Chapter 35 Behavioral Ecology
Post on 24-Feb-2016
66 Views
Preview:
DESCRIPTION
Transcript
Chapter 35 Behavioral Ecology
Define behavior. Behavior encompasses a wide range of
activities. A behavior is an action carried out by muscles
or glands under the control of the nervous system in response to an environmental cue.
Collectively, behavior is the sum of an animal’s responses to internal and external environmental cues.
The questions investigated by behavioral ecologists fall into two broad categories.1. Proximate questions concern the immediate
reason for the behavior. How is it triggered by stimuli (environmental cues
that cause a response)? What physiological or anatomical mechanisms play a
role? What underlying genetic factors are at work? Proximate causes are the answers to such
questions about the immediate mechanism for behavior.
2. Ultimate questions address why a particular behavior occurs. Ultimate causes are the evolutionary explanations for behavior.
Explain what is unique about innate behavior.•Developmentally fixed, despite differences
in development•Under strong genetic influence
Define fixed action patterns and give an example.•Sequence of unlearned behavioral acts
that is essentially unchangeable and, once initiated, usually carried to completion
•Triggered by an external sensory stimulus (sign stimulus)
•Ex. Three-spined stickleback fish attacks other males that invade nesting territory
•Sign stimulus = red underside of intruder
Define imprinting.•Type of behavior that
includes both learning and innate components; generally irreversible
•Sensitive period •Ex. Young geese follow
mother
Explain how genes and environment contribute to behavior.
•Genes and environment interact (not nature VS. nurture, but nature AND nurture)
•Observe the “norm of reaction”▫Vary based on environment?▫Similar, despite environmental differences?
•Developmentally fixed behavior is innate
Distinguish between kinesis and taxis. •Kinesis – simple change in activity/turning
rate in response to a stimulus▫Sow bugs more active in dry, less active in
humid areas•Taxis – automatic, oriented movement
toward (positive) or away from (negative) some stimulus▫Trout swim into current
Explain optimal foraging theory. •Compromise between the benefits of
nutrition and the costs of obtaining food▫Energy expenditure▫Risks of being eaten by predator while
foraging•Natural selection should favor behavior
that minimizes costs and maximizes benefits.
Explain how predation risk may affect the foraging behavior of a prey species.
•A “successful” forager will avoid areas of high risk, even though food availability might be higher in high-risk areas.
Define inclusive fitness and reciprocal altruism. Discuss conditions that would favor the evolution of altruistic behavior. •Inclusive fitness – total effect an
individual has on proliferating its genes by producing its own offspring AND by providing aid that enables other close relatives, who share many of the same genes, to produce offspring.
•Ex. Sterile worker bees labor on behalf of fertile queen
•Ex. Naked mole rat.
Define the concept of kin selection.
•Natural selection that favors altruistic behavior by enhancing reproductive success of relatives▫Weakens with hereditary distance▫Quantifiable
top related