Midterm 1 Flashcards
evolution
inherited changes over time
species
individuals that have the potential to interbreed and produce live, fertile (viable) offspring
population
groups of individuals of the same species, living in the same geographic location at the same time
natural selection
differential survival and reproduction of individuals with certain advantageous traits that contribute disproportionately to the makeup of offspring in the next generation
reproductive success
passing of genes onto the next generation in a way that they can pass those genes on
behavior
internally coordinated responses (active or inactive) of whole living organisms to internal and/or external stimuli, excluding responses more easily understood as developmental changes
tinberger’s 4 question
- what is the mechanism that causes the behavior? what causes the behavior to be performed
- how does this behavior develop during their lifetime?
- what is the function of the behavior? why is the animal performing it?
- how did the behavior evolve?
components of natural selection
differential (more born than survive, all looking for resources), individuals of a species are variable, environment is always changing (resources are always limited), contribute disproportionately to makeup of next generation
fitness
contribution an individual member of a population makes towards the next generation relative to other individuals in the same population
ethology
study of behavior or wild animals in nature by observation and experimentation
optimal trait value
trait value that confers the highest fitness in a particular environment
common black headed gull experiments
when chicks start to hatch, parents pick broken egg shell and fly away to dump it. outside color = brown, inside color = white
1. prove white eggshell is attracting predator - painted inside of shells brown and white and then put them back in nest, more predators to white eggshell
2. how far away? - leave white broken eggshell at different distances away from the nest. farthest eggshell = least amount of predators
3. painted broken eggshells multiple colors - blue, red, green, brown, white –> brown and green did not attract predators
4. took an empty broken shell: a. left it empty b. filled with cotton wood c. filled with plastic bit d. lead weight same weight as baby chick –> 4 was never removed
great tit experiments
in the field, scientists put strange object near their food path. how fast do they adapt/investigate and get their food
bold - short latency, shy - stay away from strange thing
then brought to lab: bold - shortest latency, shy - longest latency
then mated them with with themselves (boldxbold, shyxshy) for 4 gens. with each gen, bold got bolder and shy got slower
conclusions: field findings = lab findings, this behavior is inherited
field cricket experiment
male crickets sing to attract females, females want loud singing, parasitoid wasps lay eggs under the wing of the cricket) finds male crickets by the singing
what is the evolutionary charge in behavior? male wings mutated to look like females (no scraper) –> flat wing males cannot sing
how are they mating? fw males are attracted to singing males, interrupt females on their way to the singing male. females walk around a lot and are willing to mate with a male that does not sing
marine isopod experiments
2 sized male morphs
a. alpha male - largest, ornamentation on head, find and defend a spongocoel, harem of females –> most offspring that belong to him
b. beta male - smaller than alpha, enters spongocoel by looking like a female to avoid attack by alpha, has to have more than 1 female already in spongocoel
c. gamma male - very small, enters spongocoel by stealth, most successful if spongocoel has lots of females and alpha male is distracted
male mice in utero experiments
A - less in utero testosterone bc female neighbors
B - more in utero testosterone bs male neighbors
when sexually mature - A had slower ejaculation time, shorter mounting time, spent longer looking for females but had way more parental care
experiment: mixed fetuses around - move fetus next to two males next to females - is it genetic or proximate environment?
experiment: testosterone blocker in newborn male –> similar to male A
no testosterone and added testosterone later –> similar to male B
innate behavior
performed by an animal without the need for practice or experience, genetically programmed
characteristics of innate behavior (5)
heritable - encoded in DNA
intrinsic - an animal raised in isolation will perform the behavior perfectly
stereotypic - performed the same way each time in each individual
inflexible - not modified by development and expressed perfectly the first time it’s performed
consummate - fully developed and expressed perfectly the first time its performed
fixed action pattern
evolutionary adaptation to ensure that a particular stimulus elicits an adaptive response, fits all the characteristics of innate behavior, FAP increases the gain in efficiency of the behavior + automatic response
loss in terms of discrimination (bird will remove anything that is odd around nest)
greylag goose egg retrieval behavior experiments(tingerger + lorenz)
egg retrieval behavior, nest on ground
sign stimulus/proximate stimulus - seeing their egg outside the nest
FAP - goose uses beak to bring the egg back in
1. how far? FAP works up to 1.6 ft away (extent of neck bc bird does not want to get off of nest)
2. put colored and strange objects within 1.6 ft. brought in about everything within 1.6 ft
3. supernormal stimulus - triggers a huge response. placed huge egg within 1.6 ft and bird retrieved it
4. consummate: once FAP starts, goes to completion when beak and neck reaches the body
herring gull experiments
red dot on beak = sign stimulus for newborn chick, chicks peak at red dot on mother (chick’s FAP), mother’s response = regurgitate food into the mouth of the chick (mother’s FAP)
tinberger: fake stimulus
fake head with red dot - chick pecked at it
stick with red dot - chick pecked
stick with red band, not dot - chick pecked
three spine stickleback (fish)
mating season - males make nest in water, attract females with zig zag dance. if female says yes, she will lay eggs in nest. during mating season, males develop a red belly.
FAP = male-male aggressive interaction during mating season
sign stimulus = red belly
put a green filter on the light –> cannot see red –> the two males did not attack each other
imprinting
phase sensitive learning that is restricted to a small time window during development
Lorenz imprinting experiments
greylag goose, exposure to non-mother object in sensitive period, resulted in chick attachment
group A - greylag goose chick was hatched by mom (left normal)
group B - Lorenz hatched and fed the chicks
1. let both groups grow for several weeks. group A followed mom around. group B followed Lorenz around
2. Put all chicks in box with lid, put mom 50 ft away and Lorenz 50 ft away, someone lifted box. group A chicks ran to mom and group B chicks ran to Lorenz
Dr. Geoff HIll house finch experiments
male is red and males across population have variable shades of red plumage, cause = carentoids
1. captured males and females in two groups in wild
group 1 - gave them only carentoid foods –> red plumage
group 2 - no carentoid foods –> brown plumage
2. do males and female housefinches forage differently –> field observation says yes
males - look fpr carentoid foods, high energy used, exposure to predators
females - maximize calories per unit time so they can have good yolks in eggs
how do we know females want red plumage?
a. gave females choice of two males - she chose redder one
b. put baby powder on the redder male (made it white) and left less red male alone –> picked less red
c. dyed red male even more red, left other alone –> picked dyed male
proximate cue - red plumage. ultimate reason - RS
red males = good at foraging, high energy and good vision, bold, avoid predators, good looking, fight bacterial infection faster, greater parental care
sexual selection
differential sexual success, heritable features that contribute to success at obtaining mates
law of battle
struggle between individuals of one sex (generally male) for sexual control over individuals of the other sex
male-male interactions ex.) deer, elephant, seal, elk, lion, chimp
winner gets all females, all RS
features found in males - large, horns, large, claws, aggressive
sexual dimorphism - one sex is much larger than the other
males way bigger than females in animal that do the law of battle
taste for the beautiful
process by which members of one sex (generally female) choose their mates on the basis of some preference (innate)
female mate choice
features found in males - loud singing, unnatural colors, nest size, dances, giving of something
female egg vs. male sperm
gamete size
female - human egg = 0.004 in
male - human sperm = 0.0002 in
female egg vs. male sperm
yolk
female - yolk = essential for survival of embryo
male does not contribute yolk
female egg vs. male sperm
cost
female - larger yolk - more energy + better for embryo
some females lose >50% body weight
no cost for males
female egg vs. male sperm
gamete number
female human - 480 eggs/lifetime
male human - 500 million/ejaculation
female egg vs. male sperm
length of reproductive cycle
female - insects = hours; humans = 20-30 years
human male = lifetime?
female egg vs. male sperm
breeding time
female - once per season, 1-2 times per year, depending on animal
male - in many species, males can mate with many females
female egg vs. male sperm
risk
females - pregnancy, caring for eggs, caring for young = huge risk
no risk for males
bateman principle
males have high variability in RS - can have zero succesc, can have 100% success
intensity of SS means that male RS is highly unequal
in a breeding season, only a few males get to reproduce
put virgin male and female fruit flies in a jar –> allow to live 3-4 days –> egg laid, genetic testing
result: 96% of females produced offspring, 79% of males produced offspring
intrasexual selection
male-male –> winner gets all, loser gets nothing
nuptial gift
NS/SS favors females who have a genetic disposition to choose males than can provide them with tangible resources that increases the female fecundity
ex. scorpion fly - female will only mate with a male that present a cocoon (prey-dead inside) that in 19 cubic millimeters –> males will walk past a small prey –> females at that prey. copulation time increases with size of prey
ex. black widow spiders, preying mantis - sexual sacrifice, male - nuptial gift
good genes
proxy for good genes - honest indicators (what you can see)
ex. red breast of house finch is indication of good foraging
ex. pronghorn sheep - females actively search for a male that already has a haren –> indication that the male can defend territory, find good resources, and has other females
ex. peacock - cost for males = attract predators, can’t fly, can’t escape predator, no camouflage. females look at bottom of the train to see if the males can care for themselves
secondary sexual characteristics
evolved to attract females despite being positively detrimental to male survival
mosquito fish experiments
group A - young males, restricted food intake for first 3 weeks of their lives, after 3 weeks provided unlimited food
group B - young males, no food restriction, fed as normal
males are same size in both groups
put both with females –> females picked B
barn swallow experiment
females pick the symmetrical male
in experiment, they cut one of the tails or added more so it was symmetrical
sand flies experiment
round 1: 5 male virgins, 10 virgin females –> let them loose in container
took out most successful male - male 3 - that was unanimously picked in round 1
round 2: put remaining males (1,2,4,5) with 10 female virgin each in separate container
round 3: put all sons in arena with virgin females –> females picked sons of most successful male (male 3)
sexy son hypothesis
mothers want their sons to have RS –> so females select males that will pass on attractive/symmetrical traits so that their male offspring will be attractive to the next generation of females
