Tropical Deserts

7/29/2019 Tropical Deserts

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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.

Tropical Deserts

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