ECOSYSTEMS AND COMMUNITIES
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Weather includes the daily conditions of Earth’s
atmosphere at a particular time and place
Weather includes temperature and precipitation
Climate involves the average, year after year
conditions of temperature and precipitation in a
particular region
Climate is caused by the trapping of heat by the
atmosphere, latitude, the transport of heat by
wind and ocean currents, and the amount of
precipitation that results
1.
2.
solar energy
presence of certain gases in the
atmosphere
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The natural insulating blanket of the
biosphere=atmosphere
Carbon dioxide, methane, water vapor, and
a few other atmospheric gases trap heat
energy and maintain Earth’s temperature
range
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4.
Greenhouse gases allow solar energy to
penetrate the atmosphere in the form of
sunlight
Most sunlight hits the surface of our planet
and is converted into heat energy and
radiated back into the atmosphere
Heat energy is not allowed to pass out of the
atmosphere as readily as light energy enters
it
The greenhouse gases trap heat inside the
earth’s atmosphere
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Earth is a sphere tilted on its axis, so solar
radiation strikes different parts of Earth’s
surface at an angle which varies throughout
the year
0 degrees latitude=equator=sun is directly
overhead at noon all yearmore heat
90 degrees latitude=north and south
poles=sun is lower in the sky for months at a
timeless heat
The difference in heat distribution with latitude
has important effects on Earth’s climate zones
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2.
3.
Polar zones: cold areas where sun’s rays strike
Earth at low angles. Located in areas at the
North and South poles, between 66.5 degrees
and 90 degrees N and S latitude
Temperate zones: between the polar zones
and tropics; climate ranges from hot to cold,
depending on the season
Tropical zone (Tropics): near the equator
between 23.5 degrees N and S latitude. The
tropics receive direct or nearly direct sunlight all
year, making the climate almost always warm
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Unequal heating of Earth’s surface drives winds
and ocean currents, which transport heat
throughout the biosphere
Winds form because the warm air rises and cool
air sinks. Air at the equator rises at the same time,
cool air from the poles sinks. The upward
movement of warm air and downward
movement of cool air creates air currents (wind)
that move heat through the atmosphere from
regions of sinking air to regions of rising air
Prevailing winds bring warm or cold air to a region
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Similar patterns of heating and cooling occur in
oceans
Ocean currents transport heat energy within the
biosphere; the surface ocean currents warm or
cool the air above them, which affects weather
and climate of the land masses
Mountains cause moist air masses to rise, clouds
form and precipitation begins on the mountains.
Once the air mass reaches the far side of the
mountain, it has lost moisture=this is called a rain
shadow.
Read chapter 4 section 1 in your book and
complete chapter 4 section 1 guided reading
worksheets!!!!
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Biotic factors are living things within an
ecosystem.
Examples: trees, birds, plants, bacteria
Abiotic factors are physical, non-living factors
that affect an ecosystem
Examples: temperature, precipitation
***Together, biotic and abiotic factors
determine the survival and growth of an
organism and the productivity of the
ecosystem in which the organism lives.
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Habitats are areas where organisms live
A niche is the full range of physical and
biological conditions in which an organism
lives and the way in which the organism uses
those conditions
Example: the type of food the organism eats,
how it obtains this food, and which other
species use the organism as food
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Competition, predation, and various forms of
symbiosis can powerfully affect an ecosystem
Competition occurs when organisms of the
same or different species attempts to use an
ecological resource in the same place at the
same time
Resources are necessities for life. Examples
include water, nutrients, light, food and space
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Competitive exclusion principle: no two
species can occupy the same niche in the
same habitat at the same time
Direct competition in nature results in a winner
and a loser, where the losing organism fails to
survive
Predation: when one organism captures and
feeds on another organism
Predator: organism that does the killing
Prey: organism that becomes the food
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Symbiosis: any relationship in which two
species live closely together
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2.
Mutualism: both species benefit from the
relationship. Example: flowers provide
insects with food and insects help flowers
reproduce by pollinating them
Commensalism: one member in the
relationship benefits and the other isn’t
affected. Example: barnacles attach
themselves to whales. The barnacles benefit
from the constant movement of water as it
carries food particles to them. The whales
are not helped nor harmed.
3. Parasitism: one organism lives on or inside
another organism and harms it. Example:
tapeworms are parasites that live in the
intestines of mammals (host). The parasite
obtains all or part of its nutritional needs;
they weaken the host but rarely kill them
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Ecosystems and communities are always
changing in response to natural and human
disturbances.
As an ecosystem changes, older inhabitants
gradually die out and new organisms move
in, causing further changes in the community.
This process is called ecological succession.
Primary succession: succession on land surfaces
where no soil exists. Example: occurs on surfaces
formed from volcanic eruptions that have built
new islands
1.
No soil: just ashes and rock
2.
Pioneer species: first species to populate the
area (ex. Lichens, fungi and algae on rock)
3.
When pioneer species (lichens) grow, the rock
breaks apart
4.
Lichens die and add organic material to help
form soil
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Secondary succession occurs when land
cleared and plowed for farming is
abandoned.
Secondary succession also occurs after
wildfires burn woodlands
Climax species: mature, stable species that
don’t undergo further succession
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A whale dies and sinks to the barren ocean floor;
the carcass attracts scavengers and decomposers
that feast on decaying meat (ex. Sharks)
Within a year, most tissue has been eaten and the
carcass supports a smaller number of fish, crabs,
snails; the decomposition of the whale enriches
sediment with nutrients where marine worms begin
to live
When the skeleton remains, heterotrophic bacteria
decompose the oils inside the whale bones which
release compounds that serve as energy sources for
chemosynthetic autotrophs (ex. Mussels, worms,
crabs, clams)
***re-read section 4-2 pages 90-97 in your book and
complete the guided reading worksheets***
A biome is a physical environment that contains
characteristic assembly of plants and animals
The major biomes include:
1.
Tropical rain forest
2.
Tropical dry forest
3.
Tropical savanna
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Desert
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Temperate grassland
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Temperate woodlands/shrublands
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Temperate deciduous forest
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Northwestern coniferous forest
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Boreal forest
10. Arctic tundra
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The two main factors that determine climate
are temperature and precipitation
Both temp. and precipitation can be
summarized on a graph called a climate
diagram
A microclimate is a climate within a small
area that differs significantly from the climate
around it (example: San Francisco=certain
streets within the city are blanketed with a
thick fog, while the sun shines a few blocks
away)
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Each biome is defined by a unique set of
abiotic factors, particularly climate, and has a
characteristic ecological community.
Transitional areas between biomes =one
biome’s plants and animals gradually
become less frequent, while the organism
characteristics of the adjacent biome
becomes more frequent
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Mountain ranges and polar ice caps do not
fall into the major biome categories
Mountain ranges are found on all continents.
Abiotic and biotic conditions vary with
elevation
As you move up from base of mountain to
summit, temperature becomes colder and
precipitation increases. Types of plants and
animals change as a result.
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Polar ice caps involve the polar regions that
border the arctic tundra and are cold yearround
***READ PAGES 98-105 AND COMPLETE 4-3
GUIDED READING WORKSHEETS***
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3/4 of earth’s surface is covered in water
Water communities include oceans, streams,
lakes, and marshes.
Water communities are controlled by biotic
and a biotic factors including light, nutrient
availability and oxygen.
Aquatic ecosystems are determined primarily
by the depth, flow, temperature and
chemistry of the overlying water.
1. Aquatic ecosystems are grouped according
to the abiotic factors that affect them
2. Land biomes are grouped geographically
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Depth of water: distance from the shore
determines the amount of light organisms
receive
Water chemistry: amount of dissolved
chemicals (salts, nutrients, oxygen) on which
life depends
Latitude: aquatic ecosystems in polar,
temperate, and tropical oceans all have
distinctive characteristics
Two main types: flowing water and standing
water
1.
Flowing water ecosystems:
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a) rivers, streams, creeks, brooks
b) Organisms are well adapted to the rate of flow
c) Originate in mountains or hills from underground
sources
d) Rapid water has a higher amount of distilled water but
little plant life
e) Moving downhill, sediments build up and plants
establish themselves
f) Slow moving water through flat areas where turtles and
river otters make their homes
2. Standing water ecosystems
a)
Lakes and ponds
b)
Water circulates within them and usually flows in
and out
c)
Circulation distributes heat, oxygen, and nutrients
d)
Plankton live here: tiny free floating or weakly
swimming organisms that live in freshwater and
saltwater environments
e)
Phytoplankton: single celled algae supported by
nutrients in water and form the base of aquatic
food webs
f)
Zooplankton: planktonic animals that feed on
phytoplankton
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A wetland is an ecosystem in which water
either covers the soil or is present at or near
the surface of the soil for at least part of the
year
A wetland is usually a mixture of salt and
freshwater
It is a breeding ground for insects, fish,
amphibians, and migratory birds
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Bogs: usually form in depressions called
“kettle holes” left by icy sheets that melted
thousands of years ago. Sphagnum moss
grows here because water is acidic.
Marshes: shallow wetlands along rivers.
They may be underwater for all or part of a
year. Contains cattails and tall, grasslike
plants
Swamps: slowly moving water that looks like
a flooded forest. Contains trees and shrubs.
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Wetlands formed where rivers meet the sea
Mixture of freshwater and saltwater
Affected by the rise and fall of ocean tides
Most are shallow, so sunlight reaches the bottom
to begin photosynthesis
Primary producers are plants, algae and bacteria
Most primary production is NOT consumed by
herbivores. Instead, it enters the food web as
detritus=tiny pieces of organic material that
provide food for organisms at the base of the
estuary’s food web (ex. Clams, worms, sponges)
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Salt marshes: temperate zone estuaries
dominated by salt tolerant grasses above the
low tide line and sea grasses under water
Mangrove swamps: coastal wetlands that
are widespread across tropical regions.
Dominant plants are salt tolerant trees and
sea grasses. It is a valuable nursery for fish
and shellfish. The largest in the United States is
the Florida Everglades National Park
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Photic zone: well lit upper layer where
photosynthesis takes place. Depth of 200
meters; where algae and other producers
grow
Aphotic zone: permanently dark layer just
beneath the photic zone; chemosynthetic
autotrophs can survive here
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Ocean zones are based on the depth and
distance from the shore. They are the
intertidal zone, the coastal ocean, and the
open ocean.
Each zone supports distinct ecological
communities
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Regular and extreme changes in surroundings
One or two times, the zone is submerged in
seawater. The rest of the time, it is exposed to
air, sun and temperature changes
Battered by waves and strong currents
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Exists in temperate regions where exposed
rocks line the shore
Barnacles and seaweed permanently attach
themselves to rocks
Snails and sea urchins cling to rocks by their
feet
Zonation=prominent, horizontal banding of
organisms that live in a particular habitat. In
the rocky intertidal zone, each band can be
distinguished by differences in color or shape
of the major organisms
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Extends from the low-tide mark to the outer
edge of the continental shelf.
It is the relatively shallow border that surrounds
the continents.
Rich in plankton and other organisms
Example: kelp forests=giant brown algae that
can grow as much as 50 cm a day. It is found
in cold, temperate seas around the world.
They support a food web of snails, sea otters,
fish, seals, and whales
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Named for the coral animals whose hard,
calcium carbonate skeletons make up their
primary structure
Most diverse and productive environments on
earth
Coral animals=use tentacles to capture and
eat microscopic creatures; they cannot grow
in cold water or water low in salt. They live in
symbiosis with algae.
Almost all growth in a coral reef occurs within
40m of the surface
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The oceanic zone begins at the edge of the
continental shelf and extends outward
it is the largest marine zone covering more
than 90 % of surface area of the world’s
oceans
Organisms are exposed to high pressure, frigid
temperatures, and total darkness
Fish of all shapes and sizes dominate the
open ocean (swordfish, octopus)
Dolphins and whales could live here, but must
stay near the surface to breathe
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The ocean floor
Benthos=organisms that live attached to or near
the bottom (sea stars, sea anemones, marine
worms)
The zone extends horizontally along the ocean
floor from the coastal ocean through the open
ocean
Benthic ecosystems depend on food from
organisms that grow in the photic zone
(producers)
They feed on pieces of dead organic material
(detritus) that drift downward from the surface of
the water
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Chemosynthetic bacteria= support life
without light and photosynthesis
They live near deep-sea vents where
superheated water boils out of cracks on the
ocean floor
*Read pages 106-112 in your textbook.
Complete guided reading worksheets section
4-4.
**Prepare for a test!!!!