1. Deserts and Tundras Tanner and Haley
Chapter 7
Deserts and Tundras
Tanner and Haley
Picture by: cargocollective.com
Picture by: thinglink,com

2. Picture: cargocollective.com
7.1 Deserts
Rainwater moving through soil carries minerals deeper into the soil in a process called leaching
As loose soil is removed from the desert, a lower layer of soil called pavement becomes exposed
2 types of deserts:
Cool deserts- Rocky Mts, Sierra Nevada
Hot deserts- AZ, NM, TX

3. Desert Climate Normally >25 cm of precipitation a year
No water = lack of diversity
Temperatures vary due to little moisture

4. Biotic factors in the desert
Picture: animal wallpapers
Organisms have adapted to:
Lack of water
Extreme temperatures
Plants must be able to absorb scarce water from the ground (ex. spines of a cactus; reduce surface area from which water can escape)
Plants such as cacti, which have thick, water-filled tissues, are called succulents
Most desert animals get water from the plants they eat
Reptiles and insects have an outer coating that reduces loss of water
Animals have adaptations to survive the heat
EX: Nocturnal animals- animals that are active at night and sleep during the day

5. 7.2 Formation of Deserts
There are deserts on every continent of Earth except Antarctica.
Direct radiation from the sun= higher temperatures and rapid evaporation of water
Locations of deserts within the desert belts are determined by local geographic features. Ex) mountain ranges.
Often bordered by regions that are dry.
Process of changing semi arid land into a desert as a result of human activity is called desertification.

6. 7.3 Tundra Cold, windy, dry region
Picture: alaska.org
7.3 Tundra
Cold, windy, dry region
Located in the Northern Hemisphere south of polar ice caps (Canada, Alaska, Greenland)
>25 cm precipitation a year (mostly snow/ ice)
Only the top layer (active zone) thaws during summer
The frozen soil below the active zone is called permafrost (never thaws)
Short growing season and low temperatures= little vegetation
During the summer, the small amount of rainfall collects on the surface and serves as a breeding ground for animals

7. 7.3 Continued Growing season= 60 days
Picture: wikimedia commons
7.3 Continued
Growing season= 60 days
Some plants grow despite weather conditions (mosses, shrubs, grasses)
Tundra plants are small and close to the ground because the sun warms the ground
The trees (willow and birch) usually only grow to 1m tall and are more similar to shrubs than trees

8. 7.3 Continued Most of the animals don’t live in the tundra year round
Picture: Thinglink.com
Most of the animals don’t live in the tundra year round
Long-distance seasonal travel is called migration
Fewer predators= safer place to raise young
Fewer competitors
Adaptations for Caribou
Have a thick coat
Hairs are filled with air
Thicker hooves to help move easily
Few permanent species- Arctic fox, oxen, polar bears, and wolverines