domestication Flashcards
behavior
response to stimuli
behaviors performed in order to:
survive
* obtain food
* avoid predators
* care for young
* find shelter
* attract mates
natural selection’s relationship w/ behavior
B shaped by NS pressures
* fit B that allowed org to survive & reproduce were inherited
* ex: prairie dogs w/ early & loud alarm calls have ↑ survival rate ➞ more offspring that survive
relaxed selection
NS pressures are relieved due to change that eliminates initial cause of pressure ➞ traits can:
* stay the same
* be reduced
* become more variable ➞ relaxation could allow for mating ➞ change in allele freq ➞ new traits can arise
* ex: moths in tahiti exhibit less startle response to bats’ echolocation sounds compared to all others b/c no bats in envir
* ex: dom chx vs wild red jungle fowl
artificial selection
humans selectively breed for desired traits increasing allele freq
* genetics change B present at birth
* ex: southeast asian elephants still fear humans at birth but become habituated ≠ domestication
* humans have not done anything to relieve survival pressure as to change biology at birth
selection pressures of domestic vs wild
domestication does not breed selection pressures out ➞ still have same pressures to survive & reproduce but they are now relaxed pressures
* artificial selection adds “provide milk for humans” pressure to domesticated animals
* domestic cows do not need to be good at survival B ➞ will still be bred ➞ gives false high fitness
domestication
- used for distinct pupose: human purpose
animal species that have been domesticated
- humans could not domesticate many animals due to aggression ➞ could not initiate contact
- only certain animals have been domesticated b/c of B shaped by selection pressures
- ex: zebras in africa adapted strong defense B due to severe predation pressure ➞ B allow defense against humans as well
- B like:
- high vigilance
- suspicion
- aggression
1st wave of domestication
- 8,000-15,000ya
- dog = 1st ➞ grey wolf
- both humans & wolves collective group hunters
- before separate but formed association until humans captured/maintained wolves
- close proximity + human influence ➞ inbreeding ➞ dogs
- cats = semi-domesticated ➞ african wildcat
- ‘self-domesticated’ ➞ with domestic ag came mice ➞ cats eat mice ∴ cats = pest control
- some human involvement: cats associate with humans ➞ inbreeding
- horses: used for both livestock & companion
- wild horse (mongolia) = common ancestor (Przewalski’s horse closest descendent)
- cultural importance
- useful for meat, milk, transport, labor
wild-type ancestor characteristics
- highly social
- breed at an early age (<2y)
- not monogamous (no strong mating bonds)
- precocous young
- generalized feeding B
- long mating seasons (fertile window)
- limited sensitivity to envir change
- not flighty
- ex: zebras evolved in open planes with many predators ➞ very flighty = higher fitness ➞ selective pressures made them hard to domesticate
wild-type ancestors of:
sheep
pigs
dog
cat
horse
- sheep: mouflon
- pigs: sus scrofa
- dog: grey wolf
- cat: african wildcat
- horse: przewalski’s horse (last surviving species of common ancestor, wild-type extinct)
common physical characteristics of domesticated species
- black & white coloring
- wavy/curled hair
- shortened or rolled tails
- shorter snouts & smaller teeth ➞ smaller skull/brain size
- floppy ears
- neotany: characteristics of baby form ➞ domesticatd adult = stunted/malformed verson
2nd wave of domestication
- w/in last 100y
- fur animals, lab animals, new types of meat
sivler fox (fox farm) experiment
- breeding for tameness
- unintended change in fur color (to black & white), shorter snout length, & curled tail
- tame wolves exhibit B of youth
- pleiotropy
are dom animals unable to perform all B of wild-type?
- NO ➞ dom does not change in motor patterns, just when/how often B is performed (threshhold)
- ex: basenji dogs don’t bark but still can
- ex: sows gather materials & build nests during parturition, even w/out opportunity, cows will show motor patterns
- ex: domestication of red jungle fowl
- wild reprd: seasonal breeders, 10-15 eggs/y
- dom reprod: eggs all yr round
- wild pred response: altern, freeze, alarm calls
- dom pred resomse: none
- wild home: active
- dom home: inactive
- wild social interaction: active & engaged
- dom social interaction: less social
- wild feeding B: mixed food ➞ prefer to work for food = contrafreeloading
- dom feeding B: free food ➞ easy access ➞ relaxed selection
contrafreeloading
animal chooses to work for food in presence of easily accessible food
* ex: wild red jungle fowl
domestication of wild red jungle fowl
- wild reprd: seasonal breeders, 10-15 eggs/y
- dom reprod: eggs all yr round
- wild pred response: altern, freeze, alarm calls
- dom pred resomse: none
- wild home: active
- dom home: inactive
- wild social interaction: active & engaged
- dom social interaction: less social
- wild feeding B: mixed food ➞ prefer to work for food = contrafreeloading
- dom feeding B: free food ➞ easy access ➞ relaxed selection
- relaxed selection
- principle of allocation: change in priorities ➞ dom chx are inveseting more resources in growth & reprod, less in defense characteristics
behavioral genetics
scientific discipline that attempts to understand how genes affect B
* most B shaped by both
* even those w/ large envir component need appropriate envir stimuli to be expressed
* even learned B have genetic basis
* capacity for learning
* physical capabilities
* envir can be stronger than genetics if placed in the proper one:
* ex: “intelligent” mice did better in normal envir but performed the same as their less intelligent counterpart in enriched & restricted envir
* enriched envir: both did well ➞ exposure to novel objects & complexity helped performance
* restricted envir: neither did well ➞ overall effect of being kept in a barren envir
* ex: impaired cognition
* ex: B style & cross-fostering ➞ prairie voles adopted the B of their adoptive parents
* diff in time spent licking/grooming in “helicopter-parents” vs “free-range” parents
* young voles adopt B they grew up with rather than those of bio parents
characteristics of B shaped by genetics
- innate
- reflexes
- constant in form across all species
- does not need to be acquired by practice
- all indiv of species can exhibit B despite envir
- depends on internal envir
- essential for survival: B that have higher fitness
- constant over lifetime
characteristics of B shaped by envir
- acquired from experience
- involves learning (training)
- envir stimuli
- adaptable: capable of modification to changing conditions
- progressive: subject to improvement or refinement (motor movements)
Beak-pecking in baby herring gulls
chxs peck on red spot on adult’s beak so they can regurgitate food
* chx pecked red pencil over beaks ➞ from birth, not shown by adults ➞ genetics = predominate force
* evidence fo genetics:
- happens immediately after hatching
* performed in same way each time by all
* essential for survival
* inflexible
* evidence for envir:
* sensitive to changes in envir: more red = more peck
litter box use
- anything they can cover ➞ hides scent from predators or competitors
- dominant cat will not cover ➞ mark area
- cats will “bury” when nothing to bury
- abandoned/feral kitten don’t full cover (not around other cats)
- evidence fo genetics:
- early in life
- anti-predator & anti-competitor
- behavioral sequence of covering
- most cats can exhibit across species
- evidence for envir:
- abandoned kittens only partially cover
- not consistent in every way (some don’t finish, doesn’t look right)
- motor patterns depend on social status: dom vs subordinates)
- imprinting on particulat textures in certain envir
dressage in horses
evidence for genetics evidence for envir
* requires certain physical build & specific gait
evidence for envir:
* takes yrs to train = learning
* foals don’t dance immediately after birth
* changes over time
* subject to improvement
* modify/adapt
* only dance to certain music
* music changes ➞ dancing changes
* involves specific training in response to stimuli
pleiotropy
one gene controls multiple characteristics
* fox farm experiment ➞ changes in physical B when tameness was selected for
* ex: Norway mice: black color more tame than agouti ➞ gene for coat color
1º sexual characteristics
reproductive organs
* cats reprod organs are mostly internal
2° sexual characteristics
traits related to sexual dimorphism: diff in size/appearance between sexes
* ex: color of M ducks vs F
* ex: size of M elephant seals vs F
mating systems
monogamy: 1M, 1F
* social monogamy: 1M 1F that associate as pair but can reprod with others➞ share food/territory/resources, etc
* ex: tree swallows
* ex: california mouse
* sexual monogamy: sexual B restricted exclusively to pair ➞ associate together & only mate w/ each other
* ex: penguins
polygamy: >1 reprod partner
* polyandry: 1F multiple M
* rare
* F are dom: ex: honebees
* F guard resources ➞ ex: jacanas
* sexual dimorphism: ➞ex rhinebeck spiders
* polygyny: 1M multiple F
* very common
* mammals, birds, reptiles
* promiscuity: both polyandry & polygamy
* highly social animals
* best for domestication
* ex: wolves = monogamous, dogs = promiscuous
* ex: wild geese = seasonally monogamous, dom geese = promiscuous
benefits of monogamy
- allows for pred avoidance: ex: Rhinoceros hornbill live inside large tree cavity, F & hatchlings stay camouflaged inside while M collects food
-
protection: males guard females after mating ➞ ex: prairie voles
- F can only produce 1 offspring per cycle ➞ no increased benefit to mating with multiple M
- when M unleashed, F mated with partner but when M were leashed, 55% F mated with non-partner
-
reproductive success for males:
- paired M mate more often & fathered more embryos than single M
- ex: prarie voles
- selective advantage: ex: M emperor penguins incubate eggs while F go forage ➞ M = larger ➞ keep egg warmer & better protection for egg from harsh extraordinarily extreme envir & other M
female mate choice
- direct benefits: essential resources = food/water, shelter, nest/denning sites, protection from pred or other M, offspring care (main reason)
-
good genes: M pass down fitness advantage to offspring: healthier, stronger, better survival skills
* ex: European tree frog: M w/ healthy strong offspring reproduce more
* ex: roosters’ combs signify reproductive quality: F did not want to mate with M b/c of shape of his comb ➞ signified lower sperm motility = lower reprod output/success
* strong evolutionary component that F can sense somehow -
sensory bias exploration: 2º sexual trait of M matches pre-existing F preference
* ex: cichlid fish F have affinity for how eggs look ➞ M developed spots on fin that look like eggs
* ex: F prefer larger fluffs in M auklet birds
* ex: F prefer lower frequency voices in M tungara frogs
* ex: F have affinity for UV light ➞ prefer large claws that reflect UV light in M Fiddler crabs
* ex: F prefer shinier bodies of guppies -
runaway selection: F choose M based on exaggerated traits that have not been linked to increased survivability
* could potentially put M at greater risk of death in many cases & does not improve fitness
* * sexy son hypothesis: females choose mates with “most sexy” trait that offspring can inherit
* ex: peacocks’ plumes getting larger & more decorative ➞ heavier to carry & slows them down ➞ will eventually be unable to reproduce b/c of sheer mass
* ex: M long-tailed widowbirds have higher reprod success with longer tails
potentially detrimental to survival ➞ slower, heavier tail, more for predators to catch onto
F choose mating partners b/c
- female mate choice
- male-male competition
male-male competition
M compete for access to F
* general rule: bigger/faster = more reprod success
* exception: sneaker males: small M squid struggle to compete w/ large M, but can pretend to be F b/c of size & can pull tentacles in like F do when they’re interested in M then slide ride past M
polygyny = most common in domestic animals b/c
- producers like to know genetic lines
-
need many offspring to support demand ➞ monogamy would require too many animals to maintain
3.** 1 M can father many F** ➞ less animas to maintain - bulls are very aggressive ➞ fewer on farm is safer
events of reproduction
puberty: age at which reprod organs become fx
* ex: dogs ≈ 7-10mo
**estrous cycle **(F): repetitive cycle occurring when no pregnancy of rising hormones & follicle development
* estrus = “heat”; fertility window
* species-specific & dependent on gestation length
* varies across species in age & duration
* ex: tight window of duration for cows
sexual behavior process
-
advertisement of receptibility
* swollen vulva
* mucous discharge
* restless B
* female receptivity: F perform mimic mating B even when no males present (some never been around males)- mounting: F cows will mount each other
- lordosis: raised rear end (displaying rear prominently)
- ex: cats
- ex: in swine ➞ boars softly grunt, chews & spits saliva containing androstenone, sows who are in heat will stand so that they can be mounted by the boar
- B reflects internal hormone status
- producers use standing B to test for estrus: push down on F back
- flehmen response: horses/cats/dogs have olfactory bulbs & vomeronasal organs that can detect pheromones in F that are in estrus
- courtship behavior
* for M: strut, physical contact, vocalization ➞ ex: horses & turkeys
* for F: investigate, lordosis - mating behavior
- libido: external stimuli
breeding systems in domestic animals
- multi-sire: group of M placed with group of F
- ink pack marks which ewes have copulated & which were not interested ➞ tells producers which ewes need to be checked/tested & timeline ➞ tracking
- ex: rangeland sheep
- single-sire: one M placed with group of F
- common for aggressive male
- ex: bulls & beef cattle
- ex: chx
- very efficient ➞ less animals to manage & know genetics (M fathered all)
- hand-controlled: 1 M given access to 1 F
- no Q about genetics of an
- ex: stallion & mare
- artificial insemination: multi or single-sire semen
- not always safe to keep boar/bull around
- most efficient
- ex: sows & dairy cattle
factors affecting sexual B
- libido:
- F isn’t being very receptive, isn’t giving info to M
- M isn’t noticing
- hormonal issue: testosterone levels off in M, F didn’t go into heat
- performance:
- indiv not engaging in appropriate species B
- F not impressed
- copulation itself
- ex: turtle tried to mount F but completely wrong way/area ➞ don’t do it right or don’t know how to do it
- ex: broiler chx too big ➞ cannot physically mount
reproductive problems from captivity
1.** relaxed selection** : selection for physical traits not libido ➞ ex: stallions selected for racing/muscles/appearance have poor libido (directional)
2. unintentional selection: humans may avoid handling M who are more aggressive like preferentially breed docile M ➞ aggression level positively correlated w/ reprod success ➞ breeding animals w/ low reprod success (no direction)
3. artificial selection: traits interfere w/ sexual performance
* ex: english bulldogs ➞ can’t birth babes large heads
* ex: american bullies cant mount F b/c of musculature
* ex: chx cant mount F b/c of large breast size & body weight
-
inappropriate rearing conditions: in prod systems early weaning results in young animals kept in same-age & sex groups ➞ influence on B depends on species-specific natural social structure
- ex: boar reared alone = detrimental, reared in M groups = normal
- ex: ram reared alone = normal, reared in M groups = detrimental ➞ prefer other M over ewes & have fewer ejaculations in general
- ex: bull reared alone = normal, reared in M groups = normal
solutions to reproductive problems from captivity
- artificial selection: sexual performance is often heritable
- ex: sex performance in bulls is very heritable
- ex: performance in rams is not very heritable
2. manipulate rearing envir: duration & timing of isolation
*ex: M guinea pigs
3. restore libido- Coolidge effect: novel copulation changing how many F producers offer males ➞ M that reprod with diff F have shorter ejaculation time than same F
-
spectator effect: observe copulation ➞ works for bulls
does not wok for ram
unconscious evolutionary trends in parental care
- parent-offspring conflict: mother wants to maximize lifetime reprod success, must survive & invest in future offspring, offspring wants to survive easily depend on mom as long as possible
-
balance of parental care costs:
- initially: weight of survival is so heavy for current offspring ➞ invest all resources
- at some species-dependent point, investing resources in current kid (when it doesn’t need them) puts mother’s survival at risk & threatens her future kids
dam
mother
sire
father
gestation
development fetus from conception
parturition
birth
* cattle = calving
* swine = farrowing
* sheep = lambing
* horses = foaling
* goats = kidding
* dogs = whelping
* cats = queening
parity
having borne offspring
* how many litters produced as way to gauge age
* nulliparous: never had offspring
* primiparous: 1st time having offspring
* multiparous: having born multiple litters/offspring
monotocous vs
polytocous
monotocous: one young
polytocous: many young
development of offspring at birth
altricial: requires much maternal care/investment
* “requires nourishment” ➞ squishy, blind, nude
* deficient in motor control & temp regulation
* large energy investment
* polytocous small mammals
* ex: rats, cats, dogs
* tree-nesting birds
* hawk, owl, woodpecker
* need central resource point
* evolutionary ➞ fewer predators
precocial: much more developed
* “mature before its time”
* more motor & sensory development
* young can feed themselves almost immediately
* monotocous ungulates
* caves, lamb, kids
* ground-nesting birds
* penguins, domestic poultry, ducks
* less energy investment
* shorter gestation
maternal B timeline
-
nesting
* isolation preference test: cows prefer isolation during day but no difference at night- visual isolation from predators ➞ evolutionary component
- night darkness gives protection
-
responsiveness
* sensitive period: discrete length of time when B is acquired = start of bonding formation
* ex: learning song style for songbirds
* lamb-stealing for commercial shepherds ➞ abandoned animals must be bottle-fed
* responsiveness to amniotic fluid/placenta: immediately following parturition dams are highly attracted to amniotic fluid/placenta stimulates grooming on neonates ➞ repulsive after sensitive period
* ex: multiparous cows are quicker to lick newborns than primiparous or nulliparous -
discrimination: investing all her energy in her young only ➞ bonding
* sight & sound: imprinting: newly hatched hatched birds learn to distinguish shape/sound of mother & follow them- only during sensitive period
- offspring discrimination towards older indiv ➞ provides protection that helps young survive (NS)
- imprinting on each other selected against ➞ no protection
- common w/ altricial species
- sight & sound: broiler chicks in hatchery are raised in social groups (same age), no hens
- chx = precocial ➞ altricial birds cannot be domesticated ➞ requires too much human care ➞ takes too long & too $$
- smell in goats: normal nannies would not accept diff looking kid while anosmic nannies would ➞ sight = most important scent
entrainment
internal rhythm re-sets to match external stimuli
polyestrous
continuous breeders
* seasonal polyestrous: multiple cycles within a season
* timed for external cues to change internal hormones for best fitness: best resources for survival
* far N has much bigger diff in day length/season/temp than S
* producers must know cycle/effects of location
* sheep:
* anovulatory in summer (too long days = too hot)
* breeding during fall (↓ day length)
* pregnant during winter (cold temp not fit for lamb survival)
* lambing during spring (↑ day length, best resources for lambs)
polyestrous
continuous breeders
* seasonal polyestrous: multiple cycles within a season
* timed for external cues to change internal hormones for best fitness: best resources for survival
* short day: south = march-may, north = april-november
* ewe
* nanny
* doe (shorter days in fall)
* long-day: south = april-november, north = march-may
* horses
* quail
* sheep:
*
circadian rhythms & species
diurnal: active in day, inactive at night
* humans, goats, cows, sheep, poultry
* social
* herbivores
nocturnal: active in night, inactive in day
* owls, bats, large cats, racoons, mice
* prey avoiding predators ➞ hazy = harder to see
* predators adapted to prey ➞ adapted auditory senses
crepuscular: active at dawn/dusk, inactive during day/night
* swine, wolves, domesticated dogs/cats, deer, rabbits
* swine have no sweat glands ➞ way to regulate temp
* domestic pigs fed 1x (morning) on human work schedule & spend a lot more time resting than in wild ➞ can interfere with evolution
* supposed to sleep a lot
* most active at night ➞ wild prey most active at night (mice)
