Module B, Unit 8
Ecology
Mr. Mitcheltree
Hierachy of Life
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Chemical Level 
Organelle Level 
Cell Level 
Tissue Level 
Organ Level 
System Level 
Organism Level 
Population Level 
All the organisms of 1 species in a given area
Example, a population of white tailed deer
Community Level 
all the populations within
a given area
Ferns, mushrooms,
flowers, flower butterfly
and humming bird
Ecosystem Level  the community and the abotic
factors in a given area
Notice the pond is stratified (has habitat layers) with
different niches (an organism’s “job in its
environment). Things at the surface (lily pads),
things in the water colum (fish) and unseen things
on the substrate like crayfish and things in the
substrate like worms.
Biome Level  large geographical
region with a certain climate, vegetaion
and soil type.
Usually named after the dominant
vegetation, autotrophs.
Autotrophs provide the food and
habitat for the heterotrophs.
Biosphere  Earth, all Biomes
What are the Biotic and Abiotic Factors
Biotic – hawk, cactus, Gila monster, etc. All the living
factors
Abiotic – air, soil, rock, temperature, moisture, etc.
We live in the
temperate
deciduos forest
biome
Dominated by deciduous trees that
drop there leave in the fall and the
four seasons = temperate
Why is this side dryer? Rocky Mt example, creates a rain shadow.
Cold air from
the Pacific
gets cooler
when it rises,
causing
condensation
and rains to
the South of
the Mts.
Warm areas with liquid water has more biodiversity.
Which biome has the greatest biodiversity?
Why?
Tropical rain forest
Average Yearly
Rainfall
400 cm
Tropical dry forest
250–300 cm
Temperate forest
75–125 cm
Boreal forest
35–75 cm
Tropical savanna
150 cm
Desert
Less than 25 cm
Temperate grassland
25–75 cm
Tropical woodland
and scrubland
Less than 50 cm
Tundra
30–50 cm
Biome
Average
Temperature
Daytime: 34ºC
Nighttime: 20ºC
Dry season: 32ºC
Wet season: 20ºC
Climate Zone
Tropical
Tropical
Summer: 28ºC
Winter: 6ºC
Summer: 14ºC
Winter: -10ºC
Dry season: 34ºC
Wet season: 16ºC
Mostly temperate
Summer: 38ºC
Winter: 7ºC
Summer: 30ºC
Winter: 0ºC
Summer: 20ºC
Winter: 10ºC
Tropical and
temperate
Temperate
Summer: 12ºC
Temperate and
polar
Mostly temperate
Mostly tropical
Temperate
Yuma, AZ p. 101
Why low biodiversity?
Not enough liquid water
Microclimates: small areas with
different temperatures or
moisture
Why is downtown so much
warmer? Buildings and asphalt
absorb heat and release it slowly
Sun always shining: hot and dry
rocks absorbing heat
Shaded: cool and moist, notice
the ferns?
Aquatic Ecosystems: Fresh Water
Lotic = moving water
Lentic = stamding water
Different water chemistry means different aquatic organisms
Plankton
- organisms that can not swim against a horizontal current
- All tiny to microscopic in aquatic (fresh water biomes)
- A few macroscopic (big enough to see with the naked eye
in marine (salt water) environments like jellyfish
Zooplankton – animals or animal-like, heterotrops
Phytoplankton photosynthetic
Wetlands: Water, Soil and Plants
Bog: dominated by
sphagnum moss
Swamp: dominated by trees
Marsh: dominanted by
seasonal grasses like cattails
Where fresh water meets salt water
Fresh water < 5 parts per thousand CL
Salt water > 35 parts per thousand
Brackish water in estuaries in between
5-35 parts per thousand
Euryhaline – organisms that can tolerate
a wide range of salinities like blue crabs
(detritus)
Stenohaline – organisms that can only
tolerate a narrow range of salinities like
trout.
Marine Ecosystems
Photic -Enough light for
photosynthesis
Disphotic- not shown here, enough
light to see but not enough for
photosynthesis
Aphotic – not enough light to see
Most photosynthetic organisms need 500 foot candles (a measure of light intensity) for]
photosynthesis.
Below this point (called the compensation point, where photosysnthesis = cellular
respiratrion) photosynthetic organisms can not make enough food to meet their
metabolic (food) demands from cellular respiration.
Intertidal Zonation
Coral Polyp with Zooxanthellae (algae)
Niche: an organism’s “job” in its environment
One will disappear from the area due to competition
Community Interactions
Competition: Occurs when
niches overlap
occurs for mates and any
necessity for life
Intraspecific Competition
Between same species
Interspecific Competition
Between different species
Competitive Exclusion Principle
Two species can not share an identical niche, one will
disappear from the area
Problem with non-native species
Fundamental niche
Organism’s niche without competition
more resource availability
vs.
Realized niche
Organism’s niche with competition
less resource availability
Which shows realized
niche of bluegill?
Pond A
Pond A
Which fish
outcompetes the other?
Bass outcompetes the
bluegill, forcing it to
feed only on the bottom
of the pond
Pond B
Mutualism (+,+)
Ant protects aphid from predators and aphid secretes food for ant
Sea anemone gets to travel a free ride and hermit
crab is unaware
(+,0)
(+,-)
Parasite: takes resources from
host
Host: resources “stolen” by
parasite
Review of Symbiosis
Producers = Autotrophs
Autotrophs: C6H12O6 + Inorganic Nutrients Monomers  Polymers
Consumers = Heterotrophs
Get monomers directly or indirectly from autotrophs
Saprobes = Decomposers
Saprobes: Polymers Monomers  C6H12O6 + Inorganic Nutrients
In dead organisms and
to soil, air or water
their waste (feces and urine)
Fungi
Many Bacteria
Food Chain
Shows Energy Flow
The arrows in a food chain show what eats what. The arrow replaces the
phrase “is eaten by.” The direction of the arrow is very important. The arrow
must point toward the “eater.”
Leaf  Grasshopper 
Frog
 Heron
Bacteria or Fungi
Food Web
Why more “stable”? Multiple food choices
A food web shows the many possible food chains that exist in an ecosystem.
- Energy Flow in Ecosystems
Trophic Levels = feed levels
Order:
producers
always on the
bottom
Drawn to scale
over specific
period of time
Why pyramidal in shape? Energy is lost as heat at each trophic level
Lindemann’s 10% Rule
90% lost as heat, 10% energy moves on
Dependent on: - enodotherm vs. ecototherm
- ease of digestion
- food type: fats vs. carbs and protein
Pyramid of Biomass
The biomass of the producers is always greater than the biomass of the
herbivores, and the biomass of the herbivores is always greater than the
biomass of the carnivores. The biomass decreases with each additional step
in a food chain. A diagram that shows this decrease in biomass is a pyramid
of biomass.
Pyramid of Numbers
Carbon Cycle
Combustion:
CH4 + O2  CO2 + H2O
Respiration:
C6H12O6 + O2  CO2 + H2O
Photosynthesis:
CO2 + H2O  C6H12O6 + O2
Burning fossil fuels since the
industrial revolution in the 1800’s
has caused an increase in CO2
production.
Fossil fuels were geologically
trapped carbon that now is in the
atmosphere as CO2 and causing
climate change
Nitrogen Cycle
N2 about 80% of air, biologically inert
N-fixation: converts N2 into NO3- (nitrate) or NH4+ (ammonium) useable to plants to form amino
acids
occurs by lightning forming and N-fixing bacteria free-living and in root nodules of
legumes.
Decomposers
release NH4+
C ombustion
releases N2
Denitifying
bacteria convert
NO3- into N2
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The Water Cycle
Evaporation: liquid water to gaseous water
Precipitation: gaseous water to liquid water
Transpiartion, evaporation of water from the leaves of plants
Changes in
Communities
Primary Succession
Occurs on bare rock or pond formation from volcanic
island formation or glacial action
One plant community enhances the soil for the next
Changes in
Communities
Secondary Succession
Occurs after a natural disaster like a forest fir or land cleared for agriculture.
Soil is present.
Predator – Prey Interactions
As predators increase, prey decreases cause predator populations to decline from
starvation or a decrease in reproductive success.
As predator populations decrease, prey populations increase.
Population Density
Number of 1 species in a given area
White tailed deer births and deaths during research in
MD study area with a contraceptive to create sterility.
I PA, the only way to reduce deer populations is
regulated hunting, most predators have been
displaced (Cougars and Wolves). Only black bears and
coyotes remain.
Primary Productivity: The amount
of photosynthesis occuring in an
area.
Limiting Nutrient: Nutrient in
lowest amount that limits growth
(water, N, P, K, Ca, Mg) or a
photosynthetic organism.
How is this situation similar
to a fish tank in which the
fish have been overfed?
Decomposing fish food
release nutrients allowing
for algae growth.
Immigration vs. Emigration
Organisms move in
Organisms move out
If the caterpillar population doubles under optimal conditions each year and there are 10
caterpillars initially, how many will there in 4 years?
Time (years)
Population
0
10
1
20
2
40
3
80
4
160
Logistic Population Growth
Conditions are rarely optimal to
limits of food, water, space,
temperature, etc.
births = deaths
Carrying Capacity – maximum number of a species
an area can support over a given period of time.
The graph to the left shows seasonal overshoot
and decline due to limiting factors.
R = relative growth
R = (births-deaths)/N
K = carrying capacity
N= population
• Study Island 8a Ecosystems and Biomes
• 8b Energy Flow in Ecosystems
• 8c Organism Interactions and
Population Dynamics
• 8d Environmental Change
• Crash Course Biology: 12 Ecology Videos