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Chapter Introduction
Land Biomes
Lesson 2
Aquatic
Ecosystems
Lesson 3
How
Ecosystems
Change
Chapter Wrap-Up
Dr. Marli Mill/Visuals Unlimited/Getty Images
Lesson 1
How do Earth’s biomes
and ecosystems differ?
What do you think?
Before you begin, decide if you agree or
disagree with each of these statements.
As you view this presentation, see if you
change your mind about any of the
statements.
Do you agree or disagree?
1. Deserts can be cold.
2. There are no rain forests outside the
tropics.
3. Estuaries do not protect coastal areas
from erosion.
Do you agree or disagree?
4. Animals form coral reefs.
5. An ecosystem never changes.
6. Nothing grows in the area where a
volcano has erupted.
Land Biomes
• How do Earth’s land biomes differ?
• How do humans impact land biomes?
Land Biomes
• biome
• taiga
• desert
• tundra
• grassland
• temperate
Land Ecosystems and Biomes
• Scientists classify similar ecosystems
in large geographic areas as biomes.
• A biome is a geographic area on Earth
that contains ecosystems with similar
biotic and abiotic features.
• Earth has seven major biomes: desert,
grassland, tropical rain forest,
temperate rain forest, temperate
deciduous forest, taiga, and tundra.
Earth has seven major biomes.
Desert Biome
• Deserts are biomes that receive very
little rain.
• They are on every continent and are
Earth’s driest ecosystems.
• Rainwater in deserts drains away
quickly because of thin, porous soil.
• Lizards, bats, woodpeckers, and
snakes are among animals found in
deserts.
Desert Biome (cont.)
• Shallow roots of desert plant life
absorb water quickly.
• Humans have an impact
on deserts by using
valuable water.
Grassland Biome
• Grassland biomes are areas where
grasses are the dominant plants.
• Wheat, corn, oats, and other important
cereal crops grow in grasslands where
deep fertile soil supports plant growth.
• Grasslands have a wet and dry season.
Grassland Biome (cont.)
• Large herbivores such as bison and elk
and predators such as hawks and
coyotes live in North American
grasslands.
• Humans reduce habitat for wild species
when they plow large areas of grassland
to raise crops.
• Hunting has reduced the number of
large herbivores in many grasslands.
The temperatures vary
depending on the
season in the United
States grasslands.
Tropical Rain Forest Biome
• The forests that grow near the equator
are called tropical rain forests.
• They receive large amount of rain and
have dense growths of tall, leafy trees.
• Insects make up the largest group of
tropical animals.
Tropical Rain Forest Biome (cont.)
People have cleared
more than half of
Earth’s tropical rain
forests for lumber,
farms, and ranches,
where poor soil
does not support
rapid growth of new
trees.
Temperate Rain Forest Biome
• Regions of Earth between the tropics
and the polar circles are temperate
regions.
• Temperate regions have mild climates
with distinct seasons.
• Temperate rain forests are moist
ecosystems in coastal areas with rich,
moist soil.
Temperate Rain Forest Biome (cont.)
• Forests are dominated by spruce, cedar,
and redwood trees.
• Fungi and small flowering plants grow on
the moist forest floor.
• Animals include mosquitoes, owls, deer,
and bears.
• Logging can destroy the habitat of forest
species, but rich soil enables cut forests
to grow back.
Temperate Rain Forest Biome (cont.)
In what ways do humans
affect temperate rain forests?
Temperate Deciduous Forest Biome
• Temperate deciduous forests grow in
temperate regions where winter and
summer climates have more variation
than those in temperate rain forests.
• These forests are the most common
forest ecosystems in the United States.
• They include mostly deciduous trees,
which lose their leaves in the fall.
Temperate Deciduous Forest Biome
• Summers are hot and humid and
winter temperatures are often below
freezing and snowy.
(cont.)
• Some animals in temperate deciduous
forests spend the winter in hibernation.
• Humans have cleared thousands of
acres of Earth’s deciduous forests for
farms and cities.
Temperate Deciduous Forest Biome
(cont.)
How are temperate
deciduous rain forests
different from temperate rain
forests?
Taiga Biome
• A taiga is a forest biome consisting
mostly of cone-bearing evergreen trees
that only exists in the northern
hemisphere.
• It occupies more space on Earth’s
continents than any other biome.
• Winters are long and snowy and
summers are short, warm, and moist.
Taiga Biome (cont.)
Abundant insects in
summer attract
many birds, which
migrate south in the
winter.
Tundra Biome
• A tundra biome is cold, dry, and
treeless.
• Winters are long, dark, and freezing,
and summers are short and cool. The
growing season is only 50–60 days.
• Permafrost is a layer of permanently
frozen soil that prevents deep root
growth.
Tundra Biome (cont.)
• Many animals hibernate
or migrate south during
winter. Few animals live
in tundras year round.
• Drilling for oil and gases
can interrupt migration
patterns.
• Earth has seven major land biomes,
ranging from hot, dry deserts to cold,
forested taigas.
• Half of Earth’s
species live in
rain forest biomes.
• Temperate deciduous forests are the
most common forest biome in the
United States.
Which type of biome has dry and
wet seasons and grass as the
dominant plant?
A. desert
B. tropical rain forest
C. temperate deciduous forest
D. grassland
In which type of biome does
rainwater drain away quickly
because of thin, porous soil?
A. grasslands
B. deserts
C. a taiga
D. tropical rain forests
Which is the most common forest
ecosystem in the United States?
A. temperate deciduous forests
B. tropical rain forests
C. grasslands
D. tundra
Do you agree or disagree?
1. Deserts can be cold.
2. There are no rain forests outside the
tropics.
Aquatic Ecosystems
• How do Earth’s aquatic ecosystems
differ?
• How do humans impact aquatic
ecosystems?
Aquatic Ecosystems
• salinity
• wetland
• estuary
• intertidal zone
• coral reef
Aquatic Ecosystems
• There are four major types of water, or
aquatic, ecosystems: freshwater,
wetland, estuary, and ocean.
• Each type of aquatic ecosystem
contains a unique variety of organisms.
• Salinity is the amount of salt dissolved
in water.
Aquatic Ecosystems (cont.)
Water in saltwater ecosystems has high
salinity compared to water in freshwater
ecosystems.
Freshwater: Streams and Rivers
• Freshwater ecosystems include
streams, rivers, ponds, and lakes.
• Oxygen levels in streams are high
because air mixes into the water as it
splashes over rocks.
Freshwater: Streams and Rivers (cont.)
• Slow-moving river water has higher
levels of nutrients and lower levels of
dissolved oxygen than fast-moving
water.
Paul Nicklen/NGS/Getty Images
• Soil that washes into a river
from streams introduces
nutrients such as nitrogen
and can make river water
muddy.
Freshwater: Streams and Rivers (cont.)
• Willows, cottonwoods, and other waterloving plants grow along streams and
on riverbanks.
• Runoff from cities,
industries, and farms
is a source of pollution.
Dr. Marli Mill/Visuals Unlimited/Getty Images
• Dams from hydroelectric
plants stop the water’s
flow.
Freshwater: Ponds and Lakes
• Bodies of water like ponds and lakes
form in low areas on land and contain
freshwater that is not flowing downhill.
• Sunlight reaches the bottom of most
ponds.
• Lakes are larger and deeper than
ponds and sunlight only penetrates the
top few feet of water.
Freshwater: Ponds and Lakes (cont.)
• Plants surround ponds and lake shores
and surface water contains plants and
algae.
Paul Nicklen/NGS/Getty Images
• Organisms like insects,
frogs, fish, and turtles
live in shallow water
near shorelines, but few
organisms live in the
deeper, colder water of
lakes.
Freshwater: Ponds and Lakes (cont.)
Runoff from farms, gardens, and roads
wash pollutants into ponds and lakes,
disrupting food webs.
How do ponds and lakes
differ?
Wetlands
• Wetlands are aquatic ecosystems that
have a thin layer of water covering soil
that is wet most of the time.
• Wetlands contain freshwater, salt
water, or both, and are among Earth’s
most fertile ecosystems.
• Freshwater wetlands form at the edges
of lakes and ponds and in low areas on
land.
Wetlands (cont.)
• Saltwater wetlands form along ocean
coasts.
Michael S. Quinton/National Geographic/Getty Images
• More than one-third
of North American
bird species use
wetlands for nesting
and feeding.
Wetlands (cont.)
In the past, water was drained away from
wetlands to build homes and raise crops,
but today many wetlands are being
restored and preserved.
How do humans impact
wetlands?
Estuaries
• Estuaries are regions along coastlines
where streams or rivers flow into a body
of salt water.
• Most estuaries form along coastlines,
where freshwater in rivers meets salt
water in oceans.
• Salinity depends on rainfall, the amount
of freshwater flowing from land, and the
amount of salt water pushed in by tides.
Estuaries (cont.)
• Animals in estuaries include many
species that people use for food, like
oysters and clams.
• Many species of birds depend on
estuaries for breeding, nesting, and
feeding.
• Destruction of estuaries reduces habitat
for estuary species and exposes
coastline to flooding and storm damage.
Estuaries (cont.)
estuary
from Latin aestuarium, means
“a tidal marsh or opening”
Ocean: Open Oceans
• The open sea, one type of ocean
ecosystem, extends from the steep
edges of continental shelves to the
deepest parts of the ocean.
• Photosynthesis can only take place in
the uppermost, sunlit zones.
Ocean: Open Oceans (cont.)
• Overfishing threatens many ocean fish.
• Trash discarded from ocean vessels or
washed into oceans from land is a
source of pollution.
Microscopic algae and other producers in
the sunlit zone
form the base
of most ocean
food chains.
Ocean: Coastal Oceans
• Coastal oceans include several types
of ecosystems, including continental
shelves and intertidal zones.
• The intertidal zone is the ocean shore
between the lowest low tide and the
highest high tide.
• Nutrients washed in from rivers and
streams contribute to high biodiversity.
Ocean: Coastal Oceans (cont.)
Intertidal species, like crabs, fish, and
mussels, have adaptations for surviving
exposure to air during low tides and to
heavy waves during high tides.
Ocean: Coral Reefs
• A coral reef is an underwater structure
made from outside skeletons of tiny,
soft-bodied animals called coral.
• Most coral reefs form in shallow
tropical oceans and protect coastlines
from storm damage and erosion.
• Coral reefs provide food and shelter for
many animals, including shrimp, crabs,
scallops, and clams.
• Wetlands can be saltwater
ecosystems or freshwater
ecosystems.
• Coral reefs and coastal ecosystems
have high levels of biodiversity.
Paul Nicklen/NGS/Getty Images
• Freshwater ecosystems
include ponds and lakes.
Which type of zone describes the
ocean shore between the lowest
low tide and the highest high
tide?
A. twilight zone
B. intertidal zone
C. sunlit zone
D. dead zone
What is the name for an
underwater structure made from
outside skeletons of tiny, softbodied coral?
A. an intertidal zone
B. an estuary
C. a coral reef
D. a coastal zone
Which of these do many species
of birds depend on for breeding,
nesting, and feeding?
A. estuaries
B. coral reefs
C. intertidal zones
D. the open sea
Do you agree or disagree?
3. Estuaries do not protect coastal areas
from erosion.
4. Animals form coral reefs.
How Ecosystems Change
• How do land ecosystems change over
time?
• How do aquatic ecosystems change
over time?
How Ecosystems Change
• ecological succession
• climax community
• pioneer species
• eutrophication
How Land Ecosystems Change
• Ecological succession is the process
of one ecological community gradually
changing into another.
• The final stage of ecological
succession in a land ecosystem is a
climax community—a stable
community that no longer goes through
major ecological changes.
How Land Ecosystems Change (cont.)
• In a tropical forest biome, a mature
tropical forest is a climax community.
• Climax communities are usually stable
for hundreds of years.
How Land Ecosystems Change (cont.)
What is a climax community?
How Land Ecosystems Change (cont.)
• Ecological succession in new areas of
land with little or no soil, such as a lava
flow or sand dune, is primary
succession.
• The first species that colonize new or
undisturbed land are pioneer species.
How Land Ecosystems Change (cont.)
pioneer
Science Use the first species that
colonize new or undisturbed land
Common Use the first human
settlers in an area
How Land Ecosystems Change (cont.)
In areas where existing ecosystems have
been disturbed or destroyed, secondary
succession can occur.
How Freshwater Ecosystems
Change
• Freshwater ecosystems change over
time in a natural, predictable process
called aquatic succession.
• In aquatic succession the buildup of
decomposed remains accumulate over
time as soil.
• Eventually the water disappears and
the area becomes land.
How Freshwater Ecosystems
Change (cont.)
What happens to a pond, a
lake, or a wetland over time?
How Freshwater Ecosystems
Change (cont.)
Eutrophication is the process of a body
of water becoming nutrient-rich.
eutrophication
from Greek eutrophos, means
“nourishing”
How Freshwater Ecosystems
Change (cont.)
• Eutrophication is a natural process, but
humans contribute to it by introducing
fertilizer, waste, and other nutrient-rich
pollution to a body of water.
• High nutrient levels support large
populations of algae and other
microscopic organisms that end up using
most of the dissolved oxygen in the water,
leaving less available for fish and other
organisms.
• Ecosystems change in predictable
ways through ecological succession.
• The final stage of ecological
succession in a land ecosystem is a
climax community.
• The final stage of aquatic succession
is a land ecosystem.
What term refers to the first
species to colonize new or
undisturbed land?
A. a climax community
B. a pioneer species
C. a stable community
D. secondary succession species
What term refers to the process
of one ecological community
gradually changing into another?
A. pioneer succession
B. eutrophication
C. ecological succession
D. climax community
During which natural, predictable
process do freshwater
ecosystems change over time?
A. ecological succession
B. eutrophication
C. secondary succession
D. aquatic succession
Do you agree or disagree?
5. An ecosystem never changes.
6. Nothing grows in the area where a
volcano has erupted.
Key Concept Summary
Interactive Concept Map
Chapter Review
Standardized Test Practice
Each of Earth’s land
biomes and aquatic
ecosystems is
characterized by
distinct environments
and organisms. Biomes
and ecosystems
change by natural
processes of ecological
succession and by
human activities.
Lesson 1: Land Biomes
• Each land biome has a distinct climate and contains
animals and plants well adapted to the environment.
Biomes include deserts, grasslands, tropical rain
forests, temperate rain forests, deciduous forests,
taigas, and tundras.
• Humans affect land biomes through agriculture,
construction, and other activities.
Lesson 2: Aquatic Ecosystems
• Earth’s aquatic ecosystems include freshwater and
saltwater ecosystems. Wetlands can contain either
salt water or freshwater. The salinity of estuaries
varies.
Dr. Marli Mill/Visuals Unlimited/Getty Images
• Human activities such as
construction and fishing can
affect aquatic ecosystems.
Lesson 3: How Ecosystems Change
• Land and aquatic ecosystems change over time in
predictable processes of ecological succession.
• Land ecosystems eventually form climax
communities.
• Freshwater ecosystems
undergo eutrophication and
eventually become land
ecosystems.
What is a geographic area on
Earth that contains ecosystems
with similar biotic and abiotic
features?
A. desert
B. biome
C. temperate region
D. tropical rainforest
Which biome is found on every
continent and is Earth’s driest
ecosystem?
A. grasslands
B. temperate regions
C. polar regions
D. deserts
Which ecosystem can contain
freshwater, salt water, or both, and
are among earth’s most fertile?
A. grasslands
B. wetlands
C. estuaries
D. coral reefs
Which food chain’s base is made
mostly of microscopic algae and
other producers in the sunlit
zone?
A. saltwater
B. wetland
C. ocean
D. coral reef
Which term refers to the process
of a body of water becoming
nutrient-rich?
A. aquatic succession
B. ecological succession
C. secondary succession
D. eutrophication
What is the name for forests that
grow near the Earth’s equator?
A. biomes
B. deciduous forests
C. a taiga
D. tropical rain forests
Which of these is a forest biome
consisting mostly of cone-bearing
evergreen trees that only exists in
the northern hemisphere?
A. tundra
B. taiga
C. grassland
D. temperate rain forest
Salinity is a measure of the
amount of what substance
dissolved in water?
A. soil
B. bacteria
C. salt
D. algae
What are the regions along
coastlines where streams or rivers
flow into a body of salt water?
A. wetlands
B. ponds
C. lakes
D. estuaries
Which term refers to the process
of one ecological community
gradually changing into another?
A. aquatic succession
B. ecological succession
C. secondary succession
D. primary succession