bio evol REVISION Flashcards
Advantages BIPEDALISM (2) Energy & Hands
Energy efficient locomotion
(2 legs less E than 4)
-longer more rewarding journeys (more E reprod)
Free Hands
carry tools, weapons, food
^ hand dexterity, build shelters
Resources scattered further apart
Advantages BIPEDALISM (2) Thermo & Height
Increased Height
enhanced visual field –> see over tall grass (pred/l f)
improved ability to anticipate danger & find safe route
Thermoregulation
less SA exposed to direct sunlight upright position
- remain in sun for longer*
Challenges/Disadv BIPEDALISM (2)
Challenges in Childbirth
changes pelvic shape
narrower birth canal
larger cranium
increased risk of complications
Back/Joint pain
spine and joins required to support weight of whole body –> stress lower back
- increase susceptibility to injury*
Skeletal Changes (Foot)
Foot (arch)
arch –> shock absorber
also stores E and release when pushing off
E efficient, increase d & suc
hallux –> thrust –> reduced grasping ability
robust heel bone –> balance/stability maintain arches
Skeletal Change (pelvis)
Bowl-shaped - flater broader - suport abdominal organs
brings cog aover feet balance and stability
lilac blades are points of attatchement for strong locomotion muscles
- decreased energy needed to stabilise body*
Skeletal Change (femur)
Leg (femur & knee)
longer, straighter, thinner
^stride l, centres body w, E efficient
femur angles inwards (valgus angle) –> brings knees closer to COG, walking w/out swaying, more stable
Skeletal Change (Spine)
S-shaped
acts as spring, compressing slightly under pressure, absorbing shock
* increase endurance loco*
dist weight evently over lower body (reduce stress on internal organs)
supports upright posture
Cultural evolution positive feedback loop | meat –>
Meat/protein
–> greater nutrient absorbtion (more calories/E)
–> fuel brain development
–> increase cranial capacity (better communication, memory, tools, bonding)
–> more sucessful hunting
–> meat
Adv Cooked food
–> more digestible (reduced E making organs)
–> more calories E
(reduced time foraging, less food)
–> nutrient available for brain development
Brain dvelopment led to ..
Ability to form complex thought (solve prob/be creative)
–> more complex tools imagined & constructed
–> developemt of Broca and Wernickes areas (more efficient teamwork)
–> development in memory and communication
Adv of Fire
-warmth (migrate out of Africa into cooler climates)
-light @ night (extend hunting hrs)
-tool making (stronger, more resistant to wear)
-protection
-cooking
-social organisation (strengthen bonds)
Com cultural/biological evol.
Cultural evolution:
transmission of learned behaviour,
ideas and knowledge
transferred across space & time and
can occur between unrelated individuals.
Biological evolution:
occurs more slowly as favourable changes in genomes of individuals are
passed only to their offspring by natural selection
adv/disad agriculture
-abundant food supply
-additonal materials from animals
-sustain large pop
-more waste
-weather dependent
-spread of disease
-overall decline in health
Out of Africa Dispersal Theory
Modern humans (h.sapiens) originated in Africa from h.erectus & migrated out into Europe and Western Asia where they encountered, interbred and eventually outcompeted arcahic hominin populations who had left africa much earlier.
sapiens left africa in 2nd migration 100-50000yrs
Evidence of OOA
Africa –> oldest pop –> greatest genetic diversity (regional pops, decreased levels, short time to accumulate diff and small pop)
Mt DNA
Nuclear DNA (compare gene similarities –> fewer –> more closely related)
