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Physiological Adaptation

Physiological Adaptation. Life in the Lab. Physical Variables. Temperature Drosophila The knock-down time increased fourfold after 18 generations Also saw increases in flight time There was a shift in the niche E. coli

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Physiological Adaptation

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  1. Physiological Adaptation Life in the Lab

  2. Physical Variables • Temperature • Drosophila • The knock-down time increased fourfold after 18 generations • Also saw increases in flight time • There was a shift in the niche • E. coli • It is possible to adapt E.coli to specific temperatures and have them out compete their ancestor • At almost all temperatures, specializing in one temperature did not narrow the range of temperatures at which the bacteria could live

  3. Physical Variables • Osmotic Stress • Marine fish • Originally hypo-osmotic relative to environment and have chloride cells in their gills that excrete Na+ and Cl- • Guppies (a fresh water fish) have been evolved in high saline environments • Show an increase in the number of chloride cells

  4. Physical Variables • Water • Used to define where life can exist • Drosophila • Can be rapidly adapted to survive in dry environments • Surviving lines tend to have increased body mass, carbohydrate levels and water contents • Females are more resistant than males

  5. Resource Variable • Food – Starvation Stress • Drosophila • When selection took place with adults they increased resistance after about 20 generations • When selection took place with larva there it took longer to obtain the same resistance • Adaptations included increased fat storage and lowered metabolism • Flies will die of desiccation before they die of starvation

  6. Resource Variables • Food • E. Coli • When grown in low nutrient media they evolved to deal with the starvation mode • Some evidence shows they developed into cannibals eating their competitors • Some have evolved the ability to come out of the dormant mode quicker beating those that are slower to the food

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