biology - cabarrus.k12.nc.us€¦ · limiting factors in a community a limiting factor is any...
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Biology UNIT 3
Life in a Community+ Succession
Recall: What is a community?
Limiting Factors in a Community
A limiting factor is any biotic or abiotic factor
that resists the existence, numbers, reproduction,
or distribution of organisms.
Common limiting factors include sunlight,
temperature, water, nutrients, fire, soil chemistry,
and space.
Limits of Tolerance
The ability of an organism withstand fluctuations
in the environment.
Too much fluctuation will surpass the tolerance
of the organism.
Limits of Tolerance
Succession
The orderly, natural changes and species
replacement that takes place in the
communities of an ecosystem.
Occurs in stages.
Often difficult to observe because it takes
centuries.
2 Types: Primary and Secondary
Succession
Primary Succession
Takes place on barren land. (No Life, No Soil)
Ex: Lava flows that destroy everything
Starts with pioneer species
Pioneer species are usually mosses and lichens.
Eventually enough moss/lichens will die and
create organic material for soil.
After many years, this area may become a
climax community
Secondary Succession
Takes place after an existing community is
disrupted.
Ex: Forest fires
Because soil already exists, it may take less time
to become a climax community.
Compare/Contrast a
Primary+Secondary Succession
Biomes
A large group of ecosystem that share the same
type of climax community.
Can be terrestrial or aquatic.
Aquatic Biomes
Marine: Saltwater
Estuary: Mixed salt and fresh
Freshwater: Self explanatory
Marine Biomes
Oceans contain huge amount of biomass.
Most of this biomass is tiny creatures like plankton
Separated into photic and aphotic zones.
Photic zone: Shallow waters near landmasses.
Light can reach these areas.
Aphotic Zone: Deepest, least explored parts of
the ocean. No light reaches here.
Estuary
Where river meets sea.
Salinity fluctuates with tides.
Often lush with grasses.
Serves as a nursery for many marine creatures
which in turn attracts many predators.
Freshwater
Often more shallow than marine biomes.
Smaller bodies of water are more prone to
temperature variation.
Greatest biodiversity is in the warmer more
shallow part of lakes and rivers.
Terrestrial Biomes
Affected by latitude and climate.
As climate becomes more temperate, it falls into
the range of tolerance for more organisms
leading to more biodiversity.
Tundra
Closest to the poles
Treeless
Soil lacks nutrients
Extremely short growing seasons for plants.
Home to many small animals, some large
animals may migrate there during summer.
Taiga
Just south of the tundra.
Home to many coniferous trees.
Much of Canada, Northern Europe, and Asia
Soil is acidic and poor in minerals.
Trees provide more shelter and food for animals.
Desert
Dry arid region with sparse plant life.
Less than 25cm of rain
Rain is the major limiting factor for organisms.
Large areas of bare ground.
Many organisms have adaptations to conserve
water.
Grasslands
Between 25cm and 75cm of rainfall
Covered with rich soils and grasses.
Few trees
Often populated by herds of grazing animals
Much more biodiversity than desert
Also called prairie
Temperate Forest
70 to 150 cm of rain annually.
Dominated by broad leafed hardwood trees.
Settlers cleared much of this for lumber.
Soil usually consists of fertile top layer on top of
clay.
Rainforest
200cm to 600cm of rain
Lush plant growth
The most biodiversity of all biomes.
Most nutrients are tied up in biotic factors.
Support a multitude of habitats and niches for
diverse organisms.