quiz 3

communication

transfer of information from one individual (signaler) to another (receiver). afects current o future behavior and the fitness. evolution increases effectiveness of signals.

honest signaling

true communication, most stable form of communication

deceitful signaling

receiver manipulated into responding, sender uses specially evolved signal

eavesdropping

receiver utilizes a cue from a signaler, unintentional transfer of information

preexisting trait hypothesis

trait in sender that already provides information to receiver, modified into signal through ritualization

preexisting bias hypothesis

bias in sensory system of receivers that detects some signals more easily

signalers exploit bias (sensory trap)

male water mites mimic vibrations of prey when approaching a female

novel signals

preexisting bias hypothesis predicts animals will respond to stimulus that they’ve never encountered

which came first - trait or bias?

may respond to existing bias or because ancestor had trait

reliable signals

signals honest if they convey useful or correct information

3 ways to maintain honesty

sender and receiver both benefit, signals cannot be faked (index), signal is costly to fake (handicap)

indices

signal intensity related to quality, intensity of signal used to asses signalers quality, should vary gradually with quality

handicaps

all individuals capable of producing signal, but costs > benefits for low quality individuals, once benefits > costs expect individuals to produce trait

badges of status

some signals have social, not production cost, often indicate individuals dominance status in social groups, can reduce fighting

multimodal signaling

signal tradeoffs additional way to enforce honestly of signals

multiple message hypothesis

different signals convey different information

redundant signal hypothesis

different signals convey same information, protects against signaling errors or environmental noise

deceitful signaling

signaler benefits, but receiver pays cost, often involve manipulation of signal

maladaptive response to deceitful signals

novel environment hypothesis, net benefit hypothesis

novel environment hypothesis

new environmental conditions compared to original conditions in which signal evolved

net benefit hypothesis

on average, response to signal results in fitness gain

eavesdropping

illegitimate receiver exploits signal, reduces fitness of signaler

preventing eavesdropping

signals can be adapted to reduce likelihood of being intercepted by illegitimate receiver

convergent evolution in signals

multiple species of unrelated songbirds have similar alarm calls that are outside range of bird-eating hawks

mating types, biological sex, gender

huge diversity of reproductive strategies in different types of organisms

darwins theory of sexual selection

elaborate traits that lower survival evolved due to advantage provided in context of reproduction

sexual selection

form of natural selection that acts on traits used in reproduction

intrasexual selection

traits within a sex, increase competitive ability

intersexual selection

traits that increase likelihood of being chosen by opposite sex, between sexes

fundamental asymmetry of sex

fusion of gametes of dissimilar size,

female reproduction

typically limited by fecundity, ability to produce and provision offspring

male reproduction

typically limited by access to mates

batemans principle

reproductive success in males increases with # of females he mates with, # of mates has no effect on reproductive success in females, reproductive skew for males

cascading consequences of anisogamy

differences in initial investment affects other aspects of reproduction

sex role reversal

pattern of which sex competes/chooses based off differences in investment

mutual mate choice

each sex will be selective when both sexes invest heavily, strong sexual selection in both sexes, each sex competes to obtain mate of highest quality

sexual dimorphism

traits that differ between the sexes, size difference, weapons

conditional mating tactics

often has reduced reproductive success, may be temporary or permanent, fitness between tactics not equal

alternative mating strategies

strategies have genetic basis and inflexible during life

tactic

when there is no genetic basis to it and it is a conditional behavior

strategy

when it is fixed and has a genetic component

sperm competition

morphological adaptations to remove sperm from previous male

mate guarding

both males and females often mate with multiple individuals , last sperm received usually used to fertilize egg

female choice

intra and intersexual selection often intertwined, females not passive, being selective increases females fitness

direct benefit - parental care

females select ale with signal that advertises quality of parental care

direct benefits - resources

male (or his territory) provides resource females need for reproduction

indirect benefits - good genes

females select signals that indicate male quality or viability, offspring benefit by obtaining superior genetic quality, typically handicap signal in male

proximate basis of detecting good genes

major histocompatibility complex (MHC) genes help mount immune response, greater # of alleles = greater detection of more pathogen types

urbanization can

decrease habitat quality, decline population density, increase competition, change movement patterns, change diets, create a fear response to humans, create habituation

urbanization - proximate

habituation of humans

urbanization - ultimate

reproduction increase