North American Biomes

Biomes

• A large geographic region with a similar climate and characteristic plant and animal life throughout.
• There are 6 major biomes of N. America:

1. Tundra

2. Boreal Coniferous Forest

3. Temperate Deciduous Forest

4. Grasslands

5. Deserts

6. Tropical Rainforest

• Specific climatic patterns produce conditions that are suitable for particular groups of organisms, causing climax communities to develop (Biomes).
• The amount of water and energy received annually are the most important factors in determining which type of biome can exist in a region.
• Amount of water determines: desert, grassland or forest
• Amount of sun determines: the type of desert, grassland or forest

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ie. Hot Desert vs. Cold Desert

Properties of Biomes

• Desert: low rainfall and daily temperature extremes (cold nights, hot days).

- Characteristic plants are cactus and sagebrush.

Tropical Rainforest: located near the equator with very uniform conditions

- Frequent rainfall

- Characterized by broad-leafed evergreen trees

• Boundaries between biomes are not abrupt.
• Between any two given biomes is an area where a mixture of organisms from each biome exist.
• This is called a transition zone.

Aquatic Ecosystems�~Freshwater~

• Consist of moving systems (rivers) to nearly stationary systems (lakes).
• Lakes and ponds classified on nutrient levels
• Oligotrophic bodies are low in nutrients
• Eutrophic bodies are high in nutrients

Wetlands and Watersheds

• Nutrient rich and support large diverse communities
• Wetlands filter water in water cycle and are critical to this function.
• Watersheds feed larger bodies and drain into a single lake or river (pollution??)

Marine systems

• Low in nutrient value except along the coastline
• Marine algae play a large role in CO₂ absorption from the atmosphere and O₂ production.
• Very little life otherwise in most of the ocean

Intertidals

• Part –time terrestrial and aquatic ecosystems
• Water level changes 4 times a day. (in Bay of Fundy 17m between high and low tide…highest in the world!)
• Organisms here must be very hearty to survive the quickly changing conditions.

Tundra