Chapter 36 Biomes
What is a Biome?
Biome—a large region of the earth that has
characteristic kinds of organisms.
Identified by their dominant plant life and
distinctive groups of animals.
Biomes are determined by climate—
average yearly rainfall and temperature.
Land Biomes and their Climates
Ave. Yearly Rainfall
less than 25 cm
Ave. Yearly Temp.
-25oC to 4oC
-10oC to 14oC
less than 25 cm
6oC to 28oC
25oC to 28oC
0oC to 25oC
24oc to 40oC
near the North Pole.
Long, cold winters with little or no daylight
Short, cool summers with 24 hours of daylight
One meter of soil thaws in summer. The rest
Plants of the Tundra
Extreme cold, a short
growing season, and
shallow soil allow
very few plants to
grow in the tundra.
Most common are
grasses, mosses, and
Animals of the Tundra
Most common: caribou, reindeer, and musk oxen.
Small mammals include the Arctic fox, Arctic hare,
wolves, and snow shoe rabbits.
Ducks and geese nest there in the summer.
Lots of black flies and mosquitoes
Coniferous Forest —
broad region south of the
tundra made up of conebearing trees (Conifers)
Long, cold winters
Plants of the Coniferous Forest
Conifers have needleshaped leaves with a
waxy coat to protect
them from freezing
and water loss.
Examples: spruce, fir,
and pine trees.
Animals of the Coniferous Forest
Many large and small animals including:
moose, black bear, deer, squirrels, lynx,
chipmunks, eagles and migratory birds.
Coniferous Forests of N. America
Ecologists recognize three areas of
coniferous forests in North America:
Taiga—northern Canada and Alaska
Spruce-moose belt —south of the taiga,
covering most of Canada and Northern U.S.
Southern Pine Forest —covers most of
Deciduous Forest —located south of
taiga, it is the dominant biome of the
eastern U.S. and Europe.
Trees that lose their leaves
Plants of the Deciduous Forest
Many kinds of broadleafed trees that lose their
Loosing leaves prevents
water loss during winter.
Examples: maples, oaks,
chestnuts and elms.
Animals of the Deciduous Forest
A deciduous forest supports
a large number of different
kinds of animals.
Examples: deer, foxes,
raccoons, skunks, rabbits,
bears, reptiles, amphibians,
many insects and birds.
Many of these will migrate
to warmer climates during
Tropical Rainforest —located near the
equator. Support more than ½ of all plant
and animal species on Earth.
Warm all year with at least 200 cm of rain/year
Trees do not lose their leaves, creating a dense
canopy that supports much of the animal life
Plants of the Rainforest
adaptations to survive
in the hot, humid and
wet conditions of the
Thin, smooth bark
limits growth of other
plants on the trees.
Climbing vines can be
rooted in the ground
and draped over tall
trees to reach sunlight.
Leaves with drip tips to
allow excess water to
fall off; preventing
Buttresses and stilt
roots give tall trees
stability in shallow,
Epiphytes (plants that
grow on trees to get
that trap water)
Animals of the Rainforest
Rainforests are home to 50% of the world’s
animals. The different rainforests of the
world support different populations of
animals. Since the climate is the same year
round, the animals that live there cannot
tolerate changes in temperature, light, or
receive enough rainfall
(25-75cm/ yr.) to support
Hot, dry summers
Cold, snowy winters
Fertile soil ideal for farming
Dominant biome of central
Plants of the Grasslands
Many crops are grown in the grasslands
Animals of the Grassland
animals live in the
cattle, and sheep.
Desert—rainfall is less than 25 cm/ yr.
Defining characteristic of all deserts is that they
The temperature of a desert is determined by its
geographic location. Many are hot during the
day and cool at night (Sahara in Africa). Others
are actually cold all the time (Gobi in
All deserts have great temperature changes
from day to night (days are much warmer than
Plants of the Desert
Some deserts have no plants.
Others have sparse
plants life including:
Joshua tree (largest
of the yucca)
Cactus and yucca
Animals of the Desert
Most are small and have
evolved adaptations to solve the
heat and water problems, such
as: nocturnal activity,
estivation, dissipating heat,
retaining water and getting
water from plants. Examples:
Water covers 75% of the earth’s surface.
Two main types of water biomes:
Marine biome —saltwater biome. It is the
largest biome on earth.
Three areas of the marine biome:
Ocean —part of the
marine biome that is
Upper level receives
the most light and is
home to the most
organisms) and many
fish, squid and turtles.
Intertidal zone —part of the marine biome that is
underwater at high tide and exposed at low tide.
Organisms here are adapted to being exposed to
the air during part of the day. They also must
protect themselves from being hit by waves. They
include: clams, oysters, mussels and crabs
Estuary —part of the
marine biome where a
freshwater river flows
into the ocean. They
are rich in nutrients
and support many
kinds of organisms.
Saltwater/freshwater line visible
Two types of freshwater
consisting of lakes and
consisting of streams and
Lakes and ponds make-up the still-water
Algae and plankton are abundant and
support the other animal life.
The amount of dissolved oxygen
in the water determines what
kinds of organisms are found in
rivers and streams.
Fast-moving streams or rivers
are usually cool and therefore
have a lot of dissolved oxygen.
Little plankton is available so
dead leaves and insect larva are
important sources of food. Fish
such as trout are common.
Running Water Biomes
streams or rivers,
plankton is the base of
Catfish and bass are