human evolution Flashcards
acheulian
tool culture associated with h erectus and archaic h sapian. ‘choppers’ tear drop in shape carefully crafted with a slight bulge on each face. ‘cleavers’ flatter and more blade like
agriculture and farming
domestication of animals and planting of plants as crops for food, increasing productivity of settlement life, permanent structures, domestication of animals (first dogs then sheep goats…) cultivating crop plants (wheat, barley, lentil…)
archaic homo sapians
a group encompassing the many regional variants of homo sapians with robust but human skeleton existing between 400k and 100k ya
australopithecus
group of extinct omnivorous bipedal hominins. including anamensis, afarensis, africanus…
Australopithecus afarensis
early australopithecus thought to have been a common ancestor to later australopithecus and genus homo
biological evolution
transmission of genetic information from generation to generation. slow
bipedalism
habitual uprite walking on two limbs. energy efficient method favors low speed long distance movement (walking)
brachiation
method of locomotion involving moving from branch to branch swinging below the branches rather than moving along the top
brocca’s region
area of the brain controlling the muscles of the lips jaw tongue soft patal and vocal cords during speech associated with the creation of speed
cultural evolution
transmission of knowledge from generation to generation (not within a generation) over time. fast
denisovans
a theory stating mordern humans are all descended from the ancient human h. heidelbergensis between 300k to 400k ya, ancestral group of heidelbergensis left africa and split shortly after. one branch ventured north west into west asia and europe becoming the neanderthals, the others moved east becoming denisovans, and 130k ya heidelbergensis in africa became h.sapien
dentition
number, size and arrangement of teeth in skull and jaw. including presence or absense of diastema
diastema
gap between incisors and canines
foramen magnum
opening on lower side of skull where spinal cord attaches. largest hole in spinal cord goes through in the bottom of skull
gracil
term used to describe lightly built body of fossils belonging to genus australopithecus comparing them to genus paranthopus
hip girdle
long hip bone in quadrupedal animals to support abdominal organs. humans have bowl shaped girdle reducing stress on part of the hip that transmits body weight
hominin
group includes humans and prehumans
hominid
family includes apes and humans, all the great apes
hominoid
all the apes, greater and lesser past and present
homo erectus
first hominid fossil found outside africa belonging to this widely distributed homo species. first to use and maintain fire from natural source, cooked food, kept warm, exploited new habitats. marks increase in brain volume
homo ergaster
older form of homo erectus of a separate group
homo habilis
the first species in the homo lineage, and the first species associated with stone tools. oldowan tools.
the 4 milestone homo species
habilis, erectus, neanderthalensis, sapiens
homo neanderthalensis
robust, cold adapted species of homo confined to europe and west asia. superficially similar to archaic homo sapiens. long low skull with reduced brow ridge and brain volume reaching 1500cmcubed average.
homo sapiens
modern humans
hunter gatherer
nomadic, spending lots of time searching for and collecting plant foods, hunting animals, scavenging carcases. groups moved as resources changes like seasonal growth and migration of prey species
low paleolithic tools
‘old stone age’, oldowan and acheulian tool culture. fewer flakes removed not very refined
mesolithic tools
transition between paleolithic and neolithic periods. tool culture characterised as microliths, small stone flakes set into wood or bone using resin, allowing longer cutting edge for tools like sickles
mousterian
tools created by neanderthals and sapiens. sophisticated and finely worked scrapers, spear tips and axe heads often mounted on wooden shafts used as spears, bow and arrow. produced levalois techique. requires skill and to be taught and learned
mtDNA
dna in mitochondria, inherited from mother (maternally) as mitochondria in sperm destroyed by egg after fertilization. used to trace maternal lineage far back. slow mutation rates and is useful for studying evolutionary relationships. compare mtdna sequences between dif species using comparisons to build evolutionary tree. mitochondrial eve, all maternal lineage can be traced back to this individual woman who lived 200k years ago
multiregional hypothesis
dispersal hypothesis stating some human species left africa 2 million years ago (h. erectus), spread into europe and asia, evolved in parallel nto modern forms (sapien) independetly throughout with some interbreeding resulting in (regional) racial differences
nuchal crest
ridge at the back of the skull for attachment of neck muscles reduced size in bipedal organisms
oldowan
tools made by habilis called pebble tools cause look like chipped tools. ‘choppers’ several flakes struck to produce rough edges. cutting crushing or digging
paranthropus boisei
heavily built species of paranthropus in eastern africa showing marked in sexual dimorphism
paranthropus
genus of extinct hominin two accepted species robustus and boisei. not a direct ancestor of humanity but a specialised side branch. specialised feeder. smaller brain size couldve been factor to their extinction alongside gracile australophithecines
power grip
high force and low precision movement of hand using bulk of hand for force generation rather than strength of individual fingers. useful for brachiating or knuckle walking. not good for tool manipulation
precision grip
hand grip of intermediate and fingertips and thumb pressed against eo allowing more precise movement but not as much strength. useful in ability to produce fine movement needed to make tools, writing etc
prognathism
degree of protrusion of snouth or muzzle region of face
replacement hypothesis / out of africa
dispersal hypothesis stating modern humans evolved in africa left 200k ya moving out of africa outcompeted and replaced regional populations of other hominins from previous migration as they went to become the only remaining hominin. supported by mtdna
robust
term used to describe heavy skulls with large ridges for muscle attachment belonging to genus paranthropus when comparing them to australopithecus. also used to describe more solidly built physique of hominids
sagittal crest
bony projection/outcrop on top of skull for attachment of chewing muscles
sexual dimorphism
there are structural differences between sexes of species
thermoregulation
ability of the body to keep cool
upper paleolithic tools
tools crafted by sapiens in this period cover wide range of tool culture characterised by use of greater range of materials to make tools. spearheads of stone or carved antler eg. the use of tools to make tools.
valgus angle
carrying angle of thighbone ensuring knee brought weel under body during walking increasing walking efficiency eliminating sideways movement
valus angle (of femur)
femur is stronger, longer, angled inwards from hip so knees nearly touch (increase valus angle). shifting knees under hips improves balance.
wernicke’s area
area of brain concerned with comprehension of spoken words and ability to listen
y chromosome DNA
y chromosome one of 2 sex chromosomes in mammals. y only passed from father to son used to demonstrate relatedness tracing paternal lineage. paternal ancestor aprox 140k ya (theoretical adam). y can only change by mutation as doesnt recombine with x
zygomatic arch
bone structure on side of cheek through which chewing muscles go
paleolithic timeline (old stone age)
2.6mya-10,000BC
mesolithic timeline (middle stone age)
10,000-8,500 BC
neolithic timeline (new stone age)
9,000-1,800 BC
advantages of bipedalism
- greater height
- energy efficient
- less body surface in direct sunlight
disadvantages of bipedalism
- slow moving
- less stable on 2 feet than youd be on 4
- small pelvis for walking disadvantage to women
the center of gravity
is how the body is balanced within the base of support. quadrapedal organisms have wider base of support with bipedal organisms have narrower base of support
skull changes
- foramen magnum nearer center of skull to balance on top spine
- nuchal crest in humans non existent (no need for extra support to hold up head when bipedal)
- sagittal crest presence decreased
- zygomatic arch size decreased
spine changes
- human spine s shaped. shock absorber keeping body weight above hip joins for upright movement
- ape spine c shaped, slight curve counterbalances downward force of organs and chest
ribcage changes
- human ribcage flattened front to back so center of gravity is close to the spine
- ape ribcage flattened side to side in apes making more funnel shaped to accomodate large herbivore gut
pelvis changes
- short and wide bowl shape in humans reduces stress in upper body weight on hips and support internal organs. strong bones support muscles moving legs while walking. wide for baby birth
- ape is long and narrow providing large surface area for attachement of leg muscles but not good for a large braine birth
femur change
- humans long and angled in (valgus angle) from hip, knock knee stance and gait. valgus angle brings knees under center of pelvis so body weight centered through middle of pelvis when walking. buttresses of bone on knee joint prevent sideways tilting of lower leg when walking
- apes fermur short no buttresses at knee joint end. no valgus angle legs hand vartically from hips. inefficient rolling gait when walking on two legs but good for brachation.
feet change
-human toes stright, foot has arche, acts as shock absorber during running and walking. end of each step foot pivots over big toe
- apes big toe spread outward from foot and is opposable. flat feet
robust docile
big small australopithecus paranthropus
cerebrum
largest part of brain handling control of muscle function, control of speech, thought, emotion, reading, writing and learning
cerebellum
a vital component in human brain for balance and musculra coordination. coordinates gait maintains posture controls muscle tone and voluntary muscle activity. increased in size and complexity
cerebral cortex
the outer layer of the cerebrum folded extenstively in modern humans. thinking, learning, reasoning, problem solving, emotions, consciousness…
FOXP2 gene
the language gene, found on chromosome 7 codes for forkhead box protein P2, member of the FOX group of transpcription factors involved in regulation of gene expression.
