The Incredible Journey. Recap – Natural Selection There is variation between individuals in a...
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Transcript of The Incredible Journey. Recap – Natural Selection There is variation between individuals in a...
Human EvolutionThe Incredible Journey
Recap – Natural SelectionThere is variation between individuals in a populationParents pass on their traits to their offspringThe organisms with features that best suit their
environment have the best chance of survival and reproduction
Those organisms that are able to survive and reproduce pass on their characteristics to their offspring
Over time the population will become better suited to its environment
Let’s give it a try...
Natural SelectionHuman Adaptations that have been selected
for;Bipedalism (position of the ‘foramen magnum’)Reduction in size of molar teethReduction in jaw size Increased cranial capacity Cranial ridge
Comparison of skulls
CHIMPANZEE GORILLA HUMAN SKULL
• What features can you identify?• What makes the skulls different from one another?
Comparison of skullsTop of the skull (cranium) is smooth
There is no anterior-posterior crest to hold huge jaw muscles
No protruding browNo protruding jaw or teeth (ie the
teeth are vertical)No protruding nose boneTeeth are arranged in a parabolic
shape rather than a narrow u shapeSmall canines and small incisors Foramen magnum (hole for the
spine) is positioned directly underneath the skull not in the back of the skull
Australopithecus aferensisLocation: Eastern AfricaCranial capacity : 375-425 ccFossils discovered so far in
Tanzania, Kenya and EthiopiaTimeframe: 4.7 – 2.1 million
yearsFully bipedal (first!), but
arms longer than legsPossibly made tools out of
bone teeth and horn (Osteodontokeratic)
Australopithecus africanusLocation: Southern &
Eastern AfricaCranial capacity: 420-500
ccTimeframe: 3-2 million
yearsSlightly greater body sizeSmaller canine teeth than
A. aferensis Teeth structured in a more
parabolic (‘V’) shape
Australopithecus boisei (Oldoway)Location: Eastern AfricaCranial capacity: 500-550 ccTimeframe: 2.5 - 1 million yearsLargest teeth found in any
hominid groupHuge jaw, small incisors &
canines, large molars & premolars, parabolic dental structure and sagittal crest present – (hard low quality food)
Face is more vertically set
Homo rudolphonsis Earliest species of Homo (or
maybe Homo habilis?)Cranial capacity: 775ccContention as to whether the
fossils are Australopithicus or Homo
Lack of crests Smoothly rounded occipital
bone compared to Homo erectus
Homo habilis “handy man”Location: Eastern AfricaCranial capacity: 800 cc2.5-1.5 million yearsShort molars, small canines,
parabolic dental arcadeFull biped, increased leg
length, decreased arm length, shorter in stature
Fossils accompanied by primitive stone tools
Homo erectusLocation: Africa, Asia, EuropeCranial capacity: 900-1225 ccUseing Acheulian tools: hand
axe culture, large game hunting, suggestion of communication, first to use fire
Some scientists have split H. erectus into three separate species, based on the geographic region in which specimens have been found: H. ergaster (Africa), H. erectus (Asia), and H. heidelbergensis (Europe).
Homo sapienLocation: Africa, Asian,
Europe, Australia, North America
A high, rounded craniumCranial capacity: 1400-1600
ccArt & Symbolism, first to
produce fire and use languageA steep foreheadA tall and narrow nasal
opening A parabolic palate