Transcript Chapter 17 sec 2 Land Biomes

Chapter 17 sec
2
Land Biomes
Key Concept:
The kinds of plants and
animals that live in a biome
are determined by the local
climate.
Deserts
• 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.
Chaparral
• 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.
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
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.
Tundra
• 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.
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
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 yearround.
• The ground beneath large conifers is
often covered by a thick layer of
• 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.