Lecture 15 - Extreme enviroments (Antarctica) Flashcards Preview

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Flashcards in Lecture 15 - Extreme enviroments (Antarctica) Deck (21):

what seasonal changes does changes does the Antarctic go through?

Over summer ice sheets retreat making the land smaller, in winter they grow


Explain biodiversity in the antarctic

due to extreme habitat diversity is reduced, but still wide range of oraganisms


What are primary producers found here

Planktonic algea - mainly diatoms, benthic algea, icea algea although some macroaglea


What are the consumers found here (8)

Zooplankton, soft corals, annelids, molluscs, crustaceans, fish, birds, mammals


List a simple food web for this

Diatoms -> zooplankton > fish, squid > sea birds, mammals > apex predators killer whale, leopard seal


What four organisms make up the "ice food web"

Worms, Bacteria, uniceullar algea and diatom chains, curstaceans


what is the keystone species of consumers in the antarctic

Krill, form dense swamps of up to 10,000 per square meter. Swams do not mix and have different sex rations, size and stage of moult. Also commerically fished


Explain the ecology of krill

Grow to up 6cm long, feed on other zooplankton and phytoplankton, have swimming legs, filter deeding appendages, will feed on sea ice algea like a "lawnmower"


Explain the cycle of life for a krill

Fast swimmers, mature after 3 years when mate by spawning, fertilised eggs released which sink to sediment (2000-3000)m deep, then hatch into larvae called naupliii, slowly ascend developing on the way over three years. Immature krill will hide in ice carvens to avoid >predation


Explain the four adaptations of higher organisms (vertebrates) to antarctic environment

> Body form - short and fat to reduce sa/v ration, young grow rapidly
> Thick skinned with thick fur or feathers (birds have very thick downy under feathers)
> Blubber
> Antifreeze - have it in their blood to stop it solidifying


Give details on the antartic fish ecology

> have no swim bladder, neutrally buoyant
> Dint have haemoglobin
> have slow metabolism
> Large gills and scale less skin
> high cardiac output and high blood volume


Explain the antifreeze found in fish blood

Sythesized in the liver and secrete into the blood, prevent freezing by adsorbing and inhibiting growth of ice crystals, may have ice externally but inside is ice free. Possible removal of ice in the spleen


What is CCAMCR

Convention for conservation of Antarctic marine life resources


Give an example of two fish that are over exploited

Dissotichus spp. (2 types) are fished and sold in japan for £1000 per fish


Explain the birds that live / migrate here

All migrate away in the winter apart from penguins (only some species)


Explain the life of the South-polar Skua

It is the bird of prey here, arrives in September and leaves in march. Main food - Penguin chicks and eggs including fish. Parenting - lays on single egg


Explain the life of the Giant antartic petrel

Largest flying bird found here 2.2m wingspan and weigghts 5kg. Feeds on fish, offal and carrion. Arives august, leaves april


Explain the life of the Wilsons Storm petrel

Smallest bird at 10cm long, migrates 40000km per year! July feeds in Arctic, December breeds in Antarctica. Feeds on krill and organic waste


Explain the life cycle of the adelie penguin

Common, arrives in october and leaves in feb. 99% of food is krill, nests in rookeries and has the main apex predators to contend with


Explain the life cycle of the Emperor Penguin

Found on antarctic ice zones. Mating last 10 seconds and occurs one a year. Eggs laid in may male incubates the egg in large colony. During winter they are "packed in" with about 10 per square meter. Egg hatches in July


Two examples of marine mammals that are present here

Weddell seal, Leopard Seal