bio 111 final

behavior

the nervous system's response to a stimulus and is carried out by the muscular or the hormonal system

behavior is subject to ______ ______

natural selection

how -

proximate

why -

ultimate

proximate questions -

p - what environmental cue triggers breeding behavior (ex. singing and nest building?)

ultimate questions -

u - why breed in the spring? increase fitness (reproductive output)?

sensory inputs: migration

long-distance change in location

sensory inputs: fixed action patterns

tinbergen: stickleback fish (the aggressive response of the fish)

sign stimulus

external cue that triggers behavior (red belly)

migration transition

- sun
- adjust relationship in accordance with circadian clock
- use magnetic cues

how do magnetic cues work?

- magnetic structures in brains
- effects on light and photoreceptors

circannual rhythms

linked to yearly cycles of seasons (migration, reproduction)

fiddler crabs (behavioral rhythms)

- tidal rhythms
- lunar cycles

signal

specific stimulus adapted for communications

signals can be

visual, chemical, auditory, tactile, or other modality (fly courtship)

forms of animal communication

- bee dance language
- waggle dance
- karl von frisch
(used to indicate quality of food)

pheromones - chemical communication

reproduction, alarm, social cues

habituation

loss of response to signals that convey no information

Learning establishes specific links between

experience and behavior

innate behavior

instinct

imprinting

sensitive periods during development when experience influences behavior

after imprinting?

- behaviors become "fixed"
- triggers behavioral response

spatial learning

uses cues, or landmarks, to determine location in environment (ex. digger wasps)

cognitive maps

use internal neural representation of space (clark's nutcracker seed caches)

classical conditioning

arbitrary stimulus becomes associated with meaningful stimulus

Ivan Pavlov's study

dogs salivate in response to bell when paired with food

operant conditioning

behavioral response paired with reward or punishment

cognition

represented by awareness, reasoning, recollection, and judgement

ex of cognition

-honeybees recognize cues in maze
- chimpanzees can stack boxes in order to reach suspended food
- ravens can figure out how to collect food on a string

example of how development of some behaviors occur in distinct stages

- a white-crowned sparrow memorizes the song of its species during an early sensitive period
- the bird then learns to sing the song during a second learning phase

social learning

learning through the observation of others and forms the roots of culture

selection of what can explain most behaviors?

individual survival and reproductive success

optimal foraging model

cost-benefit analysis of obtaining food. maximize profits (food-energy gained) - minimize costs (energy used)

risk of predation affects ______________

foraging behavior

mating behavior includes

seeking or attracting mates, choosing among potential mates, competing for mates, and caring for offspring

promiscuous

no strong pair bonds between breeding partners

monogamous

mates remain together throughout breeding period, common in birds where both parents provide care

polygamous

individuals mate with more than one partner

polygyny

one male with multiple females (lions, lakes)

polyandry

one female with multiple males

need for parental care varies dramatically

- birds, mammals; extensive parental care
- more extensive care requires both parents
- certainty of paternity influences likelihood of paternal care
- needs of the young are an important factor constraining evolution of mating systems

sexual dimorphism

results from sexual selection, a form of natural selection

intersexual selection

members of one sex choose mates on the basis of certain traits

intrasexual selection

involves competition between members of the same sex for mates

mating behavior examples

- songs in frogs, birds
- appearance of displays

mate-choice copying

females observe mating choices of neighbors

agonistic behavior

- "fights" or displays between males to compete for access to mates
- multiple strategies may exist in populations

selfish behavior

is the norm (ex. competition, territoriality, agonistic behaviors)

altruism

behavior that seems to benefit another one at one/s own risk

why be altruistic?

passing on of one's genes to the next generation is most important - which includes genes in close relatives as well as own offspring

inclusive fitness

total amount of genes passed on through all relatives

hamilton's rule

if rB>C, then natural selection favors altruism

B in Hamilton's rule

benefit to recipient (avg. # of offspring)

C in Hamilton's rule

cost to altruist (avg. # of offspring)

r in Hamilton's rule

coefficient of relatedness - probability of shared genes between two individuals

kin selection

selection for behavior that raises a relative's reproductive success over your own. (your life is worth 2 siblings, 4 nieces/nephews, 4 grandchildren, or 8 cousins)

How to explain altruistic acts between non-related individuals?

- high-probability of the favor returned in the future
- limited to animals with strong social groups, often hunt together

sociobiology - E.O. Wilson

applied principles of animal behavior to human behavior

Edward O. Wilson cont.

- Evolution has shaped human behaviors
- behaviors have heritable components
- are we just behavioral products of our genes?

ecology

how organisms interact with each other and their surrounding environment

population

group of individuals of the same species that live in the same area at the same time

population ecology

often focuses on factors affecting changes in population density in space and time

density

# of individuals per unit area or volume (ex. # of worms/m2)

density can be _____ to measure

difficult

methods

ex. sub-sampling, aerial surveys, fecal surveys, midden piles, mark-recapture

pattern of spacing or organisms in a population

3 types
- clumped
- random
- uniform

examples of clumped dispersion

- buffalo
- swans
- fish
- lupine

life history

the pattern of growth and reproduction over the life time of an organism

life history is the result of what

trade-offs among reproduction (present and future), survivorship, competition, predator avoidance, growth, and maintenance

life history was formed by what

natural selection

semelparity

reproduce once during lifetime. organism invests all their energy in growth, development, and storage - and then expend all their energy in one, often suicidal reproductive event. big-bang reproduction (ex. bamboo, yucca plants, most insects, annual plants, agaves)

iteroparity

organism produces fewer young at one time and repeat reproductive events throughout lifetime (most vertebrates, many birds, trees, perennial plants)

low survival rate of offspring favors which reproductive strategies?

semelparity

high survival rate of offspring favors which reproductive strategies?

iteroparity

unpredictable environment favors which reproductive strategy?

semelparity

predictable environment favors which reproductive strategy?

iteroparity

ephemeral habitats often have many __________ organisms

semelparous

semelparous organisms

have a lifespan of one year (ex. overwintering as eggs)

tradeoffs of reproduction

- energy used in reproduction cannot be used for survival
- natural selection will favor maximum fitness

four factors that affect population size

birth rate, death rate, immigration rate, emigration

birth rate

the rate at which individuals produce offspring

death rate

the rate at which individuals die

immigration rate

the rate at which individuals move into the population

emigration

the rate at which individuals move out of the population

population growth +

birth rate - death rate

r

the per-capita rate of increase

if r is positive

(birth>death) then the population is increasing

if r is negative

(birth

r max

biotic potential

exponential growth equation

dN/dt = rN

carrying capacity (k)

the maximum size of the population that can be supported by the environment

logistic growth

rN (K-N)/K

N

the number of individuals

dN

the change in number of individuals in the population

dt

change in time

K

carrying capacity

what regulates population growth?

density dependent factors
- biotic factors (competition, predation)

factors that limit population size

competition for resources, disease and parasitism, predation, toxic wastes, social behavior

competition for resources

food, water, nesting sites, oxygen, nutrients, light, territory

disease and parasitism

stress-related degradation of health, infectious disease, parasitism