Lecture 11 - DA

Question 1

Define autotroph.

Answer 1

Organisms using CO2 as a source of carbon.

Question 2

Define heterotroph.

Answer 2

Organisms that use organic carbon as a source of carbon.

Question 3

Name and explain the two kinds of autotrophs.

Answer 3

Photoautotroph - Uses light to fix CO2 into organic carbon.

Chemoautolithotroph - obtains energy from the oxidation of inorganic compounds.

Question 4

What % of Earths surface is covered by water?

Answer 4

71

Question 5

What are coccoliths, and which organisms have them?

Answer 5

Calcareous plates of calcium carbonate surrounding some phytoplankton.

Question 6

Define nitrogen fixation.

Answer 6

Conversion of N2 gas to ammonia.

Question 7

How is ammonium integrated into organic carbon?

Answer 7

Assimilation.

Question 8

Define nitrification.

Answer 8

Conversion of ammonium to nitrates.

Question 9

Can nitrates be converted back to N2 gas?

Answer 9

Denitrification.

Question 10

Where is primary production highest in the ocean? Why?

Answer 10

Close to the shore, due to runoff from rivers bringing nutrients.

Question 11

Where does nitrogen fixation normally occur in the ocean, and by what?

Answer 11

In the middle of the ocean, by cyanobacteria.

Question 12

What is nitrogen fixation typically limited by, and why?

Answer 12

May have phosphorus limitations, and is an energy expensive process.

Question 13

Why would bacteria do nitrification?

Answer 13

Generates energy for them.

Question 14

Which bacteria do nitrification, and is it a rapid process?

Answer 14

Betaproteobacteria, and is a very slow process as they grow slowly.

Question 15

Are nitrites/nitrates useful to the bacteria that make them?

Answer 15

No, its waste.

Question 16

Define denitrification.

Answer 16

Anaerobic reduction of nitrate to N2 gas.

Question 17

Describe the terrestrial nitrogen cycle.

Answer 17

Fungi or bacteria live on plant roots, providing nitrate/phosphate to the plant, and getting organic carbon in return.

Question 18

Describe the phosphorus cycle.

Answer 18

Organic phosphorus mineralised by phosphatases into inorganic phosphorus by bacteria and fungi.
Phosphatase is extracellular, so Pi can be taken in by roots/mycelium.

Question 19

Do plants use organic or inorganic phosphorus?

Answer 19

Inorganic only.

Question 20

How many key processes are involved in nitrogen cycling?

Answer 20

6.

Question 21

Describe the sulphur cycle.

Answer 21

Sulphur is present in the soil in esters and amino acids.

Converted to sulphates by bacteria so plants can use it.

Question 22

Give the common name for the following:
Protheria
Metatheria
Eutheria

Answer 22

Protheria - monotremes
Metatheria - marsupials
Eutheria - placentals

Question 23

What are 2 common monotremes? Do they lay eggs?

Answer 23

Echidna, and platypus. Lay eggs.

Question 24

Where are monotremes found?

Answer 24

Only in Australia.

Question 25

Name some common marsupials.

Answer 25

Bandicoots, taz devil, wombats, koalas, kangaroos, wallabies.

Question 26

Name some placentals.

Answer 26

Rats/mice, bats.

Question 27

Out of the monotremes, marsupials, and placentals, which was first to inhabit Australia?

Answer 27

Monotremes.

Question 28

How did marsupials reach Australia, and from where? What about placentals?

Answer 28

Started in China, to NA, then SA, to Antarctica, then Australia. Placentals are similar, but only flying ones reached Australia.

Question 29

Do any organisms living in the desert cope with the heat, or try to avoid it instead?

Answer 29

All animals avoid the heat regardless of size or diet, tend to be nocturnal.

Question 30

What factor is a driving force for habitat selection and distribution in Australia, especially deserts?

Answer 30

Water.

Question 31

Do animals tend to avoid heat during the day in grasslands?

Answer 31

Yes.

Question 32

Is free water found in grasslands?

Answer 32

Yes, in some areas.

Question 33

Are open forests cooler than grasslands?

Answer 33

Yes, due to more vegetation cover and water.

Question 34

How are species distributed in open forests?

Answer 34

By strata - their height, composition, and nutrient availability.

Question 35

Is the climate constant in rainforests?

Answer 35

Yes.

Question 36

Is water freely available in rainforests?

Answer 36

Yes.

Question 37

Are rainforests good shelter for animals?

Answer 37

Yes, but too dense for large animals.

Question 38

Do alpine regions have low or high seasonal variation in temperature?

Answer 38

High.

Question 39

What provides protection in alpine regions during winter?

Answer 39

Rock cover, and burrowing into soil.

Question 40

Do alpine animals seek cover during seasonal changes?

Answer 40

Yes, but some can migrate with seasons to better cope.

Question 41

Is water scarce during summer in alpine regions?

Answer 41

Yes.

Question 42

Which native Australian mammal is distributed across the continent?

Answer 42

Echidna.

Question 43

Do echidna have a particular habitat requirement?

Answer 43

No.

Question 44

How do echidna cope in alpine regions during winter?

Answer 44

Hibernate.

Question 45

What are megafauna, and where are they now?

Answer 45

Huge car sized mammals before indigenous population came. They were hunted by them, and predated by dingoes which were introduced by aborigines. Now extinct.

Question 46

What 2 reasons led to the extinction of the taz tiger?

Answer 46

Dingo predation and human culling.

Question 47

What is the habitat requirements of the leadbeater possum like, and what are they threatened by?

Answer 47

Very specific requirements, threatened by wildfires and timber industry.

Question 48

Where are mountain pygmy possums found, and what is leading their numbers to drop?

Answer 48

Alpine regions. | Habitat loss from ski fields, wildfires, and predation by feral cats and foxes.

Question 49

Which population of taz devils does devil facial tumour disease affect?

Answer 49

Only those in Tasmania.

Question 50

What is leading to a drop in numbers of taz devils?

Answer 50

Devil facial tumour disease Road, dog and fox kills Low genetic diversity

Question 51

What 3 factors are leading to a drop in numbers of eastern barred bandicoots?

Answer 51

Habitat destruction from introduced herbivores, predation, and disease.