BIO 105 Lecture Notes - Lecture 6: Speciation, Australopithecus, Phylogenetic Tree
11 Apr 2017
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Document Summary
Fossils and dna tell the human evolution story. Similarities in bone structure reveal evolutionary relatedness between humans and other apes. Fossil hominins in the human family tree have fallen into four groups. Ancestors evolved to walk upright before our brains got bigger. As they started walking upright, their brains got bigger. The environment selected for them to walk upright, the environment selected for a bigger brain (cultural environment + physical environment) Brain uses 25% of the calories you take in. Natural selection probably halted the size of the brain because they couldn"t get enough calories. Homo erectus was the first to utilize fire ----- more calories available. For our body size, we have much smaller molars - around the time we started cooking food and our brains started growing. Homo erectus is when our brain size really exploded - it was because of the use in fire for cooking. What to study for test on thursday:
