Download Interactions in the Ecosystem

Ecology Review
Ecology is…


the study of the
interactions/relationshi
ps between living
organisms and their
biotic and abiotic
environments.
ENVIRONMENT
* surroundings of an organism that affect
its life and development.
An environment is characterized by the ABIOTIC
and BIOTIC factors.
 Abiotic factors are non-living.
 chemistry, physics and geology.
 weather, seasonal changes, tides, air quality, and
water quality
 Biotic factors are

Species
Population
living
Community
ECOSYSTEM: all of the communities that live in
an area together with the abiotic factors in the
environment
Biosphere



All the parts of Earth
that support life.
20km thick (12.4 miles)
Most life on Earth exists
between 500m below the
surface of the ocean and
about 6km above sea
level.
Abiotic and Biotic factors work
together:
Geographic location (latitude and
longitude) determines abiotic
factors(temp and climate)
which supports specific
ecosystem.
AN ORGANISM’S NICHE
 Habitat:
the actual
place an organism
lives
 Niche: both living
and non-living parts
of an ecosystem
that determines an
organism’s role in
the ecosystem.
Organisms Interactions
-Producers
-Consumers
-Decomposers
-Scavengers
PRODUCERS

Autotrophic -make
their own food.
 Phototrophic
organisms use
photosynthesis and
contain
chlorophyll
 Chemotrophic
organisms use
chemicals other than
H20, such as H2S
PRODUCERS!!!
CONSUMERS
 Heterotrophic
–ingest their own food.
-Herbivores feed on vegetation
(producers).
-Carnivores feed on herbivores or on
other carnivores.
-Omnivores feed on both producers
and consumers
-Scavengers feed on dead or decaying
organisms
CONSUMERS!!!
Scavengers
DECOMPOSERS
- Heterotrophs
- Recycle dead organic matter into
inorganic nutrients
- Use by soil.
-Bacteria and Fungi and worms
Energy in the Ecosystem
 Producers
produce
energy through
photosynthesis (Sun)
 Energy = Glucose
 Consumers take in this
energy when they eat
producers or other
consumers.
 Plants absorb less than
1% of the sunlight that
reaches them!
TROPHIC LEVELS
Different feeding
levels of organisms in
an ecosystem.
 Producers are the
first trophic level
 These relationships
can be seen in an
ecological pyramid.
 Biomass: the total
amount of organic
matter

The Ten Percent Law
Most energy does not become biomass.
 Only about 10% of the energy
entering one trophic level forms
biomass for the next trophic level.
 Known as the 10% law.

Ecological Pyramid: Energy
Shows the relative transfer of energy (joules) from one
trophic level to the next.
Food Chains
-Series of
organisms that
transfer food
between the
trophic levels
-One species at
each level
-Simple chain.
-The arrow points
toward the
organism doing
the ‘eating’.
Food Webs
-Shows the
network of food
chains
-Most organisms
feed on more
than one type
of organism at
different
trophic levels.
How do Food Webs show complexity?
 Food
Webs represent the diversity
and stability of an ecosystem
 Complex
Food Webs = more stable
ecosystem
RELATIONSHIPS IN THE ECOSYSTEM


Predator/Prey: One organism (predator)
consumes another (prey).
Competition: two or more organisms
compete to use the same limited resources
Coevolution

When two or more species evolve in
response to each other, it is called
coevolution.
 Plants and insects = Pollination
 Bees want the nectar from flowers and
the bees transport the pollen for the
flower
Limiting Factors
-Factors which are in low supply
-Limit the growth of a
population
-Ex – availability of food, water,
shelter, and space; competition
for resources, predation, and
disease
Carrying Capacity
-Maximum number of individuals of a
population that can be supported in a
given environment sustainably.
Density Independent
-Factors that affect populations
regardless of their size
-Examples:
Unusual weather (Draught, Hurricanes)
Season cycles
Human activities (damming rivers,
forest cutting)
Density Dependent
-Limiting factors that depend on population
size
-Limiting only when population density reaches
a certain level
-Does not affect small, scattered populations
-Ex-Predation, competition, disease and
parasitism