Ecology
The study of the interaction of living
things with their environment.
Cycles
• Water cycle
• Carbon cycle
• Nitrogen cycle
Water
Water Cycle
1. Evaporation is the process in which liquid bodies of
water, such as ponds, lakes, rivers, and oceans, change
into water vapor.
2. Transpiration is the evaporation of water from plant
leaves.
3. Condensation is the process where water vapor
changes to liquid or ice. (cloud formation)
4. Precipitation is when the water condenses so much
that it falls to the ground in the form of rain, snow, or
hail.
5. Once the precipitation falls to the ground, the water
may flow onto the ground or underground. The
process starts all over again.
Carbon
Carbon Cycle
1. Carbon begins in the atmosphere as carbon dioxide.
2. Plants on land, and algae in the water, take in the carbon
dioxide during the process of photosynthesis. They use
this carbon dioxide to make their own food.
3. Animals eat the plants and get the carbon from the
plants during feeding.
4. Both animals and plants die, and the carbon from their
bodies goes back into the soil during decomposition. OR
Animals breathe out carbon dioxide during the process
of respiration.
5. Over millions of years, the carbon in their bodies can
change into fossil fuels like coal, oil, and natural gas.
6. When people drive cars, or burn fossil fuels, the carbon
is converted back to carbon dioxide gas and released into
the atmosphere.
Nitrogen Cycle
Nitrogen Cycle
1.
2.
3.
4.
5.
6.
7.
Nitrogen gas is found in the atmosphere.
Nitrogen gas cannot be used by animals or plants so it has to be changed
into a solid form. This is done one of two ways…
a) Nitrogen gas is taken in by bacteria in the soil during the process of
nitrogen fixation, and the nitrogen gas is converted to ammonia
b) Nitrogen gas is converted to ammonia when lightening takes it from
the atmosphere and puts it into soil.
The ammonia is then converted into nitrates by nitrifying bacteria.
The nitrates are then taken in by plants to build their DNA and proteins.
Animals eat the plants and get the nitrogen they need.
Animals and plants die and excrete wastes. Their bodies and waste can be
converted back to ammonia, through the process of decomposition
Finally, the ammonia is converted back to nitrogen gas in the atmosphere
by the process of denitrification.
Biotic vs. Abiotic
Biotic
–Bacteria
–Protists
–Plants
–Animals
–Fungi
Abiotic
–Water
–Gases
–Weather
–Temperature
–Soil
Levels of Organization
Biosphere
Biome
Ecosystem
Community
Population
Individual/organism
Organ system
Organ
Tissue
Cell
Organelle
Molecule
atom
Most inclusive Most Exclusive
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Biosphere
• Habitat ~ Area in which a particular organism
lives. Must have physical and biotic factors
necessary for survival.
• Ecological Niche ~ The job an organism carries
out in its ecosystem. How the organism
affects the environment.
The Sun
• Source of all energy for the biosphere
Obtaining Food
• Autotroph
– Producer
• Heterotroph
– Consumer
– Herbivore
– Carnivore
– Omnivore
Food Chain
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One way flow of energy through an ecosystem
First Step ~ Producers
Primary consumer (1°)
Secondary consumer (2°)
Tertiary consumer (3°)
Grass→Rabbit→Fox→Mountain Lion
Food Web
• Shows all of the
possible food chains
in an ecosystem.
• Arrows always point
toward the
consumer.
• Identify two possible
food chains shown.
Food Web Construction Lab
• Complete the Food Web Construction and
Manipulation lab provided by Mrs.
Fairweather.
Ecological Pyramid
• Trophic Levels
• 10% Rule
Energy Pyramid
Shows the available
energy available at a
specific trophic level.
Biomass Pyramid
Shows all the available
mass at a specific trophic
level.
Pyramid of Numbers
• Shows total number of
organisms available on that
trophic level
Community Interactions
• Symbiosis: relationship in which 2 species live closely
together
– Mutualism: both species benefit
– Commensalism: one member of the association benefits and
the other is neither helped nor harmed
– Parasitism: one organism lives on or inside another and harms it
• Predation: one organism captures and feeds on another
organism
– Predator
– Prey
• Competition: organisms of the same or different species
attempt to use an ecological resource in the same place at
the same time
Mutualism
Commensalism
Parasitism
Predator-Prey Relationship
Techniques of Field Ecology
• If you were in charge of a team given the
responsibility to determine the number of
sunfish in Horseshoe Lake, discuss with your
partner how would you accomplish this task.
• Write a paragraph, in the appropriate space,
on your “Techniques of Field Ecology”
worksheet.
Techniques of Field Ecology
• Random Sampling – the organisms in a few small
areas are counted and projected to the entire
area
• Quadrant Studies – tracking changes in a small
section of the environment
• Mark & Recapture – marking a number of
individuals in a natural population, returning
them to that population, recapturing some of
them, then using a formula to determine total
number of individuals in population
Techniques of Field Ecology
• Complete the random sampling and mark and
recapture studies.
Population Ecology –
Linear Growth Curves
• Linear growth.
• In other words, growth in a straight line.
• Your hourly wage would grow linearly.
Population Ecology –
Logistic Growth Curve
• Logistic growth curve. Natural populations
grow this way!!! This is also known as an sshaped growth curve.
Be sure you can label each
part of the graph!!
Population Ecology –
Saw-tooth Growth Curve
• Predator – prey
Population Ecology - Exponential
Growth Curve
• Exponential growth. This is also known as a Jshaped growth curve.
Histograms
Positive Population Growth
The children outnumber the
adults of child-bearing age.
More than two children per
family.
Zero Population
Growth
Negative Population
Growth
The children are fairly
equal to the number of
child-bearing adults.
Average of two
children per family.
The children are
outnumbered by the
adults. Average of less
than two children per
family.
Positive Growth
Developing countries usually show
positive growth.
•The aged make up a very small
population.
•Health care may be inaccessible to many,
or may be of poor quality.
•Economy may not be stable.
•Most of population lives at poverty level.
•War may be a factor that affects young
adult and male population
Positive Growth
Zero Growth
The population is relatively stable, neither
growing nor shrinking.
•Developed countries
•Good health care.
•Good sized elderly population
•Stable economy
•Most families are middle-class
Zero Growth
Negative Growth
Population will experience decrease in near
future due to fewer children being born.
•Well developed countries.
•Larger elderly population
•Typically “rich” country.
•Future may be economically iffy – aging
population relies on government health
and pension programs that are supported
by taxes of working people.
Population Growth
Affected by 3 things:
• Number of births
• Number of deaths
• Number or individuals that enter or leave a
population.