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Ecosystems and
Communities
Chapter 4
1
Part 1—The Role of Climate
What is Climate?
• __________ is the
day-to-day condition of
Earth’s atmosphere at
a particular time and
place
• ___________ is the
average, year-afteryear conditions of
temperature and
precipitation in a given
region.
Climate
• ____________ is
caused by an
interaction of a lot of
factors:
– Atmosphere trapping
heat
– Latitude
– Amount of
precipitation
– Energy of incoming
sunlight
Climate
• Populations of plants and
animals grow, remain
stable, or vanish,
depending in part on
______
_____________________
__ such as temperature
and rainfall.
• These conditions also
affect the structure of
food webs and the flow
Earth’s Thermostat
• _________ is the only planet
in the solar system that has
temperatures that can
sustain life as we know it.
• This is because Earth’s
atmosphere serves as a
natural thermostat.
• Carbon dioxide, methane,
water vapor, and other gases
________
_________________ and
maintain Earth’s temperature
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The Greenhouse Effect
• These gasses also allow
____________ through, which gets
converted into heat energy when it
hits Earth.
• The heat gets radiated back into the
atmosphere, but can’t pass through
the gasses as easily as sunlight can
enter.
• By trapping heat and letting sunlight
through, these gasses act like glass
windows in a greenhouse. As a
result, this is called the
Effect of Latitude
• Because Earth is _________
_________________, solar
radiation strikes different
parts of Earth’s surface at
different angles throughout
the year.
• At the equator, the sun’s rays
always come in at a direct
angle, and as you move
away from the equator the
sunlight becomes less direct.
• As a result of differences in
latitude and angle of heating,
Earth has _______ main
climate zones.
Earth’s Climate Zones
1) ___________ zones: cold
areas where the sun’s rays
strike Earth at very low
angles.
2) ___________ zones: areas
near the equator that
receive direct sunlight and
are almost always warm
3) _______________ zones:
areas between the polar
and tropic zones that are
most affected by the
changing angle of the sun’s
rays throughout the year,
resulting in varied weather.
Heat Transport
• The unequal heating of
Earth’s surface drives
_____ and
__________________
• In turn, these transport
heat throughout the
biosphere.
• This happens because
cold air and water from
the poles sinks, while
warm water and air near
the equator rises.
Microclimate
• Climate conditions can
vary over very small
distances
• The climate in a small
area that differs
significantly from the
climate around it is called
a
____________________
_
– Example: in San
Part 2—Shaping an
Ecosystem
Environment
• An __________________ is
a combination of the physical
and biological factors that
influence life
• The biological influences on
an organism within an
ecosystem are called
__________ factors
– Example: the other
organisms with which it
interacts, like plants and
animals.
• The physical, non-living
influences on an organism
are called _____________
Biotic and Abiotic Factors
• Together, biotic and
abiotic factors determine:
– 1) The survival and
growth of an organism
– 2) The productivity of
the ecosystem in which
the organism lives.
Ecosystem
• In the natural world, a
combination of biotic and
abiotic factors is called
an
____________________
__
• An ecosystem is a
collection of organisms-producers, consumers,
and decomposers-interacting with each
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Habitat
• The type of
surroundings in
which an organism
lives including the
both the biotic and
abiotic factors, is
called a
_______________
_.
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The Niche
• A ______________ is the
full range of physical and
biological conditions in
which an organism lives,
and the way in which the
organism uses those
conditions.
• ____________________
__ can share the same
niche in the same habitat.
Ecological Succession
• Ecosystems are always
changing in response to
natural and human
disturbances.
• As an ecosystem changes,
older inhabitants die out, and
are replaced by new
organisms, causing more
change.
• This process of change over
time in a community is called
_______________________
_.
Primary Succession
• Succession that occurs
on land where no soil
exists is called
_________________
succession.
– Example: Earth is
covered by lava
• The first species to
populate the area is
called a pioneer
species.
– Example: lichens,
Secondary Succession
• ____________________
__ succession happens
after a disturbance
changes a community
without completely
removing the soil.
• There is no need for a
pioneer species, since
seeds and roots can
survive.
– Example:
_____________
Climax Community
• Ecological succession
proceeds until a
relatively stable state is
reached.
• The relatively stable
collection of plants and
animals that results
when an ecosystem
reaches that state is
called a
__________________
__.
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Part 3—Land Biomes
Biomes
• A ____________ is a
major ecological
community that includes
ecosystems with similar
climates and organisms.
• Since biomes are based
on climate, similar ones
can be found in different
parts of the world.
• Ecosystems identified by
their climax communities
are called biomes
Climate
• ____________ is
especially important in
determining the
characteristics of a
biome.
• The two main factors
that determine a region’s
climate—temperature
and precipitation—can
be summarized on a
graph called a
_______________
New York, NY
Major Biomes: Tundra
• The tundra is covered by
____________________
_, a layer of permanently
frozen subsoil.
• During the short summer,
the ground thaws a little
bit, and then freezes
again in the winter.
• Strong winds, low
precipitation, poorly
developed soil.
•
Major Biomes: Tropical Rain
Forest
Tropical rain forests are
home to more species than
all other land biomes
combined.
• Leafy tops of tall trees form
a dense cover called a
________, which covers the
forest floor below. In the
shade below the canopy,
there is a smaller layer of
trees called the
•
Major Biomes: Tropical Dry
Forest
Tropical dry forests occur
in places where rainfall is
seasonal rather than
year-round.
• During the dry season,
trees drop their leaves to
conserve water. Such
trees are called
________________.
• Warm year-round;
alternating rainy and dry
seasons.
Major Biomes: Temperate
Forest
• Temperate forests
contain a mixture of
deciduous and
___________________
_ (trees that produces
cones and leaves
shaped like needles)
trees.
• Cold-to-moderate
winters, warm summers,
year round precipitation,
Major Biomes: Boreal Forest
•
•
Boreal forests, also
called
_________________,
have dense forests of
coniferous trees.
Long cold winters, short
mild summers;
moderate precipitation,
nutrient poor soils.
Major Biomes: Tropical
Savanna
• _________________
receive more seasonal
rainfall than deserts but
less than tropical dry
forests.
• Savannas are covered
with grass and have
isolated small trees and
shrubs.
• Warm temperature,
seasonal rainfall,
frequent forest fires
Major Biomes: Temperate
Grassland
• Covered by grasses
and fertile soil
• Example: Plains and
prairies
• Warm/hot summers,
cold winters; seasonal
precipitation,
occasional fires.
Major Biomes: Desert
• A desert biome is any
area that has less than
______ centimeters
annual precipitation.
• Otherwise,
temperatures can
range from very hot to
very cold, sometimes
during the course of
one day.
•
•
Shaping an Ecosystem
Review
https://www.youtube.com/watch?v=D1aRSeTmQE