BIO120H1 Chapter Notes - Chapter 3-4: Arrector Pili Muscle, Glyptodont, Beringia
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BIO120H1 Full Course Notes
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Document Summary
Vestigial traits: feature of species that was once and adaptation, but has lost usefulness completely, or opted for new uses. Descends from flying ancestors, but wings don"t help it fly. Instead they help it maintain balance, mate, and threaten enemies. Most birds that evolved flightnessness did so on islands, where there is lack on mammals and reptiles that prey on birds. Flight is metabolically expensive, can be diverted to reproduction. Wings easily injured, reduce injury by reducing them. E. g mediterranean blind mole rat retains vestige of an eye. Eye has protective layer of skin, can"t form images. It contains photo pigments that is sensitive to low levels of light, help"s regulate rhythm of activity. Not connected to rest of body, only embedded in tissue. Was in herbivorous animals, was much larger, helped to break down cellulose into sugar. Serves no real purpose today, may have tissue that helps immune system, and may contain useful gut bacteria.
