{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}



Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
NOT ON PREVIOUS MIDTERMS: BIO FINAL ******BEHAVIORAL Evolution (lecture not on midterm 1): What an animal does and how it does it. Muscualr and nonmuscluar activity Proximate question- how questions about behavior -focus on environmental stimuli that trigger behavior -focus on genetic, physiological, and anatomical mechanisms underlying a behavioral act Ultimate Questions- the why questions about behavior -address the evolutionary significance of a behavior Ex: schooling in fish- how? Proximate: Sense movement of other fish by sight an d lateral line Why?-minimize predation, reduce friction. Ultimate Ethology- study of behavior, especially under natural conditions. Discipline developed mid 1900s Fixed action patterns- sequence of unlearned behaviors that are largely unchangeable -usually carried to completion once initiated -triggered by external stimuli ex) yawning, male stickleback fish, red underside of intruder stimulates attack. Imprinting: - Includes learning and innate components -generally irreversible -develops only during critical period* adaptive significance of various behaviors: - inflexible behavior adaptive when mistakes would be costly -innate behavior advantageous when learning opportunites are limited Learning- favored when individuals can make mistakes without demise & when parental care is extensive and life is long -most behaviors influenced by both genes and environments Ex. Rats good at learning navigation, domestic dog breeds have exaptations for different types of learning Directed movements have strong genetic components: 1. Kinesis: random turning or movement in response to stimulus 2. Taxis: oriented movement toward or away from stimulus 3. Migration- long distance movement of a population associated with a change of season Animal communication may also be under genetic control: 1. Chemical- ex. Insect response to pheromones often hard wired 2. Auditory- e x. Lacewing courtship songs under genetic control 3. Visual- ex-honeybee dance under genetic control Not all communication genetically determined Evolution of Social Behavior: I. Sexual Selection. Selection for mating success, may oppose natural selection - asymmetries in sexual reproduction: females typically have larger parental investment (sperm is cheap) - female reproductive success low and stable-limited by number of
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
pregnancies she can carry - male reproductive success highly variable-limited by number of successful matings When parental investment roles are reversed, other traits revers Phalaropes: parental care by males, females more ornamented, males choosy, polyandrous breeding system-female mates w/ multiple males Sex role reveral in seahorse & pipefish- males carry young in pouch and provide care - Pipefish: females larger, more brightly colored, more competitive., males choosy & prefer larger females. Even sperm is competitive -choosy females may get better genes and care for offspring Sexual selection in plants- some species sexually dimorphic II. Kin selection and Social interaction: - ex. Alarm calling in belding’s ground squirrels-most done by females, females
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}