Animal Behaviour

Question 1

What is the definition of behaviour?

Answer 1

Internally coordinated responses (action or inaction) of whole living organisms (or group) to internal and/or external stimuli, excluding responses more easily understood as developmental changes (e.g. growing thicker fur in winter is a cyclical, predictable physiological response and is developmental change rather than an internally coordinated behaviour)

Question 2

What threats can have an impact on animal behaviour?

Answer 2

Habitat loss/fragmentation
Overexploitation
Pollution
Disease
Climate change

Question 3

Which behaviours can be affected by threats?

Answer 3

Foraging
Predation
Mating behaviour
Parental care
Communication
Spatial and social behaviour

Question 4

Describe Meijer and Robbers (2014) running mice experiment.

Answer 4

Wheel running in captive rodents is often used as a measure of how healthy/happy they are.
Is this natural or neurotic behaviour?
Do wild mice run on wheels?

Placed wheels and camera traps in wild areas - food bait, predators can’t get in.
Wild mice used wheel in the wild even when food wasn’t present.
Levels of running matched population means of captive mice
Can confidently use abnormal/normal running levels as a measure of health

Question 5

What are the two categories of proximate level of animal behaviour?

Answer 5

Development = how genetic developmental mechanisms influence assembly of an animal and its internal components

Mechanism = how neuronal-hormonal mechanisms that develop in an animal during its lifetime control what an animal can do behaviourally

Question 6

What are the two categories of the ultimate level of animal behaviour?

Answer 6

Evolutionary History: EH of a behavioural trait as affected by descent with modification from ancestral species.

Adaptive Function: Adaptive value of a behavioural trait as affected by the process of evolution by natural selection

Question 7

What is the difference between the proximate and ultimate levels of animal behaviour?

Answer 7

Proximate = how questions = e.g. how behaviour is achieved, modified by experience, heritable.

Ultimate = why questions = e.g. why the behaviour evolved, influences by NS, does it relate to reproductive success

Question 8

Describe the proximate causes of monogamy in prairie voles.

Answer 8

Vasopressin: Promotes pair bonding and increases social behaviour - increased number of receptors for V in ventral pallium section of the brain, density of receptors not visible in other rodents.

Gene avpr1a affects pairing behaviour; ablating reduces pairing behaviour - injected extra copies of ventral pallidum of non-monogamous species (can induce monogamy and pairing behaviour)

Question 9

Describe the ultimate causes of monogamy in prairie voles.

Answer 9

Relationship to reproductive success:
- In ancestral species, polygynous males will often kill infants to be able to mate with the female.
- Females start mating with multiple males to confuse paternity and protect their young.
- Males decide to stick with the females to prevent female promiscuity.
- Parental males care for offspring and infants have a better survival rate, resulting in a modern species with monogamous pairs (some species can flip back to polygyny or have flexible mating systems)

Question 10

Describe the 4 levels of animal behaviour in the context of male nightingales.

Answer 10

P - Development: Birds sing in spring because they learned from their fathers.
– Isolate from young age, will have a subsong (mutated version), tutor from same species (normal song), tutor from different species (mix of subsong and trying to imitate new song)

P - Mechanism: Birds sing in spring because increasing daylength triggers hormonal changes in the body

U - EH: Birds sing in spring because it was favoured by their ancestors (doesn’t really benefit or cost but is just there, no reason to get rid of it)

U - AF: Birds sing in spring in order to attract mates

Question 11

Describe experimental test of mechanism.

Answer 11

Removing/cutting connection in specific part of the brain e.g. hypothalamus.
Changes behaviour in rats - eat too much (hyperphagic) immediately after - control (sham operation) opened brain without actually cutting connections

Question 12

Describe experimental test of function

Answer 12

Why individual magpies lay different numbers of eggs.
Gave different number of eggs to birds who usually protected different amounts. Those who regularly laid 8 eggs were able to protect 8 eggs the best.
Don’t waste eggs that they can’t feed/look after - adaptive response

Question 13

Describe comparative study of function.

Answer 13

Warning behaviour of ground squirrels (give others chance to survive but put self at risk).
Much less likely to give alarm calls if there’s no close genetic relatives around.
Most likely to give alarm calls if offspring are nearby

Question 14

What are the two branches of natural selection?

Answer 14

Natural = reproductive advantage gained through competition to survive.
Sexual = reproductive advantage gained through competition to mate

Both are ongoing at the same time but may have different intensities at different parts of an animal’s life

Question 15

What is meant by the term constraints?

Answer 15

Constraints are anything that shape the options an animal can have which can be physiological, ecological or evolutionary.

E.g. Humans evolve to walk bipedally but that narrows pelvis so birth canal isn’t big enough for brain to get bigger; wider pelvis would be unstable - can’t unevolve it

Question 16

What is the optimality theory and its assumptions?

Answer 16

Assumes individuals want to maximise reproductive output and minimise chances of death
Calculate fitness benefit of behaviour compared with other available behaviours to allow us to protect.
Net fitness benefit = chances of reproducing per unit time - chances of dying per unit time

Assumptions:
- Identify problem to be solved (decision variable)
- Choose right currency (currency variable)
- Identify available alternative solutions and constraints (constraint variable)
- Quantify cost and benefits accruing from available alternatives
- Assume appropriate genetic variation has arisen

Question 17

What is the optimality curve?

Answer 17

x axis (phenotype) represent some sort of variations that we’re interested in.
Y axis if fitness cost and benefit for each phenotype.
Want to maximise space between benefit and cost curves to predict most common behaviour in the population not just look for highest point on benefit curve

Question 18

What are the characteristics of simple optimality models?

Answer 18

Often limited number of behavioural strategies focused on a single individual.
Individuals act in isolation making decisions solely about its own behaviour.
Mainly only 1 high fitness outcome but may be multiple routes towards it

Question 19

What are the characteristics of complex optimality models (game theory)?

Answer 19

May have many behavioural strategies.
Focused on population-level outcomes (frequencies of different strategies).
Individuals interacting with others.
Multiple different fitness peaks - those at lower peak will still be present in population but different strategies

Question 20

What are evolutionarily stable strategies (ESS)?

Answer 20

Strategy which, if adopted by all members of a population, cannot be invaded by an alternative strategy

Example are scale eating cyclids (Perissodus microlepsis) - have mouths twisted in different directions. Prey fish can only protect one side at a time. Fish attack left side, prey fish defend that side until those fish can’t survive so those attacking right side increase in number. Numbers fluctuate over time until they become approx 50%

Assumptions:
- Infinite population size
- Asexual (haploid) reproduction
- All strategies are specified
- Either pairwise contests occur, or one individual competes against a group

Question 21

What is phenotypic altruism?

Answer 21

Directing behaviour to others where there’s no immediate fitness benefit to themselves e.g. hunting dogs regurgitating food for pups in pack that aren’t their own

Question 22

Describe group selection theory e.g. Wynne-Edwards (1963) and others.

Answer 22

Animals can control their own population densities through various means e.g. cannibalism, stopping reproduction at low resource level (homeostatically).
Depends partly on substitution of conventional prizes for resources as proximate subjects of competition.
Groups of animals adopting such conventional rules of competition constitute a society.
Leads to evolution of social behaviour and altruism through group selection (not individual level selection)

Question 23

Describe Inclusive Fitness Theory, e.g. Hamilton (1963) and others

Answer 23

Includes fitness of relatives as well as yourself.
Sharing genes between actors is crucial.
Explains how phenotypic altruism can evolve.
Expect higher rates of altruism between groups of closely related animals than unrelated groups.

inclusive fitness benefit of behaviour = (benefit to self - cost to self) + (B-C)(proportion of DNA that individual shares with another) + etc.

Question 24

Describe haplodiploid organisms as an argument for selection theory and inclusive fitness theory.

Answer 24

Live in colonies e.g. ants, wasps, honeybees

Diploid queen related to daughter; r=0.5
Haploid drone related to daughter; r=1
Diploid sisters are r=0.75 related
High relatedness between each other in the hive makes much more sense for workers to assist the queen in her reproduction of highly related daughters rather than having a daughter herself which will only be 0.5 related

Question 25

Describe what is meant by the prisoner’s dilemma game.

Answer 25

Two suspected criminals jailed separately and encouraged to provide evidence that the other was involved in the crime - can cooperate and not give information about other criminal or tell police.
Payoffs are for player A.
If A cooperates with B, A gets reward of only 1 year in prison.
If A cooperates and B defects, A gets sucker punishment of 10 years in prison.
If A defects and B cooperates, A gets temptation of freedom.
If both defect, both get punishment of 5 years in prison.
ESS for single game is to always defect and is always best fitness outcome for you.

Question 26

Describe tit-for-tat and delayed reciprocity.

Answer 26

Iteration of prisoner’s dilemma with the same pair permits complicated strategies which could be due to simply being erratic or environmental pressures such as energy that day.
Tit-for-tat is best strategy/ESS - cooperate on 1st move, then mimic what opponent did on te last round.
Model with tit-for-two-tats is better strategy (more forgiving, give another chance in case they made a mistake)

Question 27

Describe vampire bat food sharing as an example of tit-for-tat and delayed reciprocity.

Answer 27

Bats that share when there is need should live much longer than selfish individuals.
Donor bat loses a bit of weight and time (before starvation) but is disproportionately beneficial to recipient (gain a lot of time before starvation and gain a bit of time).
Survival gain of food sharing is at its highest when foraging success is generally high for the population.
Bats tend to be unrelated to each other - high associated and reciprocal behaviour (sometimes have high relatedness but system doesn’t seem to depend on it)

Question 28

Describe genetic transformation of maternal behaviour in mice

Answer 28

Mice can escape nest and don’t have fur to keep themselves warm so will die, part of maternal behaviour is to bring them back under her to keep her warm (fosB+).
Inactive fosB gene, female doesn’t retrieve pups (fosB-).
fosb gene affects development of the preoptic area of the brain and sensory integration.

Question 29

Describe transformation of social behaviour in mice.

Answer 29

Mice can remember social odours; as a male keeps meeting same female over and over the time sniffing her decreases.
Disable Oxt gene in male, male cannot remember social odour and spends a lot of time each time inspecting her (social amnesia)

Question 30

What is quantitative genetics?

Answer 30

Partitions genetic and environmental effects.
Assumptions are that each locus contributes additively to the trait and environmental effects are independent.
P = g + e
p = phenotypic value, g = genotypic value, e = environmental effect
Have variation in trait value around the population mean (no individuals are actually the mean, always one side or the other).

Question 31

What are genome wide association studies (GWAS)?

Answer 31

Mapping complex phenotypic traits to gene variants to identify how much is environmental effect.
Mainly used in human medicine but some wider studies e.g. genetic mapping of dog herding behaviour or maternal behaviour in sheep

Question 32

What is the interactive theory of development?

Answer 32

Interaction between environment and gene effects produces behaviour and allows evolution of that behaviour e.g. shifting behavioural roles of the worker honeybee.
First jobs are within hive before foraging.
Cleaning cells –> Feeding larvae –> Feeding next mates –> Packing pollen –> Foraging
When only had cohort of young bees, able to recognise that there wasn’t enough foraging coming in so gene expression changes and some went out to forage younger. When only had cohort of old bees, genes switch on for nursing (not as strong but still present)

Question 33

Describe the nervous system structure in starfish.

Answer 33

Nerve ring surrounding oesophagus with radial nerve in each arm.
Evidence for sensory (chemosensory) and motor neurones.
Can detect food and move towards it.
More organisation but still no clustering of neurones.

Question 34

What is the generic nervous structure in bilaterians?

Answer 34

Bilateral symmetry with head, tail, back, belly, and NS all bilateral.
Head with specialised functions perhaps resulting in clustering of neurones at this end resulting in a brain (cephalisation).
Simplest include flatworms and roundworms

Question 35

Describe the NS structure of flatworms.

Answer 35

NS has bilateral symmetry with pair of lateral NC with numerous ganglia connected by transverse nerves.
Large cerebral ganglia = primitive brain (coincide with eyespots)
Sensory projections at front

Question 36

Describe the NS structure of Roundworms e.g. nematodes.

Answer 36

4 nerve cords running length of body: Dorsal associated with motor, 2 Lateral associated with sensory input and Ventral associated with both.
Nerve ring connecting ganglia in head surrounding pharynx.
Sensory nerves extending towards Anterior end.
Neurones seem to manage with just VGCC so may predate VGSC.

Question 37

Describe the NS of Annelids e.g. earthworms, leeches.

Answer 37

Segmented, more complex NS than other worms.
Paired (fused in many cases) ventral NC with ganglia in every segment.
More active annelids have bristles (setae) that require coordination for movement.
Leeches have A and P suckers also requiring coordinated control.
More complex annelids have simple brain - large cerebral ganglia and nerve ring encircling oesophagus

Question 38

Describe the NS structure in Cephalopods e.g. squid, octopus.

Answer 38

Marked step in cephalisation and organisation.
Large head ganglia fused to form multi-brain with distinct areas and well developed eyes (driven by development of eyes).
Chromatophores allow changing of skin colour - cells containing pigment of have light reflecting properties - each driven by array of radial muscles under control of numerous nerves, requires a lot of computing power - swells up and increases area x50 when activated, appears as a small dot when inactivated.

Question 39

Describe the NS structure of Arthropods e.g. insects, crustaceans, arachnids, myriapods.

Answer 39

Diverse body plan and NS.
Tend to have well defined head with eyes and basic brain.
More complex behaviours including social interaction in some cases.
Ventral NC with paired ganglia supporting each body segment (fused similar to annelids - not always obvious)
Fusion is normally laterally but in some cases (squat animals), segmental arrangement is lost due to anterioposterior fusion of ganglia e.g. fly spider

Question 40

Describe NS structure of vertebrates

Answer 40

Pronounced cephalisation, complex SC acting as wiring interface between CNS and PNS.
Divisions into somatic and autonomic
Brain enlarged over evolutionary time, most obvious in cerebrum.
Birds have well known skills like mimicry, tools, weaving and fine flight control

Question 41

What is the encephalisation quotient (EQ)?

Answer 41

Comparison of brain:bodyweight ratio against typical animals of that group.
Calculation: C = E/S^r
C = EQ, E = brain weight; S = body weight; r = exponential constant (depends on animal group)