Chapter 17 sec Chapter 17 sec 22

Land BiomesLand BiomesKey Concept: Key Concept:

The kinds of plants and The kinds of plants and animals that live in a biome animals that live in a biome are determined by the local are determined by the local

climate.climate.

DesertsDeserts

• Very dry and often very hot biomes are called deserts.

• Plants and animals have special adaptations to live in deserts.

• For example, some plants have roots that are close to the surface, to take up water during a storm.

• Some desert animals are only active at night, when it is cooler.

• Some animals escape the heat by burying themselves in sand.

• Other animals have adaptations such as huge ears, to help them get rid of body heat.

ChaparralChaparral• A biome that has a fairly dry climate but

receives only a little more rainfall than a desert is called a chaparral.

• Chaparral is characterized by low-lying, broad-leaved evergreen shrubs and small trees.

• 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 store water.

• Natural fires are an abiotic factor that helps maintain the chaparral.

• During a fire, chaparral shrubs and trees are destroyed.

• After a fire, the chaparral shrubs grow back more quickly than the trees.

• Therefore, natural fires prevent trees from competing with chaparral shrubs for resources.

• Prey animals in the chaparral are usually gray and brown, to blend in with their environment.

• Common prey animals include quail, lizards, chipmunks, and mule deer.

• Predator animals include bobcats, gray foxes, and coyotes.

GrasslandsGrasslands• 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 temperate grasslands and tropical grasslands.

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 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 bison, 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, and zebras.

• Lions and leopards prey on these herbivores. Scavengers, such as hyenas, are also found in savannas.

TundraTundra• A tundra is a biome that has very cold temperatures and little rainfall.

• Tundras can be found near the North and South Poles.

• Tundras have permafrost, a layer of soil beneath the surface soil that stays frozen year-round.

• During the short, cool summers, only the surface soil thaws.

• Therefore, only shallow-rooted plants, such as grasses and small shrubs, can survive in the tundra.

• Mosses and lichens grow beneath these plants.

• Plants grow in clumps and low to the ground to resist the winds and cold.

• Animals also have adaptations to the tundra.

• Some animals, such as bears, hibernate in the winter when food is hard to find. Others, such as caribou, migrate over large distances to find food.

• Many animals also have extra fat to keep them warm.

• In summer, surface soils become muddy. Mosquitoes and other insects lay their eggs in the mud.

• Birds travel to the tundra to take advantage of summer insects.

• Large tundra herbivores include musk oxen and caribou.

• Carnivores include wolves.

ForestsForests• 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 forests, temperate deciduous forests, and tropical rain forests.

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 evergreen, which means they keep their leaves year-round.

• The ground beneath large conifers is often covered by a thick layer of needles.

• Little light reaches the ground of a coniferous forest, so few large plants grow beneath the trees.

• Squirrels, insects, finches, chickadees, and jays are common coniferous forest omnivores.

• Herbivores, such as porcupine, elk, and moose, also live in coniferous forests.

Temperate Deciduous Forests• Deciduous trees lose their leaves in

the fall.• Some deciduous trees shed their

leaves to save water during winter.• Others shed their leaves due to cold.

• Leaves and other materials decompose on the forest floor and keep the soil fertile.

• Fertile soil and sunlight that reaches the forest floor allow small trees and shrubs to grow.

• Animals use different layers of the forest.

• Black bears and rabbits live on the forest floor.

• Black bears are omnivores that eat nuts, berries, and animal material. Rabbits are herbivores that feed on plants.

• Squirrels and birds use the forest canopy, or the tops of trees.

Tropical Rain Forests• Tropical rain forest biomes are the most diverse places on Earth.

• This means they have more plants and animals that any other biome does.

• Tropical rain forests have warm temperatures and receive a high amount of rainfall.

• These climate conditions support a high diversity of plants.

• High plant diversity promotes high animal diversity.

• Most animals live in the canopy of a tropical rain forest.

• Omnivores include the toucan.

• Carnivores, such as the harpy eagle, eat other animals, such as howler monkeys.

• Howler monkeys are primarily herbivores.

• Most of the nutrients in a rain forest are in the plants.

• The soil is actually very nutrient-poor and thin.

• Because soil is thin, many trees grow above-ground roots for support.