L10 - Seabird Popualtion Dynamics

Question 1

How many offspring do marine mammals usually produce per year?

Answer 1

1

Question 2

What are pregnancy rates like in marine mammals?

Answer 2

Pregnancy rates are variable

• Annual in most
• Manatees/Dugongs – 1-7 years

Question 3

How do you determine age of marine mammals?

Answer 3

• teeth
• fins
• bones

Question 4

How do you tag seals?

Answer 4

Tag their flipper - can pull out

Question 5

How old do each live to?

a) Female fur seals
b) Ringed seals
c) Grey whales
d) Bowhead whales

Answer 5

a) Female fur seals - 20y
b) Ringed seals - 40y
c) Grey whales - 80+y
d) Bowhead whale - 200y

Question 6

What is the best insulation type?

a) Fur
b) Feathers
c) Blubber

Answer 6

a) When dry fur is great, when we it isn’t (apart from sea otter, where even when fur is we it acts as an insulator)

Question 7

What is special about sea otters fur?

Answer 7

it is a good insulator even when wet

Question 8

What does the Dermis contain in:

a) Seals, sea otter and polar bear
b) Cetaceans and sirenians

Answer 8

a) Seals, sea otter and polar bear
- Hair follicles
- Sebaceous & sweat glands
- Claws

b) Cetaceans and sirenians
- no hair
- no glands
- no claws
- cutaneous ridges

Question 9

How do each control their insulation?

a) seals with fur
b) seals with blubber

Answer 9

a) Fur:
- behavioural - going in the water
- autonomic - insulation changed ptiloerection (fluffing of the fur/plumage)

b) Blubber:
- behavioural - going in and out of water
- autonomic - can alter insulation effect by controlling blood flow through the shunt vessel or through the skin

Question 10

How do marine mammals cope with living in a hyperosmotic environment?

Answer 10

All marine mammals, with the exception of the sirenians, possess reniculate kidneys:

• Comprise of small lobes
• Each functions as a mini kidney
• Produce very concentrated urine