Four legs to two Australopithecines

Australopithecenes Earliest known pre-humans (4mya – 1mya fossil record)

Australopithecines Earliest known pre-humans (4mya – 1mya fossil record) All found in Africa – East African rift valley

Australopithecenes Earliest known pre-humans (4mya – 1mya fossil record) All found in Africa – East African rift valley This area is a system of fault lines where the movement of 2 tectonic plates (volcanic activity) favoured the burial and fossilisation of pre- humans and other animals.

Australopithecines Characteristics Bipedal Brains slightly larger than Chimps Canines reduced and non-protruding.

Australopithecines Characteristics Bipedal Brains slightly larger than Chimps Canines reduced and non-protruding. There is no evidence they made stone tools, but probably used wooden tools such as digging sticks. Darwin believed that bipedalism preceded brain expansion – freeing up the hands = intellectually demanding activities eg tool making.

Australopithecines Characteristics Bipedal Brains slightly larger than Chimps Canines reduced and non-protruding. There is no evidence they made stone tools, but probably used wooden tools such as digging sticks. According to teeth and skull – Australopithecines are either robust or gracile. Robust were specialised herbivores and a side-branch which died out. Darwin believed that bipedalism preceded brain expansion – freeing up the hands = intellectually demanding activities eg tool making.

Australopithecus africanus Found in 1924 in limestone cave in SA.

Australopithecus africanus Found in 1924 in limestone cave in SA. Face and jaws of a child (3-4 yrs), small brain, FM forward = bipedal.

Australopithecus africanus Found in 1924 in limestone cave in SA. Face and jaws of a child (3-4 yrs), small brain, FM forward = bipedal. Small canines, less-protruding jaw and no diastema.

Australopithecus africanus Found in 1924 in limestone cave in SA. Face and jaws of a child (3-4 yrs), small brain, FM forward = bipedal. Small canines, less-protruding jaw and no diastema. Est. to be 2.5mya as fossils not in ash.

Australopithecus afarensis Found in 1972 in Ethiopia. Valgus angle showed it to be fully bipedal.

Australopithecus afarensis Found in 1972 in Ethiopia. Valgus angle showed it to be fully bipedal. 40% complete skeleton “Lucy”

Australopithecus afarensis Found in 1972 in Ethiopia. Valgus angle showed it to be fully bipedal. 40% complete skeleton “Lucy” 1975 – first ‘family’ found. 13 mixed aged skeletons – dated 3mya.

Australopithecus afarensis features Sexually dimorphic (phenotypic difference) – males av. 1.5m and females 1m

Australopithecus afarensis features Sexually dimorphic (phenotypic difference) – males av. 1.5m and females 1m Very small brain, not much different from a chimp – 385 – 450cm3

Australopithecus afarensis features Sexually dimorphic (phenotypic difference) – males av. 1.5m and females 1m Very small brain, not much different from a chimp – 385 – 450cm3 Canines were larger than humans, and small diastema b/w upper incisors and canine.

Australopithecus afarensis features Sexually dimorphic (phenotypic difference) – males av. 1.5m and females 1m Very small brain, not much different from a chimp – 385 – 450cm3 Canines were larger than humans, and small diastema b/w upper incisors and canine. Finger bones were longer than in humans and slightly curved (like apes)

Lucy https://www.youtube.com/watch?v=awKl8eEvKtw

a. Robustus & A. boisei These strands were the ‘robust’ types of Australopithecine and died out.

a. Robustus & A. boisei These strands were the ‘robust’ types of Australopithecine and died out. Huge molars with low-working surfaces.

a. Robustus & A. boisei These strands were the ‘robust’ types of Australopithecine and died out. Huge molars with low-working surfaces. This suggests tough, vegetable diet.

a. Robustus & A. boisei These strands were the ‘robust’ types of Australopithecine and died out. Huge molars with low-working surfaces. This suggests tough, vegetable diet. Temporal muscles which raise the lower jaw – very powerful. Similar sagittal crest as in male gorillas.