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Ch. 6 - Biomes

Section 6.1: Defining BiomesBiome: a group of ecosystems that share similar biotic and abiotic conditions, large region characterized by a specific type of climate, plants, and animals

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Climate: describes the average condition, including temperature and precipitation, over long periods in a given area

Weather: the day-to-day conditions in Earth's atmosphere

Climatographs: climate diagram, shows an area's average temperature and precipitation

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Ecologist compare biomes on how productive they are, that is, how much new organic matter they generate

Net Primary Production: the organic matter, or biomass, that remains after cellular respiration

Biomes vary in their rates of net primary production.Warm and wet biomes have the highest net primary production, and cold, dry biomes have the lowest.

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Section 6.2 Biomes

Our textbook describes 10 different terrestrial biomes.

Tropical Rain ForestTropical Dry ForestSavannaDesertTemperate Rain ForestTemperate ForestTemperate GrasslandChaparralBoreal Forest (Taiga)Tundra

These biomes will be covered in your Biome Project!

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Polar Ice: covers the North and South poles of Earth

Not considered a biome since they do not have a typical assortment of plants and animals and much of the life does not live on land, but in the water

Animals have developed adaptations to survive in the near freezing water.

-some fish have "antifreeze" proteins that prevent their blood from freezing

-mammals, such as seals and whales, have thick fur or blubber to keep them warm.

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Mountains: as you go up in elevation, plant communities and climate change.

Hiking up a mountain is the equivalent of passing through several biomes.

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Section 6.3: Aquatic Ecosystems

Ecologists classify aquatic ecosystems according to criteria such as salinity, depth, and whether the water is flowing or standing.

Salinity: measures the amount of salt dissolved in water, measured in parts per thousand (ppt)

Salt water- 30-50 pptBrackish water- 0.5-30 pptFresh water- 0.5 ppt or less

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Depth- photosynthesis by aquatic plants and phytoplankton is mostly limited by available light

Aquatic Layers-Photic Zone- uppermost layer of an aquatic ecosystyem, where there

is enough light for photosynthesis

-Aphotic Zone- no sunlight penetrates and photosynthesis cannot occur

-Benthic Zone- very bottom of a body of water, depending on the depth and clarity of the water, benthic zones can be sunlit or pitch dark

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Freshwater Ecosystems: Ponds, Lakes, Inland Seas

Salinity is less than 0.5 ppt (parts per thousand)

Ponds and lakes are similar, except in size, but inland seas (example- Great Lakes) contain organisms adapted for open water.

Ponds and lakes are divided horizontally into zones: littoral and limnetic.

Littoral Zone- shallow, near shore, aquatic plants can grow from the mud and reach the water's surface

Limnetic Zone- farther from the shore, where there is no rooted plants

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Freshwater Ecosystems: WetlandsAreas of land flooded with water at least part of the year

Include freshwater marshes, swamps, bogs, and fens

Wetlands prevent flooding, recharge aquifers, filter pollutants, and provide habitats.

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Freshwater Marshes- shallow-water wetlands typified by tall, grasslike plants

Swamps- shallow-water, woody shrubs and trees

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Bogs and Fens- Bogs are wetlands characterized by low nutrients, acidic water, and thick , floating mats of vegetation (usually a type of moss). Form from either depressions when water can collect or secondary succession when a pond is filled in.

Fens are similar, but they are connected to a source of groundwater, tend to be less acidic and more nutrient-rich than bogs.

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Freshwater Ecosystems: Rivers and Streams

Bodies of surface water that flow downhill, eventually reaching an ocean or inland sea

Watershed: The area of land drained by a river and its tributaries

Characteristics, such as dissolved oxygen, temperature, water speed, organisms, and others, change from source to mouth.

Flood plain- areas nearest to a river's course that are flooded periodically

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Estuaries

Occur where a river flows into the ocean or an inland sea

Coastal estuaries are brackish ecosystems; organisms must tolerate wide salinity and temperature ranges.

Coastal estuaries are home to salt marshes and mangrove forests.

Like wetlands, estuaries help prevent flooding and soil erosion as well as provide habitats.

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OceansPacific, Atlantic, Indian, Arctic, and Southern Oceans are all connected, forming a single, vast body of water. This one "world ocean" covers 71% of Earth's surface and contains 97.5% of its water.

Currents are driven by water temperature and density differences, wind, and gravity.

Surface winds and heating generate vertical currents that transport nutrients and oxygen.

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Upwelling- vertical flow of cold, nutrient rich water toward the surface occurs when horizontal currents diverge (flow away from each other)

Downwelling- surface water sinks, occurs where currents converge (come together), transports warm water full of dissolved gases to the ocean depths

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Horizontal ocean zones: intertidal, neritic, open ocean

Vertical ocean zones: photic, aphotic, benthic

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Intertidal: Highly diverse; extreme range of temperature, moisture, and salinity

Neritic: Productive kelp forests and coral reefs provide habitats and help protect shorelines from erosion.

Open ocean: Low productivity due to low light penetration; phytoplankton base of food chain; deep sea organisms and hydrothermal vent communities

The anglerfish lures prey towards its mouth with a bioluminescent organ that protrudes from the front of its head.