Lecture 11

Question 1

What is a group of female pigs with their offspring called?

Answer 1

a sounder

Question 2

What are the different forms of group living among domesticated species?

Answer 2

• Pigs: female group, male group or solitary
• Horses: harems, bachelor herds
• Sheep: ewe flocks, seasonal male flocks

Question 3

What is the difference between wild and feral?

Answer 3

wild: never been domesticated
feral: been domesticated but let back into wild (pigs, horses)

Question 4

What are the soay sheep on St.Kilda?

Answer 4

• island off the coast of Scotland
• 1,000 sheep
• most primitive form of domestic sheep, arrived around 4,000 years ago
• went feral 1,000 years ago
• Ewe flocks with infant and juvenile offspring, on home ranges, groups and range are consistant, form small sub-groups for grazing
• Rams disperse and form small groups, establish home range, disband during breeding (rut)

Question 5

What is the usask feral horse research?

Answer 5

• Sable Island ponies - around 400 horses (herd size increasing) in Nova Scotia
• linked to growing grey seal population - hunting from humans decreased
• horses benefit because seals fertilize the grass

Question 6

What are the differences and similarities between domestic and wild animals?

Answer 6

Domestication of farm species happened 10,000 to 15,000 years ago (short)
Differences: Domesticates have… smaller brains, less active, reduced alarm responses, more socially tolerant
Similarities: same basic social characteristics are found, threshold or frequency of behaviours may change

Question 7

How does natural selection operate on genetic difference for behaviour to evolve?

Answer 7

• there must be behavioural variation within the population
• the differences must be heritable - some of the variation must be genetic in orgin
• some behavioural variations will confer greater reproductive success
• Behaviour patterns are seleceted that will increase an animals chances of survival and reproduction - “fitness”

highest benefit with the lowest cost

Question 8

What determines success in evolutionary terms?

Answer 8

survival
reproduction

Question 9

Differences between Suffolk and Blackface sheep for maternal behaviour?

Answer 9

Suffolk:
* required more assistance
* abandoned more lambs
* more aggressive
* withdrew more often from lambs

Blackface (wild type):
* shorter labour
* more grooming
* cooperated more during suckling attempts
* lower lamb mortality

Question 10

How does evolutionary theory explain groups?

Answer 10

• groupos are facilitated by cooperation - but evolutionary theory is usually described in terms of competition among individuals (beneficial to both)
• theories about selfish traits

Question 11

What are the theories explaining cooperation?

Answer 11

Kin selection
* inclusive fitness theory

Reciprocal altruism
* generosity - I give you something today, you give me something another day

Multi-level (group) Selection
* Some selection occurs at group level
* There is strength in diversity

Question 12

What is kin selection?

Answer 12

• Individuals can reproduce directly, or indirectly by aiding relatives (still helping gene pool)
• group living is facilitated by cooperation between individuals - increase genetic contribution by assisting with the success of relatives
• ex. wolves: others in pack will help raise pups
• part of the ‘inclusive fitness’ theory

Question 13

What is Hamilton’s Rule in relatedness?

Answer 13

b > c / r
* c = cost (actor)
* b = benefit (recipient)
* r = degree of relatedness

shows how much you’re willing to help someone based on how closely related you are

bigger r= smaller cost

Question 14

Why would non-relatives cooperate?

Answer 14

Reciprocal altruism:
* alternating benefits - long term relationships (I help you, expect something in return) - vampire bats

Multi-level selection:
* groups that cooperate outcompete those that don’t - lions elephants

stable societies - cooperation has long-term benefits

Question 15

What are the costs and benefits of social groups?

Answer 15

Benefits:
* thermal
* foraging
* predation

Costs:
* contamination
* competition
* conspicuous

Question 16

How does forming groups minimize costs?

Answer 16

• Limit group size - acording to resources and environment
• Social hierarchy - individuals know their place, dominants have priority access to resources
• Ritualized threats, posturing (reduces aggression)
• Social rules to reduce competition - dominant individuals feed first - alliances - preferred patners, allogrooming

Question 17

What are foraging advantages in groups?

Answer 17

Detecting food
Acquiring food
Defending food

Question 18

How do groups avoid predators?

Answer 18

Detection
Dilution
Defense

Question 19

What is detection when avoiding predators?

Answer 19

Sheep - recommended 5 flock size
* detect predators through vigilance
* shared responsibilitiesfor predator detection
* time spent grazing depends on flock size

Question 20

What is dilution in terms of avoiding predators?

Answer 20

Wildebeast
* large herds - synchronized calving (predators are satiated)
* causes confusion effect - reduces predator success

Question 21

What do cattle and horses do when avoiding flies?

Answer 21

Cattle and flies
* rosette formation

Horses and flies
* head-to-tail

Question 22

Describe the costs of groups.

Answer 22

Conspicuous:
* Groups are more easily detected
* Predators can be attracted by communication

Competition:
* Commpetition and prioritized acces to food (hierarchies)
* Acute stress when forming a group: establishing relationships
* Chronic stress from subordination (inability to mate)

Contamination:
* Increased parasite & disease transmission

Question 23

How do you minimize the costs of groups?

Answer 23

– Limit group size
* According to resources and environment

– Social hierarchy
* Individuals know their place, dominants have priority access to resources

– Social rules reduce competition
* Dominant individual(s) feed first
* Ritualised threats, posturing: reduces aggression
* Alliances: preferred partners for affiliation, allogrooming

*When groups form- benefits must outweight the costs!

Question 24

True or false: According to the inclusive fitness theory, individuals can improve their genetic contribution by assisting their relatives success, with whom they share genes with.

Answer 24

True

Question 25

True or false: Subordination within a group leads to an inability to communicate effectively

Answer 25

False

Question 26

Do belding's ground squirrels recognize close relatives?

Answer 26

* Dont remember eachother after hibernation * using body odors as a reference point to figure out who is kin * relatives are less likely to fight

Question 27

Do pigs recognize close relatives?

Answer 27

* no recognition of siblings reared apart