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

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

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

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

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.

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

7.3 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

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