Lecture 11

Question 1

Which continent is surrounded by the southern ocean?

Answer 1

Antarctica

Question 2

What environment is Antarctica classed as?

Answer 2

A polar desert

Question 3

What is a dry valley?

Answer 3

2% of Antarctica’s landmass not covered in ice. Organisms that die here are not decomposed and are exceptionally preserved

Question 4

What is the invertebrate distribution in Antarctica?

Answer 4

No flying invertebrates

Mostly Arthropoda, spiders, earthworms and mollusks

Question 5

When do seals and penguins breed? Why?

Answer 5

The breed in summer (October to January) as the peninsular has been exposed by melting ice

Question 6

Why is the southern ocean so productive?

Answer 6

Constant abiotic changes occur(temperature, salinity and density due to melting ice)

Question 7

Why do Antarctic algae layer in ice?

Answer 7

Due to their different light tolerance and nutrient requirements

Question 8

What is the keystone invertebrate species in the southern ocean?

Answer 8

Krill

Question 9

What do krill feed on?

Answer 9

Phytoplankton and algae frozen in ice over winter

Question 10

How to fish prevent freezing in the cold southern ocean waters?

Answer 10

Antifreeze mechanisms, this prevents body organs from freezing when body temp goes below zero

Question 11

What are the two methods of antifreeze in fish in the southern ocean?

Answer 11

Polyhydric alcohols (Therese are cryoprotectants)
Glyceropeptides (antifreeze mechanisms)

Question 12

What are ectotherms?

Answer 12

Organisms whose body temperatures vary with outside temperatures. Eg. Fish, invertebrates, microbes

Question 13

What are endothermic?

Answer 13

Organisms who maintain a steady body temperature (35-42 degrees) irrespective of outside temperature variation. They are warm blooded. Eg. Mammals birds

Question 14

How do endothermic keep body temperature constant?

Answer 14

Breathing oxygen(no Gill exposure to the cold) and by having a small surface area to volume ratio

Question 15

How do Antarctic birds stay warm?give species

Answer 15

Thick feathers, and they are homotherms. Examples include:petrels, gulls, albatross etc

Question 16

What do penguins feed on in the southern ocean?

Answer 16

Small Adele penguins feed on krill, larger penguins (eg empower) will preferentially feed on fish and squid but krill if they have to

Question 17

How do penguins remain insulated from the cold?

Answer 17

Covered in feathers with an underlying insulating layer of fat. Never put their entire foot on the ice, as this reduces surface area for feet lose (feet aren’t insulated)

Question 18

What is counter current heat exchange? Describe it

Answer 18

The arteries and veins are far closer to one another than when counter current heat exchange is not occurring. Artistries carry warm blood, veins cold blood. As they are closer together, warmth from arteries diffuses heat to veins carrying cold blood back from extremities. This causes the cold blood returning to the heart to be warmed, maintaining core body temperature.

Question 19

Why do seal have blubber? (Three reasons)

Answer 19

For insulation, buoyancy, and to use as an emergency food reserve if needs must

Question 20

What are the two types of whales in the Antarctic?

Answer 20

Toothless and toothed whales

Question 21

What are the three toothless whales, and what do they feed on?

Answer 21

Baleen whale- krill
Blue whale-krill and fish (herring and mackerel)
Humpback whale- scoops fish and krill

Question 22

What re the Two types of toothed whales?

Answer 22

Sperm whale- largest. Feeds on squid, fish sharks

Killer whale- feeds of fish, penguins, seals and young other whales

Question 23

When does breeding occur in Antarctica?

Answer 23

Spring and summer

Question 24

What are the two methods of breeding in Antarctica?

Answer 24

Timing breeding with the melting of ice (eg seals) or to breed in areas of free ice(common in snow petrels)

Question 25

Why is the Antarctic island South Georgia significant?

Answer 25

South Georgia is an ice free island off the coast of Antarctica, where penguins, seals and birds breed as the region is ice free

Question 26

What animals breed in South Georgia?

Answer 26

Wandering albatross, king and macaroni penguins, fur and bull seals

Question 27

What are there three animals that remain in Antarctica over winter (whilst the rest return to the sea after breeding)

Answer 27

Empower penguin
Weddell seal
Shua (bird)

Question 28

Explain what empower penguins of in winter in Antarctica.

Answer 28

The females lay the eggs, and the go to sea to feed. For these three months, the males safeguard the eggs and huddle against the cold.
Females return when the chicks have hatched for feeding, and over a five and a half month period the males and females take turns.

Question 29

Explain the wedded seals behaviour in winter in Antarctica.

Answer 29

Lives under the ocean in the ice and comes up open holes in the ice to feed. They stay in the water as it is significantly warmer than the air (1.8 degrees compared to -20 in air)

Question 30

Why are shuas unnatural in Antarctic waters?

Answer 30

They’re scavengers, and normally would migrate for winter, however increased human research stations has provided enough food for them to remain for winter