Land Biomes. Deserts. Key Concept The kinds of plants and animals that live in a biome are determined by the local climate.

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1 2 Land Biomes Key Concept The kinds of plants and animals that live in a biome are determined by the local climate. What You Will Learn Abiotic factors, such as soil, water, and climate, affect the organisms in land biomes. Organisms can be categorized by their role in an environment. Different kinds of organisms can have similar ecological roles in every biome. Why It Matters Organisms that thrive in a biome are adapted to the climate of the biome. Vocabulary desert grassland chaparral tundra Graphic Organizer In your Science Journal, make a Comparison Table that compares the characteristics of different land biomes. Figure 1 The residents of the desert biome have special adaptations to survive in a dry climate. Why are some organisms common in some areas and not in other areas? Each biome has organisms that are adapted to the conditions in the biome, such as climate. Organisms are also adapted to using the nonliving and living resources in their biome. Therefore, there are many kinds of organisms in each biome. Each organism in a biome can be categorized as a producer, a consumer, or a decomposer. Deserts Very dry, and often very hot biomes are called deserts, such as the Mojave Desert in California. Many plants and animals are found only in deserts, and have special adaptations to live in a desert. For example, some plants have widespread roots just under the surface to take up water during a storm. Plants also often grow far apart, reducing the competition for water. In order to survive in a desert, some animals are active only at night, when it is cooler. Some animals, such as the fringetoed lizard, bury themselves in the loose sands. Doing so helps these animals escape the heat and avoid predators. Fringe-toed lizards are omnivores that eat insects and parts of plants. Desert tortoises are herbivores that eat flowers or leaves and store water in a large bladder under their shells. Figure 1 shows how some plants and animals live in the desert. Name one adaptation that allows desert plants to survive with little water. 6.5.e Cactuses store water in their stems and roots. Some flowering plants bloom, bear seeds, and die within a few weeks after a heavy rain. Desert less than 25 cm (10 in.) Summer: 38ºC (100ºF) Winter: 7ºC (45ºF) Huge ears help jack rabbits get rid of body heat. Kangaroo rats do not need to drink. They recycle water from the foods that they eat. 584 Chapter 17 Biomes and Ecosystems

2 Chaparral 25 to 43 cm (10 to 17 in.) Summer: 22ºC (71.6ºF) Winter: 17.8ºC (64ºF) Chaparral A biome that has a fairly dry climate but receives only a little more rainfall than a desert does is called a chaparral. In chaparral biomes, summers are warm and dry and winters are mild and wet. Chaparral can be found in California and around the Mediterranean Sea. Chaparral is characterized by low-lying, broad-leaved evergreen shrubs and small trees that grow in dense patches, as shown in Figure 2. Evergreen plants are plants that keep their leaves all year round. Common chaparral plants include manzanita, scrub oak, and herbs. These plants have leathery leaves that help store water. During natural fires, chaparral shrubs and trees are destroyed. After a fire, the chaparral shrubs grow back more quickly than trees do. Therefore, natural fires prevent the trees from competing with the chaparral shrubs for resources such as sunlight, water, and nutrients. Natural fires are an abiotic factor that help maintain the chaparral. Animals in the chaparral are also adapted to living in this biome. Quail, lizards, chipmunks, and mule deer are usually gray and brown, which allow them to blend into their surroundings and hide from predators. Mule deer are herbivores that eat grasses and shrubs. Quails, lizards, and chipmunks are omnivores that eat insects and parts of plants. Bobcats, gray foxes, and coyotes are carnivores that prey on many of these organisms. Coyotes also prey on bobcats and gray foxes. Identify the ecological role of a shrub from the chaparral and a cactus from the desert. 6.5.c, 6.5.d Figure 2 Plants of the chaparral are adapted to recovering quickly after a natural fire. desert (DEZ uhrt) a region that has little or no plant life, long periods without rain, and extreme temperatures; usually found in hot climates chaparral (SHAP uh RAL) a type of vegetation that includes broad-leaved evergreen shrubs and that is located in areas with hot, dry summers and mild, wet winters 6.5.c Students know populations of organisms can be categorized by the functions they serve in an ecosystem. 6.5.d Students know different kinds of organisms may play similar ecological roles in similar biomes. 6.5.e Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition. Section 2 Land Biomes 585

3 Grasslands A grassland is a biome in which the vegetation is mainly grasses, small flowering plants, and few trees. Grasslands are found on every continent except Antarctica. Grasslands can be divided into two main groups: temperate grasslands, such as prairies, and tropical grasslands, such as savannas. Prairie 25 to 75 cm (10 to 29.5 in.) Summer: 30ºC (86ºF) Winter: 0ºC (32ºF) Figure 3 Bison are herbivores that once roamed North American prairies in great herds. Local Ecosystems With a family member, explore the ecosystems around your home. What kinds of plants and animals live in your area? In your Science Journal, write a paragraph describing the plants and animals in the ecosystems near your home. Prairies In temperate grasslands, such as prairies, the summers are warm, and the winters are very cold. Prairie soils are rich in nutrients because of thousands of years of decomposition. Fires, drought, and grazing prevent the growth of trees and shrubs. Prairies support small seed-eating animals, including prairie dogs and mice. Prairie dogs and mice use camouflage and burrows to hide from predators, such as the coyote. Large herbivores, such as the North American bison, shown in Figure 3, also live in prairies. Savannas A tropical grassland that has seasonal rains and scattered clumps of trees is called a savanna. Savannas are found in Africa, India, and South America. During the dry season, savanna grasses dry out and turn yellow. But the grasses roots survive for many months without water. The African savanna is home to many large herbivores, such as elephants, giraffes, zebras, and wildebeests. Lions and leopards prey on these herbivores. Scavengers, such as hyenas, will eat anything that predators leave uneaten. Some of these animals are shown in Figure 4. Name an animal from the savanna that plays the same ecological role as the North American bison. 6.5.c, 6.5.d Savanna 150 cm (59 in.) Dry season: 34ºC (93ºF) Wet season: 16ºC (61ºF) Figure 4 In the African savanna, lions and leopards hunt zebras and wildebeests. 586 Chapter 17

4 Tundra 30 to 50 cm (12 to 20 in.) Summer: 12ºC (54ºF) Winter: 26ºC ( 15ºF) Tundra Imagine a place on Earth that is too cold for trees to grow. A tundra is a biome that has very cold temperatures and little rainfall. Tundras can be found near the North and South Poles. In a tundra, the layer of soil beneath the surface soil stays frozen year-round. This layer is called permafrost. Permafrost is made up of gravel and some finer materials. During the short, cool summers, only the surface soil thaws. The surface soil is too shallow for deep-rooted plants to live. So, shallow-rooted plants, such as grasses and small shrubs, are common. Mosses and lichens (LIE kuhnz) grow beneath these plants. These plants, mosses, and lichens grow in clumps and low to the ground to resist the winds and the cold. Animals of the tundra also have adaptations for living in this biome. Some animals, such as bears, hibernate in the winter, when food is hard to find, and the cold weather is harsh. Other animals, such as the caribou shown in Figure 5, migrate over large distances to find food. Many animals in the tundra also have extra layers of fat to keep them warm through the winter. During summer, the soil above the permafrost becomes muddy from melting ice and snow. Insects, such as mosquitoes, lay eggs in the mud. Birds that prey on these insects are carnivores. Other carnivores, such as wolves, prey on herbivores, including musk oxen and caribou. Figure 5 During winters in the tundra, caribou migrate to grazing grounds that have a more plentiful supply of food. grassland (GRAS LAND) a region that is dominated by grasses, that has few woody shrubs and trees, that has fertile soils, and that receives moderate amounts of seasonal rainfall tundra (TUHN druh) a treeless plain found in the Arctic, in the Antarctic, or on the tops of mountains that is characterized by very low winter temperatures and short, cool summers How are the ecological roles of a lion in a savanna and a wolf in a tundra similar? 6.5.c, 6.5.d Section 2 Land Biomes 587

5 Coniferous Forest 35 to 75 cm (14 to 29.5 in.) Summer: 14ºC (57ºF) Winter: 10ºC (14ºF) These conifer leaves are adapted to conserve water. A coniferous forest is home to many insects and to birds that eat those insects. Herbivores that live in the coniferous forest include deer, moose, porcupines, and squirrels. Figure 6 Many animals that live in a coniferous forest survive the harsh winters by hibernating or migrating to a warmer climate for the winter. Forests Forest biomes receive plenty of rain, and the temperatures are not extreme. As in every biome, the kind of forest biome that develops depends on the climate of the biome. Three forest biomes are coniferous (koh NIF uhr uhs) forests, temperate deciduous (dee SIJ oo uhs) forests, and tropical rain forests. 588 Chapter 17 Biomes and Ecosystems Coniferous Forests Most of the trees in a coniferous forest are called conifers. Conifers produce seeds in cones. Conifers also have special needle-shaped leaves covered in a thick, waxy coating. These characteristics prevent water loss and protect the needles from cold damage. Most conifers are evergreens because they keep many of their leaves year-round. Because decomposition is slow, the ground beneath large conifers is often covered by a thick layer of needles. Also, very little light reaches the ground, so few large plants grow beneath conifers. Figure 6 shows a coniferous forest and some of the animals that live there. Squirrels and insects live in coniferous forests. Birds, such as finches, chickadees, and jays, are also common in these forests. Like squirrels, these birds are omnivores because they eat plants, seeds, and insects. Herbivores, such as porcupines, elk, and moose, also live in coniferous forests.

6 Temperate Deciduous Forests Have you seen leaves change color in the fall? Have you seen trees lose all of their leaves? If so, you have seen deciduous trees, such as oaks and maples. The word deciduous comes from a Latin word that means to fall off. Some deciduous trees shed their leaves to save water during the winter or during the dry season. Other deciduous trees shed their leaves because the leaves are damaged by the cold. Leaves and other materials decompose on the forest floor and keep the soil fertile. Fertile soils and the sunlight that reaches the forest floor allow for the growth of small trees and shrubs. Animals use different layers of the forest. For example, black bears and rabbits live on the forest floor. Black bears are omnivores that eat nuts, berries, and animals, such as rabbits. Rabbits are herbivores that feed on plants. Squirrels feed on nuts. Squirrels move between the forest floor and the tree tops or forest canopy. Birds, such as woodpeckers, nest in the canopy. Woodpeckers that feed on only insects are carnivores. Figure 7 shows some of the animals that live in this biome. Why can more plants grow on the floors of deciduous forests than on the floors of coniferous forests? 6.5.e Hibernation and Weight Black bears enter a light hibernation during the coldest parts of the year. While in hibernation, black bears have lower body temperatures and heart rates. They are also inactive and must live off their store of fat. A black bear weighs 92 kgs before hibernation. After hibernation, the bear is 30% lighter. Calculate the bear s new weight. Record your work in your Science Journal. Figure 7 In a temperate deciduous forest, mammals, birds, and reptiles thrive on the many leaves, seeds, nuts, and insects. Woody shrubs catch the light that filters through the trees. In forests, plant growth happens in layers. The leafy tops of the trees reach high above the forest floor, where the leaves can get sunlight. Temperate Deciduous Forest Ferns and mosses are scattered across the forest floor. Flowering plants often bloom in early spring, before the trees grow new leaves. 75 to 125 cm (29.5 to 49 in.) Summer: 28ºC (82ºF) Winter: 6ºC (43ºF) 589

7 Quick Lab What s Your Biome? 6.5.e 1. Measure and record the temperature outside your classroom every day for a month. 2. Using the temperature data and the descriptions of the biomes in this section, can you infer what kind of biome you live in? Explain. 3. What organisms live in your biome? Does this information help determine which biome you live in? 5 min/day for 30 days Tropical Rain Forests Tropical rain forest biomes are the most diverse places on Earth. This means that tropical rain forest biomes have more kinds of plants and animals than any other biome does. Tropical rain forests have warm temperatures and receive a high amount of rainfall, which supports a high diversity of plants. In turn, the plants support a high diversity of animals. Many animals live on the forest floor, but most animals live in the canopy. Birds, such as the toucan shown in Figure 8, are omnivores that eat fruits, reptiles, and other birds. Carnivores, such as harpy eagles, eat other animals, such as howler monkeys. Howler monkeys are primarily herbivores that eat fruits, nuts, and leaves. However, howler monkeys may also eat the maggots found in fruits. You may think that because of its diversity, the rain forest has nutrient-rich soil. However, most of the nutrients in the tropical rain forest are in the plants. The soil is actually very nutrient poor and thin. Because the soil is so thin, many trees grow above-ground roots for extra support. Figure 8 Tropical rain forests have a greater diversity of organ isms than any other biome does. 6.5.c, 6.5.d Identify a consumer found in a tropical rain forest. Trees form a continuous green roof, or canopy, that may extend 60 m above the forest floor. Woody vines climb the tree trunks to reach sunlight. Tropical Rain Forest Little light reaches the ground. Low-growing plants in the rain forest don t need a lot of light. up to 400 cm (157.5 in.) Daytime: 34ºC (93ºF) Nighttime: 20ºC (68ºF) 590

8 Review Summary 6.5.c, 6.5.d, 6.5.e A biome is characterized by a unique plant community. The plants, in turn, support unique animal communities. Plants and animals in a biome are adapted to the climate of the biome. Each organism in a biome can be categorized into the ecological role of a producer, a consumer, or a decomposer. Deserts are very dry and often very hot. Deserts support plants and animals that use little water. Chaparral biomes are fairly dry biomes that support dense patches of shrubs and trees. Animals in the chaparral blend into their surroundings to avoid predators. Tundras are cold areas that have permafrost and receive very little rainfall. Tundras support low-growing plants and few animals. Grasslands are areas where grasses are the main plants. Prairies have hot summers and cold winters. Savannas have wet and dry seasons. Three forest biomes are temperate deciduous forests, coniferous forests, and tropical rain forests. INTERPRETING GRAPHICS Use the bar graph below to answer the next two questions. Rain (cm) Rainfall on Biomes LF05SEECOL01047A Coniferous forest Temperate grassland Savanna Desert Tundra Biome 6 Identifying Which biomes receive 50 cm or more of rain each year? 7 Identifying Which biome receives the smallest amount of rain? Which receives the largest amount of rain? 8 Making Inferences While excavating an area in the desert, a scientist discovers the fossils of very large trees and ferns. What might the scientist conclude about biomes in this area? 9 Analyzing Ideas Tundra receives very little rainfall. Could a tundra accurately be called a frozen desert? Explain your answer. 0 Identifying Relationships You are looking after a friend s plant. The plant needs a warm environment, lots of water, and very little sunlight. To which biome do you think the plant would be best adapted? Explain your answer. 1 Use chaparral and tundra in separate sentences. 2 Write an original definition for grasslands and desert. q Making Inferences You are studying an area in which the temperatures are usually moderate. However, extreme temperatures occur on one or two days of the year. Which organisms would survive better in this area: organisms that are adapted to moderate temperatures or those that can tolerate extreme temperatures? Explain. 3 Describing What are the major land biomes discussed in this section? What characteristics do all biomes share? 4 Identifying How are organisms categorized in land biomes? Give an example of each category. 5 Applying What is the ecological role of a leopard in the savanna and of a harpy eagle in the rain forest? Internet Resources For a variety of links related to this chapter, go to Topic: Forests; Wildfires in California SciLinks code: HY70609; HY7C12 591