DefinitionsDefinitions HomininHominin – term that refers to humans – term that refers to humans

and their extinct erect-walking and their extinct erect-walking ancestors. They belong to the tribe ancestors. They belong to the tribe homini.homini.

Sometimes the word ‘hominid’ is used Sometimes the word ‘hominid’ is used instead of hominin but this term refers instead of hominin but this term refers to outdated classification so hominin is to outdated classification so hominin is the preferred term.the preferred term.

HominoidHominoid – term that refers to any – term that refers to any member of the superfamily member of the superfamily ‘hominoidae’‘hominoidae’

Humans are both hominins and Humans are both hominins and hominoidshominoids

Classification of HumansClassification of Humans

Animal

Chordata (vertebrates

)

Mammalia Aves

Eutheria (placental)

Marsupialia Monotremes

Primates Chiroptera

Kingdom

Phylum

Class

Sub-Class

Order

PrimatesPrimates PrimatePrimate – name of a – name of a

taxonomic group to taxonomic group to which humans, which humans, monkeys and apes monkeys and apes belong. They have belong. They have certain features in certain features in common:common: Five digitsFive digits on hands on hands

and feet that can and feet that can curl/bend around curl/bend around objectsobjects

ThumbsThumbs are are ‘‘opposableopposable’ meaning ’ meaning that they can be that they can be brought into contact brought into contact with other digitswith other digits

Flat nailsFlat nails on their on their digits with tips of their digits with tips of their digits used for sensing digits used for sensing touchtouch

Primate featuresPrimate features5 DigitsOpposable Thumb

Flat nails

Classification of HumansClassification of HumansPrimates

Anthropoidea

Prosimii

Hominoidae Cercopithecoida

Ceboidea

Hominidae Hylobatidae

Homininae Gorillinae Ponginae

Hominini Panini

Order

Sub-order

Super-family

Family

Sub-family

Tribe

GenusHomo Pan

Evolution of PrimatesEvolution of Primates

5 MYR

7 MYR15

MYR17 MYR30

MYR40 MYR

Classification

reflects the

predicted

evolutionary

history

Hominidae skullsHominidae skulls

From left to right: The skulls of a Gorrilla, Chimp, Orang-utan, and a common ancestor to humans and chimps

HomininsHominins

Humans are the only living Humans are the only living members of the tribe ‘homini’members of the tribe ‘homini’

Hominins are distinguished from Hominins are distinguished from other members of the family other members of the family hominidae because they are able hominidae because they are able to walk upright (bi-pedalism)to walk upright (bi-pedalism)

The foramen magnum

1. Chimpanzee 2. Australopithecus africanus 3. Homo erectus 4. Homo sapiens

The foramen magnum

Hominin Pelvis StructureHominin Pelvis Structure

Hominin EvolutionHominin Evolution

Hominins

Hominin EvolutionHominin Evolution

Oldest fossils found in Africa – Oldest fossils found in Africa – hominins originated in Africa hominins originated in Africa

Earliest evidence of hominins are Earliest evidence of hominins are 6 million years old6 million years old

No evidence for genus No evidence for genus HomoHomo before 2.4 million years agobefore 2.4 million years ago

Hominin EvolutionHominin Evolution

Several different hominin species existed Several different hominin species existed over certain time-frames for reasonably over certain time-frames for reasonably lengthy periods suggesting:lengthy periods suggesting: Different niches occupiedDifferent niches occupied Probably did not compete for foodProbably did not compete for food Possibly were able to interbreed for some of Possibly were able to interbreed for some of

the timethe time

Eventually some of the co-existing species Eventually some of the co-existing species may have begun to compete for food may have begun to compete for food and/or habitat, leading to the extinction and/or habitat, leading to the extinction of some speciesof some species

The genus The genus AustralopithecusAustralopithecus

Small- brainedSmall- brained Large-toothed and large Large-toothed and large protruding jawsprotruding jaws Walked uprightWalked upright – – bi-pedalbi-pedal Two types:Two types:

Graciles (slender)Graciles (slender) Robusts (heavy build) – now separate genus Robusts (heavy build) – now separate genus

ParanthropusParanthropus The graciles are possibly ancestral to the The graciles are possibly ancestral to the

human linehuman line Tool use limited – evidence has been found Tool use limited – evidence has been found

which suggests they may have used rocks to which suggests they may have used rocks to kill other animals and break bones to extract kill other animals and break bones to extract marrowmarrow

The genus The genus AustralopithecusAustralopithecus

Sexual dimorphismSexual dimorphism- - differences in body differences in body structure and specifically body mass of structure and specifically body mass of adult males and femalesadult males and females

Zygomatic arches Zygomatic arches (cheekbones) – more (cheekbones) – more pronounced – probably large cheek pronounced – probably large cheek muscles for chewing suggests high muscles for chewing suggests high fibrous content in dietfibrous content in diet

Larger waistline – Larger waistline – longer digestive longer digestive tract due to herbivorous diettract due to herbivorous diet

Habitats can be inferred from fossil Habitats can be inferred from fossil evidence – varied amongst species – evidence – varied amongst species – again suggesting different nichesagain suggesting different niches

The genus The genus HomoHomo Evidence found Evidence found

of more complex of more complex tools being tools being made and usedmade and used

Diet changed – Diet changed – smaller teeth smaller teeth fossil evidence of fossil evidence of animal remains near animal remains near human fossilshuman fossilslarger brain size larger brain size change in rib-cage change in rib-cage

size and shapesize and shape

Suggests that Suggests that meat became meat became part of the dietpart of the diet

AustralopithecusAustralopithecus Vs. Vs. HomoHomo

The genus The genus HomoHomo Compared to Compared to AustralopithecusAustralopithecus

species species HomoHomo species have: species have: Larger brains (larger cranium size):Larger brains (larger cranium size):

A. aferensisA. aferensis had a brain size of ~400-500mL had a brain size of ~400-500mL H. habilisH. habilis had a brain size of ~600-700mL had a brain size of ~600-700mL H. sapiensH. sapiens has a brain size of ~1300- has a brain size of ~1300-

1400mL1400mL Smaller teethSmaller teeth Larger skull – increased height and Larger skull – increased height and

width, straight forehead instead of width, straight forehead instead of sloping like the ancestral skullssloping like the ancestral skulls

Smaller brow-ridgeSmaller brow-ridge

http://www.amnh.org/exhibitions/permanent/humanorigins/meettherelatives/w5i1.html

Homo ErectusHomo Erectus

H. erectusH. erectus probably evolved probably evolved from from H.habilisH.habilis or or H.ergasterH.ergaster around 2 million around 2 million years agoyears ago

First hominin First hominin fossils to be fossils to be found on found on continents other continents other than Africa - than Africa - emigrantsemigrants

Homo heidelbergensis

Considered to be an intermediary or transitional form between Homo erectus and Homo sapiens

Fossils are dated between 400,000 to as recent as 40,000 years ago

Located in Africa, Asia and Europe

Homo neanderthalensis

Strongly built Evidence has been found to

suggest that they: Made sophisticated tools Built shelters Sometimes buried their dead Made clothing from animal skins

Fossils date between 150,000 to 35,000 years ago

Homo neanderthalensis

Existence overlaps with the earliest Homo sapiens

Therefore not likely to be an ancestor but a cousin of the modern human

Neanderthals are thought to have become extinct through competition with H. sapiens or disease

Homo Sapiens

Earliest H. sapiens existed in Africa around 130,000 years ago

Thought to have migrated North to Asia and Europe

Probably the first human species to use complex speech

Cro-Magnon Man Considered to be a ‘modern’ H. sapiens Produced art in caves depicting

hunting Found in regions of France and Spain Produced very sophisticated tools such

as needles, fish hooks, chisels etc. Tools and figurines made of bone have

been found Buried their dead with objects such as

figurines and necklaces

Cro-Magnon Cave Art

1. HOMO HABILIS ~ LIVED: 2.4 to 1.6 million years ago HABITAT: Tropical Africa DIET: Omnivorous – nuts, seeds, tubers, fruits, some meatBEHAVIOUR: inquisitive, tool makers, cooperative

2. HOMO SAPIEN ~ LIVED: 200,000 years ago to present HABITAT: All DIET: Omnivorous - meat, vegetables, tubers, nuts, complex foods BEHAVIOUR: complex

3. HOMO FLORESIENSIS ~ LIVED: 95,000 to 13,000 years ago HABITAT: Flores, Indonesia (tropical). Not a direct ancestor

4. HOMO ERECTUS ~ LIVED: 1.8 million years to 100,000 years ago HABITAT: Tropical to temperate - Africa, Asia, Europe DIET: Omnivorous - meat, tubers, fruits, nuts BEHAVIOUR: migrated, social relationships, used fire

5. PARANTHROPUS BOISEI ~ LIVED: 2.3 to 1.4 million years ago HABITAT: Tropical Africa DIET: Omnivorous - nuts, seeds, leaves, tubers, fruits, maybe some meat Not a direct ancestor

6. HOMO HEIDELBERGENSIS ~ LIVED: 700,000 to 300,000 years ago HABITAT: Temperate and tropical, Africa and Europe DIET: Omnivorous - meat, vegetables, tubers, nuts BEHAVIOUR: creative/imaginitive

7. HOMO NEANDERTHALENSIS ~ LIVED: 250,000 to 30,000 years ago HABITAT: Europe and Western Asia DIET: Relied heavily on meat, such as bison, deer and musk ox BEHAVIOUR: tough, stoic, used animal skins for warmth

Comparing H. erectus, H. heidelbergensis & H.

sapiensFeature H.

erectusH.

heidelbergensis

H. sapiens

Prominent brow ridges + + -

Rounded skull - - +

Big teeth + + -Sloping forehead + + -

Large Brain (1200mL +) - + +Small Face - - +

Pointed Chin - - +

Differing Hypotheses for the Human Evolution Story

Out-of-Africa: Modern humans originated in Africa and then migrated to other continents where they competed with and out-lived more primitive populations

Regional continuity hypothesis: Modern humans evolved in different regions from existing H. erectus populations in each region

Early Human Migrations based on mtDNA

haplogroups

Differences in modern human populations

Differences in modern human populations result from: Biological evolution through natural

selection resulting in physical, biochemical and behavioural differences between populations (driven by adaptations which are genetically determined)

Cultural evolution – changes in human society – passed on to people that are not genetically related

Technological evolution – expressed through production and use of tools

Questions to complete

All Quickcheck

Biochallenge Page 617 (need internet access)

Chapter Review: 2, 3, 4, 5, 7, 8, 9