1. The Earth’s Land Biomes
Chapter 20
Section 1 Land Biomes
The Earth’s 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.

2. Chapter 20
Section 1 Land Biomes

3. Chapter 20
Section 1 Land Biomes
Forests
Temperate Deciduous Forests In a temperate deciduous forest, mammals, birds, and reptiles thrive on the many leaves, seeds, nuts, and insects. Biome of Georgia

4. Chapter 20
Section 1 Land Biomes

5. Forests, continued Chapter 20
Section 1 Land Biomes
Forests, continued
Coniferous Forests Coniferous forest has evergreen trees and many animals must hibernate through the cold winters.

6. Chapter 20
Section 1 Land Biomes

7. Forests, continued Chapter 20
Section 1 Land Biomes
Forests, continued
Tropical Rain Forests Tropical rain forests have a greater variety of organisms than any other biome.

8. Chapter 20
Section 1 Land Biomes

9. Chapter 20
Section 1 Land Biomes
Grasslands
Temperate Grasslands Temperate grasslands have few trees, and many different kinds of seed and grass-eating animals.

10. Grasslands, continued Chapter 20
Section 1 Land Biomes
Grasslands, continued
Savannas A grassland that has scattered clumps of trees and seasonal rains is called a savanna.

11. Chapter 20
Section 1 Land Biomes
Deserts
Dry and Hot Biomes that are very dry and often very hot are called deserts.

12. Chapter 20
Section 1 Land Biomes

13. Chapter 20
Section 1 Land Biomes
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.

14. Chapter 20
Section 1 Land Biomes

15. Life in the Ocean Chapter 20
Section 2 Marine Ecosystems
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.

16. Chapter 20
Section 2 Marine Ecosystems
Temperature
Depth and Temperature The temperature of ocean water decreases as the depth of the water increases.

17. Depth and Sunlight Chapter 20
Section 2 Marine Ecosystems
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.

18. Chapter 20
Section 2 Marine Ecosystems

19. Chapter 20
Section 2 Marine Ecosystems

20. Chapter 20
Section 2 Marine Ecosystems
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.

21. A Closer Look, continued
Chapter 20
Section 2 Marine Ecosystems
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.

22. Stream and River Ecosystems
Chapter 20
Section 3 Freshwater Ecosystems
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.

23. Chapter 20
Section 3 Freshwater Ecosystems

24. Pond and Lake Ecosystems
Chapter 20
Section 3 Freshwater Ecosystems
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.

25. Chapter 20
Section 3 Freshwater Ecosystems

26. Wetland Ecosystems Chapter 20
Section 3 Freshwater Ecosystems
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.

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