The Incredible Journey Human Evolution The Incredible Journey

Recap – Natural Selection There is variation between individuals in a population Parents pass on their traits to their offspring The 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 Selection Human Adaptations that have been selected for; Bipedalism (position of the ‘foramen magnum’) Reduction in size of molar teeth Reduction 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 skulls Top of the skull (cranium) is smooth There is no anterior-posterior crest to hold huge jaw muscles  No protruding brow No protruding jaw or teeth (ie the teeth are vertical) No protruding nose bone Teeth are arranged in a parabolic shape rather than a narrow u shape Small canines and small incisors  Foramen magnum (hole for the spine) is positioned directly underneath the skull not in the back of the skull

Australopithecus aferensis Location: Eastern Africa Cranial capacity : 375-425 cc Fossils discovered so far in Tanzania, Kenya and Ethiopia Timeframe: 4.7 – 2.1 million years Fully bipedal (first!), but arms longer than legs Possibly made tools out of bone teeth and horn (Osteodontokeratic)

Australopithecus africanus Location: Southern & Eastern Africa Cranial capacity: 420-500 cc Timeframe: 3-2 million years Slightly greater body size Smaller canine teeth than A. aferensis Teeth structured in a more parabolic (‘V’) shape

Australopithecus boisei (Oldoway) Location: Eastern Africa Cranial capacity: 500-550 cc Timeframe: 2.5 - 1 million years Largest teeth found in any hominid group Huge 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: 775cc Contention 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 Africa Cranial capacity: 800 cc 2.5-1.5 million years Short molars, small canines, parabolic dental arcade Full biped, increased leg length, decreased arm length, shorter in stature Fossils accompanied by primitive stone tools

Homo erectus Location: Africa, Asia, Europe Cranial capacity: 900-1225 cc Useing 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 sapien Location: Africa, Asian, Europe, Australia, North America A high, rounded cranium Cranial capacity: 1400-1600 cc Art & Symbolism, first to produce fire and use language A steep forehead A tall and narrow nasal opening A parabolic palate