1. The Desert Biomes
tropical and polar
By: Emily Griffin

2. Deserts in general A desert is an area where:
evaporation exceeds precipitation
Sparse widely spaced mostly low vegetation
Cover 30% of lands surface
Can be tropical, temperate, or polar

3. Tropical deserts location

4. Examples
Sahara in North Africa
Thar in India/Pakistan
Namib Desert

5. Tropical deserts precipitation
Dry with very little rain
On average under 1” per year
 formed by high pressure zones with warm descending air currents but moisture evaporates before becoming rain

6. Tropical deserts temperature
Generally clear skies allow the sun’s rays to directly beat on the soil making it very hot
Clear skies also account for cool nights, because there is very little stored heat in sand
deserts are also very dry and hot because the
“soil” absorbs very
little moisture
Sahara Desert Temperatures

7. Tropical deserts Soil
Desert soil is low in organic matter and lack the darker soil horizons, they are unable to support much life due to the low precipitation, but are otherwise nutrient rich.
Life that the soil can support is sparse and limited to  ground-hugging shrubs, and short woody trees.

8. Biotic adaptation of plants in tropical desert
Cactus
Instead of producing leaves, desert cacti produce stems and a spine capable of holding and storing enough water to survive
Some cactus have waxy leaves to keep water in
Larger cacti need either long or spread out root systems like the saguaro cactus

9. Biotic adaptation of animals in tropical deserts

10. Biotic adaptation of animals in tropical deserts
Thorny Devil drinks water with its skin “the way the scales on the body are structured, it collects dew and channels it down to the corners of the mouth, where the lizard drinks it. You can actually watch the lizard’s skin darken as it soaks up whatever liquid remains from even the muckiest of puddles” (Zookeeper Rick Schwartz).

11. Biotic adaptations of animals in the tropical desert
Fennec fox of North Africa has big ears, loaded with blood vessels, allowing the animals to dissipate excess body heat, and thick fur to retain heat during the cold nights.

12. Human effects on tropical desert biome
Desertification through over farming, deforestation, and overgrazing leads to the creation of more deserts
Higher temperatures may produce an increasing number of wildfires that change desert landscapes by eliminating slow-growing trees and shrubs and replacing them with fast-growing grasses
Lots of oil is in deserts and oil drilling and mining damages deserts that take a long time to re-build
Nuclear waste is often dumped in deserts causing wasteland and killing species
Deserts have been used as nuclear testing grounds causing disruption in the environment even though people don’t live there

13. Polar desert
The yellow areas are the cold deserts in the world.

14. Cold desert precipitation and temperature
the average yearly precipitation ranges from cm
annual precipitation has reached a maximum of 46 cm and a minimum of 9 cm
the average winter temperature is between -2 to 4° C
the average summer temperature is between 21-26° C
The Gobi Desert

15. Soil in the cold desert biomes
The soil is:
heavy
silty
salty
relatively porous and drainage is good so that most of the salt has been leached out

16. Cold desert plant adaptations
The cold climate and salty soil lead to little plant growth
Three common plants are:
Grasses
shadscale
Lichen

17. Cold desert animals
Emperor penguins, Skua, and Kangaroo rats are all animals that live in the cold desert biome. They all have adaptation like thick fur or feathers. Also, the Kangaroo rat produces many offspring to better increase its chances of survival as a species.

18. Human effects on cold deserts
A major problem in cold deserts is desertification
Desertification is caused by:
Overusing groundwater
Overgrazing
Few humans live there, but ozone depletion and the greenhouse effect cause the colder deserts to warm up

19. Sources polar desert picture 1 slide 2 picture slide 3 picture
graph 2