Evolution: Human Evolution
- Created by: meg_lou
- Created on: 18-04-17 12:40
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- Human Evolution
- Evidence
- On the origin of species (Darwin, 1859)
- Not the first to suggest species evolve but the first with evidence and method
- Three kinds of evidence
- Fossils change through geological layers e.g. hominid skull became more round
- Structural similarities between very different species e.g. between a human arm and a bat's wing
- Major changes have been created in plants and animals through selective breeding
- A drought on the Galapagos islands left large, tough seeds which increased the beak size in finches
- Natural selection
- Organisms with characteristics most adapted to the environment are more likely to survive
- Organisms poorly adapted to the environment are less likely to pass their genes to the next generation
- A species will eventually evolve
- A species will eventually evolve
- Organisms poorly adapted to the environment are less likely to pass their genes to the next generation
- Organisms with characteristics most adapted to the environment are more likely to survive
- On the origin of species (Darwin, 1859)
- Course
- Vertebrates
- Chordates have dorsal nerve cords and some developed spinal bones
- Amphibians
- Bony fishes left the water briefly for opportunities like new food sources
- Reptiles
- Amphibians laid shelled eggs on land and developed scales to prevent loss of moisture so could live out of water
- Mammals
- Develop mammary glands to nurture young
- Eventually no longer can lay eggs
- Humans
- Emerge from the order, primates and genus, homo
- First homo species was 2 million years ago
- Homo sapiens emerged 200,000 years ago
- Spandrels - incidental nonadaptive by-products e.g. human belly button
- Exaptations - evolved to do one thing but now do something else e.g. bird's wings now for flight rather than warmth
- Convergent evolution
- Evolution of similar solutions to the same environmental demands by unrelated species
- Vertebrates
- Human Brain
- No relationship between brain size and intelligence
- Correlated with body size
- Increased in size during evolution
- No relationship between brain size and intelligence
- Evidence
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