Ch. 6 - Biomes Section 6.1: Defining Biomes Biome: a group of ...

Ch. 6 - Biomes
Section 6.1: Defining Biomes
Biome: 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 Forest
Tropical Dry Forest
Savanna
Desert
Temperate Rain Forest
Temperate Forest
Temperate Grassland
Chaparral
Boreal 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 ppt
Brackish water- 0.5-30 ppt
Fresh 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: Wetlands
Areas 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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Oceans
Pacific, 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.
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