Bio 104 6/4/96

Evaluations were done at the beginning of class. Finish Chapter 21 - Community Interactions

1. plant defenses against predation-
   • physical armor: spines, etc
   • produce secondary chemical compounds
     • distasteful or poisonous chemicals discharged
     • plants allow fruits to be eaten, for plant survival and it helps in dispersal of seeds
     • Secondary Chemical compounds
       • mustard oil
       • alkaloids and steroids, both of which are toxins
         1. cardiac glycosides
         2. poison ivy, or oak, or sumac
            • urushiol is the toxin
         3. Ricin (protein) found in the castor bean, and very poisonous
2. Ways animals protect against predation;
   • warning coloration and warning noise:
     • organisms is brightly colored and advertises that it has unpleasant qualities
   • those that survive blend in with the environment
     • cryptic coloration
   • Mimicry
     • Batesian mimicry: a harmless species (mimic) comes to resemble a harmful species (model)
     • Muellerian mimicry: both the model and the mimic are harmful

   Dr. Barstow showed examples of these animal characteristics.

3. Symbiosis: 2 or more organisms living together
   1. commensalism: One benefits, the other is neither harmed nor helped
   2. mutualism: Both benefit
   3. parasitism: One species benefits-one is harmed -sub-lethal symbiosis, the parasite doesn't want to kill the host because then it would die also.

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