Biomes of the World
5.1
What is a Biome?
-The earth has many ecosystems
-Scientists group ecosystems into larger areas called Biomes
-There are two main categories of Biomes:
-Terrestrial (land)
-Aquatic (water)
Terrestrial Biomes
• The Earth has 10 major land biomes:
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Tropical Rain Forests
Deciduous Forests
Coniferous Forests
Temperate Grasslands
Savannas
Chaparral
Deserts
Tundra
Mountains
Polar Ice
Terrestrial Biomes
• Each biome is characterized by a particular climate
• What makes the climate?
• Average annual temperatures
• Amounts of precipitation
• Both help to determine the types of plants that can grow there
• The plants, in turn, help determine what types of animals can live
in each biome
Diversity in Biomes
• The total diversity of biomes is determined largely by the
amount of precipitation and average temperature
• Living things need water to survive
• The desert and tundra biomes both get very little
precipitation, therefore have less diversity
• Rainforests get a lot of rain and have hot, humid temperatures
• This makes the rain forests the most diverse ecosystems on Earth
Location
• Biomes located closer to the equator have higher
temperatures
• Biomes are divided by latitude and location
• Polar Zone – farthest from equator
• Temperate Zone – Warmer than the polar zone
• Tropical Zone – Closest to equator
• As the latitude increases, the temperature decreases
Aquatic Biomes
• Make up more than 70% of the Earth’s surface
• Aquatic biomes are not grouped by climate
• They are grouped by water depth and salinity
• Salinity is the amount of salt dissolved in the water
• Rainfall and temperature also affect aquatic biomes
• 2 main groups of Aquatic biomes
• Freshwater
• Saltwater
Aquatic Types
• Freshwater
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Rivers
Streams
Ponds
Lakes
Swamps
• Saltwater
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Oceans
Estuaries
Coral Reefs
Saltwater Marshes
Salinity
• All biomes contain some dissolved salt and other minerals
• However, oceans contain more dissolved salt than the water
found in freshwater systems
• This salinity is measured in parts per thousand
• The salinity of ocean water is about 30 parts per thousand
• The salinity of freshwater biomes is about 0.5 parts per
thousand or less
Depth
• The depth of water also determines what kinds of organisms
can survive there
• In areas where sunlight can reach, more organisms can live
there
• Aquatic plants use sunlight to create food
• As sunlight decreases with depth, the plant and animal life
decreases
• In the deep ocean, the water is too dark for photosynthesis
Scientists and Biomes
• Scientists study biomes to learn more about how organisms
survive in different habitats
• They investigate how organisms have adapted to temperature,
rainfall, water depth, and salinity
• They also study how land biomes affect aquatic biomes
• Biomes are fragile and need protected
Vocabulary
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Biome
Terrestrial
Aquatic
Salinity
Saltwater
Freshwater