AP Biology : 8.5 Community Ecology- Study Notes

A. Behavior
➢ Instinct

  •  Inborn, unlearned behavior
  •  Sometimes triggered by environmental signals called releasers
  •  Some only last part of an animal’s life and are gradually replaced by a learned behavior
  •  Fixed action pattern
          ■ Not simple reflexes, but not conscious decisions

➢ Learning

  •  Change in a behavior brought about by experience
  •  Imprinting
         ■ Recognize mother and follow her
                  ● If mother is absent, newborns will accept the first moving object as their mother
         ■ Used to recognize members of same species
         ■ Occurs during critical period–window of time when the animal is sensitive to certain aspects of the environment
  •  Classical Conditioning
        ■ Aka associative learning
        ■ Associates a stimulus with a reward/punishment and acts accordingly
  •  Operant Conditioning
       ■ Aka trial-and-error learning
       ■ Animal learns to perform an act in order to receive a reward
       ■ Of behavior is not reinforced, conditioned response will be lost (extinction)
  • Habituation
      ■ Animal learns not to respond to a stimulus
      ■ If an animal encounters a stimulus over and over, the response will gradually lessen and may disappear

➢ Circadian rhythm=daily internal clock

B. How Animals Communicate
➢ Use chemical/visual/electrical/tactile fro communication, esp. To influence mating and social behavior
➢ Social Behavior

  •  Agonistic
          ■ Aggressive behavior as a result of competition for resources
  •  Dominance hierarchies
         ■ Often The most dominant male will become the leader of the group and will usually have best picking of food and females in the group
         ■ Once the hierarchy is established, competition and tension within the group is reduced
  •  Territoriality
          ■ Common behavior when food/nesting sites in short supply
  •  Altruistic Behavior
  •  Unselfish behavior that benefits another organism in the group at the individual’s expense

➢ Symbiotic Relationships

  •  Mutualism
          ■ Both organisms benefit
  •  Commensalism
         ■ One benefits, other is unaffected
  • Parasitism
        ■ One benefits, the other is harmed

➢ Plant Behavior

  • Photoperiodism
        ■ Plants flower in response to changes in the amount of daylight/darkness they recieve
  •  Tropism
       ■ Turning in response to a stimulus
       ■ Phototropism
                  ● Bend towards light
    ■ Gravitropism
                 ● Stems: negative gravitropism (grow away from gravity)
                ● Roots: positive gravitropism (grow into earth)
    ■ Thigmotropism
              ● How plants respond to touch
             ● Ex. ivy grows around a post
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