Bio Lab 3 - Biomes

Tropical seasonal forest

• Annual rainforest 1,500-2,500mm (60-98in) 

• Wet and dry seasons 

  • Months with little or no rain common

  • Trees shed their leaves 

    • Helps them save on water

      • Leaves evaporate water, no leaves = more water to keep 

Tropical Savanna 

• Occurs where rainfall is highly seasonal 

  • Drought persists more than half the year

    • Not enough water to support large or lots of trees 

    • Watering holes are seasonal, slowly dry over the summer 

• Dominated by grasses 

  • Not enough precipitation for large amounts of trees 

  • Fires are too frequent for large amount of trees

    • Grasses can grow back super quickly after fires

  • Supports massive herds of grazing animals

Temperate zone

• Over 60% of earth’s land mass is in the temperate zone

• Annual precipitation ranges from 200 to over 2,000mm 

• Average monthly temperatures range from 5-20 degrees celsius 

• Dominated by deciduous forest

• Growing seasons range from 4-10 months 

  • When plants are able to grow, occurs between when it frosts (end of frost to beg) 

Tropical Rainforest

• Annual rainfall greater than 2,000mm (80in) 

• Plentiful rainfall, warm climate (always warm, always wet)

• Enormous plant and animal diversity

• Net primary production (NPP) greater than any other terrestrial biome 

  • Many unique niches and endemic species

Tropical zone

• Average monthly temperatures normally above 20°C (68°F) except in the high mountains 

  • Warm all year long 

• On the equator, there is 12 hours of daylight and 12 hours of darkness

• Pronounced lack of seasons (spring, summer, winter, fall) 

Temperate Deciduous Forest

• Dominated by broadleaf trees that shed leaves

• Moderate summers and cold winters

• Growing seasons last between last (spring) and first hard frosts (fall)

• Little remains undisturbed 

Temperate Evergreen forests

• Dominant trees keep leaves

  • Evergreen conifers

• Generally less precipitation and warmer winters than temperate deciduous forests

• Summer drier than winter

  • Mild temperatures year round 

Chaparral

• Dominated by summer drought

• Evergreen shrubland and low woodlands

• Mediterranean climate

• Shrubs are sclerophyllous: “stony leafed” and have adaptations to resist water loss and wilting 

  • Have a waxy coating on leaves to prevent water-loss 

• Frequent fires, intense, fire-adapted, smaller animals 

Temperate Grasslands

• 90% have been altered by agriculture and cattle grazing

• Too dry for forests

• Wet enough to not form deserts

• Winters long and cold

• Summers hot 

• Harsh environment to live in 

• Support large herd and grazing animals like bison

• Grasses bounce back quickly because they’re used to fires, grow back quickly for more food 

Polar Biomes

• Average monthly temperatures are very cold, less than 5 degrees celsius 

• Short growing seasons, late springs, early winters 

• Very challenging to grow, ends up with 

  • Limited abundance & diversity of life 

Boreal Forest

• Cold and wet (wet during summers) 

• Growing season less than 4 months

• Winters long, dry, and bitterly cold

• Forests dominated by conifers

  • Shallow roots

• Permafrost

Tundra

• Treeless landscapes

• Dry, only 100-500 mm annual precipitation 

• Permafrost

• Growing season shorter than 3 months

• Winters are most harsh

Deserts

• Occur worldwide

• Extremely arid

• Typically below 250mm annual rainfall

• Wide variation in daily temperature

• May be cold or hot

• Plants adapted for little water

  • Succulents