Earth’s Biomes

Biomes are named after the dominant type of vegetation associated with large land areas. Biomes are dependent on two very important environmental factors: Avg. Temperature and Avg. Rainfall The three major biomes are: (1) Deserts, (2) Grasslands, (3) Forests

Polar Grasslands (Tundra) Temperate Grasslands Average Precipitation (cm) Cool Temp. Avg. Temp. Hot Temp. 91-120 Coniferous Forest (Boreal) Deciduous Forest Tropical Rain Forest 31-90 Polar Grasslands (Tundra) Temperate Grasslands Tropical Grasslands (Savanna) 0-30 Cool Desert Temperate Desert Tropical Desert

Deserts have these qualities: Precipitation is low and limiting Evaporation exceeds precipitation Sparse vegetation & clear skies Solar heat is stored in soil during day, but given off rapidly at night Hot days – Cool nights!!

Desert plants and animals Widely spaced plants Heavy wax coated leaves or no leaves Animals are most active at night

Types of deserts 1. Tropical Desert: The Sahara: hot all year, few plants, wind-blown surfaces

Types of Deserts 2. Temperate Deserts: Mojave Desert – Daytime temp. hot in summer & cool in winter

Types of Deserts 3. Cool Desert: The Gobi Desert – Warm summers & cold, cold winters

Grasslands have these qualities: Precipitation is high enough to allow grass to grow. Droughts and fires prevent permanent forests

Types of Grasslands Savanna (tropical grasslands): high avg. temps. with a prolonged dry season of 4-6 months. Rest of the year is wet.

Types of Grasslands 2. Temperate Grasslands: Strong winds that blow almost continuously & evaporation is rapid.

Types of Grasslands 3. Tundra (polar grasslands): Most of the year the climate is extremely cold with high winds & snow cover. Winters are long and avg. precipitation is low (mostly snow)

Forests have these qualities: Trees are the most dominant organism. Grows when there is more than 12” of rain a year.

Types of forests: 1. Tropical Rain Forests: constant warm temp., high humidity, daily afternoon rains, soil nutrient limited, evergreen trees

Types of forests: 2. Temperate Deciduous forests: moderate temps., changes a lot during the 4 seasons, abundant precipitation, hardwood trees, nutrient rich soils

Types of Forests: 3. Coniferous Forest (Boreal): winters are long & dry, light snowfall & short days, temps. range from cool to extremely cold, dominated by conifers, lots of bogs