A desert is defined as a region receiving less than 250mm of annual precipitation. Deserts cover 22 million square kilometers or one-fifth of Earth's surface. They form due to mountains blocking precipitation paths and climate changes. Desert ecosystems are extremely specialized, with plants like cacti adapting through thick stems that store water and reduced transpiration at night. Animals avoid heat through burrowing and have developed ways to absorb, store, and prevent water loss.

1. by
- Sairaj Ravindra Balsane

2. What is
a Desert ?
A desert is defined
a region which
receives an annual
precipitation of les
than 250mm
[10inches] on an
average
Deserts can be
hot or cold but
they are always
dry
They cover 22
million km sq or
1/5 of the
earth’s surface
Deserts are
formed by
mountains
blocking the
path of
precipitation

3. Climate change
Earthquakes cause massive distortion
Rising of the mountain ranges
Variations in Temperature
Massive decline in cold air or air pressure

4. • The seasons are generally warm
throughout the year and very hot
in the summer. The winters
usually bring little rainfall.
• These deserts are characterized
by cold winters with snowfall and
high overall rainfall throughout
the winter and occasionally over
the summer.

5. What is Desert Ecosystem ?
In an ecosystem, the biological community
intersects with the abiological physical
environment for its survival.
The desert is characterized by extreme,
specialized and very sensitive ecosystem

6. • Desert plants have highly modified features that helps them to
thrive at extreme climatic condition.
• They have short growing seasons and long dormancies.
• The well known desert plant, cactus is a succulent, meaning it
has thickened, fleshy parts to store water.
• Stem is the only part that stores water and water is stored as
thick viscous liquid.
• Cacti stem is called Phylloclade.
• Cacti have lost true leaves during their adaptation, retaining
only spines which are highly modified leaves.

7. • In the absence of true leaves, the stem
performs photosynthesis with the help of
stomata.
• Transpiration, the process in which CO2 enters
and water escapes does not take place during
day at the same time as photosynthesis but
instead occurs at night because during the
cooler more humid night hours water loss is
significantly reduced.

10. • To Avoid Heat :- The animals avoid being out
in the sun during daytime and live in burrows
to escape intense heat.
• To Dissipate Heat :- Animals have developed
long body parts that provides greater surface
area to dissipate heat. Most desert animals
are pale in colour which prevents their bodies
from absorbing more heat from the sun.

11. Adaptations in Animals
• To Absorb Water :- Desert animals have extra tubules
in their kidney that help them extract most of their
water from their urine and return it to the
bloodstream and usually the wastes are secreted in
the form of insoluble uric acid. They also filter the
moisture out of control exhaled breath through
specialized organs in their nasal cavities.
• To Prevent Water:- Water is stored in fatty tissue
whose oxidation releases energy as well as water.