L4 Hormones, clocks and behaviour

Question 1

What type of factor influencing behaviour are hormones?

Answer 1

Proximate

Question 2

What causes eating behaviour?

Answer 2

Hunger

Question 3

What hormones control hunger?

Answer 3

leptin and Ghrelin

Question 4

What does Leptin do and where is it released?

Answer 4

Released form specialised from fat storage cells, it is a hunger inhibitor. The more fat cells, the more leptin released

Question 5

What does Ghrelin do and where is it released?

Answer 5

Released from stomach in response to low leptin levels, causes hunger

Question 6

What causes motivation to mate?

Answer 6

Hormones, a balance between testosterone, estrogen and progesterone

Question 7

What is testosterone?

Answer 7

Primarily male sex hormone and anabolic steroid

Question 8

What is estrogen?

Answer 8

Primarily female sex hormone

Question 9

What is progesterone?

Answer 9

sex hormone involved in menstrual cycle, pregnancy and embryogenesis

Question 10

What is the difference between hunger and sexual motivation?

Answer 10

Hunger restores physiological balance, mating doesn’t

Question 11

What did Juergen Aschoff do?

Answer 11

Pioneer in biological rhythms, research in chronobiology,

Question 12

What is the concept of a zietgeber?

Answer 12

A time keeper, or internal clock that drives biological rhythms

Question 13

What may be the adaptive significance of a biological rhythm?

Answer 13

Synchronisation with the changing environment, whether daily, monthly or yearly, for coordination of metabolic process etc.

Question 14

What is a circadian rhythm?

Answer 14

24 hour rhythm, e.g. resting, sleeping, eating, temperature etc

Question 15

What is a circanular rhythm?

Answer 15

Monthly cycle e.g. menstruation

Question 16

What is a circannual rhythm?

Answer 16

Yearly cycle e.g. migration and reproduction, hibernation

Question 17

Regarding biological rhythms, what was the test on bending ground squirrels and what did it show?

Answer 17

Were held at constant light levels/temp to determine if hibernation timing and length stayed constant - it didn’t

Question 18

How did they test environment dependent control on circadian rhythms?

Answer 18

Shany fish normally live in tidal rock pools, removed the tidal element and investigated how long fish kept up normal cycle, which depends on the tides, lasted for about 4 or 5 cycles then stopped.

Question 19

What would you expect from an animal that lives under constant conditions and why is it significant?

Answer 19

exhibit no circadian rhythms, acts as a test for the adaptive significance of biological rhythms, shows they have a purpose

Question 20

What controls the onset pf reproduction in birds?

Answer 20

pituitary hormones

Question 21

Why is it difficult to measure hormone control and how do they do it?

Answer 21

Difficult to measure as such small measures, however radio-immunoassay can be used

Question 22

What are the benefits of testosterone?

Answer 22

Promotes sperm production and activates sexual behaviour

Question 23

What are the costs of testosterone

Answer 23

Suppresses immune system and stimulates aggressive behaviour

Question 24

How did they test sex drive in guinea pigs?

Answer 24

testes removed and sex drive recorded, levels went down until testosterone was injected, showed how testosterone affects sex drive

Question 25

What experiment was used to show how testosterone affects aggression and sexual competition?

Answer 25

showed by varying levels of testosterone in female dunnocks, the levels were higher in females competing for males in a polygynous population than females I na monogamous population

Question 26

What affect does testosterone have in egg yolk in canaries?

Answer 26

testosterone content increases with each egg laid and social rank is positively correlated with testosterone levels

Question 27

How does testosterone influence paternal care?

Answer 27

morning testosterone levels are higher in low investing men, in both monogamous and polygamous situation

Question 28

What example illustrates the costs of testosterone?

Answer 28

Side blotched lizard Uta stansburiana, throat colour depends on testosterone levels, however correlate with survival rate - lower with high testosterone levels

Question 29

Why do elevated testosterone levels correlate with reduced survival?

Answer 29

Because testosterone is an immunosuppressant