Evolutionary Trends, hominid evolution Flashcards Preview

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Flashcards in Evolutionary Trends, hominid evolution Deck (58):

Order of evolutionary ancestry

Homos (erectus, neanderthalensis)
Homo sapiens (modern humans)


Define adaptation

Structure, physiological process or form of behaviour that makes an organism better able to survive and reproduce in a particular environment


Adaption to skull?

Reduced prognathism- skull on vertebrae, reduction of teeth size, flat profile

Foramen magnum-
hominins: centrally underneath skull, skull balanced in vertebrae, limited muscles required.

Apes: Foramen magnum – Posteriorly positioned foramen magnum under the base of the skull, pushes the centre of gravity in front of the pelvis


Adaption of the spinal column

-Hominins ‘s’ shaped spine - low Center of gravity. S shape curvature brings vertebral column directly under weight of skull. Improves balance in upright position. While the lumbar vertebrae is thick & wedge shaped from front to back supporting the upper body weight.

Gorilla- C shaped - high Center of gravity. C shaped curvature of the spine projects centre of gravity forward of the pelvis/ for improved balance in the quadrupedal position.


Adaption of Jaw?

A- protruding jaw

H- flat allowing for skull to balance on top of spine because weight in front of foremen magnum = weight behind


Adaption of pelvis?

Hominins: bowl shaped and broader supporting abdominal organs, transferring weight, helping with childbirth and pregnancy and providing muscle attachments for large gluteal muscles

Gorilla- elongated flat pelvis Allows hind limbs to move under centre of gravity which is in front of the pelvis.


Adaption of hip and femur

- head of femur large and fits into acetabulum (hip socket) of the pelvis because pelvis is broad. femurs converge towards the knees ensuring:
Weight distribution and creating the carrying angle. Remaining close to the central axis of the body when walking = stability, rotation from lower leg and foot, stride instead of swaying walk

Gorilla: Hip joint located behind head/ trunk
femur positioned vertically so no carrying angle

Hominin: pelvis shape makes hip sockets further apart and femur sit in acetabulum So joint is more forward = carrying angle


Adaption of knee?

Hominin knee - bicondylar angle bringing feet in line with Center of gravity when walking
= weight transferred from femur to outer hinge so outer ligament is larger and stronger than inner ligament
no energy required to stand
Naturally resistance to knee bending backwards


Adaption of foot?

Ape- opposable big toe + knuckle walking
Hominin- lost opposablity; big toe pushes off
Structured to transfer weight equally
Two arched ( longitudinal and transverse)


Adaption of centre of gravity

- longer human legs= lower centre of gravity
- lower centre of gravity = increased stability when moving bipedally or standing erect


What is muscle tone?

Partial contraction of skeletal muscles and is an essential element for maintaining upward stance.


Human brain vs ape brain?

H- more dev. Cerebral cortex (more convulsions and SA )
- average 1350cm cubed

A- 400 to 500cm cubed


What are endoclast?

Impressions inside skull made from rock or some other solid materials


Define prehensile

Grasping; refers to the digits of a hand or a foot that can grasp an object. Prehensibility is the ability to grasp objects


Origin, location and cranial capacity of Australopithecines afarensis ‘lucy’

Australopithecus afarensis
East Africa
3.9 mya- 3 mya
Cranial capacity of 375-550


Origin, location and cranial capacity of Australopithecus africanus?

South Africa
3.0- 2 mya
Cranial capacity: 420-500


Origin, location and cranial capacity of Paranthropus robustus?

East and South Africa
2.5- 1.1 mya
Cranial capacity: 500-545


Origin, location and cranial capacity of Homo habilis?

Eastern Africa
2.4- 1.5 mya
Cranial capacity of 500-800


Origin, location and cranial capacity of Homo erectus?

Asia and europe
1 mya- 300 000ya
Cranial capacity of 1000-1250


Origin, location and cranial capacity of Homo neanderthalensis?

Europe and Asia
230000- 28000 ya
Cranial capacity of 1450


Origin, location and cranial capacity of archaic Homo sapiens?

Africa Asia and Europe
300000 ya
Cranial capacity of 1100-1400


Location, origin and cranial capacity of modern Homo sapiens?

160000 ya
Cranial capacity 1350


Define binomial system

The system of naming organisms using the generic (genus) and (species) names to describe a species


Define phylum

A catergory of biological classification; one of the principle divisions of a kingdom; consists of one of more classes


What is a phylogenetic tree

A diagram showing evolutionary relationships between related organisms; also called a dendrogram


Define order

A category in the classification of organisms; the order of classification between class and family


What is in hominidae ( family level)

Hominins includes all modern and extinct chimpanzees, gorillas, orangutans and and humans


What is in hominins ( tribe level)

Includes extinct ancestors of humans and modern humans



The group consisting of all modern & extinct Great Apes (that is, modern humans, chimpanzees, gorillas & orang-utans plus all their immediate ancestors).


Define Hominins

The group consisting of modern humans, extinct human species & all our immediate ancestors.


Define evolution

Slow gradual change in characteristics of a species. Great Apes Humans Relative size of cerebral cortex


Relative size of cerebral cortex
Apes v Humans

Smaller cranial capacity
Sagittarius crest
foremen magnum towards back
Prominent brow ridges
Less rounded cranium

Larger cranial Capacity
No Sagittarius crest
Vertical forehead
foramen magnum moved centrally below
Reduced brow ridges
Rounded cranium


Mobility of digits
apes v humans

Less opposable first digit
Opposable big toe
Precision grip
Power grip
Shorter thumb relative to other digits

More opposable first digit
Non-opposable big toe
Precision grip
Power grip
Longer thumb relative to other digits


apes v humans




Apes v humans

prognathic face
Large jaw
No chin
Larger molars & canines 5. Diastema
U shape dental arcade

Flatter face
Small jaw
Definite chin
Smaller molars & canines
No diastema
Parabolic dental arcade "


Adaptions to ribcage

reduced size/ weight

Gorilla: Apes have a rounder, barrel shaped rib cage, pushes the centre of gravity in front of the pelvis. It is also large to support abdominal organs.

Hominins: pelvis supports abdominal organs


What is the carrying angle

Carrying angle- convergence of femur at the knee
So weight is distributed to the center of the body
= increased stability when moving
= striding gait = body rotates towards midline as walk pulling leg into a straight line.


Define primate

A member of an order of mammals that includes lemurs, lorises, tarsiers, monkeys, apes and humans


Define culture

Culture – The range of learned behaviour patterns acquired by a species/population


Tool trends

Trends – Increase in the variety of tools made. Increase in the complexity of manufacturing process of the tool. Increase in the quality of workmanship. Increase in the range of materials used to produce tools. Increase in the number of different activities tools are used for


Tool culture used by Australopithecines/ Paranthropus?

Oldowan/ 2.6- 1.7 mya

"Pebble tools, chippers, scrapers , flakes and chisels.
Stone/ Percussion flaking


Tool culture used by Homo habilis

Oldowan/ 2.4- 1.5mya "Pebble tools, chippers, scrapers , flakes and chisels.
Stone/ Percussion flaking"


Tool culture used by Homo erectus

Acheulean/ 1.7 mya– 100000

“Stone +Percussion flaking
Flaked around all edges
Hand axes/ teardrop shapes"


Tool culture used by Homo neanderthalensis

Mousterian/ 200000 – 400000

"Stone, wood, bone-> ‘hafting’
Specific tools- piercing, gouging, scrapes
Flint stone"


Tool culture used by early cromagnon Homo sapiens

43000 – 26000
Stone, wood & bone/ punch flaking


Tool culture used by later cro magnon Homo sapiens

22000 – 19000
Characterised by pressure flaking stones to produce artful willow leaf and laurel leaf points.

Used Stone, wood & bone/pressure flaking


Tool culture used by latest cromagnon Homo sapiens

18000 – 12000
Dominance of bone and antler tools over flint and Stone.
Used wood & bone/Hafting, punching & pressure flaking


Australopithecines/ Paranthropus lifestyle, food, hunter gatherers?

Lifestyle: slept in trees at night, during day- terrestrial, had home bases

Food- herbivores- hard, brittle. Ate seeds/ nuts. Ate grasses/ fruits/ tubers

Hunting/gatherers- gatherers


Homo habilis lifestyle, food, hunter gatherers?

Homo Habilis
Lifestyle: interdependent, lived together in small groups

Food- omnivores: mainly plants, eating meant occasionally. Protein + lipids = brain development

Hunting/ gathering: both hunters/ scavengers for meat. Some bones show cuts made by stone tools and teeth showing how they ate meat -> food sharing


Homo erectus lifestyle, food, hunter gatherers?

Homo erectus
Lifestyle: independent from environment-> used it to their advantage: built shelters and used fire

Food: omnivores/ meat- fish and deers. Veg- nuts and fruits (70%). Fire- cooked-> safe to eat.

Hunter/ gathering: skilful hunters, employing many capturing techniques eg, using fire to herd elephants and gathering tools from 33km away to capture prey.


Homo neanderthalensis lifestyle, food, hunter gatherers?

Homo neanderthanlensis
Lifestyle: caves, harsh conditions-> able to adapt and respond to environment. Clothes-> animal hides

Food- omnivores- 80% meat p- mammoths, rhinos, deers and horses. Preserved and STORED meat.

Hunting/ gathering; strong built and able to run long distances to catch prey, they even herded prey into areas where they could ambush them. - organised hunting.


Homo sapiens lifestyle, food, hunter gatherers?, social systems, communications beliefs and tools.

Homo sapiens
Lifestyle: scattered -> small populations, nomadic-> villages, better shelters

Food: meat based (archaic). Domesticated plants/ animals ( farming + agriculture) ~ 12000 years ago

Hunting/ gathering: able to catch prey using tracking methods and cages to trap them temporarily. Hunted bisons, venisons, reindeers, rabbits. Plants, seeds, Nuts. Also herded animals


Australopithecines/ Paranthropus social systems, communications, beliefs and tools?

Social systems- males stayed close to home and collected food. Females dispersed after puberty and cared for the young. They were no neighbouring groups

Communication- no speech, vocal cords are similar to chimps making only rudimentary sounds

Beliefs- N/A

Tools- oldowan


Homo habillus social systems, communications, beliefs and tools?

Social system: liked to share things and look after each other, increased interdependence and group close knit and able to function as a social and economic unit. Men hunted, women and females gathered.

Communication: hands (visual signals), voice (simple)- pressure for communication increase, speech producing area bigger

Beliefs- N/A

Tools: oldowan


Homo erecus social systems, communications, beliefs and tools?

Social system: women- gatherers due to demand for child caring. Care of young was becoming increasingly important. Also a greater emphasis on mutual cooperation and complex society developed.

Communication: gene for speech + language may have developed. Pressure for speech increased and spoken language may have arisen

Beliefs: NA

Tools: Archeulian tool culture


Homo neanderthalenisis social systems, communications, beliefs and tools?

Social systems: cared for disabled, shared resources developed social systems for sharing food and other resources, traded with Homo sapiens and older children learned from adults

Communication: relatively advanced language skills. Larynx similar to H. Sapiens

Belief: strong indication they buried their dead suggesting they believed in life after death. Ceremonial burial seems to be practiced. Art and music development.

Tools: Moustierian tool culture


Homo sapiens social systems, communications, beliefs and tools?

Social system- innovations in clothing, complex social system, very few members involved in food production and most occupied in other pursuits,

Communication: symbolic language-> written

Beliefs- artistic, innovative. Religion. Art, music. Jewellery, body modifications, rituals and ceremonies.

Tools: aurignacian, solutrean, magdalenian, upper Palaeolithic tools


Bipedal vs quadrupedal adaptions

Quadrupedal C shaped spinal curve
Less wedge shaped lumbar vertebrae Thinner lower vertebrae
Longer, narrow pelvis
Lesser carrying angle
Longer arms than legs
Longitudinal arch only

S shaped spinal curve
More wedge shaped lumbar vertebrae
Thicker lower vertebrae
Shorter, wider pelvis Greater carrying angle Shorter arms than legs
Longitudinal/transverse Larger heel bone"