Human Evolution

Question 1

Evolution of the Homininae - Themes

Answer 1

Evolutionary themes (in order of
occurrence)
Locomotion
cooling drying climate; expansion
of savannahs

Diet
thin to thick enamel
reduced canines
reduced prognathism

Brain
cranial capacity
fluctuating climate
Mosaic pattern of human
evolution (NOT progressive)
Long gaps
Different rates

Answer 2

Chimps are nearest living relatives
Nearest common ancestor ca 6-7 MA
Share ca 99% of coding DNA (closely
related)

Shared traits due to
shared common ancestor
* e.g. Y-5 molars
no tail

convergent evolution
male cooperation(?)
* warfare(?)

Question 3

Prognathism

Answer 3

Condition in
which part of
the face below
the nose is
pushed out

Question 4

Brachiation (4)

Answer 4

Method of
movement that uses the arms to
swing from branch to branch

Question 5

this is a distinction in the early hominin line from its ancestor

Answer 5

Diastema = Space between the upper canine
and incisor that accommodates the lower canine

must have a place for gap for canine, due to large canine

Question 6

chimp skeleton male

Answer 6

1. Hindlimbs shorter
   than forelimbs
2. Long pelvis
3. Knuckle walking
4. Protruding face
5. Spinal cord and the
   vertebrae enter into
   the cranium
   posteriorly

Question 7

Australopithecus Group

Answer 7

Erect & bipedal
Relatively long forelimb (ape-like
Sexually dimorphic (chimp-like)
* Small brains (chimp-like)
Intermediate teeth
- slight diastema
reduced canine
thicker enamel than ape

Question 8

Locomotory transition: Arboreal suspensory to
bipedal (3.8 mya)

Answer 8

Australopithecus: warming, drying climate
> forest to savannah woodland
1. Postural adaptation for
feeding

2. Thermoregulatory
   (reduce surface area for insolation)
3. Energetics of movement over open ground
4. Carrying objects
5. Wading hypothesis

Question 9

Australopithecus
afarensis
(4.2 - 2.9 mya)

Answer 9

LUCY
40% complete skeleton
Adult female
105-150 cm; 29-42 kg
Sex dimorphic
Skull/dentition
small braincase
prognathism
reduced canine
little bit of a diastema
Pelvis broad & narrow
Femoral neck long
Femur slants inward
› early bipedal
BUT arms somewhat longer
relative to legs than in humans
* slept & foraged in trees

Question 10

Paranthropus (3 - 1 mya)

Answer 10

S & E Africa
Bipedal
Small brains
Robust masticatory
apparatus but not
entire bodv
Small incisors
Reduced canines
Massive cheek teeth
Large masticatory
muscle
as per bony attachment
on sagittal crest and
mandible

Question 11

3 major genera

Answer 11

australopithecus
paranthropus
homo

Question 12

australopithecus

Answer 12

biped, gracile, small brain

Question 13

paranthropus

Answer 13

biped, robust crania, small brain

Question 14

homo

Answer 14

biped, gracile, relatively larger brain

Question 15

earliest homo

Answer 15

H. Habilis and H. rudolfensis

east africa

forelimb proportions similar to A. afarensis

slightly enlarged brain (wide variation in body size larger too)

reduced facial size and smaller teeth

Question 16

parallel sided dental arcades

Answer 16

chimp mandible, bottom jaw forms a rectangular shape, this is because their faces are prognatic, most apes are like this

Question 17

parabolic dental arcades

Answer 17

human mandible, bottom jaw forms a u shape, face is becoming flatter and flatter, and we are losing that prognatism

Question 18

reduction in jaw size and facial flattening

Answer 18

our faces became more flatter because of our diet and invention of cooking the food that we ate become softer, and easier for our ancestors to chew the foot items, this allowed the facial flattening and contributed to our teeth getting smaller.

Question 19

stone tools

Answer 19

cutting marks on bones = human hunting

concentrations of bones and stones suggesting central place foraging - carying meat back to a camp
(shows homo hobolis had base camps)

Question 20

the pilo-pleistocene

Answer 20

Rapidly cooling climate
ice sheets & land bridges;
more of ocean ways are in
ice sheets
changes in vegetation
Cooling selects for
increased body size
Environment of evolution
of Homo ergaster and H.
erectus
Reduction in hominin
diversity

Question 21

bipedal femurs

Answer 21

longer shaft, longer neck, and change in distal morphology, pan has small upper part, australopheitics has larger upper boney part, homo has largest femur

Question 22

‘Nariokotome Boy’: H. ergaster

Answer 22

~1.8 mya
Approx. 12 years old
micro lines in teeth
Brain 850-1000+ cc
Tall (approx. 1.9 m at adult)
Fully committed to terrestrial
life
long legs
narrow hips
narrow shoulders
barrel-shaped chest
short arms
Longer development period
* later eruption of molars

Question 23

Homo ergaster & H. erectus

Answer 23

H. ergaster in Africa from 2.0 - 0.6 mya (?)
Mostly Acheulian tools
- controlled fire
hunting of large mammals
Some disperse from Africa early to Eurasia and Asia
H. erectus in Asia approx. 1.8 - 0.1 mya
less complex tools than H. ergaster
controlled fire
dead end group but persists longer than H. ergaster

Answer 24

Bipedal locomotion precedes tools and big brains
Tool use/modification precedes period of greatest
encephalization
‘Slowed down’ life history may begin in H. ergaster
teeth human like in size and proportion
Meat consumption, handaxes, fire
First major dispersals of hominins from Africa to Eurasia
* H. ergaster at approx. 1.8 mya to Eurasia

Question 25

anagenesis definition

Answer 25

transformation of a single species over time

Question 26

homo heidelbergensis
similarity with homo ergaster

Answer 26

brow ridge

Question 27

homo heidelbergensis major derived feature

Answer 27

more rounded, higher skull, which is a major difference between homo heidelbergensis and homo ergaster

Question 28

when did homo heidelbergensis

Answer 28

roughly 600,000 and 200,000 years ago was originally found in africa, but migrated into europe and asia

Question 29

difference between modern humans and homo heidelbergensis in skull morphology

Answer 29

higher cranial bolt
brow ridges
in terms of overall shape, human skull is more globular, homo heidelbergensis is more oval shaped

Question 30

differences in mandible traits within humans and homo heidelbergensis

Answer 30

in homo heidelbergensis, smooth mandible, homo sapeins has an out jutting of the mandible and the fusion of the two parts of the mandible, the chin

Question 31

skull characteristics used to identify neanderthals

Answer 31

large elongated skull, ridges that are supraorbital ridges, bump at the end of skull which is very diagnostic

nederthals had an anatomy for colder climate, smaller forehead

Question 32

what are neanderthals and homo sapiens

Answer 32

they’re sister species, derived from a common ancestor

there is aslo evidence for admixture (we was both fuckin lol)

Question 33

neanderthal lifestyle

Answer 33

probably buried their dead, lived in caves, hunted big game, hunter gathers, evidence of cannibalism

Question 34

Cro Magnon: Early
H. sapiens (50-30 kya)
lifestyle

Answer 34

Decorative art, figurines, more
complex tools (Upper
Paleolithic), raw material
transport, shelters, burials etc.

Question 35

Obstetrical Dilemma

Answer 35

Human pelvis bowl-shaped
adapted for bipedality
- but restricts size of birth
canal
BUT giving birth requires a
birth canal wide enough to
allow baby’s head through
Dramatic increase in brain
size after becoming bipedal
created a problem ->
obstetrical dilemma

Question 36

Maternal Adaptations

Answer 36

Increase in neonatal
cranium > selective
pressure on
size of opening of female
pelvis resulting in sexual
dimorphism of the human
pelvis
softening of pubic
symphyses at end of
pregnancy

Question 37

Neonate adaptations

Answer 37

Bones of cranium not
fused
able to slip >
allow
compression
during birth
space for rapid
postnatal brain
development

Question 38

Life history of
Homo sapiens

Answer 38

Short to normal gestation for size
Altricial (‘undeveloped’) at birth
Rapid post-natal brain growth
Long juvenile period for size
Relatively short inter-birth interval
delayed age at sexual maturity
post-reproductive life span