Land and Aquatic Biomes

Land Ecosystems and Biomes

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When you go outside, you might notice people, grass, flowers, birds, and insects. You also are probably aware of nonliving things, such as air, sunlight, and water. The living or once-living parts of an environment are the biotic parts. The nonliving parts that the living parts need to survive are the abiotic parts. The biotic and abiotic parts of an environment together make up an ecosystem.

Earth’s continents have many different ecosystems, from deserts to rain forests. Scientists classify similar ecosystems in large geographic areas as biomes.
A biome is a geographic area on Earth that contains ecosystems with similar biotic and abiotic features. As shown in Figure 1, Earth has seven major land biomes. Areas classified as the same biome have similar climates and organisms.

Figure 1 Earth contains seven major biomes.

 

Biodiversity in Ecosystems and Biomes

The abiotic factors in each major land biome determine which organisms can live in those ecosystems. The organisms that live in deserts might not survive in tropical rain forests. However, each biome supports a variety of species. The number of different species in an area is its biodiversity. The greater the biodiversity in an ecosystem, the more likely that ecosystem will be sustainable.

 

1 NOTE

Desert Biome

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Biodiversity, Human Impact

Students should understand that not all deserts are hot. The primary characteristic of a desert is that it gets very little precipitation. Use the following scaffolded questions to assess students’ understanding.

Guiding Questions

What are some animal and plant species in many deserts?

Animals in deserts include lizards, bats, owls, and snakes. Plants include spiny cacti and thorny shrubs.

What happens to rainwater in a desert, and why does it happen?

Rainwater drains away quickly because the soil is thin and porous.

Most of Antarctica is covered with ice and snow, so why are parts of this continent considered to be deserts?

Parts of Antarctica get very little snow each year (and no rain), so they are considered to be deserts.

Desert Biome

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Deserts are biomes that receive very little rain. They are on nearly every continent and are Earth’s driest ecosystems.

• Most deserts are hot during the day and cold at night. Others, like those in Antarctica, remain cold all of the time.

• Rainwater drains away quickly because of thin, porous soil. Large patches of ground are bare.

Biodiversity

• Animals include lizards, bats, woodpeckers, and snakes. Most animals avoid activity during the hottest parts of the day.

• Plants include spiny cactus and thorny shrubs. Shallow roots absorb water quickly. Some plants have accordion-like stems that expand and store water. Small leaves or spines reduce the loss of water.

 

Tom Vezo/Minden Pictures/Getty Images

Human Impact

• Cities, farms, and recreational areas in deserts use valuable water.

• Desert plants grow slowly. When they are damaged by people or livestock, recovery takes many years.

David Muench

 

9 NOTES

Grassland Biome

Biodiversity

Human Impact

Visual Literacy : U . S . Grassland

Differentiated Instruction

Differentiated Instruction

Fun Fact

Careers in Science

Reading Strategy

Grassland Biome

Explain that the term grassland covers many terrains, including prairies, savannas, and meadows. Any environment in which grasses are the dominant plants is called a grassland.

Biodiversity

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Students should understand that grasslands contain many kinds of animals. Additionally, grasslands have deep, fertile soil, so they are good for farming.

Guiding Questions

What are three animals that live in African savannas?

Answers will vary. Students may say giraffes, zebras, gazelles, elephants, and lions live in African savannas.

Where do most trees grow in grasslands?

Trees grow along the banks of streams and rivers.

Reading Check Why are grasslands called “breadbaskets”?

Grasslands are called “breadbaskets” because they are where most of the world’s wheat, corn, barley, and other cereal crops are grown.

Human Impact

Explain that human use of grasslands can be a negative factor for the animals living there. Use the questions below to gauge students’ understanding of the reading.

Guiding Questions

Name a large American herbivore that was greatly reduced in numbers by hunting and loss of habitat.

The American bison was hunted almost to extinction in the 1800s.

Why does human use of grasslands usually have a harmful impact on grassland animals?

It reduces the habitat available to the animals.

Visual Literacy: U.S. Grassland

Have students study the U.S. Grassland graph. Then ask the questions below.

Differentiated Instruction

Bison/Buffalo Explain that the “buffalo” that once roamed across the American plains by the tens of millions are correctly called bison. Bison and buffalo are related, but they are different species. True buffalo are in Asia and Africa. Have students read about these animals and write a short report that describes the difference between the two species.

Differentiated Instruction

Bison Hunters How can animals that number in the tens of millions be hunted to near extinction in a few decades? Have students research the hunting of the North American bison in the 1800s and the reasons for it. Instruct them to present an oral report on the bison and its near extinction. Ask them to include information on how conservation efforts have allowed the animals’ numbers to increase.

Fun Fact

Passenger Pigeons Passenger pigeons once numbered in the billions east of the Rocky Mountains. These birds were hunted ruthlessly in the 1800s for food and simply to get rid of them. By the early 1900s, the passenger pigeon was extinct. Bring a picture of a passenger pigeon to class and tell students the history of these birds, which once darkened the sky for hundreds of kilometers.

Careers in Science

Prairie Ecologist A prairie ecologist gives scientific and technical advice, often in conservation action planning. Prairie ecologists often work in grassland systems in states such as North Dakota, South Dakota, Ohio, and Minnesota. To become a prairie ecologist, a person must complete college and then additional years in school to obtain an advanced degree.

Reading Strategy

Summarizing Have students summarize the sections in this lesson. Then tell them to share their summaries and discuss positive aspects of the summaries, as well as aspects of each summary that could be improved.

Grassland Biome

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Grassland biomes are areas where grasses are the dominant plants. Also called prairies, savannas, and meadows, grasslands are the world’s “breadbaskets.” Wheat, corn, oats, rye, barley, and other important cereal crops are grasses. They grow well in these areas.

• Grasslands have a wet and a dry season.

• Deep, fertile soil supports plant growth.

• Grass roots form a thick mass, called sod, which helps soil absorb and hold water during periods of drought.

1. Reading Check Why are grasslands called “breadbaskets”?

Grasslands are called “breadbaskets” because they are where most of the world’s wheat, corn, barley, and other cereal crops are grown.

 

Biodiversity

• Trees grow along moist banks of streams and rivers. Wildflowers bloom during the wet season.

• In North America, large herbivores, such as bison and elk, graze here. Insects, birds, rabbits, prairie
   dogs, and snakes find shelter in the grasses.

• Predators in North American grasslands include hawks, ferrets, coyotes, and wolves.

• African savannas are grasslands that contain giraffes, zebras, and lions. Australian grasslands are
   home to kangaroos, wallabies, and wild dogs.

Laura Romin & Larry Dalton/Alamy

Human Impact

• People plow large areas of grassland to raise cereal crops. This reduces habitat for wild species.

• Because of hunting and loss of habitat, large herbivores—such as bison—are now uncommon in
   many grasslands.

(t) Comstock/PunchStock, (b) Jim Brandenburg/Minden Pictures

Chuck Haney / DanitaDelimont.com

 

3 NOTES

Tropical Rain Forest Biome

Biodiversity

Human Impact

Tropical Rain Forest Biome

Students should understand that tropical rain forests are all near the equator, and they contain half of Earth’s species. Use the questions below to gauge students’ understanding of the text.

Guiding Questions

Reading Check Where do most organisms live in a tropical rain forest?

Most tropical organisms live in the forest canopy, which is the uppermost portion of the forest.

The soil of a tropical rain forest is thin and lacks nutrients. How do you think a tropical rain forest can support such a dense growth of trees and other plants?

In a tropical rain forest, nutrients from organic matter decay on the forest floor and are quickly absorbed by networks of shallow tree roots and recycled.

Biodiversity

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Tropical rain forests have the most diverse array of organisms of any biome. Ask students these questions to assess their understanding.

Guiding Questions

What are three kinds of plants that live on tree branches in the rain forest canopy?

Mosses, ferns, and orchids all live on canopy branches.

What are some examples of the most abundant animals in a tropical rain forest?

Insects, such as beetles, termites, ants, bees, and butterflies, make up the largest group of rain forest animals.

Human Impact

Explain that human activity has had a huge and often negative impact on tropical rain forests.

Guiding Questions

What have been the main reasons for clearing tropical rain forests?

They are being cleared for their wood and to establish farms and ranches.

Why does it make little sense to clear a tropical rain forest to create farmland?

Because the soil of a tropical rain forest is thin and deficient in nutrients, it makes poor farmland.

Tropical Rain Forest Biome

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The forests that grow near the equator are called tropical rain forests. These forests receive large amounts of rain and have dense growths of tall, leafy trees.

• Weather is warm and wet year-round.

• The soil is shallow and easily washed away by rain.

• Less than 1 percent of the sunlight that reaches the top of forest trees also reaches the forest floor.

• Half of Earth’s species live in tropical rain forests. Most live in the canopy—the uppermost part of
  the forest.

1. Reading Check Where do most organisms live in a tropical rain forest?

 

Most tropical organisms live in the forest canopy, which is the uppermost portion of the forest.

Biodiversity

• Few plants live on the dark forest floor.

• Vines climb the trunks of tall trees.

• Mosses, ferns, and orchids live on branches in the canopy.

• Insects make up the largest group of tropical animals. They include beetles, termites, ants, bees, and
   butterflies.

• Larger animals include parrots, toucans, snakes, frogs, flying squirrels, fruit bats, monkeys, jaguars,
  and ocelots.

Gavriel Jecan/Getty Images

 

Human Impact

• People have cleared more than half of Earth’s tropical rain forests for lumber, farms, and ranches.
  Poor soil does not support rapid growth of new trees in cleared areas.

• Some organizations are working to encourage people to use less wood harvested from rain forests.

age fotostock/Photolibrary

(l) Jacques Jangoux/Mira.com (r) Frans Lanting/CORBIS

 

10 NOTES

Temperate Rain Forest Biome

Biodiversity

Human Impact

Visual Literacy : U . S . Temperate Rain Forest

Differentiated Instruction

Differentiated Instruction

Differentiated Instruction

Teacher Demo

Fun Fact

Reading Strategy

Temperate Rain Forest Biome

One of the biomes of the temperate regions is the temperate rain forest biome. Temperate rain forests are mostly in coastal areas, have mild, rainy winters and cool, foggy summers. Have students make a Foldable like the one shown at the beginning of the lesson to compare and contrast desert and temperate rain forest biomes.

Biodiversity

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Students should be able to list some of the many plants and animals in a temperate rain forest.

Guiding Questions

What are a few of the trees and forest-floor plants that grow in a temperate rain forest?

Accept any three or four of the following: Trees include spruce, hemlock, cedar, fir, and redwood. Plants include fungi, ferns, mosses, vines, and small flowering plants.

What are a few of the animals that live in temperate rain forests?

Accept any three or four of the following: mosquitoes, butterflies, frogs, salamanders, woodpeckers, owls, eagles, chipmunks, raccoons, deer, elk, bears, foxes, and cougars.

What do all the trees mentioned in this part of the lesson have in common?

They are all conifers, or cone-bearing trees. A temperate rain forest is also called a temperate coniferous forest.

Human Impact

Explain that the North American temperate rain forest biome extends from the lower west coast of Canada to Northern California. The main threat to this biome is logging.

Guiding Questions

Key Concept Check In what ways do humans affect temperate rain forests?

Humans affect temperate rain forests mainly by cutting down the trees for lumber.

Why are areas that have been heavily logged able to grow back?

They have rich soil that nourishes the growth of new trees.

Visual Literacy: U.S. Temperate Rain Forest

Have students study the graph, then ask them the following questions.

Differentiated Instruction

Moist, Mild Coastal Air Students may wonder why temperate rain forests are usually in coastal areas. Explain that many coastal areas, including the Pacific Northwest, have a mild climate because prevailing winds from the ocean keep temperatures within a much narrower range than is typical of an inland continental climate. In addition, those winds bring in moisture that produces clouds and rain.

Differentiated Instruction

Reverse Rain Pattern Most temperate regions get the bulk of their precipitation in warm-weather months. In a temperate rain forest, the reverse is true. Have students conduct research to learn why rainfall in a temperate rain forest decreases when the weather warms up. Ask them to deliver an oral report to the class about what they learned.

Differentiated Instruction

Tree Farms ELL students may wonder what a tree farm is. Explain that some trees are grown for the sole purpose of being cut down after a few years. Tree farms are private reserves that grow trees for lumber and wood products. Some tree farms grow evergreens that are sold as holiday decorations.

Teacher Demo

Cones Bring a cone from a conifer tree to class. Explain that trees that produce these cones are called conifers. Point out that such cones are usually called pine cones, whether or not they are from pine trees. Have students do some reading to learn the purpose of cones on many kinds of conifers. Explain that not all conifers are evergreen trees, and not all evergreen trees are conifers.

Fun Fact

Giant Redwoods The redwood trees of Northern California are huge, and one species—the giant sequoia—is the largest living thing on Earth. The largest giant sequoia is called General Sherman. It is 83 m tall and has a trunk that is 33 m in circumference at its base. The trunk of General Sherman weighs nearly 1,300 metric tons, as much as 10 diesel locomotives. Redwood trees can be ancient. The annual growth rings of one giant sequoia that was cut down revealed that the tree was 3,200 years old.

Reading Strategy

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Reading about Redwoods Encourage students to learn more about redwood trees. Suggest that they try to find out why some redwoods grow to be so big and old. Is it the genetics of the trees; the nature of the soil; the mild, rainy climate; or a combination of those factors?

Temperate Rain Forest Biome

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Regions of Earth between the tropics and the polar circles are temperate regions. Temperate regions have relatively mild climates with distinct seasons. Several biomes are in temperate regions, including rain forests. Temperate rain forests are moist ecosystems mostly in coastal areas. They are not as warm as tropical rain forests.

• Winters are mild and rainy.

• Summers are cool and foggy.

• Soil is rich and moist.

Biodiversity

• Forests are dominated by spruce, hemlock, cedar, fir, and redwood trees, which can grow very large
   and tall.

• Fungi, ferns, mosses, vines, and small flowering plants grow on the moist forest floor.

• Animals include mosquitoes, butterflies, frogs, salamanders, woodpeckers, owls, eagles,
  chipmunks, raccoons, deer, elk, bears, foxes, and cougars.

M DeFreitas/Getty Images

 

Human Impact

• Temperate rain forest trees are a source of lumber. Logging can destroy the habitat of forest species.

• Rich soil enables cut forests to grow back. Tree farms help provide lumber without destroying
   habitat.

1. Key Concept Check In what ways do humans affect temperate rain forests?

Humans affect temperate rain forests mainly by cutting down the trees for lumber.

Doug Sherman/Geofile

Comstock Images/Alamy

 

3 NOTES

Temperate Deciduous Forest Biome

Visual Literacy : Temperate Deciduous Forest

Differentiated Instruction

Temperate Deciduous Forest Biome

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Biodiversity, Human Impact

Explain that there is considerable biodiversity in a temperate deciduous forest. Help students understand that humans have had a major impact on temperate deciduous forests throughout the world. Use the questions below to informally assess students’ understanding.

Guiding Questions

What are deciduous trees?

They are trees that lose their leaves in the fall.

What happens to deciduous trees in the winter?

They stop growing until spring.

Key Concept Check How are temperate deciduous forests different from temperate rain forests?

Temperate rain forests are moist ecosystems mostly in coastal areas, where winters are mild and summers are wet and cool. Temperate deciduous forests are in regions that have more extreme seasons. Summers are hot and winters are cold.

Why have many deciduous forests around the country been cleared in recent centuries?

They have been cleared to make way for farms and cities.

Visual Literacy: Temperate Deciduous Forest

Have students study the graph shown below and ask them the following questions.

Differentiated Instruction

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Comparing Forests Have students work with a partner to review the differences between a deciduous forest and a coniferous forest. Instruct them to write down some of the features of each kind of forest.

Temperate Deciduous Forest Biome

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Temperate deciduous forests grow in temperate regions where winter and summer climates have more variation than those in temperate rain forests. These forests are the most common forest ecosystems in the United States. They contain mostly deciduous trees, which lose their leaves in the fall.

• Winter temperatures are often below freezing. Snow is common.

• Summers are hot and humid.

• Soil is rich in nutrients and supports a large amount of diverse plant growth.

(t) Tom Till

 

Biodiversity

• Most plants, such as maples, oaks, birches, and other deciduous trees, stop growing during the
  winter and begin growing again in the spring.

• Animals include snakes, ants, butterflies, birds, raccoons, opossums, and foxes.

• Some animals, including chipmunks and bats, spend the winter in hibernation.

• Many birds and some butterflies, such as the monarch, migrate to warmer climates for the winter.

Human Impact

Over the past several hundred years, humans have cleared thousands of acres of Earth’s deciduous forests for farms and cities. Today, much of the clearing has stopped and some forests have regrown.

1. Key Concept Check How are temperate deciduous rain forests different from temperate rain forests?

Temperate rain forests are moist ecosystems mostly in coastal areas, where winters are mild and summers are wet and cool. Temperate deciduous forests are in regions that have more extreme seasons. Summers are hot and winters are cold.

(l) Bruce Lichtenberger/Peter Arnold, Inc., (r) Russ Munn/CORBIS

 

1 NOTE

Taiga Biome

Biodiversity, Human Impact

Be sure students know that the taiga biome is Earth’s largest biome.

Guiding Questions

What is the main human impact on the taiga?

The main human impact is the harvesting of trees.

With regard to biodiversity, what does the taiga biome have in common with the temperate rain forest biome?

They both have mostly coniferous trees.

Taiga Biome

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A taiga (TI guh) is a forest biome consisting mostly of cone-bearing evergreen trees. The taiga biome exists only in the northern hemisphere. It occupies more space on Earth’s continents than any other biome.

• Winters are long, cold, and snowy. Summers are short, warm, and moist.

• Soil is thin and acidic.

(l) age fotostock/SuperStock, (b) Marvin Dembinsky Photo Associates/Alamy

 

Biodiversity

• Evergreen trees, such as spruce, pine, and fir, are thin and shed snow easily.

• Animals include owls, mice, moose, bears, and other cold-adapted species.

• Abundant insects in summer attract many birds, which migrate south in winter.

Human Impact

• Tree harvesting reduces taiga habitat.

 

7 NOTES

Tundra Biome

Visual Literacy : Taiga and Canadian Tundra

Differentiated Instruction

Differentiated Instruction

Teacher Demo

Fun Fact

Reading Strategy

Tundra Biome

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Biodiversity, Human Impact

Explain that a biome can sometimes be created by either latitude or altitude. The tundra biome can be at high latitudes—south of the North Pole—and at high altitudes in mountainous regions.

Guiding Questions

What kinds of plants grow in the tundra biome?

Tundra plants include shallow-rooted mosses, lichens, and grasses.

What prevents tundra plants from growing deep roots?

Root growth is stopped by permafrost, a layer of permanently frozen soil.

Visual Literacy: Taiga and Canadian Tundra

Have students study the graphs, then ask the following questions.

Differentiated Instruction

Melting Permafrost Global warming is causing changes to some biomes. In parts of the tundra, permafrost has been melting. Have students learn about this development and what effects it may have. Ask them to present an oral report about what they learned.

Differentiated Instruction

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Reviewing Terms Taiga and tundra are words ELL students may never have heard before. Work with them to be sure they understand these terms. For taiga, have students echo the term and then point out the illustrations for this biome. Guide students in identifying and naming the brown bear and evergreen trees. Repeat with tundra and lemming, moss, and grass.

Teacher Demo

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The Varied Northern Hemisphere If your classroom doesn’t have a globe or a world map, bring one in. Show students why the taiga and tundra biomes are almost exclusively in the northern hemisphere. There are huge land masses in the high northern latitudes.

Fun Fact

Alpine Tundra The tundra biome at high altitudes is called alpine tundra (as opposed to arctic tundra, the biome found at high latitudes). Many mountains throughout the world contain alpine tundra regions. Mount Kilimanjaro, an extinct volcano that towers more than 5,790 m above the surrounding plain in equatorial Africa, has tundra near its icy summit.

Reading Strategy

Uncommon Usage Suggest to students that they select three or four short sentences from this section that contain words that are used in a variety of ways. Have students discuss their meanings with a partner and write what each sentence means to them. Examples of sentences to discuss might be: Snow is common. Soil is rich. Summers are short. Soil is thin.

Tundra Biome

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A tundra (TUN druh) biome is cold, dry, and treeless. Most tundra is south of the North Pole, but it also exists in mountainous areas at high altitudes.

• Winters are long, dark, and freezing; summers are short and cool; the growing season is only 50–60
   days.

• Permafrost—a layer of permanently frozen soil—prevents deep root growth.

(tr) age fotostock/SuperStock, (b) Andre Gallant/Getty Images

 

Biodiversity

• Plants include shallow-rooted mosses, lichens, and grasses.

• Many animals hibernate or migrate south during winter. Few animals, including lemmings, live in t
   tundras year-round.

Human Impact

• Drilling for oil and gas can interrupt migration patterns.

 

Earth’s aquatic ecosystems

Freshwater: Streams and Rivers

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Freshwater ecosystems include streams, rivers, ponds, and lakes. Streams are usually narrow, shallow, and fast-flowing. Rivers are larger, deeper, and flow more slowly.

• Streams form from underground sources of water, such as springs or from runoff from rain and
    melting snow.

• Stream water is often clear. Soil particles are quickly washed downstream.

• Oxygen levels in streams are high because air mixes into the water as it splashes over rocks.

• Rivers form when streams flow together.

• Soil that washes into a river from streams or nearby land can make river water muddy. Soil also
    introduces nutrients, such as nitrogen, into rivers.

• Slow-moving river water has higher levels of nutrients and lower levels of dissolved oxygen than
   fast-moving water.

Arthur Morris/Visuals Unlimited/Getty Images

(t) Comstock/PunchStock, (b) Paul Nicklen/NGS/Getty Images

 

Biodiversity

• Willows, cottonwoods, and other water-loving plants grow along streams and on riverbanks.

• Species adapted to fast-moving water include trout, salmon, crayfish, and many insects.

• Species adapted to slow-moving water include snails and catfish.

Stephen Dalton/Minden Pictures

 

Human Impact

• People take water from streams and rivers for drinking, laundry, bathing, crop irrigation, and
  industrial purposes.

• Hydroelectric plants use the energy in flowing water to generate electricity. Dams stop the water’s
  flow.

• Runoff from cities, industries, and farms is a source of pollution.

(tl) Dr. Marli Mill/Visuals Unlimited/Getty Images, (b) Medioimages/PunchStock

Freshwater: Ponds and Lakes

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Ponds and lakes contain freshwater that is not flowing downhill. These bodies of water form in low areas on land.

• Ponds are shallow and warm.

• Sunlight reaches the bottom of most ponds.

• Pond water is often high in nutrients.

• Lakes are larger and deeper than ponds.

• Sunlight penetrates into the top few feet of lake water. Deeper water is dark and cold.

Jean-Paul Ferrero/Minden Picture

 

Biodiversity

• Plants surround ponds and lake shores.

• Surface water in ponds and lakes contains plants, algae, and microscopic organisms that use
  sunlight for photosynthesis.

• Organisms living in shallow water near shorelines include cattails, reeds, insects, crayfish, frogs,
  fish, and turtles.

• Fewer organisms live in the deeper, colder water of lakes where there is little sunlight.

• Lake fish include perch, trout, bass, and walleye.

1. Reading Check Why do few organisms live in the deep water of lakes?

Deep water is dark and cold. Little sunlight penetrates, therefore photosynthesis cannot occur. Fewer primary food sources—such as algae—live in deep water.

Lynn & Donna Rogers/Peter Arnold, Inc.

 

Human Impact

• Humans fill in ponds and lakes with sediment to create land for houses and other structures.

• Runoff from farms, gardens, and roads washes pollutants into ponds and lakes, disrupting food
  webs.

2. Key Concept Check How do ponds and lakes differ?

Students should recognize that ponds are shallow, warmer, and higher in nutrients, while lakes are deeper and colder, with fewer organisms living where there is little sunlight.

(tr) Photograph by Tim McCabe, courtesy USDA Natural Resources Conservation Service, (b) Image Ideas/PictureQuest

 

5 NOTES

Wetlands
Biodiversity, Human Impact

Have students preview by discussing the photos. Read the section. Define wetlands. Some students may not be familiar with wetlands or may have them confused with ponds. Point out on a local map where wetlands are located, and discuss their importance in maintaining healthy aquatic ecosystems. Next, discuss why the nutrient levels and biodiversity are particularly high in wetland areas. Then discuss why there are efforts to protect and restore wetland ecosystems. Use the scaffolded questions below to informally assess students’ understanding of the reading.

Guiding Questions

What is a wetland?

A wetland is an aquatic ecosystem that has water covering soil most of the time.

How do humans impact wetlands?

Wetlands have been drained to build homes and roads or to raise crops.

Why are wetland areas of particular importance for North American bird species?

More than one-third of North American bird species use wetlands for nesting and feeding.

Visual Literacy: Wetlands

Copy the graphic organizer below on the board or on chart paper. Have students complete the concept map by providing information about wetlands. Add information about where wetlands are found in the center circle. Add one species per circle in the circles radiating from the center circle.

Differentiated Instruction

Wetlands Importance Have students study the role of wetlands in minimizing destruction from hurricanes. Some students may choose to focus on the relationship between wetlands destruction and devastation such as that caused by Hurricane Katrina in August 2005.

Teacher Demo

Fragile Aquatic Ecosystems Gather a clear container half-filled with water, a dropper, motor oil, dirt, objects such as small blocks or pieces of metal, plastic, or other pollutants. (Note: a water plant can be added for effect.)

1. Explain that the water represents an aquatic ecosystem.

2. Place several drops of oil in the container. Have students describe the results. Add other pollutants. Discuss the impact on the ecosystem as each pollutant is added.

3. Talk about the difficulty in cleaning up an aquatic ecosystem once it has been negatively impacted.

Fun Fact

Wetlands Destruction The United States Geological Survey estimates that approximately 100 million acres of wetlands are in the lower 48 states. Wetland restoration efforts are in place, but wetland losses continue to outpace wetland gains.

Wetlands

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Some types of aquatic ecosystems have mostly shallow water. Wetlands are aquatic ecosystems that have a thin layer of water covering soil that is wet most of the time. Wetlands contain fresh water, salt water, or both. They are among Earth’s most fertile ecosystems.

• Freshwater wetlands form at the edges of lakes and ponds and in low areas on land. Saltwater
  wetlands form along ocean coasts.

• Nutrient levels and biodiversity are high.

• Wetlands trap sediments and purify water. Plants and microscopic organisms filter out pollution and
  waste materials.

Biodiversity

• Water-tolerant plants include grasses and cattails. Few trees live in saltwater wetlands. Trees in freshwater wetlands include cottonwoods, willows, and swamp oaks.

• Insects are abundant and include flies, mosquitoes, dragonflies, and butterflies.

• More than one-third of North American bird species, including ducks, geese, herons, loons, warblers, and egrets, use wetlands for nesting and feeding.

• Other animals that depend on wetlands for food and breeding grounds include alligators, turtles, frogs, snakes, salamanders, muskrats, and beavers.

Michael S. Quinton/National Geographic/Getty Images

 

Human Impact

• In the past, many people considered wetlands as unimportant environments. Water was drained
  away to build homes and roads and to raise crops.

• Today, many wetlands are being preserved, and drained wetlands are being restored.

1. Key Concept Check How do humans impact wetlands?

Wetlands have been drained to build homes and roads or to raise crops.

(tl) James L. Amos/Peter Arnold, Inc., (b) Steve Bly/Getty Images

 

4 NOTES

Estuaries
Biodiversity, Human Impact

Have students read the section. Write biodiversity and human impact on the board or chart paper. Direct students’ attention to the images about estuaries. Have students note details in the images and generate lists under each heading. Discuss difficulties presented when estuary ecosystems have been harmed and need to be restored.

Guiding Questions

What is an estuary?

An estuary is a region along the coastline where streams or rivers flow into a body of salt water.

On what does the salinity of an estuary depend?

The salinity of an estuary depends on rainfall, the amount of freshwater flowing from the land, and the amount of salt water pushed in by tides.

How has human impact affected estuaries?

Estuaries have been filled with soil for roads and buildings, resulting in reduced habitat for estuary species, flooding, and storm damage.

Visual Literacy: Estuaries

Draw the graphic organizer shown below, on the board or chart paper. Add information to the graphic organizer as it is generated by the students. Discuss how the factors of an ecosystem are interconnected. Draw a large circle around the graphic organizer. Label the circle human impact.

Differentiated Instruction

Interviewing Organize students into small groups. Have each group do an email or phone interview with a government official knowledgeable about wetlands or estuaries, such as a local university extension office, state natural resources official, or state park ranger. Students should use questions approved by you. Rehearse with students how to talk with an official on the phone. Have students report on what they learned.

Differentiated Instruction

Charting Concepts Have students create a chart as shown.

1. Have students return to their aquatic ecosystems chart.

2. Tell them to complete the chart for wetlands and estuary ecosystems.

3. Ask student pairs to share their charts and add to them where needed.

Estuaries

10.A.iv

Estuaries (ES chuh wer eez) are regions along coastlines where streams or rivers flow into a body of salt water. Most estuaries form along coastlines, where freshwater in rivers meets salt water in oceans. Estuary ecosystems have varying degrees of salinity.

• Salinity depends on rainfall, the amount of freshwater flowing from land, and the amount of salt
  water pushed in by tides.

• Estuaries help protect coastal land from flooding and erosion. Like wetlands, estuaries purify water
  and filter out pollution.

• Nutrient levels and biodiversity are high.

Tom & Therisa Stack/Tom Stack & Associates

 

Biodiversity

• Plants that grow in salt water include mangroves, pickleweeds, and seagrasses.

• Animals include worms, snails, and many species that people use for food, including oysters,
   shrimp, crabs, and clams.

• Striped bass, salmon, flounder, and many other ocean fish lay their eggs in estuaries.

• Many species of birds depend on estuaries for breeding, nesting, and feeding.

B. Moose Peterson

 

Human Impact

• Large portions of estuaries have been filled with soil to make land for roads and buildings.

• Destruction of estuaries reduces habitat for estuary species and exposes the coastline to flooding
  and storm damage.

David Noton Photography/Alamy

1

1 NOTE

WORD ORIGIN

Write aestuarium on the board or chart paper. Write estuary beneath it. Have students identify parts of the words that are similar. Define aestuarium and write the meaning next to the word. Define estuary and write the meaning next to the word. Talk about the similarities in the meanings. Remind students that many words in English have Latin origins.

Ask: Why is it important to monitor what flows into and out of an estuary?

to protect the habitat species that live in the estuary and ocean ecosystems

WORD ORIGIN

estuary
from Latin aestuarium, means “a tidal marsh or opening.”

 

4 NOTES

Ocean: Open Oceans
Biodiversity, Human Impact

Direct students’ attention to the ocean diagram. Discuss the different types of marine life that are in each zone, noting where photosynthesis occurs and the importance of producers in an ocean ecosystem. Next, have students study the photos of ocean species. Gather and share other photos of ocean species. Discuss the biodiversity in an ocean ecosystem. Then ask students to discuss the photo of the fur seal in relation to human impact on open oceans. Use the scaffolded questions below to informally assess students’ understanding of the reading.

Guiding Questions

What covers most of Earth’s surface, freshwater or salt water?

ocean water with high salinity

Reading Check Which organisms are at the base of most ocean food chains?

Microscopic algae and other small producer organisms that live in the sunlit zone are at the base of most ocean food chains.

What is the effect of overfishing?

Overfishing threatens the populations of many ocean fish.

Visual Literacy: Open Oceans

Direct students’ attention to the diagram of ocean zones. Beginning with the sunlit zone, have students provide examples of ocean species that live in each zone. Discuss the species that move between zones.

Differentiated Instruction

Flashes of Light! Have students research bioluminescent organisms living in the twilight zone. Have them place images of their three favorite bioluminescent organisms on plain paper. Students should write a short paragraph about each organism and place the paragraph next to the image.

Real-World Science

Exxon Valdez Oil Spill In 1989, the Exxon Valdez oil tanker lost 11 million gallons of crude oil. The spill profoundly affected the biodiversity of the Prince William Sound ecosystem. Studies conducted 20 years later show pockets of lingering oil. Species’ recovery in the intertidal zone continues to be monitored, with some species listed as recovered, while others, such as the Pacific herring, have not recovered.

Ocean: Open Oceans

10.A.iv

Most of Earth’s surface is covered by ocean water with high salinity. The oceans contain different types of ecosystems. If you took a boat trip several kilometers out to sea, you would be in the open ocean—one type of ocean ecosystem. The open ocean extends from the steep edges of continental shelves to the deepest parts of the ocean. The amount of light in the water depends on depth.

• Photosynthesis can take place only in the uppermost, or sunlit, zone. Very little sunlight reaches the
   twilight zone. None reaches the deepest water, known as the dark zone.

• Decaying matter and nutrients float down from the sunlit zone, through the twilight and dark zones,
   to the seafloor.

(b) Camille Lusardi/Photolibrary

Biodiversity

• Microscopic algae and other producers in the sunlit zone form the base of most ocean food chains.
  Other organisms living in the sunlit zone are jellyfish, tuna, mackerel, and dolphins.

• Many species of fish stay in the twilight zone during the day and swim to the sunlit zone at night to
  feed.

• Sea cucumbers, brittle stars, and other bottom-dwelling organisms feed on decaying matter that
  drifts down from above.

• Many organisms in the dark zone live near cracks in the seafloor where lava erupts and new s
  eafloor forms.

 

1. Reading Check Which organisms are at the base of most ocean food chains?

Microscopic algae and other small producer organisms that live in the sunlit zone are at the base of most ocean food chains.

Gregory Ochocki/Photo Researchers

Human Impact

• Overfishing threatens many ocean fish.

• Trash discarded from ocean vessels or washed into oceans from land is a source of pollution. Animals such as seals become tangled in plastic or mistake it for food.

Doug Allan/Getty Images

 

3 NOTES

Ocean: Coastal Oceans
Biodiversity, Human Impact

Write intertidal zone on the board or chart paper. Create a student-generated list to note a variety of different ways humans have an impact on coastal ocean ecosystems. Use the questions below to gauge students’ understanding.

Guiding Questions

Where does sunlight reach in a shallow coastal ecosystem?

Sunlight reaches to the bottom in a shallow coastal ecosystem.

What two types of adaptations must species living in an intertidal zone have?

Species must have the ability to survive exposure to air during low tides and to heavy waves during high tides.

Differentiated Instruction

Overfishing Group students. Have each group research the effects of overfishing along the coastlines of the United States. Have students present a visual report to the class on their region. Reports should include maps and/or charts.

Teacher Demo

Plastic Bags Have students generate a list of how plastic bags are used, where they are used, and where and how they are discarded. Create a small rock hill using a clear container. Add water and pieces of a plastic bag. Slowly drain the water from the rocks. Note how the plastic bag pieces cover the rocks and the bottom of the container. Discuss the impact of plastic bag pollution on intertidal zones.

Ocean: Coastal Oceans

10.A.iv

Coastal oceans include several types of ecosystems, including continental shelves and intertidal zones. The intertidal zone is the ocean shore between the lowest low tide and the highest high tide.

• Sunlight reaches the bottom of shallow coastal ecosystems.

• Nutrients washed in from rivers and streams contribute to high biodiversity.

 

Gavriel Jecan/Photolibrary

Biodiversity

• The coastal ocean is home to mussels, fish, crabs, sea stars, dolphins, and whales.

• Intertidal species have adaptations for surviving exposure to air during low tides and to heavy waves during high tides.

Human Impact

• Oil spills and other pollution harm coastal organisms.

 

2 NOTES

Ocean: Coral Reefs
Biodiversity, Human Impact

Direct students’ attention to the photo of the coral reef. Have students search for and discuss details in the photo. Discuss the importance of coral reefs to a region’s ecosystem, as well as the impact of oil spills on a coral reef ecosystem. Use the questions below to assess students’ understanding of the information.

Guiding Questions

How are coral reefs important to coastlines?

They protect coastlines from storm damage and erosion.

Why are coral reefs critical to the survival of other ocean species?

They provide food and shelter for many different ocean species.

Differentiated Instruction

Charting Concepts Have students create a chart as shown.

1. Have students return to their aquatic ecosystems chart.

2. Have students complete the chart for the three ocean ecosystems.

3. Share and compare charts as a large group.

Ocean: Coral Reefs

Another ocean ecosystem with high biodiversity is the coral reef. A coral reef is an underwater structure made from outside skeletons of tiny, soft-bodied animals called coral.

• Most coral reefs form in shallow tropical oceans.

• Coral reefs protect coastlines from storm damage and erosion.

Biodiversity

• Coral reefs provide food and shelter for many animals, including parrotfish, groupers, angelfish, eels, shrimp, crabs, scallops, clams, worms, and snails.

Human Impact

• Pollution, overfishing, and harvesting of coral threaten coral reefs.

Comstock Images/PictureQuest

Lesson Review

Visual Summary

Earth has seven major land biomes, ranging from hot, dry deserts to cold, forested taigas.

Half of Earth’s species live in rain forest biomes.

Frans Lanting/CORBIS

Temperate deciduous forests are the most common forest biome in the United States.

Tom Till

Freshwater ecosystems include ponds and lakes.

Jean-Paul Ferrero/Minden Picture

Wetlands can be saltwater ecosystems or freshwater ecosystems.

Steve Bly/Getty Images

Coral reefs and coastal ecosystems have high levels of biodiversity.

 

Lesson Assessment

10.A.ii
10.A.iv

Use Vocabulary

1. Define biome using your own words.

A biome is a geographic area on Earth that contains ecosystems with similar biotic and abiotic features.

2. Distinguish between tropical rain forests and temperate rain forests.

Tropical rain forests are warm and rainy all year. A temperate rain forest is cooler and goes through seasons, receiving varying amounts of rain during the year—most in the winter and least in the summer.

3. A cold, treeless biome is a(n) __________.

tundra

4. Define the term salinity.

Salinity is the amount of salt dissolved in water.

5. Distinguish between a wetland and an estuary.

A wetland is a shallow-water ecosystem with soil that stays wet most of the time. It can be salty or freshwater. An estuary is a shallow-water ecosystem that forms where streams and rivers empty into a body of salt water. It has both salt water and freshwater.

6. An ocean ecosystem formed from the skeletons of animals is a(n) __________.
Understand Key

Concepts

7. Explain why tundra soil cannot support the growth of trees.

Frozen soil, or permafrost, prevents deep root growth.

8. Give examples of how plants and animals adapt to temperate deciduous ecosystems.

Answers may vary. Some plants lose their leaves in winter. Others stop growing. Many animals migrate in winter. Others hibernate.

9. Where would you find plants with stems that can store large amounts of water?

       A.desert

       B.grassland

       C.taiga

       D.tundra

10. What does the pink area on the map below represent?

       A.taiga

       B.tundra

       C.temperate deciduous forest

       D.temperate rain forest

11. Where would you find trees that have no leaves during the winter?

       A.estuary

       B.tundra

       C.temperate deciduous forest

       D.temperate rain forest

12 Which biomes have rich, fertile soil?

       A.grassland and taiga

       B.grassland and tundra

       C.grassland and tropical rain forest

       D.grassland and temperate deciduous forest

13. Which ecosystem contains both salt water and freshwater?

       A.estuary

       B.lake

       C.pond

       D.stream

14. Describe what might happen to a coastal area if its estuary were filled in to build houses.

Estuaries protect coastal regions from flooding and erosion. If it was filled in, the area would experience more flooding and erosion.

15. Which is NOT a freshwater ecosystem?

       A.oceans

       B.ponds

       C.rivers

       D.streams

16. Where would you find species adapted to withstand strong wave action?

       A.estuaries

       B.wetlands

       C.intertidal zone

       D.twilight zone

17. Which ecosystem has flowing water?

       A.estuary

       B.lake

       C.stream

       D.wetland

18. Which ecosystems help protect coastal areas from flood damage?

       A.estuaries

       B.ponds

       C.rivers

       D.streams

Interpret Graphics

119. Determine What is the average annual rainfall for the biome represented by the chart below?

about 240 cm

20. Summarize Information Copy the graphic organizer below and fill it in with animals and plants
      of the biome you live in.

Answers will vary according to location.

Critical Thinking

21. Briefly describe the characteristics of Earth's seven major land biomes. List examples of plants
      and animals that live in each biome.

Desert: driest biome, little precipitation, hot days, cold nights, large patches of bare ground; plants: cacti, thorny shrubs; animals: lizards, bats, woodpeckers, snakes
Grassland: wet and dry seasons, deep fertile soil, sod; plants: trees, wildflowers; animals: bison, elk, prairie dogs, insects, snakes, hawks, ferrets, coyotes, wolves, giraffes, zebras, lions, kangaroos, wallabies, wild dogs
Taiga: long, cold, snowy winters; short, moist, warm summers; plants: evergreens (spruce, pine, fir); animals: owls, mice, moose, bears
Temperate deciduous forest: hot, humid summers; subfreezing winters with snow; plants: deciduous trees (maples, oaks, birches); animals: snakes, ants, butterflies, birds, raccoons, opossums, foxes
Temperate rain forest: mild, rainy winters; cool, foggy summers; plants: spruce, hemlock, cedar, fir, redwood trees, ferns, mosses, vines, small flowering plants; animals: mosquitoes, butterflies, frogs, salamanders, woodpeckers, owls, eagles, chipmunkcs, raccoons, deer, elk, bears, foxes, cougars
Tropical rain forest: year-round warm temperatures and high precipitation; plants: vines, mosses, ferns, orchids; animals: beetles, termites, ants, bees, butterflies, parrots, toucans, snakes, frogs, flying squirrels, fruit bats, monkeys, jaguars, ocelots
Tundra: dark, freezing winters; short, cool summers; plants: mosses, lichens, grasses; animals: lemmings

22. Plan an enclosed zoo exhibit for a desert ecosystem. What abiotic factors should you consider?

Answers will vary. Possible answer: The temperature of the ecosystem should be controlled to be hot during the day and cold at night. The ground in the ecosystem should be dry and mostly bare.

23. Recommend one or more actions people can take to reduce habitat loss in tropical and taiga 
      forests.

Answers might include the need to preserve forests by reducing the need for logging—for example, using lumber from tree farms, reducing paper use, and recycling paper and other wood products.

24. Compare mammals that live in tundra biomes with those that live in desert biomes. What
      adaptations does each group have that help them survive?

Possible answers: Tundra mammals: thick fur, hibernation, migration to warmer climates during winter; Desert: active at night or at dawn and dusk to avoid heat, do not need much water to survive

25. Analyze You are invited to go on a trip to South America. Before you leave, you read a travel
       guide that says the country you will be visiting has hot summers, cold winters, and many wheat
       farms. What biome will you be visiting? Explain your reasoning.

Grassland. Grasslands and temperate deciduous forests have hot summers and cold winters, but cereal crops such as wheat are usually planted in grassland ecosystems.

26. Interpret Graphics The following climate data were recorded for a forest ecosystem. To which
       biome does this ecosystem likely belong?

temperate rain forest

27. Earth contains a wide variety of organisms that live in different conditions. How do Earth’s
      biomes and ecosystems differ?

Sample Answer: Earth’s ecosystems and biomes differ in the amount of precipitation they receive and average temperatures. Organisms are adapted to live in each biome’s specific climate and weather pattern.

28. Observe two biomes. How do the different environments of these biomes support different
     varieties of organisms? Explain.

 

Science is Awesome

Answers will vary based on the biomes observed.

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