The Earth

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Chapter 20
The Earths Ecosystems
Preview
Section 1 Land Biomes Section 2 Marine
Ecosystems Section 3 Freshwater Ecosystems
Concept Mapping
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Section 1 Land Biomes
Chapter 20
Bellringer

• Write the answers to the following questions in
  your science journal
• What is a biome?
• List seven land biomes.

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Section 1 Land Biomes
Chapter 20
Objectives

• Distinguish between abiotic factors and biotic
  factors in biomes.
• Identify seven land biomes on Earth.

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Section 1 Land Biomes
Chapter 20
The Earths Land Biomes

• Abiotic Factors Abiotic factors are the nonliving
  parts of an environment.
• Biotic Factors Biotic factors are the living
  parts of an environment.
• Biomes A biome is a large area characterized by
  its climate and the plants and animals that live
  in the area.

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Section 1 Land Biomes
Chapter 20
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Section 1 Land Biomes
Chapter 20
Forests

• Temperate Deciduous Forests In a temperate
  deciduous forest, mammals, birds, and reptiles
  thrive on the many leaves, seeds, nuts, and
  insects.

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Section 1 Land Biomes
Chapter 20
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Section 1 Land Biomes
Chapter 20
Forests, continued

• Coniferous Forests Coniferous forest has
  evergreen trees and many animals must hibernate
  through the cold winters.

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Section 1 Land Biomes
Chapter 20
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Section 1 Land Biomes
Chapter 20
Forests, continued

• Tropical Rain Forests Tropical rain forests have
  a greater variety of organisms than any other
  biome.

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Section 1 Land Biomes
Chapter 20
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Section 1 Land Biomes
Chapter 20
Grasslands

• Temperate Grasslands Temperate grasslands have
  few trees, and many different kinds of seed and
  grass-eating animals.

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Section 1 Land Biomes
Chapter 20
Grasslands, continued

• Savannas A grassland that has scattered clumps of
  trees and seasonal rains is called a savanna.

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Section 1 Land Biomes
Chapter 20
Deserts

• Dry and Hot Biomes that are very dry and often
  very hot are called deserts.

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Section 1 Land Biomes
Chapter 20
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Section 1 Land Biomes
Chapter 20
Tundra

• Polar Tundra In polar tundra, the layer of soil
  beneath the surface soil stays frozen all of the
  time. This layer is called permafrost.
• Alpine Tundra Alpine tundra also has permafrost.
  But alpine tundra is found at the top of tall
  mountains.

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Section 1 Land Biomes
Chapter 20
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Section 2 Marine Ecosystems
Chapter 20
Bellringer
Write the answer to the following question in
your science journal What are abiotic factors in
marine ecosystems?
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Section 2 Marine Ecosystems
Chapter 20
Objectives

• List three abiotic factors that shape marine
  ecosystems.
• Describe four major ocean zones.
• Describe five marine ecosystems.

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Section 2 Marine Ecosystems
Chapter 20
Life in the Ocean

• Abiotic Factors Marine ecosystems are shaped by
  abiotic factors including water temperature,
  water depth, and the amount of sunlight that
  passes into the water.
• Plankton Trillions of plankton live in the ocean.
  Plankton are tiny organisms that float near the
  surface of the water.

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Section 2 Marine Ecosystems
Chapter 20
Temperature

• Depth and Temperature The temperature of ocean
  water decreases as the depth of the water
  increases.

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Section 2 Marine Ecosystems
Chapter 20
Depth and Sunlight

• The Intertidal Zone The intertidal zone is the
  place where the ocean meets the land.
• The Neritic Zone As you move farther away from
  shore, into the neritic zone, the water becomes
  deeper.
• The Oceanic Zone In the oceanic zone, the sea
  floor drops sharply
• The Benthic Zone The benthic zone is the ocean
  floor. The deepest part does not get any sunlight.

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Section 2 Marine Ecosystems
Chapter 20
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Section 2 Marine Ecosystems
Chapter 20
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Section 2 Marine Ecosystems
Chapter 20
A Closer Look

• Intertidal Areas Intertidal areas are found near
  the shore. These areas include mudflats, sandy
  beaches, and rocky shores.
• Coral Reefs Coral reefs are found in warm,
  shallow areas of the neritic zone. Reefs provide
  homes for many marine animals and plants.
• Estuaries An area where fresh water from rivers
  spills into the ocean is called an estuary.
  Plants and animals living in estuaries must be
  able to survive in a changing concentration of
  salt.

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Section 2 Marine Ecosystems
Chapter 20
A Closer Look, continued

• The Sargasso Sea An ecosystem called the Sargasso
  Sea is found in the middle of the Atlantic Ocean.
  The ecosystem contains floating rafts of algae.
• Polar Ice The Arctic Ocean and the ocean around
  Antarctica have icy waters, which are rich in
  nutrients. Many fishes, birds, and mammals live
  in this ecosystem.

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Section 3 Freshwater Ecosystems
Chapter 20
Bellringer
Write the answer to the following question in
your science journal What are four freshwater
ecosystems?
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Section 3 Freshwater Ecosystems
Chapter 20
Objectives

• Describe one abiotic factor that affects
  freshwater ecosystems.
• Describe the three zones of a lake.
• Describe two wetland ecosystems.
• Explain how a lake becomes a forest.

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Section 3 Freshwater Ecosystems
Chapter 20
Stream and River Ecosystems

• Water in Streams and Rivers The water in brooks,
  streams, and rivers may flow from melting ice or
  snow. Or the water may come from a spring.
• Tributaries Each stream of water that joins a
  larger stream is called a tributary.

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Section 3 Freshwater Ecosystems
Chapter 20
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Section 3 Freshwater Ecosystems
Chapter 20
Tributary, River System, and Drainage Basin
Click below to watch the Visual Concept.
Visual Concept
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Section 3 Freshwater Ecosystems
Chapter 20
Pond and Lake Ecosystems

• Life near Shore The are of water closest to the
  edge of a lake or pond is called the littoral
  zone. The plants in the littoral zone are homes
  to small animals.
• Life Away from Shore The area of a lake or pond
  that extends from the littoral zone across the
  top of the water called the open-water zone.
  Beneath the open-water zone is the deep-water
  zone, where no sunlight reaches.

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Section 3 Freshwater Ecosystems
Chapter 20
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Section 3 Freshwater Ecosystems
Chapter 20
Wetland Ecosystems

• Marshes A treeless wetland ecosystem where
  plants, such as grasses, grow is called a marsh.
  Muskrats, turtles, frogs, and birds live in
  marshes.
• Swamps A wetland ecosystem in which trees and
  vines grow is called a swamp. Water lilies and
  other plants grow in standing water. Many fishes,
  snakes, and birds also live in swamps.

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Section 3 Freshwater Ecosystems
Chapter 20
From a Lake to a Forest

• Build Up of Sediments Water entering a standing
  body of water usually carries nutrients and
  sediments. These materials build up on the bottom
  of the lake or pond.
• Formation of a Wetland Over time, the pond or
  lake is filled with sediments. Plants grow in the
  new soil and the pond or lake starts becoming a
  wetland. The wetland then may develop into a
  forest.

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The Earths Ecosystems
Chapter 20
Concept Mapping
Use the terms below to complete the Concept
Mapping on the next slide.
land biomes biotic factors tundra biomes marine freshwater abiotic factors grasslands

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The Earths Ecosystems
Chapter 20
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The Earths Ecosystems
Chapter 20