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Evolution Lec 13 15Feb02 http://life.uiuc.edu/animalbiology/105/ ID: eee105 Password: prAIRie The ecological theater The evolutionary drama Evolution by Natural Selection is not random Selection is non-random How are complex structures “designed” by natural selection? Eyes have evolved in many animals In single celled animals light meters direction detectors In multicellular animals Eyes have evolved in many animals a shadow detector a pinhole camera Octopus eye is a camera eye Vertebrate eye Octopus eye Convergent Evolution Vertebrate eye a “backwards” retina Octopus eye a direct eye How did eyes evolve? A better question is how do genes control the construction of an eye? A better question is how do genes control the construction of an eye? If a characteristic is genetically controlled it has evolved Nature red in tooth and claw? not necessarily Nature red in tooth and claw? not necessarily often cooperation e.g. mutualism Mutualism mycorrhizal fungi Mycorrhizal fungi share nutrients with tree roots Nature red in tooth and claw? not necessarily often cooperation e.g. mutualism Cleaning symbioses Cleaning symbioses Symbiosis = living together Nature red in tooth and claw? not necessarily often cooperation e.g. pollination Wind-pollinated plants have inconspicuous flowers Pollination An example of coevolution Bees see ultraviolet light nectar guides Honeybees learn Honeybees learn and communicate flower location to fellow workers
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