quiz chapter 16 and 17

Social insects: Haplodiploidy

• Females → diploid, fertilized

• Female Workers → promote wellbeing and development of siblings (indirect fitness)

• Female Queen reproduces

• Males (minority) Drones → haploid, not fertilized → related to sisters ¼

• One sister is related ¾ to other sister

Eusociality

• Division of labor (some reproduce, some do not)

• Cooperative rearing of young

• Overlapping generations → older and younger cooperation

• Queen → fertilization

• Workers → control feeding of larvae

• Social insects and 1 mammals (naked mole rat)

Female works are sterile, so

• They maximize reproductive success of mothers by raising siblings

• Working to promote wellbeing of siblings because they do not reproduce

Hymenopteran Sex Ratio Hypothesis (Trivers and Hare)

Conflict between queens and workers → queen has the same genetic relationship, but daughters are needed more

• R for sisters → 1.5

• R for sisters-brothers → 0.5

• R for queen-son → 0.5

• R for queen-daughter → 0.5

Sex Ratios by Ant Worker Results

• Primary sex ratio from queen determines, secondary from worker (manipulate ratio)

• 97% single queen → singly mated

• Multiply mated → some colonies (queen) mated to several males

Singly mated secondary ratio (workers)

• Female pupae → skewed towards female (more sisters)

• Altering ratio favoring females

Multiply mated

• Genetic relationship decreases

• More males vs females

• Sex ratio towards more males

Reciprocal altruism

• Based on one individual from group behaves in way that benefits others → expects reciprocal relationship in future

Examples of reciprocal altruism

• Baboon is grooming the other, expectation in future for the baboon to return the favor

• Vampire bats, when they have no opportunity to feed → provide blood meals from member of group (blood regurgitation)

Factors favoring reciprocal altruism

• Long life

• Low rate of dispersal (stay local)

• Long parental care

• Flexible dominance hierarchies

• Good memories and recognition

• Character detection and punishment

Flexible dominance hierarchies (reciprocal altruism)

• Someone at top, individuals support each other → will benefit, go up hierarchy

• Individuals can collaborate/support each other → elevate

Good memories and recognition

Keeping tabs on who has helped them in the past

Reciprocal mobbing in pied flycatchers

• Whenever they encounter a predator (owl) → they mob it

• Mobbing behavior is effective in large groups of birds

• Put artificial owl to see mobbing. Put group of birds in cage couldn’t assist

• As a result → the birds in the cage were not protected when the wooden owl was placed next to them

Vampire bats

• Harem (1 male, several females)

• Social thermoregulation → in cold

• Allomothering → females feed other pups (pups of other mothers)

• Need to drink 50-100% → find large mammal to make incision and drink blood

• Juveniles fail to get blood meals → put them in danger (need to feed everyday bc it is not a high quality food)

Food sharing in vampire bats

• Female will lick the side of the face of another female to “beg” for blood

• To regurgitate into the mouth of another female (accept blood)

Degree of Association of Blood Sharing Pairs

More individuals share blood if they are in close proximity to one another (close when trying to stay warm)

• Members of same related colony, bc the most sharing was parental investment, NOT altruism

Development of food sharing relationships

• Separate groups, mixed 2 groups tg to introduce them

• Became familiar with one another because of grooming, results in more meal sharing between them (develop relationship with grooming, low stakes behavior)

Grooming increases before blood donation

• Grooming increases with familiar bats before meal is shared

• Establishing familiarity then sharing meal

Non-kin adoption in the common vampire bat

• Two females were grooming each other a lot → then fed each other a lot

• Pregnant female died after giving birth, the other female died and took care of the pup (taking responsibility bc she was already lactating)

Chimpanzees and cooperation (male behavior)

• Coalitionary aggression → walk along periphery (around) territory, attack chimps from other groups

• Hunting → hunt monkeys together

• Meat sharing

• Defend territory

• Seven years of observation → looking for mate behavior

Chimpanzee kin and non-kin relationships

• In every case, the relationships were associated with non kin → come together to do everything together

Prosocial emotions

• Empathy → not just a human characteristic

• Reciprocity

• Ability to follow rules

• Reconciliation

Empathy (example)

Two juveniles → more empathy for those who have had mothers over those who are orphans

Empathy (Masserman experiment)

Rhesus monkeys were trained to pull a chain and obtain food following a blue or red light

• Pulling a chain either delivered food or shocked and delivered food → caused reduction in chain pulling

• Some monkeys prefer to starve over being shocked (high level of empathy)

Do primates have a sense of fairness? (video)

• 2 monkeys trained

• Given token, monkey gives them rock → desirable reward over undesirable reward (didn’t want the fruit given, wanted the same fruit as the other monkey)

• Threw the undesirable fruit every time they were given it

Primate characteristics

• Forward facing eyes → vision is important (binocular vision)

• Grasping hands and feet → humans have lost grasping feet

• Flattened nails

• Large brains

• Social behavior

• Parental care (increased)

Phylogenetic tree of primates (molecular clock)

• Difference in monkeys → do not have a tail

• Tree is from 20 million years ago-today

• Humans branched off from chimpanzees (closest relatives) approximately 6-7 Mya

Hominins

Extinct taxa that are more related to humans than chimpanzees

Bipedality

Walking on two

Lack a canine honing complex

• Mouth of chimpanzee → enlarged top canines → rubs against lower canines (keeps them sharp)

• Space in lower jaw (Diastema) → higher level of sexual dimorphism

• Humans have reduced canines, no diastema

Distribution of hominins

• 3-2 mya and 2-1 mya → coexisting groups with one another

• Genus homo: species meeting like Neanderthals and Homo sapiens or etc. → ALWAYS HYBRIDIZATION

Geographic distribution of Extinct and Extant great apes

• African origin (oldest records)

• Expansion to Eurasia → red stars

• Europe (mediterranean) → warm and humid environment, tropical forests

• Some point this environment cooled down → lineages either went extinct or went back to Africa (extinction or contraction)

Sparse fossil record

14-10 million years ago (critical period for some hominin species)

Hominin fossil sites

• All are from Eastern and Southern Africa

• Relevant to geography of Eastern Africa → minor platea that form (divides hominin)

• Experiencing tectonic, volcanic activities and many lakes that separate them

East African Great Rift

• Terrain

• Volcanic activity

• Fissures forming in Kenya (3 km long) bc of movement of plates

Awash Ethiopia and Tanzania

Terrain is ideal for finding fossils