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4-1 The Role of Climate
What is climate?
◦ Weather is the day-to-day condition of
Earth's atmosphere at a particular time
and place.
◦ Climate refers to the average year-afteryear conditions of temperature and
precipitation in a particular region.
◦ Organisms vary in their adaptations to
climate and in their tolerance for
conditions that exceed the normal range.
Five factors that affect climate
1.
2.
3.
4.
5.
The greenhouse effect: the trapping of heat
by gases in the atmosphere keeps earth
warm
Latitude: the angle of the sun’s rays on that
part of the earth
Movement of heat all over the biosphere
by air and ocean currents: warm air/water
rises and cold air/water sinks driving wind
and ocean currents
Amount of precipitation
Shape and elevation of landmasses
1. The Greenhouse Effect
◦ Our atmosphere is a natural insulating
“blanket” about 12km high that
maintains suitable temperatures ranges
for life on earth because it traps heat.
Greenhouse Gases
Called GHGs
 Atmospheric gases
that trap the heat
energy of sunlight
include:

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carbon dioxide, CO2
methane, CH4
water vapor, H2O (g)
nitrous oxide, N2O
The Greenhouse
Sunlight
Effect
◦ The natural
situation in
which heat is
retained in
Earth’s
atmosphere by
this layer of
gases.
Some heat
escapes into
space
Greenhouse
gases trap
some heat
Atmosphere
Earth’s Surface
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In a greenhouse, light can come in but
heat can’t go out!

GHGs in the
atmosphere allow
solar radiation to
enter the
biosphere but
slow down the
loss of heat to
space.
Global Warming
As the concentrations of GHGs increase
within the atmosphere, more infrared
radiation is absorbed and less escapes
directly to space, resulting in amplified
warming.
 This is called the Enhanced Greenhouse
Effect or Global Warming.

Signs of Change….
Enhanced Greenhouse Effect

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Solar energy that has been absorbed by Earth's surface is
then emitted in a different form.
Since Earth is much cooler than the Sun, it emits weaker
radiation with longer wavelengths, in the infrared range.
Some of this infrared radiation passes through the
atmosphere unimpeded, but the majority is absorbed by
GHGs and then reemitted in all directions-towards space,
to other GHG molecules, and back to Earth's surface.
GHGs block most of the infrared radiation within the
atmosphere that would otherwise escape directly into
space.
GHG molecules have a significant impact on Earth's climate
by acting as a barrier for escaping "heat".
2. Latitude and Climate
 Because
of
differences in
latitude and
thus the angle
of heating,
Earth has
different
climate zones
Quick Review Latitude & Longitude
The Earth’s Main Climate Zones
the three major climate zones depend on latitude
Sunlight
90°N North Pole
Arctic Circle
Sunlight
Most direct sunlight
66.5°N
Tropic of Cancer
Temperate
23.5°N
Equator
Tropic of Capricorn
0°
Tropical
23.5°S
Sunlight
Temperate
Antarctic Circle
Sunlight
Polar
66.5°S
90°S South Pole
Polar
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Earth has three main climate zones.
 These climate zones are caused by the unequal heating of
Earth's surface.
 Near the equator, energy from the sun strikes Earth almost
directly.
 Near the poles, the sun's rays strike Earth's surface at a
lower angle.
 The same amount of solar energy is spread out over a
larger area, heating the surface less than at the equator.
Three Major Climate Zones
 Polar
Zones
◦ Cold areas, near North and South Poles
◦ Sun strikes at low angles
◦ between 66.5° and 90° North and South
latitudes.
 Temperate Zones
◦ Middle zone between polar and tropics
◦ Climate ranges between hot and cold, depending
on the season
 Tropical Zones
◦ Near the equator
◦ Receive direct sunlight making it warm all year
round
◦ between 23.5° North and 23.5° South latitudes.
3. Heat Transport in the Biosphere

Unequal heating of Earth’s surface drives
winds and ocean currents, which transport
heat throughout the biosphere.
 Warm air over the equator rises, while
cooler air over the poles sinks toward the
ground.
 Cold water near the poles sinks, then
flows parallel to the ocean bottom, and
rises in warmer regions.
Heat transport in the Biosphere
Earth's winds and
ocean currents
interact to help
produce Earth's
climates.
 The curved paths
of some currents
and winds are the
result of Earth's
rotation.

4. Amount of Precipitation

A warmer climate spurs the evaporation
of water from land and sea and allows the
atmosphere to hold more moisture—thus
setting the stage for more extreme
precipitation.
5. Elevation

At higher elevations temperatures drop
and precipitation increases.
4-2 What Shapes an Ecosystem?

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Biotic and abiotic factors determine the survival &
growth of an organism & the productivity of the
ecosystem where the organism lives.
Biotic factors: all the living things an organism
interacts with.
Abiotic factors: Physical, or nonliving, factors
that shape ecosystems. Include:
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
temperature
precipitation
humidity
wind
nutrient availability
soil type
sunlight
Habitat
The area where an organism lives
 Includes both biotic and abiotic factors
 think of it as the organism’s “address” in the
ecosystem

Niche
The full range of physical & biological
conditions where organism lives and the way
the organism uses those conditions.
 Physical conditions: include temperature
 Biological conditions: include place in the
food web
 No two species can share the same niche in
the same habitat BUT different species can
occupy similar niches.
 think of it as the organism’s “occupation” in the
ecosystem
Interactions within communities
1.
2.
3.
Competition for resources - A resource is any
necessity of life, such as water, nutrients, light,
food, or space.
Predation – one organism feeds on another;
population size often controlled by predation.
Symbiosis – two species living close together
SYMBIOSIS INCLUDES:
1. mutualism: both benefit
2. commensalism: one benefits, other not affected
3. parasitism: one benefits, other is harmed
1. Competition
Competition occurs when organisms
attempt to use an ecological resource in
the same place at the same time.
Direct competition in nature often results
in a winner and a loser—with the losing
organism failing to survive.
 The competitive exclusion principle:
no two species can occupy the same niche
in the same habitat at the same time.
SYMBIOSIS
Mutualism
Commensalism
Parasitism
Ecological Succession
Ecosystems are constantly changing in
response to natural & human disturbances.
 This series of predictable changes that
occurs in a community over time is called
ecological succession.
 Sometimes, an ecosystem changes in
response to an abrupt disturbance.
 At other times, change occurs as a more
gradual response to natural fluctuations in
the environment.

Primary Succession
Occurs on surfaces where no soil exists
such as rock surfaces after volcanoes erupt
or after glacial retreat
 The first species to populate the area are
called pioneer species
 No soil

Primary Succession
Secondary Succession
Occurs in response to natural events such
as fires, hurricanes, or logging
 Soil is present.
 Community interactions tend to restore the
ecosystem to its original condition

Secondary Succession
Videos Succession

http://youtu.be/V49IovRSJDs
Webquest Secondary Succession
https://sites.google.com/site/ecologicalsuc
cessionwequest/secondary-succession
 http://www.slideshare.net/SeanHildebrand
t/ecological-succession-and-communityinteractions
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ECOLOGICAL SUCCESSION
OF STREAMS
Marine Succession after a wood fall
Succession in Marine Ecosystems
◦ Succession can occur in any ecosystem,
even in the permanently dark, deep ocean.
◦ In 1987, scientists documented an unusual
community of organisms living on the
remains of a dead whale.
◦ The community illustrates the stages in
the succession of a whale-fall community.
Marine Succession after a whale fall

A whale dies and sinks to the ocean floor.
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Marine Succession after a whale fall

Within a year, most of the whale’s tissues have been
eaten by scavengers and decomposers.
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Ecological Succession after a whale fall
The decomposition of the whale’s body
enriches the surrounding sediments with
nutrients.
 When only the skeleton remains,
heterotrophic bacteria decompose oils in
the whale bones.
 This releases compounds that serve as
energy sources for chemosynthetic
autotrophs.
 The chemosynthetic bacteria support a
diverse community of organisms.

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4-3 THE EARTH’S BIOMES

A biome is a complex of terrestrial
communities that covers a large area and
is characterized by certain soil and
climate conditions and particular
assemblages of plants and animals.
Biomes and Climate
The climate of a region is an important
factor in determining which organisms
can survive there.
 Within a biome, temperature and
precipitation can vary over small
distances.
 The climate in a small area that differs
from the climate around it is called a
microclimate.

Two
components
of climate,
temperature
and
precipitation,
can be
summarized in
a graph called
a climate
diagram.
Average Temperature (°C)

Average Precipitation (mm)
Biomes and Climate
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Climate Diagrams
Which month
has lowest
precipitation?
 Which month
has highest
precipitation?
 What is the
average
temperature &
precipitation
in July?
Average Temperature (°C)
Average Precipitation (mm)

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The Major Biomes
◦ The world's major biomes include:
 tropical rain forest
 tropical dry forest
 tropical savanna
 desert
 temperate grassland
 temperate woodland and shrubland
 temperate forest
 northwestern coniferous forest
 boreal forest (taiga)
 tundra
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Other Land Areas – don’t fit easily
into major Biome categories

Mountain Ranges
◦ Abiotic and biotic conditions vary with
elevation.
◦ Temperatures become colder as you
move from base to summit.
◦ The amount of precipitation increases as
you move from base to summit.
◦ Plants and animals also change, adapting to
the changing environment.
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Other Land Areas – don’t fit easily
into major Biome categories

Polar Ice Caps
◦ The polar regions are cold all year round.
◦ In the north polar region, the Artic Ocean is
covered with sea ice and a thick ice cap.
◦ Dominant organisms include mosses, lichens,
polar bears, seals, insects, and mites.
In the south polar region, Antarctica is
covered by a layer of ice nearly 5 kilometers
thick in some places.
 The dominant wildlife includes penguins and
marine mammals.

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4-4 Aquatic Ecosystems
Nearly three-fourths of the Earth’s
surface is covered with water; only 3% is
fresh water.
 Almost all bodies of water contain a wide
variety of communities governed by biotic
and abiotic factors including light, nutrient
availability, and oxygen.

Main Factors that govern aquatic
ecosystems
Depth of water (distance from the shore):
determines the amount of light that
organisms receive
 Flow: flowing-water or standing-water
 Temperature: warmer near the surface &
affects dissolved oxygen
 Chemistry of the water: refers to the
amount of dissolved chemical substances
(nutrients and oxygen) on which life
depends

Flowing-Water Ecosystems
Rivers, streams, creeks and brooks originate
in mountains or hills and flow over land
 Organisms that live there are well adapted
to the rate of flow
 Turbulent water near the source has little
plant life.
 As the water flows downhill, sediments build
up and enable plants to grow.
 Downstream, water may meander slowly,
where turtles, beavers, and river otters live.

Standing-Water Ecosystems
Includes lakes and ponds
 Water flows in and out
 Water also circulates within them
distributing heat, oxygen and nutrients
 Provides habitats for organisms such as
plankton

◦ Phytoplankton: unicellular algae; the base of
many aquatic food webs.
◦ Zooplankton: unicellular animals that feed on
phytoplankton
Freshwater Wetlands
Water either covers the soil or is present
near the surface at least part of the year
 Very productive ecosystems because they
serve as breeding grounds for insects, fish,
and birds.
 Includes

◦ Bogs – form in depressions where water
collects
◦ Marshes – shallow wetlands along rivers
◦ Swamps – look like flooded forest
Estuaries
A type of wetland formed where river meets
sea – or fresh water meets salt water.
 Are affected by the ocean tides.
 Includes salt marshes (along the coast in
temperate zones) and mangrove swamps (in
tropical regions).
 Most of the primary production (by plants, algae
& bacteria) is NOT consumed by herbivores but
enters the food web as detritus.
 Organisms that feed on detritus include clams,
worms and sponges.
 Many young animals feed and grow in estuaries
then head out to sea to mature, returning to
reproduce.

Marine Ecosystems
The photic zone: the thin upper layer of the
ocean that receives light where algae and
other producers can grow.
 The aphotic zone: is permanently dark.
 Other zones are based on distance from the
shore:

 the intertidal zone
 the coastal ocean
 the open ocean
Land
Marine Ecosystems
200 m
1,000 m
Coastal
ocean
Open
ocean
4,000 m
6,000 m
Continental
shelf
Continental
slope
and continental
rise
Ocean
trench
10,000 m
Abyssal
plain
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Photic
zone
Aphotic
zone
Marine Ecosystems

Intertidal Zone
◦ Organisms that live in the intertidal zone
are exposed to regular and extreme
changes in their surroundings.
◦ Competition among organisms in the
rocky intertidal zone often leads to
zonation, the prominent arrangement of
organisms in a particular habitat in
horizontal bands.
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Adaptations in the intertidal zone
Here organisms are exposed to
temperature extremes, waves, wind and
high and low tides.
 Barnacles and seaweed attach to rocks.
 Snails, sea urchins and sea stars cling to
rocks with suckers on their feet.

Marine Ecosystems

Coastal Ocean
◦ Extends from the low-tide mark to the
outer edge of the continental shelf.
◦ Falls within the photic zone, and
photosynthesis occurs throughout its
depth.
◦ Often rich in plankton and many other
organisms.
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Marine Ecosystems

Coastal Ocean
◦ Kelp forests
 named for their dominant organism, a
giant brown alga
 one of the most productive coastal
ocean communities
 support a complex food web
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Marine Ecosystems

Coral Reefs
◦ Found in tropical coastal waters
◦ Named for the coral animals whose
calcium carbonate skeletons make up their
primary structure.
◦ An extraordinary diversity of organisms
flourishes among coral reefs.
◦ Reef-building corals grow with the help of
algae that live symbiotically within their
tissues.
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Marine Ecosystems

Open Ocean = The Oceanic Zone
◦ Extends from the edge of the continental
shelf outward.
◦ It is the largest marine zone.
◦ Most of the photosynthetic activity on
Earth occurs in the photic zone of the
open ocean by the smallest producers.
◦ Fish dominate the open ocean.
◦ Marine mammals must stay close to
surface to breathe.
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Marine Ecosystems

Benthic Zone – the ocean floor
◦ The ocean floor contains organisms that
live attached to or near the bottom;
depend on food from organisms in the
photic zone.
◦ These organisms are called benthos.
◦ Chemosynthetic primary producers
support life without light near deep-sea
vents.
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Life in the Oceanic Zones