Theories/Paradoxes/Rules Etc

Question 0

ESS - Evolutionarily Stable Strategy

Answer 0

If all the members of the population adopt it, no mutant strategy can do better

Question 1

Game Theory

Answer 1

• Fitness consequences of a behavioural strategy
• Costs and benefits of an action depend on other members of the population’s actions
• Effects so social competition within species & how it shapes the evolution of traits

Question 2

Hawkes & Doves

Answer 2

• Hawks always fight to kill
• Doves display never engage
• Mix of hawks and doves when average payoff for hawk = average payoff of dove
• ESS established in 2 ways:
  1.) 7/12 hawks in population and 5/12 doves
  2.) Individuals playing hawk 7/12 of the time and acting dove 5/12 of the time.
  Examples in nature - narwhals are hawks, lions are doves

Question 3

Reciprocity

Answer 3

• Benefit of altruism to recipient is greater than cost to donor
• Due to time delay, vulnerable to cheating
• Can be stable evolutionarily
• Donors must recognise and refuse cheats
• Sufficient interactions to allow net benefits to all donors
• Benefit of aid must outweigh cost of donating

Question 4

Anisogamy & Bateman’s Principle

Answer 4

AKA Heterogamy
Sexual reproduction by fusion of dissimilar gametes
(Differ in size, form etc.)
Sperm & Egg
Female eggs - large, nutritious, immobile
Male sperm - small, DNA only, mobile
- Causes eagerness in males and passivity in females

Bateman’s Principle

1. Sperm outnumber eggs, males compete & success depends on number of mates
2. Eggs are large, nutritious and more costly than sperm. Females should be choosy and success depends on parental care

Question 5

Fisher Process (sexy sons) 
Runaway selection

Answer 5

• Mothers choose mate via arbitrary attractive traits
• Traits may reduce survival, higher reproductive success
• Trait & preference linked –> positive feedback
• Elaborate traits favoured.

Question 6

The Lek Paradox

Answer 6

• If all females prefer same traits they will become the fixed traits in the population
• All males becoming identical would decrease value of female choice
• Genetic diversity is maintained by:
  Deleterious mutations
  Parasite host coevolution

Question 7

Hamilton’s Rule

Answer 7

rbB > rcC. (B is benefit C is cost)
3 nephews survive = 0.25 x 3 = 0.75
1 offspring dies = 0.5 x 1 = 0.5
–> net gain of 0.25 units through Altruism therefore altruistic behaviour spreads

According to Hamilton’s rule, kin selection causes genes to increase in frequency when the genetic relatedness of a recipient multiplied by the benefit to the recipient is greater than the reproductive cost to the actor.

Question 8

Eusociality

Answer 8

• Ants - worker, soldier, male, queen
• Cooperative care of young
• Sterile castes
• Overlap of generations

Fortress defenders and life defenders

Question 9

What are Timbergen’s four questions?

Answer 9

1. Development - How does the behaviour develop?
2. Mechanism - What stimulates the behaviour short term?
3. Function - What is the behaviour for? How does it promote survival?
4. Evolution - Where has the behaviour come from?

Question 10

What happens when there is a failure of mutations to occur?

Answer 10

Persistence of non-adaptive traits
E.g. Arctic squirrels react to “snakes” even though they are not usually present anymore (this behaviour remains from their ancestors)

Question 11

What is pleitropy?

Answer 11

Where genes have multiple developmental effects (not usually beneficial)

Question 12

What is optimality theory?

Answer 12

Greatest benefit related to cost

Most likely to see in population

Question 13

What is convergent evolution?

What is divergent evolution?

Answer 13

Convergent evolution:
Distinct ancestry, shared behaviour

Divergent evolution:
Shared ancestry, divergent behaviour

Question 14

What is a male biased operational sex ratio?

Answer 14

Means there are more sexually competing males that are ready to mate than sexually competing females ready to mate

Question 15

What are the consequences of parental care?

Answer 15

Increased offspring survival
Decreased ability to produce more offspring

It is more beneficial to females as they gain less from further copulation

Question 16

What are secondary sex characteristics?

Answer 16

Enhanced traits involved in mating / sexual selection e.g.
Weaponry 
Body size
Sensory/locomotive apparatus
Dominance hierarchies

Question 17

Why do males develop friendships with females?

Answer 17

They help protect her offspring

She rewards them by mating with them

Question 18

Direct benefits of female selection

Answer 18

Parental care
Food
Territories (quality and size)
Spermatophore (nutritional)

Question 19

Genetic benefits of polyandry

Answer 19

Fertility insurance hypothesis - mating with several males decreases risk that some eggs remain unfertilised

Good genes hypothesis - mate with several males as social partner may have decreased genetic quality compared to others

Genetic compatibility theory - several males, increased sperm variety, good chance sperm will be a good match for eggs

Question 20

Material benefits of polyandry

Answer 20

More resource hypothesis - more mates = more resources revived from sexual partners

More care hypothesis - more mates = more caregivers for offspring

Better protection hypothesis - more mates = more time with protesters to stop sexual harassment

Infanticide reduction hypothesis - more mates = more confusion about offspring paternity - less infanticide

Question 21

What is the alternative name for intra-sexual selection?

Answer 21

Sperm competition

Question 22

What is the alternative name for inter-sexual selection?

Answer 22

Cryptic female choice

Question 23

What does pre-copulatory sexual selection consist of?

Answer 23

Male male competition and female choice

Question 24

What does post-copulatory sexual selection consist of?

Answer 24

Sperm competition and cryptic female choice

Question 25

What are requirements for sperm competition?

Answer 25

``` Mating with multiple males Sperm storage (ejaculates to overlap) ```

Question 26

Adaptations for avoidance of engagement in sperm competition

Answer 26

``` Physical barriers of female remating Chemical barriers of female remating Mate guarding Takeover avoidance Genetic morphology Copulation duration Testes size Sperm characteristics ```

Question 27

Examples of cryptic female choice

Answer 27

``` Preventing full copulation Influence sperm transport/storage Selective sperm use Selective egg laying Differential allocation of eggs Selective abortion Mating plug removal Remating ```

Question 28

Costs of social living

Answer 28

Conspicuous Increases disease and parasite transmission Increases food competition Time and energy expenditure of subordinates increases (dealing with dominant companions) Males are vulnerable to cuckoldry Females are vulnerable to egg tossing and reproductive interference

Question 29

Benefits of social living

Answer 29

Dilution effect - defence against predators Others can assist when dealing with pathogens Subordinates remain safely in group Males can cuckold others They can toss/dump eggs and decrease others reproductive success

Question 30

What is mutualism?

Answer 30

Shared direct fitness gain (e.g. Lion pride prey capture) Mutual dependence is necessary to social well being Symbiosis - beneficial to organisms involved

Question 31

What is obligate altruism?

Answer 31

Permanent direct fitness loss (potential for indirect gain) | E.g. Honey bee workers forage for colony

Question 32

What is facultative altruism?

Answer 32

Temporary direct fitness loss with potential for indirect gain followed by repro E.g.florida scrub jay helps nest gaining parental territory

Question 33

What is altruism?

Answer 33

Acting to increase another individual's lifetime number of offspring at cost to ones survival and reproduction

Question 34

What is kin selection?

Answer 34

There is no difference between gene copies produced by helping offspring of siblings. (Increase your own fitness this way) natural selection in which an apparently disadvantageous characteristic (especially altruistic behaviour) increases in the population due to increased survival of individuals genetically related to those possessing the characteristic.

Question 35

What does inclusive fitness consist of?

Answer 35

Direct fitness + Indirect fitness

Question 36

What is haplodiploidy?

Answer 36

Sex determination system Males develop from unfertilised eggs & are haploid Females develop from fertilised eggs and are diploid (This determines sex of all members of insect order Hymenoptera - bees, ants, wasps)

Question 37

What do fortress defenders do?

Answer 37

E.g. Aphids, termites Nest and feed inside protected home Favoured if nest is defendable and can hold many or if finding a new nest is hard

Question 38

What do life defenders do?

Answer 38

E.g. Ants, wasps and bees Forage outside the nest risking predation Grouping, ensuring loss of dependent brood

Question 39

Differences in parental care between short and long lived birds

Answer 39

Short lived birds (N.america) Spend more time & energy protecting offspring as may be their only chance. Nest predators - short lived birds stopped feeding to protect offspring Long lived birds (S.america) Minimise risk to themselves as they will have future chances to breed Adult predators - long lived birds stopped feeding to protect themselves

Question 40

What is polygamy?

Answer 40

One member/sex mates multiple times (other sex doesn't)

Question 41

Types of communication and their subtypes

Answer 41

Auditory - songs, calls, drumming Chemical - pheromones, scent, taste Visual - coloration, ornamentation Tactile - grooming, nuzzling

Question 42

Selection on signallers

Answer 42

Maximise detectability - physical environment and audience E.g.rufous collared sparrows sing slower trills in forest than grassland Minimise costs Energetic costs - displays when competing for food (display depends on level of hunger B>C) Northern fulmar, low cost - wing raising, high cost - ramming from behind Detection by predators - great tit alarm calls (mobbing call = call to arms! sweet call alerts co specifics but less chance of detection)

Question 43

What is signallers aim?

Answer 43

Manipulate receiver behaviour in a way that benefits signaller

Question 44

How do signals maintain honesty?

Answer 44

Physical constraints on deceit Handicap principle

Question 45

How does worker behaviour develop in bees?

Answer 45

Different task performance rates peak at different ages. | E.g. Foraging peaks in older bees whereas feeding larvae peaks in young bees.

Question 46

Single gene effects

Answer 46

FosB - maternal care in mice Oxt - social amnesia Drosophila - sister and rover phenotypes

Question 47

What do homeobox genes do?

Answer 47

Control genes in embryogenesis | They are homologous across animals

Question 48

What does chase away selection do?

Answer 48

Exploits pre-existing sensory bias | No benefit to female