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Tropical DesertsStarter Q: How
can Isurvive
here?
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Large Leaf Surface Area
Plants need to
capture as muchsunlight as possible,
therefore large leaf
surface area enables
it to do so.
Extremely Tall
The height of the tree
enables it to capture
as much of the suns
energy as possible
Drip Tip Leaves
Plants need to
dispose of water asquickly as possible so
that mould or bacteria
cannot form on their
leaves in the hot and
humid atmosphere.
Buttress Roots
Soil is thin in the rainforest,
so the extremely tall trees
need to stabilise and have an
enormously thick stem to
enable them to stay upright.
Thin Bark
Plants transpire just
like humans to release
hot water vapour. Thin
bark enables it to dothis.
If you planted aKapok Tree in the
Desert it would die!!!
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So you know about deserts?
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Tropical Desert Characteristics
Example of an extreme environment
High day time temps averaging 40C in
summer, 25C in winter. Tropical deserts generally occur in bands
around Earth around to tropics of Cancer
and Capricorn 23 N and S. Sparse (vertically challenged!) vegetation.
High pressure, dry descending air.
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Factors creating Deserts Word Wall:
Latitude?
Air behaviouror pressure?
Sun energy(insolation)?
Precipitation?
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TASK:
Annotate this typical desert scenehow do these plants survive? Youve got
clues from the sort exercise and the design a plant characteristic list. Why dothese plants have the features they have? Examiners tip: not all featuresapply to all plants identify characteristics of different plants in the photo
If youre struggling, check out Pg65 with theadaptations of Xerophytic plants.
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Xerophytic Plants A xerophyte orxerophytic organism (xeromeaning dry, phytemeaning
plant) is a plant which is able to survive in an environment with little availablewater or moisture, usually in environments where potential evapotranspirationexceeds precipitation for all or part of the growing season. Plants like the cactiand other succulents are typically found in deserts where low rainfall amountsare the norm.
POSSIBLE ADAPTATIONS:Shallow, broad roots to catch
infrequent rains.Deep roots to tap into
deep ground water.Thick waxy cuticle to retain water,
reducing transpiration.Thorns/needles (anti-predation).
Some needles are actually leaves!Stores water in trunk (can swell up).
Tolerance to salt (Date Palm)Rapid flowering response.
Seeds can remain dormant for years.Quick life/reproductive cycle.
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Less Surface Area
Reduces the plants
exposure to the warmair, reducing the
chance of water
evaporating from the
plant.
Tiny Hairs on Plant
Provides the plant
with a wind break
which reduces air flow
around the plant,reducing the chance
of potential water
evaporation.
Colour of Plant/Hairs
Many Xerophytes are
light in colour in orderto reflect sunlight
which reduces the risk
of water evaporation.
Swollen Trunk/Leaves/Roots
Enables water storage which
helps the plants survive
prolonged dry periods.
Deep Root System
Roots go right down to
the water table to
provide the maximum
possible chance ofwater uptake.
Xerophytes
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QUICK QUIZ - Say what you see!
Aloe Cacti and Mediterranean Scrub vegetation
Algarve, southern Portugal.(not far from the Sahara Desert and much like it in summer time!)
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Setting up your homework:
Deserts offer prime opportunity fordevelopment in many ways.
Can be exploited as they are not in thefore-front of peoples minds
Development contrasted drasticallybetween LEDCs and MEDCs.
Are there Economic Development
opportunities in Hot Deserts?
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TASK:
Read through the statements on the sheet.
Which ones do you think apply to LEDCs,
MEDCs or both. Use a three colour or
symbol key to show this.
Think back to other topics you have covered
what are the main issued faced by LEDCs?
This will help you.
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