Midterm 2 Flashcards
Define each primate diet and give examples of each Frugivore Folivore Insectivores Gumnivores
Frugivore- fruit -spider monkeys, guenons Folivore- leaves - colobines, howler monkeys Insectivores- insects - bushbabies Gumnivores- plant gum - mouse lemurs
What do organisms need from food?
A. Vitamins minerals trace elements to regulate bodily processes eg. Na, K, Mg, Ca…. used for fluid regulation nervous system function etc.
B. Nutritional components
1. Proteins:
Essential amino acids not manufactured by the body
2. Carbohydrates:
Energy and also roughage
Simple sugars - easily digested…glucose/fructose
Complex sugars- difficult to digest….cellulose
What should be avoided in food?
A. physical defences such a spines and thorns
Protective ants
B. Chemical defences:
Plant secondary compounds
Alkaloids: toxins leave the gut and disrupt metabolic processes such as nicotine and caffeine
Tannins : digestibility reducing agents dose-dependent example green tea green fruit
What kind of food has what you need Fruit Flowers Leaves Saps/gums Insects/meat
A. Fruit: simple sugars no protein
B. Leaves: complex carbohydrates( but difficult to digest) protein and vitamins but also secondary compounds
C. Flowers: simple sugars in nectar and protein in Pollen
D. Saps/gums: simple+ complex sugars water minerals
Insects/meat:protein, fat
What is homeostasis?
Internal body temperature maintenance by an organism
What is Basal metabolic rate?
The amount of energy needed for homeostasis
What is basal metabolic rate determined by?
Body size
The larger the body, the more energy needed to fuel it.
What is the major determinant in diet choice?
Energy
What is the formula for Keiber’s law??
.75
BMR=70(body weight)
Demonstrate keibler’s law and how it shows that larger species need fewer calories per unit body weight
Tarsier bw- 0.1kg
BMR 12.5
BMR/kg=125
Gorilla bw- 100kg
BMR 2214
BMR/kg = 22.2
Why do larger species need fewer calories per unit body weight??
- BMR devoted to maintaining internal body temp. Which gets sucked out by environment (i.e most of BMR to combat heat loss)
- heat loss occurs through skin
-amount of heat you lose and therefore the BMR needed to combat heat loss, is determined by how much skin you have
SURFACE AREA!!!!
How does surface area scale with body size? Formula
SA=(vol).67 power
Example with cubes
Smaller the cube the higher the surface area:volume ratio
Bigger cube the lower SA:VOL ratio
See slide 18 basic life problems
Being large means you have proportionately less SA for your volume
… proportionately less heat loss
Being large is good way to conserve heat (energy)
Explain how guy capacity is important factor foe diet choice
Food digestibility (how much time in stomach) called gut retention Which is a function of gut capacity which scales with body size
How does gut capacity scale with body size
Gut capacity=(body weight)1.05 power
Food digestibility improves with increased body size
What are the implications for diet choice in small animals?
- High relative BMR
- Small gut capacity
- need high quality, rapidly assimilated food
Few food choices
What are the implications for diet choice in large animals?
- Low relative BMR
- Large gut capacity
- can tolerate low quality hard to digest food
More choices
What does ultimate diet choice depend on?
Availability of food types and energy needed to harvest them
What are the interrelated factors that diet choice is governed by?
Body size
➡️SA:VOL
➡️heat loss ➡️BMR
➡️gut capacity➡️food digestibility
Food quality ➕availability
What are the basic feeding adaptations to the feeding niche?
Body size Teeth slide 37 Gut anatomy (slide 38) Body composition Behavior
What are the 3 types of teeth adaptations and what are they used for?
- Hexagon top and bottom for cutting meat
- Squares top and bottom - crushing/grinding - fruits and seeds
- Small sharp triangles top and bottom grind/ cut - leaves
What are the parts of the gut anatomy?
Stomach- primary digestion
Small intestine- primary absorption
Caecum- blind pouch.. symbiotic bacteria
Large intestine- water and some nutrient absorption
Explain the gut specializations for folivory
Stomach enlargement/ subdivision Caecum enlargement (hindgut fermentation) and ceacotrophy (ingestion of feces)
What is important to know about body composition adaptation for diet choice?
Reduction of energetically expensive tissues in folivores
Lean muscle mass
Brain size
Leaves and fruits
What are the three behavioural dietary adaptations?
- General Activity level eg. Folivores lethargic because a) reduces energy consumption
b)improves digestion - Ranging - frugivores should have larger home range with patches of food fruit
Folivores smaller ranges with more abundant and uniform food sources
leaves - Territoriality- non territorial over lapping ranges or territorial non overlapping ranges
What are the benefits of territoriality?
Reduced resource competition and reduced mate competition
What are some if the costs of territoriality?
Energetic cost to patrol
Risk of injury
Opportunity costs to feeding time lost to territory maintenance
Exclusion of neighbours resources
When should you be territorial?
When benefits out weigh the costs and when you CAN be terriorial
D=defensibility index DPL= daily path length d'= diameter of home range D=DPL/d' D > 1 permits territoriality D < 1 prohibits territoriality
Summary of diet choice adaptations
Diet choice↔️ body size ⬇️ Physical structures Teeth Gut morphology Muscle mass brains Diet choice ⬇️ Behaviour Activity level Ranging Territoriality ⬇️ Also affects details of how you actually forage
What are the Anti predator strategies of adaptation for survivial?
- Cryptic eg. Peppered moth
- Conspicuous but toxic eg. Dendrobates frogs, monarch butterfly
- Conspicuous startling - butterfly wings that look like head of snake
- conspicuous but confusing - zebra
Explain predator counter strategies
Coevolutionary arms race
Pre-evolving skills to avoid predators predators evolving skills to stay ahead of prey
Pray evolving skills to beat those skills and etc.
Eg.reduced sensitivity to aversive pray features
Eg toxin resistance for unpalatable prey
What are primates antipredator strategy
Grouping
What are the antipredator benefits to grouping
- More eyes- predator detection
- Reduce the per capita vigilance costs
- Better active defence
- Dilution effect… The selfish herd
- Improved foraging efficiency
- Better intergroup competitive ability
What are some of the costs to grouping
- More conspicuous to predators( anti predator)
- Increased food competition within groups
- Increased social competition within groups (mates, alliance groups) snd stress
- Increased risk of disease transmission
What are the two evolutionary models of grouping?
- Resource defence (Wrangham)
2. Preditation/intra group food competition (van schaik)
Resource defence evolutionary model of grouping
Explain.
Sociality (grouping) adaptation to improve resource access
I. Food is most limiting to females who try to reduce competition
ii. Females distribute themselves in space in relation to food
a. Low-quality abundant food
- females solitary
b. High-quality scarce, patchy food
- female group harvest food/ defend…
Intergroup competitive ability or
Group with Kin intra group competition
Resource defence evolutionary model of grouping
Predictions and evidence
- Groups should be composed of female kin
- Females should be active in resource defence
- Large groups should have resource access
- Females in larger groups should have higher LRS
Resource defence evolutionary model of grouping
Problems and exceptions
- Not all fruigvorous species group
- Some folivores live in very cohesive groups
- Not clear that females in larger groups have higher LRS
The evolutionary model of grouping
Preditation Intra-group food competition (Van Shaik)
Explain.
Sociality (grouping) is an adaptation to avoid predation
Size of groups constrained by intra group feeding competition
i. Grouping occurs to reduce costs of predation risk.. larger groups favored
ii. As group size ⬆️,
feeding comp. in group ⬆️thereby ⬇️food intake rate
Ultimate group size is balance between reduced predation and increased feeding competition
Optimum group size:
Food intake rate maximized
Predation risk minimized
Evolutionary models of grouping
Predation\intra-group food competition
Predictions and evidence
- Behaviour should very with predation risk
- vigilance higher in small groups
- groups are smaller on islands without predators - Terrestrial groups should be larger than arboreal groups - true!
- Smaller groups should suffer higher predation
- juvenile mortality should be higher and some small groups (resource stress?)
Evolutionary models of grouping
Predation\intra-group food competition
Problem/exceptions
- Hard to actually quantify predation risk
2. Many small vulnerable species are solitary
Predation and grouping of Galagos
Body size:small Diet: insectivore Predator pressure? High Grouping? No * Territorial? Yes Scent marking to reduce territorial costs *grouping constrained by diet choice which determined by body size Nocturnal to reduce predation risk
Predation and grouping of squirrel monkey
Body size:small Diet: fruit Predator pressure?high Grouping? Yes (20-50) Territorial? No though D>1 Defends local patches
Predation and grouping
Baboons
Body size:medium Diet: omnivore Predator pressure?yes Grouping? Yes (30-100+) Territorial? No D<1
Predation and grouping of Gorillas
Body size: very large Diet: leaves Predator pressure? Low Grouping? Yes * Territorial? No * some other factor operating... either diet choice or predation pressure favour grouping
What is a social group?
A set of conspecific animals that interact regularly more so with each other then with members of other social units or groups
What is social organization?
The size, sexual composition,and spatiotemporal cohesion of a social unit that includes
Groups size
Operational sex ratio: adult male/adult female ratio
Cohesive vs fluid
What is a mating unit?
The individuals that mate within a social unit
-Describes the subset of social interactions
-Substructure of mating adults - not all adults get to mate (especially males)
What is social structure?
How group members interact with each other- resulting relationships within the social unit
Ie. female bonded or non female bonded
What are the four variations in primate social groups?
1)Group composition
2)Dispersing sex
3)Cohesion
4)Primary bonds within the group :
Female-female relationships
Female-male
Male male
What are the five main possibilities of group composition?
Solitary Pair living (or monogamy) Multi male -unifemale (polyandry) Unimale- multifemale (polygyny) Multimale- multifemale
Solitary group composition
(Aka roving or dispersed polygyny)
Explain and examples
-Mother and Young only consistent grouping
-male ranges be overlap that of several females
Examples - nocturnal stepsirhines
All lorises/galagos, small lemurs, orangutan
Group composition
Pair living - monogamy
Explain and give examples
- One male and one female with their immature offspring
-good to be territorial
-tend to be monomorphic (m and f look very similar) - male- female bond and male involvement with kids variable
-common in birds but rare in primates/mammals
Ex. Gibbons, simangs, marmosets, indri, owl monkeys and titi monkeys
Group composition
Multimale unifemale
Polyandry
Explain and examples
- One female paired with 2 or more males
- males may be relates
- very rare- maybe found in tamarins and 20% of lar gibbons
Group composition
Unimale and multifemale
Polygyny or Harems
Explain and examples
-Several adult females and offspring, one resident male
-all male groups common
-typically sexually dimorphic
- one male units may join supertroops
Ex. Hamadryas, geladas, patas, some gorillas and some howlers
Group composition
Multi male multi female
Explain and give examples
-Multiple adult females and males plus offspring
- multiple matings (promiscuous mating)
- paternity uncertain
Ex. Most Baboons and macaques, vervet and squirrel monkeys, capuchins, ring tailed lemurs, some colobines
What is philopatric sex?
The Philopatric sex stays with natal group and stays with their kin/family as adults
In all Primate groups one sex or both sexes disperse from their natal group
What is the dispersing sex?
The dispersing sex leaves the natal group and does not live with kin/family as adults
Philopatry=
Primary bonding pattern
What are the two non-female bonded groups?
Explain each and give examples
- Male bonded- females disperse and males are Philopatric (resident)
Some male kinship bonds
Ex chimpanzees bonobos and Muriqus - Bisexual dispersal- both sexes disperse- no one lives with Kin, patterns of behaviour not determined by kinship
Solitary and pair living species alsogorillas, hamadrayas howlers
Where do dispersing animals go
- They remain solitary
- They may join a unisex group(All male)
- They may join a breeding/bisexual group
- They would form a new group
What is the difference between cohesive and fluid groups? give examples of each
Cohesive- Close spatial proximity
- coordination of activity
Ex. Black howlers
Fluid-spatially dispersed
-Little coordination of activity
Ex chimpanzees
Explain fission fusion of chimpanzee society
Multi male multi female
Females disperse
a fission–fusion society is one in which the size and composition of the social group change as time passes and animals move throughout the environment; animals merge (fusion)—e.g. sleeping in one place—or split (fission)—e.g. foraging in small groups during the day. For species that live in fission–fusion societies, group composition is a dynamic property.
Why are there so many different groups ?
Many factors interact to produce variability that we see in social groups
What are the factors that offer variability in social groups
Feeding competition
Population density
Predation and infanticide
Phylogeny - evolution
What are the two critical aspects of social behavior (regarding reproduction)?
Mating+parenting=reproductive success
Why Sex?
Costs of sex?
- cost of meiosis (halving of genetic contribution)
- cost of mating (search time/energy, disease)
Why sex? What are the benefits?
- recombination (new variation… f(x) in variable environments
- avoid accumulation of deleterious mutations ( reduce mutation load)
Briefly describe Van Valens ‘ Red Queen’ hypothesis for the evolution of sex
an evolutionary hypothesis which proposes that organisms must constantly adapt, evolve, and proliferate not merely to gain reproductive advantage, but also simply to survive while pitted against ever-evolving opposing organisms in an ever-changing environment. The hypothesis intends to explain two different phenomena: the constant extinction rates as observed in the paleontological record caused by co-evolution between competing species,[1] and the advantage of sexual reproduction (as opposed to asexual reproduction) at the level of individuals.[2]
What are the 3 ways the basic aspects of reproductive physiology influence mating and parenting behavior (derivative social behavior)?
1) Different levels of initial and subsequent investment by males (polygyny and minimal male investment) and females (anisogomy+internal fertilization, lactation, gestation)
2) different levels of variance in lifetime reproductive success of females and males
- females low (constrained by interbirth intervals (IBI) and
-males high
3) different limiting factors to LRS foe males and females
-females limited by access to resources
-males to fertile females
Outcome? Females will have smaller body size (favour early maturation and longer reproductive career) Will be selective and choosey about who they meet with because every reproductive attempt is costly
Explain the life history of a standard male mammal
Males
1)Gamete supply infinate( continuous production)each one cheap
2) males can desert after fertilization (Limited or no investment and off springs survival) … to seek additional matings
3) potential for multiple meetings in males creates intense competition among them for access to females…
….. which favours ardent males who compete vigorously
….. which creates selection on traits (body size, weapons etc.) that aid in competition
- delayed maturation Side effect to invest in these traits …. shortening reproductive careers and intensifying competition
Males maximize LRS by maximizing matings
How are females LRS constrained?
Primarily by resource access
What determines number of females in a group?
Resources and predator pressure
What determines number of males in a group?
# of females Reproductive synchrony of females
Females distribute according to???
Males?
Predation and resources
Males map onto females
What are the females adaptions for acquiring resources? 3
1) Philopatry and sometimes grouping
2)within group aggressive competition for resource access ( dominance hierarchy in non folivores)
3) reproductive suppression
Multiple females but only one breeds - limiting resource competition from other females offspring eg tamarins wild dogs and mongoose
How does social dominance hierarchy correlate with LRS?
-earlier menarche (first menstration) - eg. 200 days earlier in HRF (high ranking females)
-shorter inter birth intervals (1 year vs. 2 years in seasonal breeders)
-faster conception, fewer miscarriages, higher infant birth weight
- better infant survival
- longer lifespan
In combination these reproductive advantages result in higher LRS for HRF’s
Eg. Gelada and chimps
What constraints do males have on LRS?
Mate access
What are the two routes that males have for adaptations for mate acquisition
1- Intra- sexual selection
(Male-male competition)
-adaptations for outcompeting rival males
2- inter-sexual selection (female choice)
- adaptations for attracting females
What is sexual selection theory?
Addendum to natural selection that focuses specifically to adaptations which improve an organisms chances of reproducing… even though they might be costly in terms of survival
What are physical adaptations of males to outcompete rival males
1-large body size- takes more time and energy to grow big, but this cost baby more than compensated by higher mating frequency eg gorillas and baboons
2-traits that emphasize or exaggerate body size- again, additional energy invested in these traits may be compensated by increased mating
Eg. Long tailed macaque, silverback gorilla
3- fighting weapons eg canines, horns
4- genital adaptations eg sperm plugs
Damsel fly with penis spines, large testes
5- female mimicry and sneaking mating eg orangutan sneeker raping females
What are the behavioural adaptations for outcompeting rival males?
1- cooperative alliances example Lions and baboons
2-infanticide- avg. male tenure length =8mths
Female IBI= 2 yrs
Intense male mating pressure
Females resume estrus in 1-5 mths
What are female counter strategies?
1- pseudo-estrus behaviour to combat infanticide
Females (esp. pregnant ones) become more sexually receptive and will solicit immigrant male to mate .. in the hope he doesn’t count
2- sexual swellings - swellings advertise ovulation … which incites male competition… best quality male wins
… if syncronized, swellings also reduce monopolizability and so increase number of males from which females may be able to choose
3- concealed ovulation and promiscuous meeting
-hide signs of ovulation and mate with many males….
confuses paternity and selects for male tolerance of infants and perhaps even active care
What is parental investment?
Optimal parenting:Managing your investment in offspring
General theory Selection should favour parents who bias investment in offspring that provide greatest return: - reproductive returns e.g. Grandkids Or - payback (Resource contributions)
Offspring are not necessarily all equal
What are the differential costs of parental investment? 3
I) length of investment
Males in some organisms which are slowly so longer investment period
In many of the species female stay at home so investment into adult hood?
2) amount of investment
If males mature later and attain larger body size this may require more investment
3) philopatry and dispersal
If females Philopatric, they may increase resource competition
What are some differential benefits of parental investment?
Give examples
1) reproductive returns
- males have very high reproductive potential (Grand child potential high though risk also high)
Female reproductive potential low but more predictable
2) social benefits
- if females Philopatric they may cooperate and improve mothers social standing and hence access to resources
Complex strategic problem for parents
Lizards alligators turtles
- temperature dependent sex determination
Mammals: chromosome all sex determination less flexible so skews are less radical but sometimes observed
Explain sex bias ratio in old world monkeys.
-Females philopatric (stay with natal group)
-Resource competition
-dominance heirarchies
-rank predicts resource access
- correlates with reproductive success
HRF harass LRF - especially those with female offspring to minimize female recruitment to group and thus resource competition
- injury of LRF, aggression towards them by HRF and lower infant survival rates of LRF
Soooooo
HRF- daughters beneficial to maintain of improve matrilineal status
LRF-daughters costly so produce sons who are not burdened by mothers low rank
Overall local resource enhancement/ competition
Studies show LRF produce more males than females
Why are male mortality rates higher in humans?
Testosterone
Parental investment
Optimal parenting- managing your investment in offspring
What are the two options?
1) bias the sex ratio
2) differential parental solitude (favoritism)
What is the reproductive insurance hypothesis?
Using the bird example of having 3 chicks a day apart and the strongest survives
- when resources are plentiful- parents can raise multiple offspring and there is less competition
- when resources are scarce: parents can’t raise all offspring and offspring compete vigorously
What are the constraints of reproductive insurance hypothesis?
Constraints:
1) it is hard to predict resource abundance in advance (as to reduce # of laid eggs)
2) can’t always be sure first egg laid will hatch properly and succeed - many unknowns
What are the three methods of human differential solitude (favoritism)?
1) genetic biased abuse in infanticide
2) sex biased nursing patterns
3) biased inheritance patterns
What types of conflict arise when parents you strategies to maximize their reproductive success?
1) conflict between parents and offspring
2) sibling rivalry
The optimal allocation of resources from the parents perspective May not be optimal from the perspective of other offspring
What is the concept of parent offspring conflict?
There is a point in the parenting of offspring that any additional investment has little value and detracts from parents ability to produce more offspring
- parents then curtail anymore additional investment in offspring and turn to production of offspring to maximize LRS
- what maximizes parents LRS may not maximize offspring eg. Gelada monkey mom weaning baby
Baby wants milk which is rich in fat and nutrients
Resulting …conflict btwn parent and offspring about length and amount of investment and conflict among siblings about amount of investment each gets.
What strategies will offspring use to secure additional investment?
- manipulating parental psychology eg regressive behaviour mimicking infants
- schmoozing and whining
Selection will favour strategies in offspring for soliciting and securing additional investment
What is the limit to the conflict and rivalry found among parents and siblings??
-offspring all related
- upper limit beyond which competition for parental resources is maladaptive
I.e at some point resources don’t benefit you anymore, you should relent and allow diversion to siblings
How does relatedness contribute to conflict?
An individual is twice is related to its own kids then to its siblings kids but parents are equally related to their kids kids example grandparents
This results in conflict
What is inclusive fitness?
The successful passing of genes to offspring
Individuals reproductive success
What is the inclusive fitness working principle?
Selection favours individuals who act selfishly to maximize their genetic representation in future generations
What are the two routes and individual would take to maximize their inclusive fitness?
Individual reproduction and reproduction of kin
How does helping your own kin help your inclusive fitness?
Kin share copies of your genes
-so you can increase your own inclusive fitness( representation of your genes in future generations) by helping your kin reproduce and reproducing yourself
What does inclusive fitness understanding clarify?
-Family members should be generally tolerant or actively cooperative (genetic interests overlap)
-you should also sometimes compete
(Because genetic interest don’t overlap completely sample 100%
- there should be a limit to that competition
Explain Hamiltons rule
Hamiltons rule
Cooperation is favoured by selection when:
(r)B>C
Otherwise compete
r=degree of relatedness btwn actor and recipient
B=benefit to recipient
C=cost to actor
If r = 0 cooperation not favoured because cost paid by actor is for benefit of unrelated participant
Cooperation btwn non relativesnot evolutionary stable and not favoured by selection and would quickly disappear
If r>0 cooperation favoured depending on cost and benefit
What is kin selection?
A type of natural selectionwhere is individual attempts to ensure the survival of its own genes by checked in closely related individuals first
- cooperative behaviour can be favoured by selection if it improves the reproduction of kin
What are the 3 basic predictions about kin selection? Describe each
1)cooperation should be more likely if cost low and benefits high
Most common forms of cooperation in primates
-low costs - grooming, co-feeding, proximity/affiliation
-benefits - predator protection- (rare- typically mothers of offspring
2) cooperation should happen primarily among kin
E.g old world monkeys - females philopatric- females cooperative, males compete
Chimps- males philopatric- males cooperative, females compete
3)varies with kinmanship
Eg. Ow monkeys- cooperate with related females in group, compete with unrelated females (matrilineally organized dominance hierarchies)
Chimps - males cooperate with other males in group (even tolerate mating w females) but will attack/kill males feom other communities
What do owm females do after a fight?
They selectively redirect aggression at kin of former opponents
Define following words
Phenotypic altruism = genotypic selfishness
Phenotypic- observable traits
Altruism - organism helping another without a benefit
Genotypic- genetic
Selfishness
What are the 3 types of cooperation?
Mutualism
Altruism
Reciprocal altruism
Explain mutualism
Multiple individuals working together towards a common goal that is then shared. Mutual, simultaneous benefit to all. No problem for Darwinian natural selection.
Eg. Mutualistic hunting
And mutualistic pray defense
Altruism explain
Asymmetric costs and benefits for participants.
Some pay the cost some reap of the benefits
Among kin- may have indirect effect on IF- not really altruistic
Non kin- truely altruistic
Eg. Baboon male coalition altruism
What is reciprocal altruism and why can it be tricky
When organisms that are non kin help each other out
There is a cost to helping but it will be reciprocated in the future
This is tricky as there is constant temptation to deflect, cost may be more than the future benefit
What are the certain conditions that can make reciprocal altruism stable?
1) stable groups with infinite opportunity for future interaction - temptation to defect over-ridden
2) if indiv. Can recognize each other and recall past interaction- restricts helping to other helpers
3) if cheater can be punished,,at least future support can be with held.
Under these conditions, reciprocal altruism among non kin can be stable and evolve but complex social problem
Give examples of reciprocal altruism
1- male alliances in baboons
2- agonistic support after grooming in vervet monkeys
3-non primates- blood meal sharing in bats
Why is reciprocal altruism uncommon?
1- unstable, requires complex social cognitive abilities
2-involves exchanging currencies that make it hard for us to detect although it is present
Explain female bonded social structure
Female bonded
-males disperse and females philopatric/
resident
-natal males leave and immigrant adult males join
-groups comprised of closely relates females and unrelated males
-female kinship ties frame and organize female social life within the group
-Kinship bonds influence patterns of association, grooming, dominance, agnostic support, mate choice, etc.
