Science Chapter 4 Study Guide
The Earth’s Ecosystems
SECTION 1: LAND BIOMES
Main Ideas
Biome
LAND BIOMES
Forest biomes
Grasslands
Savanna
Desert
Tundra
Polar tundra
Alpine tundra
There are eight kinds of land biomes: temperate deciduous forests,
coniferous forests, tropical rain forests, temperate grasslands,
savannas, deserts, polar tundra, and alpine tundra. Each land
biome contains organisms that are well-suited for the abiotic and
biotic elements that are present.
A large region characterized by a specific type of climate and
certain types of plant and animal communities. A biome is made
up of many related ecosystems.
There are three kinds of forest biomes: temperate deciduous,
coniferous, and tropical rain forests. Temperate deciduous forests
have trees whose leaves will turn colors and fall off between
autumn and winter. Coniferous forests consist mainly of conifers,
or evergreens. These have special needle-shaped leaves that stay
green all year long and do not fall off all at once. Tropical rain
forests have more variety of plants and animals than anywhere
else on Earth. Warm temperatures and high rainfall amounts allow
a lot of plant growth and densely-growing tall trees.
These are biomes made up mainly of grasses, small flowering
plants, and a few trees. The two main kinds of grasslands are
temperate grasslands and savannas. In temperate grasslands, the
summers are warm and the winters are cold. The soil is very rich in
nutrients. Savannas have a lot of rainfall during some seasons and
very little in others.
A grassland that often has scattered trees and that is found in
tropical and subtropical areas where seasonal rains, fires, and
drought happen
A region that has little or no plant life, long periods without rain,
and extreme temperatures: usually found in hot climates. Many of
the organisms living in deserts have special features that allow
them to survive in the dry climate.
A treeless plain found in the Arctic, in the Antarctic, or on the tops
of mountains that is characterized by very low winter
temperatures, short, cool summers, and very little rainfall. There
are two types: polar and alpine.
Found near the North and South Poles, the layer of soil below the
surface, called permafrost, stays frozen all year long.
Similar to polar tundra but found at the tops of mountains above
the tree lines. It receives a lot of sunlight and a moderate amount
of rainfall.
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SECTION 2: MARINE ECOSYSTEMS
MARINE ECOSYSTEM
Main ideas
Marine ecosystem
Plankton
Phytoplankton
MAJOR OCEAN ZONES
Major zones in the
ocean
Intertidal zone
Neritic zone
Oceanic zone
TYPES OF MARINE
ECOSYSTEMS
Benthic zone
Estuary
Coral reef
The abiotic factors that affect marine ecosystems are temperature,
water depth, and sunlight. The major zones found in the ocean are
the intertidal zone, the neritic zone, the oceanic zone, and the
benthic zone. Many different kinds of organisms live in marine
ecosystems, from producers like phytoplankton to consumers like
whales.
The ecosystems that are found in the oceans of the Earth. They are
affected by abiotic factors: temperature, water depth, and
sunlight. The surface of the oceans is much warmer than the
deeper parts, and tropical seas are much warmer, too, than the
polar seas. These temperatures affect the animals that live in the
oceans. Water depth affects the oceans in that producers need
sunlight in order to produce food. The average depth of the oceans
is 4,000 meters, but sunlight does not reach deeper than 200
meters.
Tiny organisms that float near the surface of the ocean. Many are
producers, using photosynthesis to make their own food. They are
the base of most ocean food chains. Large consumers, such as
whales, feed on plankton.
Plankton that use photosynthesis to make their own food
The major zones in the ocean are based on things such as water
depth, sunlight, and water temperature. Those zones are the
intertidal zone, the neritic zone, the oceanic zone, and the benthic
zone.
The place where the ocean meets the land. Organisms of the
intertidal zone are covered with water at high tide and exposed to
air at low tide. An intertidal area can include mudflats, sandy
beaches, and rocky shores.
This area has warm, sunlight water and is where the ocean floor
begins to slope downward.
This zone contains the deep water of the ocean and is where the
sea floor drops off quickly. Phytoplankton live near the surface,
where there is sunlight.
This is the ocean floor. It receives no sunlight and is very cold.
An area where fresh water flows into the ocean. Organisms living
here must be able to survive the changing amounts of salt in the
water.
These areas are named for the small animals called corals that
form the reefs. Corals live together in a colony. When they die,
their hard skeletons remain, forming a rock-like structure called a
reef. The reefs then become home to many marine animals. Coral
reefs are some of the most diverse ecosystems on Earth.
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SECTION 3: FRESHWATER ECOSYSTEMS
Main ideas
MAJOR FRESHWATER
ZONES
FRESHWATER
ECOSYSTEMS
Freshwater ecosystems
Spring
A place where water from underground flows to the surface
Tributary
A stream of water that joins a larger stream
River
A very strong, wide stream of water
Littoral zone
Open-water zone
Deep-water zone
Wetland
WETLANDS
An important abiotic factor affecting freshwater ecosystems is how
quickly the water moves. Many types of producers and consumers
live in freshwater ecosystems, from plants to fish. The three zones
of a lake or pond are the littoral zone, the open-water zone, and
the deep-water zone. There are two main types of wetlands:
marsh and swamp. Over time, a lake can become filled with
sediment, filling in the shallow areas first. Plants begin growing
here. As more and more of the lake fills in with sediment, the lake
becomes a swamp. Eventually, this becomes a forest as secondary
succession occurs.
Brooks, rivers, and swamps are example of freshwater ecosystems.
The water may come from melting ice or snow, or from a spring.
Marsh
Swamp
The area of water near the edge of a pond or lake. Here, sunlight
reaches the bottom, allowing producers to grow.
The area of a lake or pond away from the littoral zone near the
surface. This zone is as deep as the sunlight can reach. Producers
and consumers live here.
This area is beneath the open-water zone. No sunlight can reach
here, so producers cannot grow here. Scavengers and
decomposers grow here, feeding on the dead organisms that sink
from above.
An area of land that is sometimes under water or whose soil
contains a lot of water. Wetlands help control floods, soaking up
large amounts of water during heavy rains. The rainwater sinks
into the ground and helps refill underground water supplies. There
are two main types of wetlands: marshes and swamps.
A treeless wetland, they form along the shores of lakes, ponds,
rivers, and streams. Grasses and other small plants are the main
producers; consumers such as turtles, frogs and birds live here.
A wetland in which trees and vines grow. They form in low-lying
areas and near slow-moving rivers. Trees and vines are important
producers; consumers such as birds, fishes, and snakes live here.
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Deciduous
Conifer
Major Land Biomes
Tropical rainforest
Major ocean zones
Freshwater zones
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Desert
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