hominin evolution
DESCRIPTION
Hominin Evolution. Definitions. Hominin – term that refers to humans and their extinct erect-walking ancestors. They belong to the tribe homini. Sometimes the word ‘hominid’ is used instead of hominin but this term refers to outdated classification so hominin is the preferred term. - PowerPoint PPT PresentationTRANSCRIPT
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Sometimes the word ‘hominid’ is used instead of hominin but this term refers instead of hominin but this term refers to outdated classification so hominin is to outdated classification so hominin is the preferred term.the preferred term.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