Mammalogy Exam 3

test on november 20, lectures 8-

What are the two components of sexual selection?

-female choice of mates - intersexual selection

-male-male competition for mates - intrasexual selection

What is intersexual selection?

female choice of mates

What is intrasexual selection?

male-male competition for mates

What is sexual dimorphism? (3)

-common in birds and mammals

-differences between sexes, often manifested in morphological or behavioral traits, ex. color, decorations, size

-shaped by both female choice and male-male competition

What is Bateman’s Principal? (2)

-male reproductive success is often limited by access to females, as sperm is not energetically costly

-female reproductive success of most limited by resources needed to produce eggs AND ability to nourish offspring

What is the definition of sex regarding mammals?

all about gamete size, not by genitals

What is the innate conflict between sexes? (2)

-linked to offspring care

-differential parental investment by the two sexes lies at the heart of most evolutionary hypotheses about sexual behavior

What is anisogamy? (3)

-form of sexual reproduction that involves the union of two gametes that differ in size or form

-the smaller gamete is male, a sperm cell

-the larger gamete is female, an egg cell

What is disruptive selection?

an evolutionary process where extreme traits are favored over intermediate traits, leading to increased variation within a population

What are indicator models? (2)

-indicators of female choice

-females want to mate with males with “good genes”, assumes that a trait favored by females indicated male fitness

ex. testosterone-based traits, Fisherian selection, symmetry

What is Fisherian selection?

also known as runaway selection, describes how an exaggerated trait, particularly a secondary sexual characteristic, can evolve through a positive feedback loop between female mate choice and male expression of the trait

-much more prevalent in birds, biggest mammal example is extinct Irish Elk with GIANT antlers

What is the handicap hypothesis? (2)

-linked to testosterone

-males need to handle the cost of testosterone, very energetically costly

What is meant by “truth in advertising” regarding female choice? (2)

-male handicaps must be honest and linked to overall fitness of male

-more room for deception with behavior traits, not “obvious”

What makes testosterone so costly? (8)

-spermatogenesis (sperm production)

-secondary sex characteristics

-muscular hypertrophy

-high energetic costs

-oncogenic links

-increased mortality

-aggressive behavior

-immune system supressant

How does attraction work in humans? (6)

-all 5 senses are responsible for determining attractiveness

-sight: symmetry, full hair and smooth skin are indicators of good genes

-smell: pheromones!

-hearing: men like higher pitches, women like lower pitches

-touch: duh

-taste: kissing ;)

What is significant of dominance hierarchies and male-male competition? Give an example. (3)

-typically little to no female choice in these systems

-typically no parental investment by males

-sperm competition

ex. elephant seals, common in deer and antelope

What is sperm competition? Give examples. (5)

-male-male competition

-mate guarding

-physical removal of another males sperm

-increased sperm numbers

-duration of copulation

What are lek mating systems? Give examples (4)

-no parental care needed

-males aggregate at traditional sites (leks) and compete for female attention (fighting each other)

-provide no essential resources to females other than male sperm so they are in areas that maximally facilitate female visiting and male display

-females select a male, facilitates comparison of males by females and the accurate selection of the “best” mate

ex. topi, Uganda kob

Why do females typically live longer than males? (4)

-costs of testosterone

-men are aggressive! more risk taking

-short sex chromosome in males - less genetic information to work with

-having two long sex chromosomes means that each gene has an exact copy!

What is post-copulatory competition? (3)

-competition for fertilization that occurs after mating, especially when a female mates with multiple males

-urine as a releaser pheromone (territorial marking)

-Whitten and Bruce Effect

What is the Whitten effect? (2)

-females housed together display extended estrous cycle when exposed to the urine of sexually mature male mice

-large percent of females enter estrous (heat) within a few days

What is the Bruce effect? How does it work? (5)

-pregnancy block

-exposure to urine from an unfamiliar male prevents embryo implantation/terminates pregnancy, causing a recently mated female mouse to return to estrus

-male pheromones shut down hormonal pathways

-typically only happens shortly after fertilization

-findings are controversial

What is infanticide? Give examples of organisms (3)

-intentional killing of offspring

-male reproductive strategy, resource scarcity, social status

-seen in lions, primates, rodents, horses

What is parental investment? How often is this seen in mammals? (5)

-any behavior that increases the offspring’s chance of survival at the cost of the parents ability to produce future offspring

-only 6% of mammals show both maternal and paternal care

-frequency in altricial and precocial young

-frequency in semelparous (rare in mammals) and iteroparous

-alloparental care

What are semelparous mammals? (3)

-rare in mammals

-males die shortly after mating

-seen in rodents

What are iteroparous mammals?

mammals that reproduce many times throughout their lives

What is the term for a male mammal that dies shortly after mating?

semelparous

What is the term for a mammal that reproduced many times throughout their lives?

iteroparous

What is alloparental care? Give examples (2)

-care provided by an individual other than the biological parent

-seen in rodents, primates, social carnivores – links to kin selection

What are the four basic mating systems and what do they mean?

-monogamy: exclusive mating between one male and one female

-polygyny: males mate with multiple females

-polyandry: females mate with multiple males

-polygynandry/promiscuous: both males and females have multiple mating partners

How does the spatial distribution of resources effect mating systems? (2)

-clumped distribution has higher potential for polygamy

-uniform distribution has little potential for polygamy

What is the relationship between monogamy and polygyny in mammals? (2)

-true monogamy is rare in mammals 5%-9% mostly in primates and canivora

-forms of polygyny include resource defense, female defense, and leks

What is the difference between true monogamy and social monogamy?

-true monogamy: requires it in both social and sexual contexts

-social monogamy: focuses on the shared social structure, which may or may not include sexual exclusivity

How does sexual selection apply to humans? (2)

-serial monogamy is common in western societies

-culture and moral codes set us aside from the rest of the animal kingdom

What is perceptual/primary consciousness? What organisms have it?

the basic, immediate awareness of sensory information, such as sights, sounds, without the ability to reflect on it, most mammals are capable of this, ex. a cat understanding that you are initiating play time when you show their toy

What is reflective consciousness? What organisms are capable of it?

the ability to think, experience feelings, self-awareness, humans are the most notable, however mammals that pass the mirror test (maybe reflective?) include elephants, apes, and dolphins

Is there evidence of reflective consciousness in cats? (4)

-do not pass the mirror test, but show other forms of self awareness

-spatial awareness, problem-solving, memories, object permananence

What is the righting reflex?

-postural reflex that allows mammals to orient their bodies and return to an upright position after being displaced, using a combination of vestibular, visual, and somatosensory input

-crucial for balance, cats are able to twist their bodies midair to land on their feet

What is the significance of slow blinking in cats? (3)

-slow blinking is typically a sign of trust or relaxation

-direct eye contact is scary

-they will often respond with a slow blink back

What are significant characteristics of Family Felidae? (6)

-vibrissae

-clavicles anchored in bone

-obligate carnivores: unable to synthesize amino acids that are only found in meat

-crepuscular

-tapetum lucidum

-FRAP

What is FRAP?

frenetic random activity period aka zoomies!

What is allorubbing? What is the evolutionary significance of this?

-cat rubbing, typically on your hand, leg, face, or foot

-scent exchange, reinforces social bonds

What types of consciousness behavior studies have been done on cats? (6)

-name awareness

-object permanence

-paired attachment (to human owners)

-body language, vocalizations, emotional state

-learning

-social referencing

What is object permanence?

the understanding that objects continue to exist even when they can't be seen, heard, or touched

Why do cats meow and purr?

-most likely in order to communicate with humans

-purring is thought to mimic the frequency of a human baby cry

What is classical conditioning?

-a type of learning where an involuntary response to a natural stimulus becomes associated with a previously unrelated, or neutral, stimulus

-ex. pavlovs dogs - learned to drool at the sound of the dinner bell

What is operant conditioning?

-a learning process where behavior is controlled by the consequences that follow it, such as reinforcements or punishment

-ex. clicker training - if i do this behavior, i get a snack! ill do it again

What is counterconditioning?

-replacing an undesirable emotional response to a stimulus with a new, positive one by pairing the stimulus with a high-value reward

-ex. using treats to change a cats fear of the vacuum

What is significant of cat social referencing?

-there is evidence that cats can read and contextualize human expressions and their responses to stimuli

ex. if you’re scared of a new object, your cat will too

How has evolution shaped the behavior of cats? (3)

-climbing behavior

-preference for enclosed spaces and ambush predation

-dislike being picked up or handled from above - fear of aerial predators

When were cats domesticated? (2)

-first thought to be 4000 years ago in Egypt

-could be as early as 10000 from paleontological evidence in Cyprus associated with the rise of agriculture

What are cultural/environmental differences between cats that live in the US vs Japan? (2)

-US cat culture focuses on individualism and household pets,

-Japanese cat culture incorporates felines into public life, with environmental differences in housing and stray cat management

Why has homosexuality evolved? (4)

-”evolutionary paradox”, can’t reproduce naturally, so what’s the point?

-there is plenty of gay stuff happening elsewhere in the animal kingdom, ex. in giraffe and sheep mating, males prefer males!

-has a genetic component! many hypotheses

-one is that alleles coding for gay behavior may boost an individuals ability to form social bonds - survival over reproduction

What is significant of dolphins learning abilities and communication? (6)

-observational learning: using tools to imitate human behaviors, like using a seagull feather to scrape algae from an underwater window

-rate of learning: captive dolphin learning a new trick every day to receive food

-have “signature whistles” to differentiate each other

-aiding behavior: help other dolphins that are injured

-some understanding of word-like signals

-pass the mirror test

What is significant of primate learning abilities and communication? (3)

-recognition of other individuals

-can learn to use human tools

-experiments with ASL

What are instincts?

natural, unlearned, and involuntary tendency of an organism to perform a specific behavior in response to a stimulus, without thought or reason, ex. removing your hand from a hot oven to

What is learning in regards to mammals? (2)

-the act of acquiring new/modifying existing knowledge, behaviors, skills, etc.

-may involve synthesizing different types of information

What is a natural, unlearned behavior in response to a stimulus called?

instinct!

What is sensitization?

-an increase in a response to a neutral stimulus when it occurs after a rewarding or punishing stimulus

-ex. pavlovs doggies

What is habituation?

-desensitization

-a reduction in previously displayed response when no reward or punishment follows

-ex. shock collar no longer effective, dog keeps doing bad behavior that they used to not do

Female choice of mates is known as intersexual selection or _________ selection

epigamic

How is anisogamy an example of disruptive selection?

selection favors extreme gamete size (small and large) over intermediate sizes

Why is Fisherian selection rare in mammals?

females typically do not chose a male over one specific trait, traits are often difficult to maintain

What is the evolutionary significance of female attraction to males with symmetrical features?

show more developmental stability - better at changing with their environmen

Name two physiological reasons to explain why males have shorter lifespans than females

-costs of testosterone

-short sex chromosomes, less genetic information

How does the Whitten effect provide an example of female-female competition for potentially receptive male mates? (2)

-synchronized estrous creates a situation where multiple females become receptive to the single male at nearly the same time, intensifying competition for that male's mating opportunities

-females are forced to compete for the same limited pool of receptive males

Why is it thought that only females who have recently been impregnated are susceptible to the Bruce effect?

fetus is early in development, much less costly than terminating a well-developed fetus

What is the term for offspring that need significant parental care after birth?

altricial

What is the term for offspring that does not need significant parental care after birth?

precocial

What is an evolutionary explanation for the positive selection of alloparental care in mammals?

most likely caring for young that shares genetic information with them, still increases fitness

What is the central trade-off a female must consider according to the Polygyny Threshold Model? Answer should include ‘monogamy’, ‘polygamy’, ‘habitat quality’(2)

-a female can choose one of the best males that holds the best territory, but because the male and his habitat quality is high, he will be highly coveted by other females and therefore most likely polygamous and give little parental care

-a female can choose a lesser male that has mediocre territory, and because he is less coveted he will most likely be monogamous and be more involved in parental care