Chapter 19 Lesson 1 – p682-689

LAND BIOMES

Vocabulary

Biome – a geographic area on Earth that contains ecosystems with similar biotic and abiotic features

Desert – biomes that receive very little rain Grassland – biomes are areas where grasses are

the dominate plants Temperate – Regions of Earth between the

tropics and the polar circles Taiga – forest biomes consisting mostly of cone-

bearing evergreen trees Tundra – biome that is cold, dry, and treeless

Land Ecosystems and Biomes

The living or once-living parts of an environment are the biotic parts

The nonliving parts that the living pasts need to survive are the abiotic parts

An ecosystem includes an environments: Biotic factors Abiotic factors *Cultural factors

Land Ecosystems

Earth’s continents have many different ecosystems, from deserts to rainforests.

Scientists have classified similar ecosystems in large geographic areas called biomes

Biomes are geographic areas on Earth that contain ecosystems with similar biotic and abiotic factors. Earth has 7 major land biomes with similar

climates and organisms

The Seven Major Land Biomes

• Deserts

• Grasslands

• Tropical Rain Forests

• Temperate Rain Forests

• Deciduous Forest

• Taiga

• Tundra

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

• Deserts are hot during the day and cold at night• However in Antarctica the deserts

remain cold all year.• Rain drains away quickly because of

thin, porous soil. Large patches of ground are bare.

The Seven Major Land Biomes Deserts

Temperature v. Precipitation

The Seven Major Land Biomes

Biodiversity Animals include lizards, vats,

woodpeckers, and snakes. Most animals avoid activity during the hottest parts of the day

Deserts

The Seven Major Land Biomes

Biodiversity Plants include spiny cactus and

thorny shrubs. Shallow roots absorb water quickly.

Deserts

The Seven Major Land Biomes

Biodiversity Some plants have accordion-like stems that expand and

store water Small leaves or spines reduce the loss of water

Deserts

The Seven Major Land Biomes

Human Impact Overuse of water resources Because plant grow slowly,

impact to desert plants can take a long time to recover

Deserts

The Seven Major Land Biomes

Human Impact Overuse of water resources Because plant grow slowly,

impact to desert plants can take a long time to recover

Deserts

The Seven Major Land Biomes

• Grassland biomes are areas where grasses are the dominant plants.• Also called prairies, savannas, and

meadows.• Grassland are the world’s “breadbaskets.”

• Wheat, corn, oats, rye, barley, plus other cereal crops are grown here

• Grasslands have wet and dry seasons• 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

Grasslands

The Seven Major Land Biomes

• Biodiversity• Trees grow along streams and

rivers• Large herbivores graze here• African savannas and Australian

grasslands are home to many different animals.

Grasslands

The Seven Major Land Biomes

• Human Impact• Over cultivation reduces wild

habitats• Over hunting

Grasslands

The Seven Major Land Biomes

• 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• Soil is shallow and easily washed away• <1% of sunlight reaches the forest floor• Half of Earth’s species live in tropical

rain forests. Mostly in the upper canopy.

Tropical Rainforest

The Seven Major Land Biomes

• Biodiversity• Few plants live on the dark forest floor• Vines climb tall trees• Mosses, ferns, and orchids live on

branches.• Insects make up the largest group of

tropical animals• Many larger animals such as snakes,

monkeys, and jaguars

Tropical Rainforest

The Seven Major Land Biomes

• Human Impact• People have cleared more than 50% 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

Tropical Rainforest

The Seven Major Land Biomes

• Regions of Earth between the tropics and the polar circles are temperate regions.• Distinct seasons• Mild climates• Temperate rain forests are moist

ecosystems mostly in coastal areas• Winters are mild and rainy• Summers are cool and foggy• Soil is rich and moist

Temperate Rainforest

The Seven Major Land Biomes

• Biodiversity• Mainly very tall trees such as spruce,

hemlock, cedar, fir, and redwoods• Fungi, ferns, mosses, vines, and small

flowering plants grow on the floor• Many animals including butterflies,

mosquitoes, frogs, owls, eagles, deer, elk, and bears

Temperate Rainforest

The Seven Major Land Biomes

• Human Impact• Over logging• Rich soil allows cut forests to

grow back quickly• Tree farms help provide lumber

without destroying habitats

Temperate Rainforest

The Seven Major Land Biomes

• Temperate deciduous forests grow in temperate regions where winter and summer climates have more variation than those in temperate rain forests

• These are the most common in the US

• Most of the trees are deciduous, meaning they lose their leaves during fall• Winter temperatures are below freezing

and snowy• Summers are hot and humid• Soil is rich in nutrients and supports a

large amount of diverse plant growth

Temperate DeciduousForest

The Seven Major Land Biomes

• Biodiversity• Most plants stop growing during

winter and begin again in spring• Animals include snakes, ants,

raccoons, foxes• Some animals hibernate, like

chipmunks and bats• Many animals migrate, like

butterflies and birds

Temperate DeciduousForest

The Seven Major Land Biomes

• 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

Temperate DeciduousForest

The Seven Major Land Biomes

• A taiga is a forest biome consisting mostly of cone-bearing evergreen trees

• They exist 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

Taiga

The Seven Major Land Biomes

• Biodiversity• Evergreen trees, such as spruce, pine,

and fir, are thin and shed snow easily• Animals include cold-adapted species

like mice, owls, moose, and bears• Abundant insects attract migrating

birds in the summer

Taiga

The Seven Major Land Biomes

• Human Impact• Over logging also known as

tree harvesting

Taiga

The Seven Major Land Biomes

• A tundra biome is cold, dry, and treeless

• Most tundra is south of the North Pole, but also exists in mountainous areas at high altitudes• Winters are long and freezing• Summer are short and cool• Growing seasons is on 50-60 days• Permafrost – a layer of permanently

frozen soil – prevents deep root growth

Tundra

The Seven Major Land Biomes

• Biodiversity• Plants include shallow-rooted

mosses, lichen, and grasses• Many animals hibernate or migrate

south for the winter• A few animals, like lemmings, live

there year round

Tundra

The Seven Major Land Biomes

• Human Impact• Drilling for oil and gas can interrupt migration patterns

Tundra