L33 Terrestrial Ecosystems (Deserts, Tundra and Peatlands)

Question 1

where is the tundra biome found?

Answer 1

high latitudes

Question 2

where is the desert biome?

Answer 2

mid latitudes

Question 3

what biome are you most likely to find at high altitudes on tops of mountains?

Answer 3

tundra

Question 4

what does a rain shadow lead to?

Answer 4

arid dry conditions

Question 5

what is the annual rainfall in deserts?

Answer 5

<250mm per year

Question 6

what is climate variation in the desert like?

Answer 6

high variation in temperature, 50 degrees during day and below freezing at night

Question 7

what are three ways organisms in the desert can ‘tolerate drought’?

Answer 7

1) intensification of water absorption
2) reduction of transpiration
3) CAM - Crassulacean acid metabolism photosynthesis

Question 8

how do plants intensify their water absorption?

Answer 8

shallow roots that are spread very far horizontally or by deep tap roots of >15m

Question 9

what plant adapts to the desert biome by intensifying water absorption?

Answer 9

agave filifera have dew/fog traps which capture fog moisture

Question 10

what is an air plant?

Answer 10

they have no roots in the ground, they absorb all moisture from atmosphere through leaves example tillandsia

Question 11

what are the absorption scales on tillandsia called?

Answer 11

trichomes

Question 12

how do plants reduce the level of transpiration?

Answer 12

closing stomata

hair around stomata prevents wind flow

Question 13

how much water is lost via stomata from transpiration/ gas exchange in photosynthesis?

Answer 13

95% of water absorbed is lost

Question 14

what is CAM?

Answer 14

crassulacean acid metabolism photosynthesis

Question 15

when is CAM used?

Answer 15

when stomata are closed during the day to prevent water loss
this also leads to reduced photosynthesis
CO2 is taken in at night and is used up the next day during photosynthesis

Question 16

what are the 3 ways a plant completes photosynthesis?

Answer 16

C3, C4 Cycle and CAM

Question 17

what is the most popular plant in the desrt biome?

Answer 17

Threophytes (annuals) because they have a short life cycle

Question 18

what occurs in tundra due to low precipitation?

Answer 18

permafrost

Question 19

why are there no trees in the tundra?

Answer 19

too windy, cannot root in permafrost

Question 20

why are there limited species in the tundra?

Answer 20

it is too cold and arid

Question 21

what is peat?

Answer 21

partially decaying organic matter of plant origin formed under wet anaerobic conditions

Question 22

how is peat able to form?

Answer 22

OM is produced at a faster rate than at which it can be broken down

Question 23

what is the accumulation of peat per year in Ireland?

Answer 23

1mm

Question 24

what layers does peat consist of?

Answer 24

acrotelm layer, water layer and catotelm layer

Question 25

what is acrotelm?

Answer 25

biologically active top layer of peat

Question 26

what is catotelm?

Answer 26

biologically inactive and permanently waterlogged bottom layer of peat

Question 27

what is a fen?

Answer 27

a fen is a minertrophic form of peat which occurs when OM fills a shallow lake

Question 28

what does minerotrophic mean?

Answer 28

it is highly nutritious for plants

Question 29

why is peatland popular in Ireland?

Answer 29

high rainfall leads to anerobic conditions

Question 30

what is a blanket bog?

Answer 30

a form of peat when OM builds up on pre-waterlogged soils

Question 31

where are blanket bogs found?

Answer 31

in areas of >1200mm rain and >200 rain days

Question 32

what does ombrotrophic mean?

Answer 32

dependent on atmospheric moisture for its nutrients example blanket and raised bog

Question 33

what is the challenge for plants in blanket bogs?

Answer 33

fen bogs pH is 7, in blanket bogs it is <4 due to high rainfall

Question 34

what plant adaptations have evolved for living in peat?

Answer 34

1) Mycorrhizae 2) Efficient Recycling 3) Xeromorphs 4) Carnivorous Habit 5) Efficient ion exchange

Question 35

what are xeromorphs?

Answer 35

in summer drought they have small leaves and waxy cuticles (prevent water loss) in winter they freeze over

Question 36

what is carnivorous habit?

Answer 36

plants that trap and digest insects for nutrients

Question 37

what is a huge advantage of peat?

Answer 37

it filters water - high efficiency in ion exchange

Question 38

why can plants not grow on peatlands?

Answer 38

no nutrients

Question 39

how are peatlands advantagous?

Answer 39

they absorb lots of water preventing flooding | they sequester 25% of global carbon and store it

Question 40

what will happen bogs with increasing temperatures/ climate change?

Answer 40

they will release carbon