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I. Ecology
A. the study of the interactions organisms have
with each other and with their environment.
B. word “ecology” by Earnst Haeckel in 1866
from the Greek “oikos” meaning “house economy”
C. Interactions happen in the biosphere
a. Thin layer of Earth where life exists
(5 mi below ocean to 3.5 mi above surface)
b. Divided into 3 regions:
1. Lithosphere-land
(rocks, sand, soil)
2. hydrosphere-water (oceans, lakes, rivers, clouds, underground)
3. atmosphere-layer of air surrounding Earth
II. Levels of organization in the biosphere
(species population community ecosystem biome biosphere)
A. Species
1. organisms that look alike and can reproduce
2. live in a specific environment called a habitat
3. biodiversity – the variety of species in an ecosystem
B. Population - group of the same species living in the
same place at the same time
C. Community - all of the populations living in an area
D. Ecosystem - all of the communities in an area plus the
abiotic factors of the environment.
1. biotic factors – living things in an ecosystem
2. abiotic factors – nonliving things in an ecosystem
Ex) temperature, rainfall, nutrients, etc
E. Biome – very large area with unique ecosystem because of
unique climate (temperature & precipitation)
III. Population Interactions
A. The maximum number of organisms that an area can
support is called the ecosystem’s “carrying capacity”
B. The carrying capacity is determined by limiting factors
1. Density-Dependent Limiting Factors
Things that affect large, dense populations more
than smaller, less dense populations.
Ex: food, space, disease
2. Density-Independent Limiting Factors
Things that affect populations regardless of their
size or density.
Ex: floods, fire, drought
Carrying Capacity
~80 Deer
C. Limiting factors cause populations to interact in several ways:
1. territories - establishment of own area
2. predator/prey-one organism kills another
3. symbiosis - two organism living closely
a. parasitism-one organism feeds off another without
killing it (one benefits, one is harmed)
b. mutualism-both organisms benefit
c. commensalism-one organism benefits, other is
unaffected
V. Ecosystems
1. each organism in an ecosystem has a specific niche
a. the role/job of an organism in an ecosystem.
b. how it deals with the biotic and abiotic
forces in its habitat.
c. what it eats, what it feeds, where it lives, how it
reproduces, etc.
2. Ecosystem are all about energy flow
a. all energy on Earth originates from the sun
b. an ecosystem is made of many trophic levels
Step in Food
Chain
Name of Trophic
Level How it Feeds
Other Terms to Describe this Trophic
Level
1st producer
Autotroph
(energy from sun) Plants
2nd Primary Consumer Heterotroph
(eats P’s) Herbivores
Organisms that are
PC’s + any other
Consumer are
Omnivores
3rd
Secondary
Consumer
Heterotroph
(eats PC’s) Carnivores
4th Tertiary Consumer Heterotroph
(eats SC’s) Carnivores
5th Quaternary
Consumer
Heterotroph
(eats TC’s) Carnivores
Final Decomposers Heterotroph
(eats dead things) Fungi & Bacteria
Return the stored
energy & nutrients
back to the PC’s
c. several ways to show energy flow in an ecosystem:
1) food chains=simple order of who-eats-who
*overly simplified
*unstable
2) food pyramids=show how the energy in each
trophic level decreases.
*10% Rule – only 10% of the energy passes
along to the next trophic level.
Producers
(Autotrophs)
Primary
Consumers
(Heterotrophs)
Secondary
Consumers
(Heterotrophs)
Tertiary
Consumers
(Heterotrophs)
3) Food webs=network of food chains showing all
feeding relationships in an ecosystem.
*more realistic than a food chain
*show ecosystem stability
d. Not only energy flows through an ecosystem.
Pollution also gets passed along from one level to the next
and gets stronger as it collects in the organism at the top of
the food chain. This process is called
biological magnification or
bioaccumulation.
Examples of Bioaccumulation:
1. DDT - bald eagles nearly went extinct because the fish
it ate had eaten bugs killed by DDT pesticides. The
eagles’ eggs had shells that were too thin to survive
because of the pollution passed along the food chain.
2. PCB’s-chemical used to make electrical
insulators and wood sealants
-carcinogenic
-build up in fat
3. Heavy metals
*lead-from batteries, old paint, water pipes
-birth defects, brain damage
-“Mad Hatter’s” disease
(tremors, nerve damage, insanity)
-build up in fish fat
*mercury-from mines and paper mills
-brain damage, deformities
-also builds up in fish fat
VI. Natural Ecosystem Change
A. most ecosystems change over time in a predictable
sequence called ecological succession.
B. Communities and niches appear and disappear.
C. Steps in land succession:
1. pioneer species
-the first organisms to colonize bare rock
-mosses, insects, lichens
secrete enzymes that
break rock into sand
*weathering and lichens turn rock into soil
2. Intermediate Species
grasses and shrubs - build soil more
fast-growing trees
3. Climax community (oak and maple trees)
-not replaced by another
community unless the
area is disturbed by fire, flood,
logging, etc.
Different areas of the world have different abiotic factors
(temperatures, rainfall, etc.) so they develop different
climax communities.
An area with a unique climax
community is called a biome.
Ex) rain forest, desert,
tundra, savanna, etc.
D. Primary vs. Secondary Succession
E. Steps in Lake Succession:
1. Oligotrophic lake
-clear, cold water with
lots of oxygen
-sandy bottom
without weeds
-few nutrients
-salmon, trout
-Lake Michigan
2. Mesotrophic lake
-starting to fill in
with debris
-warmer, murkier,
weeds, lower oxygen
-bass, bluegill
-Muskegon Lake
3. Eutrophic lake
-very much filled in
with debris
-warm, muddy, shallow,
no oxygen
-frogs, snakes, carp
-Muskegon Marsh
*people speed up the eutrophication (aging) of lakes
by putting excess nutrients into the water from
lawn fertilizers and sewage.
VII. Ecosystem Disruption
A. Each part of an ecosystem is
necessary and interdependent
B. Several things can cause an
ecosystem to become unstable
and potentially collapse:
1. Stochastic Events – natural disruptions such as
storms and earthquakes
2. Removal of a Species – “The Lesson of the Kaibab”
3. Pollution – the wrong substances in the wrong
place in the wrong quantity
a. point-source pollution=from a single
identifiable place (factories, dumps, etc)
b. nonpoint-source pollution=from many places
(parking lot runoff, lawn fertilizers, etc)
4. Habitat Fragmentation – breaking one large area into
several small areas.
a. interrupts territories
b. interrupts migrations
c. increases edge area
5. Invasive Species – nonnative organisms that disrupt
established ecosystem energy flow.
Examples of Invasive Species of the Great Lakes:
Zebra Mussels & Quagga Mussels
Sea Lamprey
So, how’d they get here???
Emerald Ash Borer
Eurasian Watermilfoil & Curly-Leaf Pondweed
Round Goby
And the famous………
Asian Carp
Management plans for invasive species typically involve 4 steps:
1. Prevention
How are we trying to keep it from spreading to
other areas?
2. Detection
How do we know that it is in an ecosystem?
3. Control & Management
How are we trying to get rid of it?
4. Restoration & Rehabilitation of the Ecosystem
How are we trying to fix an ecosystem once the
invasive population is reduced or eliminated?
VIII. Cycles of Matter
A. Water Cycle
B. Carbon Cycle
IX. Fossil Fuels – carbon from the remains of organisms
that lived long ago.
A. Types of Fossil Fuels:
1. Coal-compacted plant remains from ancient
swamps.
-burned to heat water to spin turbines to
make electricity.
2. Petroleum-liquid formed from remains of
microorganisms in ancient seas.
-made into gasoline, grease, oil, plastics
3. Natural Gas-gas formed along with petroleum
-cleaner burning
B. Problems with fossil fuels
1. nonrenewable-can’t make more
2. hazardous to extract & transport
3. puts carbon (CO2) into atmosphere that is
supposed to be locked up underground.
X. Our Atmosphere
A. Greenhouse Effect-natural process of Earth’s
atmosphere trapping sun’s energy to keep warm.
B. PROBLEM: burning fossil fuels thickens the CO2 layer
around Earth and too much heat is trapped in,
resulting in “Global Warming”.
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