Ani nimal Beh Behavior Why Study Behavior ior? Evolutionary - - PDF document

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Ani nimal Beh Behavior

Wh What t is s Be Behavior?

Behavio ior

• everything an animal does & how it does it
• response to stimuli in its environment

Why Study Behavior ior? Evolutionary perspective…

• part of phenotype
• acted upon by natural selection
• lead to greater fitness?
• lead to greater survival?
• lead to greater reproductive success?

Under erstan anding Beha havior

Causes of Beh Behavior Proximate cause: “how” a behavior occurs or is modified based on its imme mmediate interactions with the environment Ulti ltimate cause: “why” a behavior occurs in context of natural selection

• how does behavior

contribute to survival and reproduction

Male songbird what triggers singing? how does he sing? why does he sing? Courtship behaviors in cranes how does day length influence breeding? why do cranes breed in spring? BEHAVIOR: A male stickleback fish attacks other male sticklebacks that invade its nesting territory. PROXIMATE CAUSE: The red belly of the intruding male acts as a sign stimulus that releases aggression in a male stickleback. ULTIMATE CAUSE: By chasing away other male sticklebacks, a male decreases the chance that eggs laid in his nesting territory will be fertilized by another male.

Types es of Beha havior

Is it na nature e or nu nurture? e?

• Inna

nnate behavior:

behavior performed correctly and in the same way by all individuals of a species, without previous experience (genetic cause)

• “built in”, not learned,
• Fixed Acti

tion Pattern (FAP):

innate behavior that occurs as an unchangeable sequence of actions

• triggered by sign stimulus
• conducted to completion once

started

• ensures that activities essential to

survival are performed correctly and without practice

The graylag goose responds to an egg

• utside her nest with a set of specific
• actions. Even when the egg is removed, the

goose will continue to push at the air with her beak until she completes the FAP

Types es of Beha havior

Inna nnate Behavior

• r

Fixed ed Action ion Patter ern

Sign Stimuli- Attack on red belly stimulus Court on swollen belly stimulus

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Types es of Beha havior

Inna nnate: Di Direct cted mo movements ts Taxis

• change in direction
• automatic movement toward

(positive taxis) or away from (negative taxis) a stimulus

• phototaxis
• chemotaxis

Kinesis

• change in rate of movement in

response to a stimulus

Positive rheotaxis keeps trout facing into the current, the direction from which most food comes. s. Kinesis increases the chance that a sow bugs will encounter and stay in a moist environment.

Types es of Beha havior

Inna nnate: : Migratio tion

• Regular, long-distance change in location
• Environmental cues: sun, stars, earth’s magnetic field,

landmarks monarchs

Circad cadia ian n rhyth thm:

• Internal biological clock
• follows an approximately 24-

hour natural cycle

The Suprachiasmatic nuclei (SCN) region is located in the hypothalamus of the

• brain. The SCN sends signals throughout

the body in response to dark and light.

The circadian clock in the hamster brain signals a change in coat color according to season by releasing the hormone melatonin.

Plants can have two internal clocks:

• ne sensitive to light and the other

sensitive to temperature

Sign gnal: stimulus that causes a change in behavior; basis of animal communication Pheromones – chemicals emitted by members of one species that affect other members of the species (eg. Queen bee, fruit fly, fish, termites, trees, humans)

• Visual

l signals ls – Warning flash of white of a mockingbird's wing

• Tacti

tile (touch) – Male fruit fly taps female fly

• Auditory signals

ls – screech of blue jay or song of warbler

Hone neybe bee e dance nce lang nguag age

• bee returning from the

field performs a dance to communicate information about the distance and direction of a food source

Minnows after alarm Minnows before alarm

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Types es of Beha havior

Lear arned ned behavio iors rs

• modified by experience
• variable, changeable
• flexible with a complex &

changing environment Inte nteracti tion of Gen Genes and nd Ex Experience How does inheritance and experience form a particular behavior? Biologists mated two different species to form a hybrid species Conclu lusion: hybrid offspring could alter inherited behavior based on experience.

Types s of Lear earning ng

Lear arning ing: a change in an animal's behavior resulting from specific experiences Types pes of learn rning ing:

• 1. Habitu

tuation: type of learning in which an animal stops responding to a repeated stimulus that conveys little or no important information ex: ticking of a clock

• 2. Imp

mprinting: learning that is limited to a specific time period in an animal's life and that is usually irreversible learning + innate components criti tica cal learning period : time period in which imprinting takes place

Lorenz enz: : Gre reylag ag goose e expe experi rimen ent

Cont ntrol: : mother rears young in nest Expe perimental: Lorenz rears young in incubator Result: Cont ntrol group: normal imprinting, followed mother, had normal goose relationships Ex Expe perimental group: imprinted on Lorenz, followed him, preferred human relationships to geese

BEHAVIOR: Young geese follow and imprint on their mother. PROXIMATE CAUSE: During an early, critical developmental stage, the young geese observe their mother moving away from them and calling. ULTIMATE CAUSE: On average, geese that follow and imprint on their mother receive more care and learn necessary skills, and thus have a greater chance of surviving than those that do not follow their mother.

Types pes of Learn rning ing

3.

• 3. Spati

tial l Learning

• Cogn

gniti tive Map Map: internal representation of spatial relationship among objects in an animal’s surroundings Birds use spatial maps to relocate nut caches

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Some organisms move in response to a recognized object or environmental cue, a land ndmark.

t No nest Nest

• 4. Associ

ciative learning: g: learning to associate a stimulus with a consequence

• Classical conditioning
• learning that a particular stimulus
• r a particular response is linked

to a reward or punishment

• rat will push a level if it receives

food for pushing the level

• predator avoids specific prey

associated with a painful experience

• Operant conditioning
• trial & error learning
• associate behavior with reward
• r punishment

ex: learning what to eat Pavlov’s dogs Insight: the ability to respond appropriately to a new situation without previous experience

• 5. Cogniti

nition: n: process of knowing that involves awareness, reasoning, recollection, judgment

• Problem-solving behavior relies on cognition
• 6. Social

ial learn rning ing: learning by observing others Monkeys learn correct use of alarm calls Select ection ion for ind ndivid idual al survival al and nd re reprod product ctive succes ccess can n expl explain in most t behaviors iors

Foraging: g: food-obtaining behavior

• Recognize, search for, capturing, and consuming food
• Minimize costs / Maximize benefits
• Costs- energy expenditure

and the risk of being eaten

• Crow will drop a whelk (a mollusc) from a height to break its shell
• Trade-off between the height and the number of times it must drop
• Researchers determined total flight height (energy) was

minimized at 5 m  Average crow flight height: 5.23 m

Matin ting Behavio ior r & Mate te Choic ice

Sexual selecti ction: seeking and attracting mates, choosing and competing for mates

pat ater ernal al care e by male e jaw awfish

Monogamous species Polygynous species Polyandrous species

Promiscuous Monogamous Polygamous (polygynous) Polyandry

Partners Many One 1 M + many F 1F + many M Structure Showy Similar Showy male Showy female Care None Much Male = little Male = none

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Sexual seleti tion: ornaments correlate in general with health and vitality Courtship ritual: elaborate behavior of individuals of the same species before mating

Mate e Choice ice

Mal Males Agonisti tic behavior: threats, rituals, and sometimes combat; settles disputes over resources Fema males Mat Mate Choice Copying: g: copy the mate choice of others

Soci cial l Be Behaviors

Competi titive Beh Behaviors (pack animals)

• Aggressive behavio

ior: symbolic threat display or a physical struggle between individuals of the same species

• Domin

minance hierarchy : ranking of individuals in a group based on aggressive behavior

• Territ

itorial behavior: behavior that protects territorial rights ex: chatting squirrels marking areas with urine

Geneti netic c Basis is of Behavio ior

• Certain behaviors in prairie voles are under

relatively strong genetic control

• ADH (vasopressin) triggers pair-bond formation and

aggression by male voles

Differences s in oxyto tocin (a hormone) receptors s in 2 species of voles High oxytocin levels in prairie voles (monogomous) Low oxytocin levels in montane voles (promiscuous)

Altru ruistic tic Social ial Behavior

• r

Altr truism : selfless behavior Reduce individual fitness but increase fitness of others in population i.e. bee societies; naked mole rats

• Inclu

nclusive fitness: total effect of producing own offspring (pass on genes) + helping close relatives

• Kin selecti

ction: type of natural selection; altruistic behavior enhances reproductive success of relatives

Altru ruism can n be expl explain ined ed by by inc nclusive e fitnes ness

Ha Hamil ilton’s Rule and nd Kin n Select ctio ion: quantitative measure for predicting when natural selection would favor altruistic acts among related individuals Benefit to the recipient (B) Cost to the altruistic (C) Coefficient of relatedness: fraction of genes shared; r Ha Hamil ilton’s rule: : rB > C

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Example: : Assume the average individual has two children. As a result of the sister’s action:

• The brother can now father two children, so

B  2

• The sister has a 25% chance of dying and not being

able to have two children, so C  0.25  2  0.5

• The brother and sister share half their genes on

average, so r  0.5 If the sister saves her brother rB rB ( 1)  C ( 0.5)

Game e Theor

• ry (tit

t for tat stra rateg egy)

• Individuals always cooperate on first encounter
• An individual treats another the same way it was

treated the last time they met

• individuals will always cooperate, unless their
• pponent cheated them the last time they met
• reciprocal altruism

Ind ndivi ividuals who eng ngage e in n a tit-for

• r-tat

tat stra rateg egy hav ave e a higher er fitnes ness than n ind ndivid ividual als who are re always selfish ish

Evolu lution an and d Human n Culture

• No other species comes close to matching the social learning

and cultural transmission that occur among humans

• Human culture is related to evolutionary theory in the distinct

discipline of sociobiolo logy gy

• Human behavior, like that of other species, results from

interaction between genes and environment

• However, our social and cultural institutions may provide the
• nly feature in which there is no continuum between humans

and other animals

Stu tudy for th the e test est!