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Chapter 19 - Human Ancestors Cheat Sheet (DRAFT) by

Unit 4 Human Biology ATAR

This is a draft cheat sheet. It is a work in progress and is not finished yet.

What is the chapter about?

How evidence from fossil discovery shows the physical appearance and evolut­ionary pathways of hominins.

How the enviro­nment has affected hominin evolution

- Using geological and chem info and info abt the fossil can tell us more abt the enviro­nment at the time
- Early hominins were ape-like. Their hands and arms showed features suited to being arboreal - similar to modern orangutans
- Many believe bipedalism originated in an arboreal ape-like hominin in a forest enviro­nment bc orangutans move over small springy branches bipedally, using their arms for balance. This upright locomotion may have been used where there we gaps in the forest canopy and early hominins needed to travel across open ground
- 5-6 mil yrs ago, enviro­nment changed. Became colder and forest areas became smaller.
- As forest areas became smaller, they were separated by large grassl­ands. Natural selection favoured those were bipedal, as those that were more arboreal cldnt swing from trees

Advantages of bipedal locomotion (erect stance)?

- increased