L33 Terrestrial Ecosystems (Deserts, Tundra and Peatlands) Flashcards
where is the tundra biome found?
high latitudes
where is the desert biome?
mid latitudes
what biome are you most likely to find at high altitudes on tops of mountains?
tundra
what does a rain shadow lead to?
arid dry conditions
what is the annual rainfall in deserts?
<250mm per year
what is climate variation in the desert like?
high variation in temperature, 50 degrees during day and below freezing at night
what are three ways organisms in the desert can ‘tolerate drought’?
1) intensification of water absorption
2) reduction of transpiration
3) CAM - Crassulacean acid metabolism photosynthesis
how do plants intensify their water absorption?
shallow roots that are spread very far horizontally or by deep tap roots of >15m
what plant adapts to the desert biome by intensifying water absorption?
agave filifera have dew/fog traps which capture fog moisture
what is an air plant?
they have no roots in the ground, they absorb all moisture from atmosphere through leaves example tillandsia
what are the absorption scales on tillandsia called?
trichomes
how do plants reduce the level of transpiration?
closing stomata
hair around stomata prevents wind flow
how much water is lost via stomata from transpiration/ gas exchange in photosynthesis?
95% of water absorbed is lost
what is CAM?
crassulacean acid metabolism photosynthesis
when is CAM used?
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
what are the 3 ways a plant completes photosynthesis?
C3, C4 Cycle and CAM
