Lecture 16 & 17: Hammond

Question 1

Why do animals behave as they do?

Answer 1

Proximate reason- HOW- Mechanism
Ultimate reasons- WHY- Evolution
Links to tinbergens 4 questions

Question 2

What are tinbergens four questions?

Answer 2

Proximate: Causation, Development and Ontogeny
Ultimate: advantage and function, history and phylogeny

Question 3

How do you scientifically study animal behaviour

Answer 3

How do they do it? –> How would you find out? –> Hypothesise –> experiment.
Why do birds throw eggs out of their nest –> could attract predators? –> birds with removed egg shells suffer less predation –> experiment –> true or false
Repeat

Question 4

Define an adaptation:

Answer 4

A characterisitc that improves the chances of an organism transmitting its genes to the next generation.

Question 5

Can an adapted characteristic can be behavioural?

Answer 5

YES- e.g. egg shell removal –> increased offspring survival –> increased frequency of trait

Question 6

How does natural selection produce adaptation.

Answer 6

Start with variation within a species –> some variation is heritable –> competition between individuals –> some varying heritable traits are better adapted to the environment –> these variants leave more offspring –> increased frequency.

Question 7

What can vary in an organism to produce varying success?

Answer 7

Variation in alleles, variation in expression levels

–> variation in development and function

Question 8

Why is selection not very strong on a group?

Answer 8

One ‘selfish’ mutant would destroy order in a group that was behaving in a ‘good of the group’ way –> increased frequency of selfishness

Question 9

What is the strongest unit of selection?

Answer 9

Individuals- organisms survival vehicles for the immortal germ line

Question 10

What is the trade-off between brood size and individuals?

Answer 10

More offspring = smaller

Fewer offspring = heavier –> increased survival.

Question 11

What have manipulation experiments in Whythyam Woods shown us about optimal brood size?

Answer 11

Optimum brood size is a higher number than the modal brood size.

Question 12

Why is optimal brood size greater than modal brood size.

Answer 12

Hypothesis 1: increased brood size –> decreased adult survival.
Hypothesis 2: Manipulation neglects cost of egg development.

Question 13

What determines the optimal brood size.

Answer 13

Largest positive difference between benefit and cost.

Insert diagram

Question 14

What has manipulating the numbers of eggs in a brood showed us- what was done?

Answer 14

Either:

• Add 2 chicks to the brood (free chicks)
• Add 2 eggs (free eggs)
• Remove 4 eggs (causes bird to lay 2) and add 4 back (full costs)

Question 15

What has adding 2 chicks in different ways showed us?

Answer 15

Insert diagram

Hypothesis 1 disproved, support for Hypothesis 2 however female fitness decreases with increased cost.

Question 16

What determines optimal brood size?

Changing the brood size experiments

Answer 16

Individual interests
The perrcentage of young fledged is always highest when the experiment brood size = inital clutch size
Number of eggs proportional to territory.

Question 17

What causes changes in the laying dates of eggs?

Answer 17

Increasing warmth has lead to earlier laid eggs

Question 18

Is the difference in egg laying time due to individual plasticity of genetics?

Answer 18

Insert diagram

Individuals are plastic depending on temperature

Question 19

Is the link between laying dates and warmth causative or just a correlation?

Answer 19

Due to food supply (caterpillars) are emerging earlier.

Earlier laid eggs have a greater food supply

Question 20

How is the changes in egg laying dates an example of adaptation?

Answer 20

Plasticity is heritable –> plasticity genes are passed onto the next generation (in higher frequency if proportionally more survive).

Question 21

What produces the final phenotype?

Answer 21

Phenotype = Genes + Environment

- If environment is constant then variation must be due to genetics.

Question 22

What is the difference between baboons?

Answer 22

Papio h. hamadrya- herd females with one male units which then are further organised into clans –> bands –> troops MALE phylopatry
Papio h. Anubis - no herding, no organisation, FEMALE phylopatry

Question 23

How / why can behaviour be selected for?

Answer 23

Due to heritable genetic component

- Dogs (herding, retrieval)

Question 24

Does the ability to learn have a genetic basis?

Answer 24

Blow flies selected for depending on speed of associating proboscis extension reflex with sucrose reward.

• Fast flies mated together, stupid flies mated together
• -> extreme populations

Question 25

What link is there between gene number and response time?

Answer 25

Simpler the trait (fewer genes) –> faster fixation

However prenatal, nutritional and experimental variation changes this.

Question 26

How does drosophilia sitter and rover populations change depending on density?

Answer 26

Rover is dominant 70:30 to sitter
Rover is best in high density groups and sitters in low.
–> sitters can be transgenically modified with over-expressed cGMP dependent protein kinase –> rover like phenotype.

Question 27

What is the differences in mating behaviour between different vole species?

Answer 27

Prairie voles - monogamous males
Montane voles - promiscuous males
Differences in promoter micro-satellites 
 --> PV lots, MVs few 
Insert diagram

Question 28

What happens if you aritifically select for long and short micro-satellites.

Answer 28

Causes behavioural differences.
- Insert diagram
Longer micro-satellites –> more social
–> no pattern across phylogeny

Question 29

Is there any patterns with micro-satellites across the phylogeny?

Answer 29

No even though there are distinct differences between voles there is no association across the phylogeny, not even in primates

Question 30

Are identical twins more likely to be similar due to increase genetic similarity (concordance)

Answer 30

Female infedility is heritable:

38% concordance with number of sexual partners, 41% with epidoes of infidelity. Normally 0.3-0.6 heritable

Question 31

Define heritability

Answer 31

The extent to which individual genetic differences contribute to individual differences in observed behaviour

Question 32

Describe the debate about genes and human behaviour?

Answer 32

Genes explain 40% of human behaviour- should the ‘best’ behaviour e.g. mating and IQ, be selected for.
Blank slate theory- only our environment affects our behaviour.
Naturalistic fallacy- morals are culturally determined.