hominins
Sahelanthropus, Orrorin, Ardipithecus
Second Set of Core adaptations
tool use
megadonty (really big teeth)
Second core of Early hominins
Australopithecus
Kenyanthroupus
Paraanthropus
3 Australopithecus species
anamensis
afarensis
africanus
Extra name for Australopithecus afarensis
Lucy
Australopithecus africanus (3 traits)
primitive ape like cranium
bipedal like modern humans
bipedalism is the first major adaptation
In Dikika:
what?
when?
means?
bones with cut marks
3.4 MYA
evidence of tool use
Knowledge of Dikika tools is…
limited because of context (stone tools just lying on the surface)
In Lommeki: What? When? Where? Important point?
Lomekwian stone tools
3.3 MYA
Kenya
found in context (in a matrix)
Lomekwian stone tools:
are?
features (3)?
major point?
simplest possible stone tools you can manufacture
big, crude, unknown use
basic stone tools present by 3.3 MYA
Ethiopia:
what’s here?
when?
called (4)?
new kind of stone tools
2.5 MYA
Oldowan tool industry, Mode 1, Early Stone Age, Lower Paleolithic
Classic Oldowan tool?
Characteristics?
possible use?
pebble chopper + flakes
easy to make but more complex and planned than Lomekwian
animal bones showing evidence of systematic butchery
Australopithecus garhi
importance?
traits?
hominin in same place as animal bones
typical Australopithecine
early stone tools (3)
first made by hominins with ape-sized brains
used to butcher animals
used for hunting or scavenging (prob scavenging)
chimp stone tools are
not very modified and thus hard to distinguish from ordinary rocks
Austrolopithecus garhi leg
length increased = get more efficient bipedalism with larger stride
from ___ to ____ MYA there was ______ in brain size
cranium that is _____ with _____ facial skeleton
cheek teeth: (2 traits + 2 implications)
canines: (2 traits + 3 implications
habitually ____, retain _____ adaptations
7; 3; not much increase
prognathic; large robust
thick enamel and large = suggests new diet of tougher food/needs to be more resistant to wear
smaller, less honing facet (decreases competition, new
diet, tool use)
bipedal, climbing
Hypotheses for Evolution of Bipedalism (2)
Greater efficiency - knuckle walking inefficient, bipedal highly efficient
endurance running - good at running for slow speeds for a long time over long distances/ persistence hunting
Why become bipedal? (2)
changing environment - expansion of grasslands in East Africa from 5 MYA to present
maybe bipedalism is initially a compromise for living in Savanna and forest/woodland
Au. Adaptations
derived and like homo (4)
derived and different from homo (1 - with 3 parts)
habitual biped
thick enamel
reduced canines
tool use
large molars -> megadonty -> extreme megadonty
Oldurai Gorge:
What was found here (2)
first oldowan tools
Paranthopus boisei
Paranthopus boisei (6)
orthognathic enormous cheek teeth sagittal crest small brain larger temporal fossa robust australopithcine
Paranthopus (5)
extinct by 1 MYA extreme megadonty robust australopithcine sexual dimorphism tool use?
Paranthopus sexual dimorphism (2)
high levels of male contest competition for mates
males and females in different niches
change in chewing adaptations suggest change in
diet
ancestral -> derived (most australopiths)
ripe fruit ->
thinner enamel ->
smaller cheek teeth ->
tougher harder and/or more abrasive food items
thicker enamel
larger cheek teeth
