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Ecology & the Biosphere. Chapter 18. Biomes. Major terrestrial or aquatic life zone Aquatic biomes Occupy roughly 75% of Earth ’ s surface Freshwater Marine Terrestrial biomes Classified based on vegetation type. Aquatic - Freshwater.
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Ecology & the Biosphere Chapter 18
Biomes • Major terrestrial or aquatic life zone • Aquatic biomes • Occupy roughly 75% of Earth’s surface • Freshwater • Marine • Terrestrial biomes • Classified based on vegetation type
Aquatic - Freshwater • Typically have a salt concentration of less than 1% • Standing water • includes lakes and ponds • Flowing water • rivers and streams • Wetlands • Cover less than 1% of Earth • Contain a mere 0.01% of its water • Harbor about 6% of all described species • Are used for drinking water, crop irrigation, sanitation, and industry
Photic zone Benthic realm Aphotic zone
Aquatic - Marine • Typically have a salt concentration around 3% • Oceans • Intertidal zones • Coral reefs • Estuaries
High tide Low tide Pelagic realm (open water) Man-of-war (to 50 m long) Turtle (60–180 cm) Oarweed (to 2 m) Sea star (to 33 cm) Photic zone Brain coral (to 1.8 m) Phyto- plankton Zoo- plankton Blue shark (to 2 m) 200 m Sponges (1 cm–1 m) Sperm whale (10–20 cm) Intertidal zone Continental shelf “Twilight” Hatchet fish (2–60 cm) Sea pen (to 45 cm) Octopus (to 10 m) Aphotic zone Gulper eel (to 180 cm) 1,000– 4,000 m Sea spider (1–90 cm) Benthic realm (seafloor from continental shelf to deep-sea bottom) Rat-tail fish (to 80 cm) Brittle star (to 60 cm) Anglerfish (45 cm–2 m) No light Glass sponge (to 1.8 m) Tripod fish (to 30 cm) Sea cucumber (to 40 cm) 6,000– 10,000 m
Terrestrial • Tropical Forest • Savanna • Desert • Chaparral • Temperate Grassland • Temperate broadleaf forest • Coniferous forest • Tundra • Polar ice
30º N Tropic of Cancer Equator Tropic of Capricorn 30º S Key Temperate broadleaf forest Tropical forest Savanna Coniferous forest Arctic tundra Desert High mountains (coniferous forest and alpine tundra) Chaparral Temperate grassland Polar ice Figure 18.27
Tropical Rainforest • occur in equatorial areas • temperature is warm • days are 11–12 hours long year-round • 200-400 cm rain • 79-157 inches
Savannas • dominated by grasses and scattered trees • warm year-round • Experience 30-50 cm rainfall • 12–20 inches • dramatic seasonal variation
Deserts • driest of all biomes • Less than 30 cm • 12 inches • May be very hot or very cold • 140 to -22 F
Temperate Grasslands • mostly treeless • 25-75 cm rain per year • 10–30 inches • Experience frequent droughts and fires • characterized by grazers including bison and pronghorn in North America
Temperate Broadleaf Forest • Occurs throughout midlatitudes • sufficient moisture to support the growth of large trees • 75-150 cm rain • 30-60 inches • Includes dense stands of deciduous trees in the Northern Hemisphere
Coniferous Forest • “Temperate rainforest” • dominated by cone-bearing evergreen trees • Includes the taiga • largest terrestrial biome on Earth
Tundra • Covers expansive areas of the Arctic between the taiga and polar ice • characterized by • Permafrost • permanently frozen subsoil • Bitterly cold temperatures • High winds
Polar ice • high latitudes • north of the arctic tundra in the northern hemisphere • Antarctica in the southern hemisphere • Only a small portion of these land masses is free of ice or snow • Even in summer!
