Section 2 + Midterm

Question 1

Natural selection
How does a species change over time?

Answer 1

• natural selection: process of change
• main process > natural selection: occurs when individuals with certain traits are more likely than individuals with other traits to survive and reproduce and to pass on their traits to the next generation.
• natural selection : is the primary mechanism of biological change over time

Question 2

According to Darwin definition of natural selection?

Answer 2

• natural selection is differential reproduction: some individuals have more offspring behind than others.
• it operates at level of individual.

Darwin also pointed out that natural selection occurs when 3 conditions are met.
1. Variation in traits among individuals in a species ( need diversity)
2. Heritable: this variation is heritable ( can be passed on genetically)
3. Reproductive success; relationship exist between the traits.

Question 3

Stier writes;

Answer 3

Behavioural adaptation is sensitive to influence environment, should not be confused with misleading concepts of genetic determinism meaning that behaviour was entirely controlled and predestined by genes. Infact evolutionary theory assumes that behaviour like all other complex traits has both a genotype or genetic component and phenotype which is expression of an individual’s genotype as it affected by environmental influences.

Question 4

Who survives ? Who doesn’t?

Answer 4

• individual who happen to have the traits/ variation( morphology and behaviour) that helps them survive.
• who doesn’t: individual who happen to have the traits/ variation( morphology and behaviour) that doesn’t helps them survive.

Explanation: the environment selects some variants over others. Natural selection predicts that traits should evolve that provide an advantage ( vs any cost) to individuals who possess the traits

Question 5

Critics of evolutionary theory challenge implication that ants, baboon even human make conciliatory decision or thought calculations about how their behaviour will affect their fitness

Answer 5

• evolutionary theory decline such untestable assumptions about conscious intentionality underlying the fitness consequences of behaviour. Instead, They believed that strategies as patterns increase fortunes and therefore have functional or adaptive significance and not mental processing of the consequences by organism.

Question 6

From stier:

Answer 6

No single way rule that makes a particular behaviour idea under all possible circumstances.

Question 7

Fitness/ reproductive success

Answer 7

• individual ability to reproduce successfully compared to other members of the same species.
• low fitness= low reproductive success
  -High fitness = high reproductive success

Question 8

The traits that are well suited to the environment

Answer 8

-is an advantage for individuals survival and reproductive success
- increase frequency of the future generation ( pass on to generation)

Question 9

Traits that are not suited to the environment

Answer 9

• is a disadvantages to individual survival and reproductive success
• decrease frequency in future generations

Question 10

Natural selection and change

Answer 10

• natural selection operates on individual. Individual survive and reproduce or not.
• there is variation
• there is no absolute variant- depend on environments. ( environment only do the selecting)

Question 11

Recap: change / evolution/ adaptation by natural selection

Answer 11

the differential survival and reproductive success in each parental generation ( natural selection) leads to:
- change in frequency of traits from one generation to next( change/ evolution)
- think of adaptations as having traits that meet the characteristics/challenges of your environment.

Question 12

Altruism( popular definition ) and biological definition below

Answer 12

• popular definition of altruism: helping and selfless behavior ; opposite to selfish behaviour; recipient benefits , actor/ donor experience a cost( no benefits)
• biological definition; behaviour that potentially improves the reproductive success of the recipient, while costing the actor/donor( but there could be a potential benefit to actor/ donor.

Question 13

Examples of Altruism

Answer 13

• predator alarm: individual calls when they see predators and attract attention to themselves( cost) to colour, the rest group benefits. Caller attracts predator and got eating.
  Stier writes: such individuals that behave in altruistic ways should lose out in the fitness game to others who behave in more selfish ways to enhance their fitness.
• defending a group member from a predator: an individual interven in a predator situation ( cost)
• helping another individual in a fight; an individual aggressively intervening in a fight ( cost)

Question 14

Altruism and group selection

Answer 14

1. Originally behaviour was thought to evolve because it was “ for the good of the group”. Eg predators Alarm calls is good for group but the caller make sacrifices for the group by being eating.
2. This is called group selection
3. Group selection : defined as acting on the group rather than individual; the group is the level of selection, not in individual.

Question 15

Problem with group selection

Answer 15

• for group selection to work, groups with altruist would have to have higher group fitness that those without altruists.
• according to stiers: difficulties with group selection lies with its mechanisms. For group selection to work, group with altruists would have higher fitness than. Groups without altruist.
  Points: group altruist was mostly rejected as an explanation for altruism.

Question 16

Why altruism hard to explain

Answer 16

• based on natural selection, behaviour that increases the survival rate and reproductive success of the actor/ donor will be passed to higher rate of next generation.
• behaviour that decreases the survival rate and reproductive success of the actor/ donor will not passed on ( this is costly)

Question 17

The problem isn’t explaining that altruism exists in primates ; but we know it does. It only explaining how it could have evolved via natural selection if it is costly to the donor?

Answer 17

• answer : altruism evolved by Kin ( relatives)selection not by groups selection
• kin selection is an evolutionary strategy that favours altruistic behavior towards your relatives because it ( might) result in an increase in your genetic contribution to the next generations. Kin selection is a subset of natural selection; increase your reproductive success via relatives / the success of your relatives by hamiltion.
• evolutions predicts that individuals should behave in way that not only promotes their reproduction but also that of genetic relatives
  Stier write: although behaviour is by definition, an acts has actual or potential cost to an individual own fitness., “these cost may be offset by the benefits to an individual’s relatives”= which results in benefits to that individual inclusive fitness.

Question 18

Inclusive fitness

Answer 18

• individual fitness / reproductive success + the fittnes / reproductive success of your relatives.
  Even if you don’t reproduce, it’s possible the your genetic materials with our relative who reproduce is represented in next generation

Question 19

Hamilton rule / formula ( equation that predicts when kin selection should occur.

Answer 19

• (C<BxR ) = cost Less than benefits x relativedness
  
  1. the cost (c) to the actors/ altruist individual fitness
     2.benefits (b) to the recipient individual fitness ( in other words, offspring that would not have been produced without help of actor/ altruist)
     
     3. The degree of relatedness( r) between the actor/ altruist and the recipient ( the proportion of genes shared by actor and recipient )
• altruist behaviour is predicted to occur when the cost (c) to the actor is less, than benefits (b) times relatedness (r).

Question 20

Relatedness will always be a fraction except

Answer 20

In identical twins which is 1 to 0

Question 21

R is

Answer 21

Coefficient of relatedness

Question 22

How to calculate relatedness; you share a proportion of your genes with your relatives

Answer 22

• your self and twin = 1%
• you, your siblings, parents and your child = 50%
• full aunt or uncle, grandparents, full niece or nephew, grandchild = 0.25
• great grandchild, great aunt or uncle, great parents, full cousin = 0.125

Question 23

Evolutionary biologists J. B. S. Haldane said

Answer 23

• I will lay down my life for two brothers or eight cousins 0.5 x 2=1
• it hard to measure Hamilton rules but in reality, we can use proxy of Hamilton rules and look at outcomes; we can look at positive correlation between the coefficient of relatedness between the actor and recipient and tendency to engage in helping behavior

Question 24

Looking at outcome / correlation between relatedness and helping behaviour

Answer 24

= most altruism in primate does occur between close kin

Question 25

Kin+ grooming in primates

Answer 25

• kin relationship makes it straightforward why individuals would groom their kin
• close kin are more credential than distance kin
• the limit to preferential treatment = degree of relatedness at which points nepotism appears to drop off = relative with an r< 0.125 tends to be treated as non- kin, not treated preferentially.

Question 26

Why nepotism drop off?

Answer 26

According to Stier “ the related of threshold for altruism “ by stiers
1. Fail to recognize kin
2. Individual are : unlikely to benefits their inclusive fitness from any preferential kinds of treatment.

Question 27

How primates recognize kin

Answer 27

• smells
• recognizes their relationship, close associate between infant and mother results in recognition or familiarity with kin( social experience)
  Important to figure out , because Hamiltons rule will only work is altruist acts are limited to close kin.

Question 28

Does altruism ever occur between non- relatives?

Answer 28

• Yes,
• but altruism in non kin cannot be explained by kin selection, but only can be explain by reciprocal Altruism.

Question 29

Section 3: reciprocal Altruism

Answer 29

• Helping behaviour between non kin
• I will scratch your back if you scratch min( reciprocity between non relatives)
• Stier write; for reciprocal altruism of occur, the cost must be offset by the benefits to be gained when the recipients reciprocates with an altruistic act of his or her own.
  Several condition are required for reciprocal offset:
  1. Frequent interaction
  2. Recognition of individual
  3. Remember past interactions
  4. Assisting those who provided past assistance

Point to note; when this condition are met, individuals that help others are predicted to get helps in the future. Grooming or support given to an individual will be reciprocated later.

Question 30

Evidence of reciprocal altruism in primates eg old world monkeys.

Answer 30

• grooming go up in hierarchy ( lower ranking females groom high ranking than visa versa)
• support conflict goes down hierarchy ( higher ranking provides support for lower ranking females than vies versa)

-Points to notes: grooming for support is evidence of reciprocal altruism in primates called grooming for support models

Question 31

Does helping behaviour ever occur between non- kin without evidence of reciprocal altruism?

Answer 31

• Yes
  Thee type of behavior could evolve through mutualism

Question 32

Mutualism

Answer 32

• Cooperation between two or more individuals where each gains a benefit/ shared advantage eg male to male completion in bonbons where one group trying to take over the other group even though one of the has to be alpha.
• mutualism is not reciprocal altruism.
• mutualism can be selfish behaviour ( there is no cost to the individual in terms of returning/ reciprocating favours.

Question 33

Survival + reproduction part 2

Answer 33

• survival are not enough alone, but
  Surval+ reproductive are the keys to understanding adaptation and evolutionary change over time.

Question 34

Sexual selection

Answer 34

• some traits possess by individual mostly male were impossible to explain via natural selection.
  Instead of aiding individuals in term of survival, these traits could be detrimental to survival which Darwin called Secondary sexual characteristics ( this traits serve no survival purpose nor the mechanical process of reproduction. He attributes this to sexual selection

Question 35

What are secondary sexual characteristics?

Answer 35

1. Traits that appears at sexual maturity ( generally in males)
2. Distinction between adult males and females that go beyond basic reproductive differences.which is
3. Refers as sexual dimorphism
4. Primates examples : sex, size , colouration , weaponry eg teeth etc.

Question 36

Sexual dimorphism in primates

Answer 36

Cheek phalanges in orangutans males during sexual maturity ( two morphotypes)
- they don’t have cheek pouches
- those male who do not have no phalanges are experiencing “ arrested development “ of their secondary sexual characteristics. ( eg no cheek phalanges, smaller body size than other adult males).female are reluctant ( unwilling ) to mate with these kinds of morphotypes. Thou they are matured and look like adult rather than immature.

Question 37

Why another mechanism needs to explain secondary sexual characteristics?

Answer 37

they are not easily explained by natural selection;
- costly to produce
- sometime even detrimental to survival ( make individual more obvious to predators; i.e peacock)

Question 38

Secondary sexual characteristics

Answer 38

• do not provide advantages for survival but for mating advantages for male.
• not evolve by natural selection

How these traits evolve if not by natural selection;
- sexual selection: predicts there is variation in the ability to compete with member of their own sex, to access mates and attracts members of the opposite sex. (competition for mates)

Question 39

Review ( natural selection vs sexual selection)

Answer 39

• natural selection: involves survival and physical environment. How well you respond to physical environment
• sexual selection: involves reproduction and social environment ( in general, this mean that pressure in acquiring mates if you are a male or choosing mate if you are a females.

Question 40

Two main mechanisms for sexual competition

Answer 40

1. Male - male competition
2. Female choices

Question 41

Video 2

Answer 41

Both male are in state of must once a year they do monsoon cleans in front of of ears swell up testosterone which soars to 60times more than normal levels, they become restless and aggressive. This huge bulls are in their prime. Different from African elephants, besides age and size 90% giant have tusks. African elephants fights with their tusk locked and their trunks draped over them holding their trunk in their mouth perhaps avoid stepping on them.even without tusk, the aggression is not mistaking.
Elephants here once have tusk just as African cousin but centuries of hunting change everything.kill off males with biggest ivory and only smaller tusk male get to breed to pas on their genes with the contest becomes weaker may back off. Why most males go into must during the monsoon is a misery females are receptive on and off all year round these fight are more to do with dominance and territory and sex.

Question 42

Female choice ( inter- sexual selection)

Answer 42

• Darwin’s hypothesized that some traits mostly found in males evolved not for survival but for advantages they provided their wearers but not because females preferred them.

Question 43

Sexually selected traits likely evolve in female choice

Answer 43

• behavioural or acoustic courtship display
• Ornaments
• pelage/ plumage
• colouration

Points to consider;
1. Traits in female choice could be different depending on species in question
2. Wasting energy shows possession of energy

Question 44

Good gene models

Answer 44

• female choices can lead to evolution of very different traits in different species
  
  • showing that the thread that runs through these traits is that they are likely “honest signal” about males health
• honest in sense that males who weren’t in good health can not produce these traits. Female choosing male saw perform these display ornaments/ colouration because they are in good health of some sort - the phenotypic/ eternal display is predicted to have some relationship to their genetic/underlying health.

Question 45

Handicap principle

Answer 45

• the idea being that these exaggerated traits disadvantages a male/ cot a lot to reproduce and energy can’t go toward aspect
  
  • but these sexually selected traits enable females to assess individual male ability despite his burdensome ornament= “honest signal”
• eg long tails or bright colouration are costly to produce but not function in battle for protection.

Question 46

Parental investment theory

Answer 46

• Intrasexual competition = male to male competition.
• intersexual selection = female choices

Question 47

Why female and male have different reproductive strategies

Answer 47

• parent investment theory helps us understand what we see morphology and behavior

Question 48

What is parental investment?

Answer 48

• any investiment by parents in an individual offspring that increases offspring chances of survival and hence reproductive success at the cost of parent ability to invest in other offspring

Question 49

Parent all investment and sexual selection

Answer 49

1. Intrasexual competition ( male-male competition)
2. Intersexual selection ( females choices)
   - in mammals female tend do invest more in an offspring compare to male

Question 50

Different level of parental investment (PI)

Answer 50

Minimum obligatory biological investment ; typical males female PI in mammals is 95%

Female ( high) ; few large nutrient rich egg, 1 of apply 400( humans ), gestation, , lactation.

Male (low); many tiny sperm, 1of approximately 4 billion ( humans), no gestation, no lactation

Question 51

+ limited investment budget

Answer 51

• any investment that a parent make in one offspring decreases the ability to invest in others.
  Limited investment means spending in. One place means not spending in another.

Question 52

Take home point

Answer 52

Different initial and the subsequent level of parental investment lead to very different reproductive strategies for males and females

Question 53

Prediction

Answer 53

Female have high parental investment: 1. Females will be choosier than males in who they want to mate with eg fox
2. Access to food limits female reproductive success ( which is different than males )

Males invest less in offspring: prediction;
1. Male are less choosy; attempt to obtain many fertilization as possible
2. Access to females limits male reproductive in male reproductive strategies

Question 54

Limiting factors to reproductive success in individuals females and males

Answer 54

Females : limited it access to an energetic resource such as food why? Coz conception, gestation, and lactation are energetically expensive

Males :
- limited to access reproductive opportunities ( estrus female)
Why?: to mate or not to mate, females represent resource that most strongly affect male reproductive success

Question 55

How can male increase their probability of mating?

Answer 55

• from the evolutionary point of view, estrus females are the main limiting resources for males. Thinking about mating for reproduction.

Question 56

What is estrus?

Answer 56

Estrus means conceptive ( period around ovulation when the female is about to conceive
-1. it can be concealed or revealed ovulation ( hidden) no conspicuous behavior / morphological changes around ovulation.eg white- faced capuchin
2. In other species female advertise. The timing of their ovulation through sexual swelling or perceptive behaviour( engaging in to establish sexual interaction).eg hamdryas baboon

Question 57

Sexual swelling

Answer 57

1. Male perspectives: advertise to male when copulation count most
2. Female perspective: they can also help females make the “ best choices “ about who to mate with.

• Sexual swelling may be graded signal so that female can confused or bias paternity
  
  • graded in term of probability of ovulation rather than its actual timing.
• female uses bias paternity; to advertise to her preferred male he approximate date of ovulation
• female can confused paternity; the longer the period of swelling the more difficult for male to predict the day of ovulation. Females can mate with several males.

Question 58

More on Estrus

Answer 58

• if it’s not synchronized in group= one male can monopolize mating
• if synchronized in group = one male cannot monopolize mating

Question 59

How male can increase their probability of mating?

Answer 59

-1.priority access to model : male competition
2. Alternate male strategy; sexual coercion ( male guarding + infanticide) , all male band + female. Choice

Question 60

Priority to access models

Answer 60

• estrus female/ mating with estrus female are potential objects of competition for males. This set up condition for dominance hierarchy ( higher rank male get more access to females and vice versa

Question 61

Dominance hierarchy

Answer 61

• ranking individual based on outcome of aggressive and submissive interaction over time…
  The result = asymmetry between individual in terms of relationship = this maintains the dominance hierarchy.
• dominance can inflict cost on other/ to win physical confrontation over subordinates lower ranking. Subordinates may show submissive behavior in an interaction so that no direct conflict occur.

Question 62

Priority to access model prediction

Answer 62

High rank should lead to increased access to resources = priority access to limiting resources and ultimately to increasing reproductive success
- rank effect on access to resources

Question 63

Priority access model observation

Answer 63

• in nearly all primates , for which paternity data are available, high ranking tend to sir more offspring than lower ranking males but not always

Conclusion: we can say the fit between dominance status and reproductive success is strong for male. ( Competition in all male so just to have access females

Question 64

Variation in male reproductive skew

Answer 64

• whenever you see a big skew it’s mostly explained by the priority to access Model.

-eligatarian muiriqui have lowest variance in make reproductive skew.

Question 65

Dominance hierarchy in chicken is called

Answer 65

• pecking order

Question 66

Males competes in variety of ways

Answer 66

• using and misusing infants
  1. Use infants to protect them from harms ( protection hypothesis)
  2. Agnostic hypothesis ( males use infants for protection purposes to benefits himself

Question 67

Cost of direct competition

Answer 67

Aggressive interaction can be more violets and risky in males in order to have access to female estrus has potentially greater consequences for male fitness compare to female having access to prefer food resources has female fitness.

Like Stier write: at first glance, like all male malls seem to have it easy compared to female mammals coz male don’t get pregnant or bear the energetic burden of lactation. They only worry about staying alive and mating and yet in nearly all primate species known as, fewer male survive old age than females.
Points: fewer males tend to survive to old compare to female of same species

Question 68

Priority to Access model and make philopatric species

Answer 68

Males remain in their natal group eg chimps and bonobos

Question 69

Three main benefits for males of being philopatric( living with male kin)/ patrilocal

Answer 69

1. Few extra- group to contend with ( don’t need to fight anyone outside group) general benefits
2. Access to female ( female are transferring to the group disperse at maturity) general benefits
3. Female forming inter-community attacks ( mostly chimps and few other like spider monkeys) fighting for resources like food, water etc

Question 70

In chimps?

Answer 70

Mal don’t inherit rank form their father vs age group but some other animals does

Question 71

What rank based on chimps

Answer 71

• intrinsic : size , fight ability
• extrinsic : coalition( coalition between male is particularly important in determining dominance among chimps
  Point : high ranks and paternity tend to be positively correlated in male chimps)

Question 72

Male dominant rank in bonobos

Answer 72

No rank inheritance from father and no form of coalition with one another
- mother helps so. Climb hierarchy
Points : they also have positive correlation in males

Question 73

Section 2 topic 2

Question 74

Alternate male startegies

Answer 74

• sexual coercion : mating female by force during fertility by increasing the chance that female will mate with him at a time when she is likely to be fertile decrease chances of mating with other males at some cost to females.
• the timing/ context of sexual coercion: male aggression towards female that can often takes place when a female is in estrus.

Question 75

Why do male aggressing a conceptual concept females ?

Answer 75

• with hypothesis: sexual coercion can function as a way to increase access to mating /fertilization attempts.
• the outcome of sexual coercion: A male attempt to manipulate female reproduction in that males favours

Question 76

Unpacking this statement

Answer 76

• male reproductive success is limited by access to fertile females
• male are predicted to focus on trying to gain additional opportunities to mate.
• males interested in mate quantity, combine with female interest in quality creates widespread conflict of interest between the sexes.
• male also can offer benefits to females to sway female choices ed helping rearing young. Male- female friendship

Question 77

Sexual coercion and body size

Answer 77

• predicted to occur in species with sexual dimorphism
• size differences works in a males favours
  Eg silver black gorilla
• Sexual coercion is a by- product of sexual selection
  • larger body size in males = product of sexual selection = product of male - male competition
• secondary advantage of large body size = sexual coercion

Question 78

Sexual coercion and dimorphism

Answer 78

• Sexual dimorphism: relationship between sexes are more likely to be characterized by sexual coercion
  Eg Gorilla, Hamadryas
• sexual monomorphism :more egalitarians relationship between sexes make have no physical advantage over females. Eg callitrichids, Gibbons

Question 79

Types of sexual coercion

Answer 79

1 infanticide : killing of infants to gain access to their mothers. Common among primates, 1/3 to 1/2 of infants die due to male infanticide. At least 8 hypothesis suggested to explain male infanticides but only one has received major support ( sexual selection hypothesis of infanticide )

2. Harassment: directing sexual solicitation, follows and perhaps aggression towards females that are reluctant to mate
3. Intimidation : aggression to receptive females that may make the female more likely to mate with other male in future rather than other males.
4. Mate guarding: staying I. Proximity to the female and aggressively keeping other males away from her( use k no y against less dominant)
5. Mate herding: controlling female movement to keep her away other group of males
   6 forces copulation; forcing females to mate when she is unwilling

Question 80

Sarah hrdy proposes that male infanticide has been selected for because it increases the performers “ reproductive success relative to other mammals
This requires 3 conditions to be met.

Answer 80

1. Infanticide male doesn’t killl his own infant
2. Inter birth interval of the female has to be shortened because of infanticide
3. Infanticidal males mate with the females

Question 81

2 females counter strategies to infanticide

Answer 81

1. Female- female bonded( coalition against males ) cooperation against male aggression
2. Females seek out male protection ( males protects females friends and their infants
   - main benefit for females : males friend protecting infants from other males
   - Main benefit for male ;
   
   • preferential grooming for male
   • and male may get to mate with the female in future. Yellow bonobos.
3. Paternity confusion: female mating with multiple males may prevent attack for infants
   - males are not predicted to attack an infant if they have mated with their mother. Eg chimps

Question 82

The critical resource for female reproduction is

Answer 82

FOOD
- point: female to female competition is based on food resources
-reproductive is energetically costly for females.
- internal gestation ( fetus growth/ development)
- lactation ( milk production and feeding of infants)
- parental care (carrying infants)

Good access to food ensures female reproductive success more than finding mates. Notes, sexual access doesn’t limit female reproductive success.

Question 83

Female- female competition to mates

Answer 83

• among non-humans males are rarely resource for females
• though at times female -female competition occur for access to male set resources they provide, competing for male friends etc. male are rarely a critical resource for females.

Question 84

High quality food

Answer 84

• rich in easily digestible energy and protein; growth diets
• insect, young leaves, flowers, seeds( protein), vertebrates; all contains carbohydrates, proteins, lipids,

Question 85

Low quality food

Answer 85

• poor energy and proton, subsistence diets eg mature leaves
• they are high in cellulose and dietary fibre, Tannins and Alkaloids
• takes longer to digest

Question 86

Some other primate’s consideration

Answer 86

1. Digestibility and edibility
2. Morphological adaptations
3. Body size and sex differences and energetic

Question 87

1. Digestible and edibility :

Answer 87

i. traits that makes plants attractive to primates ( evolutionary speaking, the plants aims to be eating)
ii. Reproductive parts: seeds gets dispersed
iii. Seed dispersal by some primates eg frugivores.

Another plant strategy: “mast “( en masse ) fruiting, the aim in this case to not to be eating entirely. They are many trees of the same but different species flower and fruits in synchrony making it impossible for animals to eat all of their fruits

Question 88

Traits making plants unattractive

Answer 88

• some part of the plants “do not aim “ to be eating ( evolutionary speaking)
  1. Physical deterrent : physical attribute that make plants unattractive eg
  spine, shells and husks.
  2. Chemical deterrents: chemical attribute to plants. Aka secondary compounds that make it difficult or dangerous to digest eg tannins ( bind to proteins, reduces digestibility) and alkaloid ( bitter taste )

Question 89

2. Primate morphological adaptations. Primates adaptation to chemical deterrent

Answer 89

• Sacculated: complex stomach of colonies ( leaf) eaters
• cercopithecine: cheek pouches ( fruit eaters )

Primate adaptations to chemical deterrent : eg charcoal ingestion

Question 90

+ sexual differences in diet

Answer 90

Stiers: nearly all primates studied, female have higher quality diets than males of their species. In other words female are picked about what they eats and focus their diets as much as possible on food that contains the highest digestive energy, protein and other essential nutrients they can find
1. Better quality diets explained by small body size in sexual dimorphism species ; but hid true even in sexually monomorphic species
2. Factors in reproductive efforts/ investment greater for females vs males

Question 91

Three key variable affecting females feeding behavior;

Answer 91

1. Food quality
2. Spatial distribution
3. Temporary availability ( seasonality)

Question 92

Spatial distribution of food patches

Answer 92

• evenly and clumped
  1. evenly:
• matured leaves and grasses
• not monopolizable - not worth it
• induces scrambles ( not direct)

2. Clumped/ patchy distribution:
   - eg fruits , young leaves
   - high quality foods
   - monopolizable / worth competing over
   - induced contest competition ( direct )

Question 93

How to deal with seasonality

Answer 93

1. Change diet: switch to fall back food
   - eg black and white colobus eats mature leaves
   - fall back food/ mature leaves allow group to maintain cohesion in lean times.
2. Fission -fission: change ranging / grouping patterns to maintain high quality first eg chimps

Question 94

Section 3

Question 95

Socio-ecological theory

Answer 95

• sociology- ecological theory predicted that primates sociality respond in predict way to food distribution eg spatial, food quality and temporal distribution). I.e, we are saying female primates respond in largely predictable ways to their food environments.
• suggesting that female behaviour shapes primates social evolution. In nonhuman primates, females typically drive the evolution of the social structure highlight importance of focusing on females when studying primates social evolution.

Question 96

Due to food being the most important limiting factors for nonhumans primates females:

Answer 96

• the social structure that we observe in primate species is predicted to be largely representative of
  -females mapping onto the distribution of food. And male mapping to females
• there is no social ecological models for males.

Question 97

Socio- ecological theory

Answer 97

• female dispersal within and between the group ( low), female philopatry ( no), female ranking ( egalitarian) e.g brown lemurs, muriquis.
• residential egalitarian: within the group ( low), between group( high) , female philopatry ( yes ), female ranking( egalitarian), patas monkey most guenon.
• residential nepotistic: within the group ( high), between group( low) , female philopatry ( yes ), female ranking( nepotistic and despotic), vervet monkeys and macaques.
• residential nepotistic: within the group ( high), between group( low) , female philopatry ( yes ), female ranking( nepotistic but ), Sulawesi monkeys.

Question 98

Female -female competition

Answer 98

• food competition ( within vs between group competition): relationship across female kin
• food competition ( contest vs scramble) : types of competition and intensity of competition
  - contest competitions :
  nature of competition: direct aggressive
  Scramble contest :
  Nature of competition: indirect and non aggressive

Question 99

Scramble competition:

Answer 99

• low quality food, evenly distributed not monopolizable reources
• nature of competition: indirect and not aggressive
• first com first serve type of food depletion becomes problematic as groups gets bigger leading to declination in energy intake per group. However, food resources in large groups are depleted faster than smaller groups
• primates in large group can mitigate some of cost of food depletion via behavioural responses.

In general, food size effects on feeding behavior

Question 100

Scramble for food

Answer 100

• Larger groups have larger home ranges
• larger groups have longer day journey ( to access food, cost things to do, energy consumption)

Question 101

Problems interfering scramble competition

Answer 101

1. Difficult to measure: comparing day journey length home range size between several group of different size . Control for other factors (i.e ecology)
2. Difficult to determine fitness consequences + increased energetic cost of living in a larger group experience less predation or better success in intergroup

Question 102

1. Dispersal egalitarian relationships

Answer 102

• no direct competition
• no allies to access food within group
• Egalitarian relationships = no hierarchy
• female disperse from natal group. Many folivores

– contest competition not important in diaper egalitarian but scramble is