chapter 3: communities, biomes, and ecosystems · chapter 3: communities, biomes, and ecosystems....
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Did you include your
family and friends?
Did you include your
school?
Did you include plants and
animals ?
A biological community is a group of interacting populations that occupy the same area at the same time.
Any abiotic or biotic
factor that restricts the
numbers, reproduction, or
distribution of organisms
is called a limiting factor.
Abiotic limiting factors include
sunlight, climate, temperature,
water, nutrients, fire, soil
chemistry, and space.
Biotic limiting factors include
living things, such as other plants
and animal species.
For any Environmental factor, there is
an upper limit and a lower limit that
define the conditions in which an
organism can survive.
The ability of any organism
to survive when subjected to
abiotic or biotic factors is
called tolerance.
Within any particular ecosystem
abiotic and biotic factors are
constantly changing.
May be in small ways such as a
tree falling or on a larger scale
such as a population going
extinct.
The change in an ecosystem
that happens when one
community replaces another as
a result of changing abiotic and
biotic factors is called
ecological succession.
1. Primary successionEstablishment of a community in an area of
bare rock or sand, where no topsoil is present.
A mature community can eventually develop from
bare rock. That community will then be known as a
climax community because there is little to no
change in the composition of species.
2. Secondary succession
Secondary succession is the orderly
and predictable change that takes
place after a community or
organisms has been removed but the
soil has remained intact.
Effects of Latitude and Climate
Weather is the condition of the atmosphere at a specific place and time.
In order to understand why weather varies, it is important to first understand latitude and climate conditions.
Latitude
The distance of any point on the surface
of earth north or south from the
equator is latitude.
• Light from the sun strikes the earth more directly at the equator than at the poles. As a result the earth is heated differently at areas.
• Ecologist refer to these areas as polar, Temperate and tropical zones.
Climate
The average weather conditions in an area, including temperature and precipitation, describe the
area’s climate.
An areas latitude has a large effect on its climate.
Other abiotic factors such as elevation, continental landmass, and ocean currents also affect climate.
Biomes are classified primarily according to the characteristics
of their plants and animals, along with their temperature
and precipitation.
Tundra Extends in a band
below the polar ice
caps across northern
Europe, north
America, and Siberia
in Asia.
Treeless biome with a
layer of permanently
frozen soil below the
surface called
permafrost.
Boreal ForestSouth of the tundra.
Band of dense evergreen forest that extends across N. America, Europe, and Asia.
Also called Northern Coniferous Forest, or taiga.
Longer summers than tundra
Lacks permafrost.
Temperate Forest Cover much of south Eastern
Canada, the eastern united states, most of Europe, and parts of Asia and Australia.
Composed mostly of broad-leaved, deciduous trees.
Shed leaves in autumn.
Fallen leaves return nutrients to the soil.
All four seasons occur in the temperate forest.
Temperate Woodland and Shrubland
Found in areas of less annual rainfall than temperate forest.
Areas surrounding Mediterranean seas, on the west coast of North and South America, in south Africa, and Australia.
Dominated by shrubs.
Temperate GrasslandCharacterized by fertile soils that
support a thick layer of grass.
Grazing animals keep the grass low.
Found in the middle latitudes of North America, South America, Asia , Africa , and Australia.
Called “Steppes” in Asia; “prairies” in N. America ;” pampas and Llanos” in S. America ; ”Savannas” in Africa; and “Rangelands” in Australia.
DesertExist on every
continent except for Europe.
An Area in which annual rate of evaporation exceeds the rate of precipitation.
Home to a wide variety of animals.
Tropical SavannaCharacterized by grasses
and scattered trees in climate that receives less precipitation than some other tropical areas.
Occur in Africa, S.America , and Australia.
Lions, Zebras, elephants cheetahs, etc. are common to this area.
Tropical seasonal forest
Also called tropical dry forests
Grow in areas of Africa, Asia, Australia, and South and Central America.
Tropical rain forest Warmer temperatures and large
amounts of rainfall throughout the year.
Found in much of Central and South America, Southern Asia, West central Africa, and northeastern Australia.
Most diverse of all land biomes.
Tall, broad-leaved trees with branches heavy with moss, ferns, and orchids make up the canopy of the tropical rain forest.
Shorter trees, shrubs, and plants make up another layer (understory).
Other Terrestrial Areas
Mountains As you go up a mountain,
Abiotic factors such as temperature and precipitation, change.
Because of this many communities can exist on the side of a mountain.
Other Terrestrial AreasPolar regions
Border the tundra at high altitudes.
Cold all year.
Coldest temperature ever recorded, -89°C = -128°F
Is able to sustain life, even with extreme temperatures.
Fresh Water Ecosystems: On earth the major fresh water ecosystems include ponds, lakes, streams, rivers, and wetlands.
• Plants and animals in these ecosystems are adapted to the low salt concentration (compared to the ocean) and are unable to survive in areas of high concentration.
~2.5 % of the water on earth is freshwater
Of that 2.5%,
68.9 % is contained in glaciers
30.8 % is groundwater
0.3 % are found in ponds, lakes, rivers,
streams, and wetlands.
The water in rivers and streams flows in
one direction, beginning at a source known as a headwaterand traveling to the mouth, where the
flowing water empties into a larger body of
water.
The slope of the landscape will determine the speed of the water flow.
Land is steep = flows quickly
This quick flow will cause lots of sediment to be picked up and carried by the water.
Sediment is a material that is deposited by water, wind, or glaciers.
• During the spring and fall, as the water warms or cools, turnovers occur.
• The top and bottom layers of the water mix and this results in a uniform water temperature.
• This mix circulates oxygen and brings nutrients from the bottom to the surface.
Nutrient poor lakes, called oligotrophic lakes, are
found often high in the mountains.
Few plants and animals are found as a result of small
amounts of organic mater and nutrients.
Nutrient-rich lakes, called eutrophic lakes, usually
are found at lower altitudes.
Many plants and animal species are present as a result of
organic matter and plentiful amounts of nutrients.
Lakes and ponds are divided into three zones
based on the amount of sunlight that penetrates
the water.
The area closest to the shore is called the littoral
zone.
The water in this zone is shallow ( allows sunlight to hit the
bottom).
In these shallow waters organisms such as plants and algae
thrive.
Area of high photosynthesis
Consumers habitat this zone such as frogs, turtles, worms,
coruscations, insect larva and fish.
The limnetic zone is the open water area that is well
lit and is dominated by plankton.
Many species of fish live in this zone because food is
readily available.
• Plankton are free
floating photosynthetic
autotrophs that live in
fresh water or marine
ecosystems.
The Profundal zone is the darkest part of a lake.
Much colder and lower in oxygen than the other
two zones.
Limited number of species live in this harsh
environment.
Wetlands Area saturated
with water that supports aquatic plants.
Areas of land such as:
Marshes
Swamps
Bogs
EstuariesEcosystem formed when freshwater from a river
or a stream merges with the salt water from the ocean.
o Dominant producers in these areas are algae, seaweeds, and marine grasses.
o Many species of marine fishes use estuaries as nurseries for their young.
Salt Marshes
Similar to Estuaries
Composed of salt-tolerant grasses
Support different species of animals, such as shrimp and shellfish.
Spray zone
Dry most of the time.
Only during high tide is this area sprayed with water
Few plants and animals live in this environment.
High-tide Zone Under water
only under high tide (receives more water than the spray zone)
Plants and animals are able to live in this zone
Mid-tide zone
Undergoes several disruption twice a day as the tides cover and uncover the shoreline with water.
Organisms in this environment must adapt to long periods of air and water.
Area to depth about 200m of the pelagic zone is called the Photic zone (euphotic zone).
Shallow enough for sunlight to be able to penetrate.
Divided into the epipelagic zone and mesopelagic zone
Autotrophic organisms:
Seaweed
Plankton
Animals:
Fish
Sea turtles
Jellyfish
Whales
Dolphins
Below the photic zone is the Aphotic zone.
Area where sunlight is unable to penetrate.
Remains in constant darkness
cold
Organisms that depend on light energy cannot live in this zone.
Benthic zone; Area along ocean floor that consist of sand, salt, and dead organisms
As depth increases, light and temperature decreases.
Species diversity increases with depth (not hypothermal zone)
Deepest region of the ocean is called the abyssal zone.
Very cold waters
Most organisms in this region rely on food material that drifts down from the zones above.
Coral reefs
Most diverse ecosystems
Found in warm shallow marine waters
Form natural barriers between continents that support the shoreline from erosion
Dominant organisms are corals
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