1. Earth’s Biomes

2. 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

3. 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

4. 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!!

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

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

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

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

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

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

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

12. 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)

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

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

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

16. 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