Lecture 4 - Hormones & clocks

Question 1

What hormone causes less hunger?

Answer 1

leptin

Question 2

What hormone causes more hunger?

Answer 2

ghrelin

Question 3

Where is leptin released from?

Answer 3

fat storage cells

Question 4

Where is ghrelin released from?

Answer 4

stomach

Question 5

What is a circadian rhythm?

Answer 5

24 hour cycle

e.g. sleep wake, body temp

Question 6

What is a circalunar rhythm?

Answer 6

monthly

e.g. menstrual cycle

Question 7

What is a circannual rhythm?

Answer 7

1 year

e.g. migration, reproduction

Question 8

How would you test a circadian rhythm?

Answer 8

animal under constant conditions, day and night irrelevant, no circadian rhythm
naked mole rat

Question 9

Describe breeding birds internal clock circannual rhythm

Answer 9

pituitary hormones control onset of reproduction when day length and internal rhythms coincide

Question 10

Drosphillia sex peptides and receptivity

Answer 10

females mated to males unable to supply sex peptide as likely to copulate again within 48 hours as virgin females

Question 11

What does testosterone do? Name 4

Answer 11

promotes sperm production
activates sexual behaviour
aggression
suppresses immune system

Question 12

Sex drive in male guinea pigs

Answer 12

castrated = motivation to mate decreases
individual differences disappear
testosterone therapy = rose back to pre-levels

Question 13

Aggression female dunnocks

Answer 13

variable mating system, sometimes polygyny

T conc higher in females competing for males in polygynous groups

Question 14

Bird egg yolk

Answer 14

canaries, level dictates how enthusiastically to break out of shell
last chick = size disadvantage, compensates last to hatch

Question 15

Paternal care

Answer 15

monogamous men = high T, low investment

more so in polygynous - interferes with parental care

Question 16

Costs of testosterone

Answer 16

reduced immune function = reduced survival
side blotched lizard - throat colour variation
orange = highest t, lowest survival