Chapter 21
Ecosystems
Table of Contents Section 1 Terrestrial Biomes Section 2 Aquatic Ecosystems
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Chapter 21
Section 1 Terrestrial Biomes
Objectives • Identify the eight major biomes. • Compare tundra with taiga. • Compare the different kinds of forests. • Compare the different kinds of grasslands. • Describe the adaptations of desert organisms. Chapter menu
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Chapter 21
Section 1 Terrestrial Biomes
The Major Biomes • The major types of terrestrial ecosystems, known as biomes, are tundra, tropical forest, temperate forest, taiga, temperate grassland, savanna, chaparral, and desert.
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Chapter 21
Section 1 Terrestrial Biomes
Earth’s Major Biomes
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Section 1 Terrestrial Biomes
Tundra • Tundra is a cold biome characterized by permafrost under the surface of the ground.
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Section 1 Terrestrial Biomes
Tundra
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Section 1 Terrestrial Biomes
Forests • Tropical Forests – Tropical forests receive abundant rainfall and have stable temperatures. – They have a greater species richness than any other biome.
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Section 1 Terrestrial Biomes
Tropical Rain Forest
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Section 1 Terrestrial Biomes
Forests, continued • Temperate Forests – Temperate forests have coniferous trees, which bear seeds in cones, or deciduous trees, which shed their leaves each year.
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Section 1 Terrestrial Biomes
Forests, continued • Temperate Deciduous Forests – The trees in temperate deciduous forests shed all of their leaves in the fall.
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Section 1 Terrestrial Biomes
Temperate Deciduous Forest
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Section 1 Terrestrial Biomes
Forests, continued • Taiga – Taiga is cold but is warmer than tundra and receives more precipitation. – Taiga is dominated by coniferous forests.
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Chapter 21
Section 1 Terrestrial Biomes
Taiga
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Section 1 Terrestrial Biomes
Grasslands • Temperate Grasslands – Temperate grasslands occur in areas with cold winters and hot summers. – They are dominated by grasses and herds of grazing animals.
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Section 1 Terrestrial Biomes
Grasslands, continued • Savanna – Savannas are tropical grasslands with alternating wet and dry seasons. – They are dominated by herds of grazing animals.
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Section 1 Terrestrial Biomes
Savanna
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Section 1 Terrestrial Biomes
Grasslands, continued • Chaparral – Chaparral is found in coastal regions with warm, dry summers and mild winters. – It is dominated by dense, spiny shrubs.
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Section 1 Terrestrial Biomes
Grassland
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Section 1 Terrestrial Biomes
Deserts • Deserts receive less than 25 cm (9.9 in.) of precipitation per year.
• Desert inhabitants have adaptations for conserving water.
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Chapter 21
Section 1 Terrestrial Biomes
Desert
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Chapter 21
Section 2 Aquatic Ecosystems
Objectives • Identify the major ocean zones. • Compare the aphotic zone with the photic zone.
• Compare the neritic zone with the oceanic zone. • Describe estuaries.
• Compare eutrophic lakes with oligotrophic lakes. • Explain the significance of gradient in rivers and streams.
• Describe freshwater wetlands. Chapter menu
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Chapter 21
Section 2 Aquatic Ecosystems
Ocean Zones • The photic zone in the ocean receives light, but the aphotic zone does not. • Other zones of the ocean are defined based on their relative locations.
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Section 2 Aquatic Ecosystems
Ocean Zones, continued • The Intertidal Zone – In the intertidal zone, organisms must be able to tolerate drying and pounding by waves.
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Chapter 21
Section 2 Aquatic Ecosystems
Intertidal Zone
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Section 2 Aquatic Ecosystems
Ocean Zones, continued • The Neritic Zone – The neritic zone receives nutrients from the bottom of the ocean and from land. It is the ocean’s richest zone in terms of the number of species and individuals.
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Section 2 Aquatic Ecosystems
Neritic Zone
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Section 2 Aquatic Ecosystems
Ocean Zones, continued • The Oceanic Zone – Production in the oceanic zone is limited by a shortage of nutrients.
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Section 2 Aquatic Ecosystems
Oceanic Zone
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Section 2 Aquatic Ecosystems
Ocean Zones, continued • Estuaries – Estuaries are very productive areas where rivers and streams flow into the sea.
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Section 2 Aquatic Ecosystems
Freshwater Zones • Lakes and Ponds – Oligotrophic lakes are clear and lacking in nutrients. – Eutrophic lakes are rich in nutrients and are often murky.
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Section 2 Aquatic Ecosystems
Three Lake Zones
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Section 2 Aquatic Ecosystems
Freshwater Zones, continued • Rivers and Streams – Rivers and streams are bodies of water that flow down an elevation gradient within a watershed.
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Section 2 Aquatic Ecosystems
Freshwater Zones, continued • Freshwater Wetlands – Freshwater wetlands are areas of land, such as marshes and swamps, that are covered with fresh water for at least part of each year.
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Chapter 21
Section 2 Aquatic Ecosystems
Freshwater Biomes
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Standardized Test Prep
Multiple Choice 1. Why are estuaries more productive than most other biomes? A. Estuaries contain vast coniferous forests. B. Estuaries have shallow, nutrient-laden water. C. Estuaries get more sunlight than other biomes. D. The majority of land on Earth is covered by estuaries.
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Standardized Test Prep
Multiple Choice, continued 1. Why are estuaries more productive than most other biomes? A. Estuaries contain vast coniferous forests. B. Estuaries have shallow, nutrient-laden water. C. Estuaries get more sunlight than other biomes. D. The majority of land on Earth is covered by estuaries.
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Standardized Test Prep
Multiple Choice, continued 2. Which of the following characterizes the neritic zone of the ocean? F. It receives little sunlight. G. It supports very few species. H. It is exposed to the air by low tide. J. It receives nutrients washed from land.
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Standardized Test Prep
Multiple Choice, continued 2. Which of the following characterizes the neritic zone of the ocean? F. It receives little sunlight. G. It supports very few species. H. It is exposed to the air by low tide. J. It receives nutrients washed from land.
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Multiple Choice, continued 3. Which of the following is true of temperate deciduous forests? A. They are found near the equator. B. They have the lowest rainfall of any biome. C. They undergo seasonal changes in temperature. D. They have the highest species richness of any biome.
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Multiple Choice, continued 3. Which of the following is true of temperate deciduous forests? A. They are found near the equator. B. They have the lowest rainfall of any biome. C. They undergo seasonal changes in temperature. D. They have the highest species richness of any biome.
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Multiple Choice, continued 4. Which of the following best describes the water of all eutrophic lakes? F. cold G. salty H. murky J. lifeless
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Multiple Choice, continued 4. Which of the following best describes the water of all eutrophic lakes? F. cold G. salty H. murky J. lifeless
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Multiple Choice, continued Use the graph below to answer question 5. The graph shows the relative temperature, precipitation, and soil nutrient content in a specific biome.
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Multiple Choice, continued 5. Which of the following biomes is best represented by this graph? A. tundra B. desert C. tropical rain forest D. temperate grassland
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Multiple Choice, continued 5. Which of the following biomes is best represented by this graph? A. tundra B. desert C. tropical rain forest D. temperate grassland
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Multiple Choice, continued Complete the following analogy: 6. grasses : savanna :: coniferous trees : F. taiga G. tundra H. desert J. temperate deciduous forest
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Multiple Choice, continued Complete the following analogy: 6. grasses : savanna :: coniferous trees : F. taiga G. tundra H. desert J. temperate deciduous forest
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Multiple Choice, continued Use the graph below to answer question 7. The graph ranks several types of biomes in terms of their relative productivity.
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Multiple Choice, continued 7. If a scientist needed to add a bar representing the temperate grassland biome to this graph, where should the bar be placed? A. to the left of desert B. between savanna and estuary C. between estuary and tropical rain forest D. to the right of tropical rain forest
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Multiple Choice, continued 7. If a scientist needed to add a bar representing the temperate grassland biome to this graph, where should the bar be placed? A. to the left of desert B. between savanna and estuary C. between estuary and tropical rain forest D. to the right of tropical rain forest
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Short Response Biomes are very large terrestrial ecosystems that contain a number of smaller but related ecosystems. Describe how the major biomes are characterized.
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Short Response, continued Biomes are very large terrestrial ecosystems that contain a number of smaller but related ecosystems. Describe how the major biomes are characterized.
Answer: The major biomes are distinguished by abiotic factors and by the presence of characteristic plants and animals.
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Extended Response Base your answers to parts A & B on the information below.
Ecologists recognize the following ecological zones in the ocean: photic, aphotic, intertidal, neritic, oceanic, pelagic, and benthic. Part A Describe the factors used as a basis for distinguishing the zones. Part B Relate these factors to the types of organisms that inhabit each zone. Chapter menu
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Extended Response, continued Answer: Part A Factors used as a basis for distinguishing the ecological zones of the ocean are depth, distance from shore, and penetration of sunlight. Part B Student responses should explain that the ocean can be divided into zones along a vertical axis on the basis of light penetration (photic and aphotic zones) or nearness to the bottom (benthic and pelagic zones), or along a horizontal axis on the basis of distance from shorelines (intertidal, neritic, and oceanic zones). Responses should also describe typical organisms and adaptations for each of these zones. Chapter menu
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