Download Unit A Ecology Notes 2011 No pictures

Bio 20:Unit 1A
Chapters 1 and 2
Nelson Pages 6-16
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The narrow zone around the earth where life exists.
Biosphere consists of 3 components:
 Lithosphere, Hydrosphere and Atmosphere.
Biotic = living organisms (life forms).
Abiotic = nonliving component (geological and physical
factors).
• Ecological studies investigate a specific
environment by looking at the following:
1.Organism (the individual).
2. Population (group of individuals).
3.Community (1 or more populations).
4.Ecosystem (community and abiotic factors
interact).
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Composed of 3 regions:
 Troposphere, Stratosphere and Mesosphere.
 2 outer regions of atmosphere: Ionosphere and
Magnetosphere.
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Composed of gases:
 78% Nitrogen, 21% Oxygen, 0.03% Carbon
Dioxide and 1% Argon/other gases.
cell
tissue
organ
population
organism
Organ
system
community
ecosystem
biome
TASK: Write down the
definitions for each of the
bolded terms
biosphere
Smallest living
part of an
organism
Group of organisms
of same species,
living in same area,
during same time
Group of different
species living in same
area
Groups of cells
with similar
function
Groups of
organ systems
that make up
the organism
A community and its
physical and
chemical
environment
Groups of tissues
with similar
function
Groups of organs
with similar
function
Large area and its
organisms
Narrow zone around
Earth with life
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Biodiversity = # of species in an ecosystem.
James E. Lovelock:
 Gaia hypothesis = earth is like 1 living organism.
Dynamic equilibrium = continuous changes with
environments constantly adapting.
 What happens when the biodiversity of an
ecosystem decreases?
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 Give 1 example (page 9 in text).
 What effects were there? Why?
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A change in any organism level of the
ecosystem has extreme consequences.
The species that is most sensitive to changes
in an ecosystem is an indicator species.
Amphibians are especially vulnerable. Why?
▪ See page 12 and 13.
•Example: bald eagle as indicator species
•Killed by:
1.) Settlers and farmers
•Threat to livestock
2.) Toxic chemical wastes produced by industries
entered food chain
•Egg shells became very thin
b) Equilibrium Unbalanced
•At risk species
•Classified depending on degree of risk
a.) Endangered
•Species is close to extinction in all parts of the country or in
a large location
b.) Extirpated
•Species no longer exists in one part of the country but can
be found in others
b) Equilibrium Unbalanced
c.) Threatened
•Species that is likely to become endangered if factors that
make it vulnerable are not reversed
d.) Special concern
•Species at risk due to low or declining numbers at the
fringe of its range or in a restricted area
Biosphere 1 = Earth
Biosphere 2 = Artificial biosphere created in Arizona - one of
the largest living laboratories in the world
 An airtight greenhouse that covers 3.15 acres and 7.2 million
cubic feet volume
 Includes a rainforest, a million gallon salt water ocean, a
coastal fog desert and 4 other wilderness ecosystems
 The Texas investment company that owns Biosphere 2 north of
Tucson, Arizona is selling the place. Billionaire Ed Bass
dropped $200 million in the 1980s to build Biosphere 2 as a
prototype "space colony." The experiment suffered major
scientific and managerial problems and was eventually opened
to the public as a tourist attraction.
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13
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The decline of the wolf:
 Thousands of wolves died after they ate poisoned bison carcasses
that had been laid out as bait.
 1880-90’s: ranchers killed wolves; in Canada anyone bringing in a
wolf skin was paid by the government.
▪ Montana = 80 000 wolves were destroyed between 1883-1918.
 Wolves decline allowed coyotes to increase. Coyotes eat smaller
prey (voles, mice, squirrels, eggs of ground birds); these prey
decreased in number.
 Wolves left remains of prey; without these remains, scavengers like
the magpies, ravens and vultures.
 Elk population exploded with no predators; stripping the land of
plants. Disease spread rapidly and the population started to decline.
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1987- plan to import wolves from Canada to Yellowstone.
35 wolves have been transplanted since 1996; ranchers were
opposed to this.
Signs of change:
 Elk move from open fields to treed areas.
 Vegetation is recovering.
 Small predators (kit fox) are increasing population.
 5 cows and 53 sheep killed by wolves in Idaho; ranchers were
compensated for losses.
Frontier view:
1.
1.
“to feed ourselves and the hungry world, we must open up, clear and claim
wilderness areas for ranching and other forms of agriculture. Wolves
endanger the effort. They kill cattle and sheep. They must be removed
wherever they interfere with farming and ranching and they should not be
reintroduced once they have been extirpated”.
Stewardship view:
2.
1.
“humans are the most intelligent animals on the planet. It is our duty to take care of
other species and preserve our world. Once we recognize that we have damaged the
ecosystem, we must try to repair the damage using whatever resources are available
to us. Wolves must be preserved in all ecosystems where they are now found, and
reintroduced to ecosystems where they once lived”.
Ownership view:
3.
1.
Canadians do not own wild animals or plants just because they live in Canada. We
have no right to move them around wherever we fell like it. It may have been a
mistake to kill the wolves of Yellowstone, but we have no right to take the wolves
and move them to a place they haven’t been before. It is better to let the ecosystem
in the park find a new balance.”
Nelson Pages 20-37
1. Matter and Energy Relationships
• Matter and energy are essential
components of the universe and
living organisms.
• Matter - everything that takes up
space and has mass
• Energy - the capacity to do work
• the biosphere is composed of a
variety of ecosystems
• each ecosystem has a structure
based on
a) energy flows
b) matter cycles
Remember
this!!!
Energy Flows,
Matter Cycles!
a. Ecosystem Structure
Trophic level = category of
organisms defined by how
they get energy.
• An ecosystem = all the
organisms living in a
community and all the
abiotic factors they interact
with.
1) Autotroph (producers)
• organisms that:
1. get energy from sunlight or
nonorganic energy sources.
2. convert inorganic compounds to
organic forms.
3. are the basic trophic level in an
ecosystem; supports all other
organisms
Chemosynthesis:
•Chemoautotrophs require only carbon dioxide,
water and an energy source to make nutrients.
•This energy is emitted from hydrothermal
vents near the edges of Earth’s crustal
plates.
•Usually found in caves or deep oceans.
•Many animals thrive in the
extreme environment around
hydrothermal vents.
–Tube worms: survive on
energy from bacteria.
2)Heterotroph (consumers) : organisms that derive their
energy by consuming other organisms.
a) Primary Consumers
- herbivores (eat only plants)
b) Secondary and Tertiary Consumers
- carnivores (eat other animals)
- omnivores (animals which eat both producers and
consumers)
3) Decomposers
- organisms that derive their energy from
dead organisms and waste products.
1. Scavengers (eat tissues from dead organisms).
2. Decomposers (feed on detritus).
Why is decomposition important?
2. Trophic Levels in Ecosystems
Trophic levels
• the steps in the transfer of
energy and matter within a
community (feeding levels)
• species in an ecosystem are
divided into trophic levels on the
basis of their main source of
nutrition.
• three main types of trophic
levels are producers, consumers,
and decomposers.
Count trophic
levels as steps
from the
original
energy source
Food chain movie
organization of trophic
levels where energy flows
from producer to primary
and secondary consumers
(and others if present)
 Simple feeding sequence:
who eats who?
 Not representative of
complex ecological
relationships.
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• interconnected food
chains within an
ecosystem
• highlight the complex,
real-world interactions
between species
•
makes connections from
primary producers,
through consumers, and
back to decomposers
Food Chain Movie
•Most stable ecosystems have complex and well developed food
webs  the removal of one of its organisms may have little effect
•Where abiotic factors limit the # of organisms, webs begin to
look more like food chains
•The lower the biodiversity, the simpler the food web, the
more vulnerable each organism is to changes in the
ecosystem
The behavior of energy is best explained by the Laws
of Thermodynamics.
Where do
photosynthesis
and cellular
respiration fit
in? What are
they?
3. Laws of Thermodynamics:
a) First Law of
Thermodynamics
•Energy cannot be created or
destroyed, only changed from one form
to another
b) Second Law of
Thermodynamics
•With each successive energy transfer,
less energy is available to do work. In
biological systems, this “waste” energy
is often heat.
4. Ecological Pyramids
Because of the loss of energy with trophic levels, there are two
consequences for the ecosystem:
1. Because productivity is lower at higher trophic levels, there is less
biomass.
2. Lower biomass at higher trophic levels, combined with large
body size of top consumers, results in lower population.
Densities.
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• results in a stepwise decrease in energy (pyramid).
• there are 3 types of pyramids commonly used by ecologists.
a) Pyramid of numbers
- # of organisms at each trophic level
- each bar represents
numbers relative
- pyramids are
to the pyramid base
based on data
from a given area
eg: 1 km 2
tertiary consumer
secondary consumer
Primary consumer
Producer
b) Pyramid of Energy
- energy stored by each trophic level is given in calories or
Joules. Energy per unit area per unit time (Kcal/m2/yr).
Efficiency of energy transfer:
c) Pyramid of Biomass
– stored energy is represented by biomass (dry weight)
Biomass per unit area per unit time (g/m2/yr)
•Energy is lost at each step in a food chain or web; the
general estimate of this loss at each step is 90%, so only
10% of energy consumed is available to the next trophic
level. This is known as the 10% rule.
Photosynthesis and Cellular Respiration
•Photosynthesis equation:
CO2 (g) + H2O (l) + energy  C6H12O6 (glucose) + O2 (g)
•Cellular respiration equation:
C6H12O6 (glucose) + O2 (g)  CO2 (g) + H2O (l) + energy (heat and ATP)
•Chemosynthetic
organisms:
•Require CO2 (g) + H2O (l) +
energy
•Energy required is H2S,
NH3, Fe 3+ , S8
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Matter is continually
entering ecosystems.
What if some of the
matter entering a food
chain was harmful?
How would it affect
the ecosystem?
Hunting & Fishing
•With introduction of horses into N. America, humans were able
to increase hunting of animals, e.g., bison
•Larger nets and an increase in boats have reduced marine fish
e.g, cod, halibut, salmon
Monocultures
•Biologists estimate 6 to 15 million different species of
organisms
•Humans rely on 700 different species of plants
•Wheat, rice, cotton, barley, corn
•Humans tend to use a focused amount of species; useful wild
plants have been destroyed to grow food crops
•Negative consequences to using monocultures
•Plants become susceptible to pests and disease
•Plants may lead humans to cures or medicines for
diseases but are lost
•Eventually, soils cannot support non – native species of
plants
•Barley and wheat are not suited for rich fertile soils
found in tropics
•Soils become deficient in their N and P minerals
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Have had largest impact on food webs
Benefit society
 Reduce # of pests (weeds, molds, insects, birds, etc.) to
 crop production
 Reduce spread of disease (malaria, West Nile)
Negative consequences to ecosystems:
 Eliminating an insect species on small island using DDT
reduced spread of malaria, however, entire food web of
island was affected
▪ Other insects disappeared - then lizards - then cats increasing rat population – outbreak of disease = more
problems!!!
•Biological amplification/ magnification
• Build up of toxic chemicals in tissues of organisms, as one
moves up food chain
• Therefore, the higher the trophic level, the greater the
concentration of toxins
•Example: DDT accumulation
in Peregrine Falcon creates
thin shells, therefore breaking
easily
•Numbers of falcons in
Canada decreased so
dramatically, that they were
close to extinction
•Negative consequences to pesticides
•“Non – target” species become affected
•Many pesticides are not species – specific
•Affect reproductive ability and embryo development
•Leads to at – risk species
•Moves up the food chain, eventually to humans
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1. The term tropic level refers to the position of a species on a food
chain (i.e., its feeding level). Producers are at the first trophic
level, primary consumers (herbivores) are at the second trophic
level, etc.
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2. A secondary consumer eats meat, usually primary consumers.
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3. A food chain consists of a single path (e.g., algae →
zooplankton → minnow → bass → heron), whereas a food web
involves several pathways (e.g., algae → zooplankton → minnow
→ seagull → coyote linked to the chain above).
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4. The reactants of photosynthesis are carbon dioxide, water, and
energy. The products are oxygen and glucose.
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5. The reactants of cellular respiration are oxygen and glucose.
The products are carbon dioxide, water, and energy.
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6. Inorganic chemicals, such as hydrogen sulphide
(H2S), ammonia (NH3), ferrous ions (Fe2+), and sulfur
(S8), are used as a source of energy by
chemosynthetic bacteria.
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7. The first law of thermodynamics states that the
total amount of energy in a system remains constant,
but it can be transformed into different forms. The
second law of thermodynamics indicates that as
energy is transformed from one form to another,
some of it is lost in unusable forms (such as heat).
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8. About 10 % of the energy available in a plant
(producer) is transferred to a primary consumer
because the plant uses the rest to carry on other
processes, such as photosynthesis, growth, and
reproduction.
Pages 40-69
Life on Earth depends on recycling of essential chemical
elements
 Because nutrient circuits involve both biotic and abiotic
components of ecosystems, they are also called
biogeochemical cycles
 Biogeochemical cycles:
 Water cycle
 Carbon (oxygen) cycle
 Nitrogen cycle
 Phosphorus cycle
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Cycling of Matter
•2 processes:
a.) Digestion
•Complex, organic molecules are broken down into
simpler molecules
•Become part of body structure
b.) Decay
•Decomposers break down organic matter in dead
bodies and feces
•Become part of living world in the future
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Why do organisms need water?
Water is a polar molecule; because of this it
has interesting properties.
 Melting and Freezing points.
 Hydrogen bonds change properties.
Properties of Water
Importance of Water to Organisms
•Absorbs and releases thermal E and moderates temperature
fluctuations
•Is the medium in which metabolic reactions occur
•Is “universal” solvent
•Makes up > 60 % of cell’s mass
•Supplies hydrogen atoms to producers during
photosynthesis; oxygen atoms to all organisms during
cellular respiration
•Is a reactant in some metabolic activities and a product in
others
Water: A Polar Molecule
•Water molecules are held together by covalent bonds
•Region of “-” charge is created near O atom
•Region of “+” charge is created near H atom
•“-” end of one H2O molecule repels “-” end of another
H2O molecule but attracts “+” end
•Attraction of opposite charges creates a hydrogen
bond
•Pulls water molecules together
•H bonds explain:
•High melting and boiling points
•More E required to break bonds
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Water plays a critical role by:
 Maintaining global heat balance.
 Acting as a solvent in reactions.
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Movement of water through environment:
from atmosphere to earth.
Volume of water remains constant, specific
amounts vary in phases; water continuously
cycles.
Hydrologic Cycle pg 42-48
Recall – E flows in an ecosystem, matter is recycled - including
water
Water Cycle
Animation
Water Cycle
Animation 2
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http://bcs.whfreeman.com/thelifewire/content/chp58/5802001.
html
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Transpiration: Loss of water from plant
leaves.
Evaporation: changing from a liquid to gas.
Condensation: changing from a gas to liquid.
Precipitation: snow or rain.
Percolation: movement of a liquid through a
porous material (e.g.. Soil).
Leaching: removal of solute by percolation.
Water beneath the Soil
• 2 sources of fresh H2O
1. Surface H2O – from precipitation above ground
2. Ground H2O – above ground H2O moves down through soil
• Percolation
• H2O percolates faster through larger soil particles
• H2O eventually fills lower levels of soil (sand and
gravel)
• Water table forms above a layer of relatively
impermeable bedrock or clay
•Leaching
•Seeping H2O carries dissolved organic matter and
minerals to lower layers of soil
•Plants reduce leaching by extending long branch roots
deep into soil
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Acid rain occurs because of poisonous gases
that are released when fossil fuels are burnt.
Gases enter atmosphere, return to earth in
rain or snow = acid rain.
acid rain animation
Acid Deposition and the Hydrologic Cycle
•Coal - burning plants, metal smelters, and oil refineries
release sulfur, during combustion
•Sulfur is released as a poisonous gas, sulfur dioxide (SO2)
•Processing of nitrogen fertilizers, combustion in automobiles,
and fossil-fuel burning power plants produce various nitrogen
oxides (NOx)
•SO2 and NOx combine with H2O droplets, to form acids in
atmosphere
•Acids return to Earth’s surface as snow or rain (acid rain)
•Acid precipitation kills fish, soil bacteria, as well as aquatic
and terrestrial plants
•Alkaline soils minimize impact by neutralizing acids before
runoff to streams and lakes
•SO2 and NOx can remain airborne, depending on weather
conditions
•Dry pollutants can combine with moisture and form acids
on lawns, surface of lakes, and respiratory tracts of
humans
•Scrubbers have been placed in smokestacks to remove
harmful emissions; lime has been added to lakes to neutralize
acids; public groups have lobbied for legislative acts
•pH scale is logarithmic, thus, whole numbers represent a 10 fold change
•pH 5.5 - 5.9 is considered "normal"
•Acid precipitation leaches out (removes) heavy metals (e.g.,
mercury) in soil and are washed into lakes and rivers
•Affects fish species
•Acid rain reduces productivity of crops and harms
vegetation
•Acid surges are periods of short, intense acid deposition in
lakes and streams
•Occur during a spring snow melt or a rainfall after a
prolonged drought
Role of H2O in Nutrient Cycling
•Carries with it organic matter and nutrients
•Thus, part of nitrogen and phosphate cycles
•Part of carbon and oxygen cycles
•“Capillary action” during transpiration, due to H bond
•Essential in photosynthesis and cellular respiration
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Cycling of Carbon and Oxygen.
Carbon is a component of all living and dead
organisms; considered organic.
Plants perform Photosynthesis (Carbon
dioxide --- glucose) and Animals/Plants
perform Cellular respiration (Oxygen --Carbon dioxide and energy).
Soil organisms (bacteria) decompose dead
organisms and return carbon.
The Oxygen Cycle
•O2 is an integral part of photosynthesis and cellular respiration
•Cycling of O is part of C cycle
•O produced by plants during photosynthesis 
atmosphere  living things during cellular respiration
•O is also incorporated in the following:
•Ozone (O3)
•CO2
•Rocks
•Decomposition
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Oceans store excess
CO2
 Gas reacts with
H2O to form an
inorganic
compound: calcium
carbonate (CaCO3)
Shellfish use (CaCO3)
to make their shells
 Carbon is stored in
shells at bottom of
the ocean
 Ocean is another
carbon sink
http://bcs.whfreeman.com/thelifewire
/content/chp58/5802002.html
74
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Dead organisms are compressed into fossil
fuels; when it is burned, it releases carbon
into the atmosphere.
Added Carbon disrupts natural cycling,
leading to climate change.
The Greenhouse effect: Carbon Dioxide traps
energy in the atmosphere and increases the
temperature of the earth.
Greenhouse Effect - animated diagram
•Greenhouse Effect and C Cycle
•Trapping of thermal E is caused by GH effect
•Wavelengths strike Earth’s surface and are reflected in
form of long-wave radiation
•Atmospheric gases trap radiation as a blanket of
heat
•Since middle of 19th century, human activities have
increased concentration of GH gases (25 %)
•Canada is a world leader of world’s total CO2 output, on
a per capital basis
•Prediction of an  in global temp.’s of 2 to 5OC (global warming)
•Ave. global temp. is 15OC, but has increased by 1 OC in last
40 years
•Melting of polar ice caps could  sea level by over 3 meters
•Some regions of world -  in rainfall while others, 
•Tundra and boreal regions
•Changes in vegetation patterns
•S. prairies may become deserts
•Bogs and muskegs could  decay of CH4 gas into
atmosphere
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Extent that materials reflect sunlight; higher
the albedo = more reflection.
Snow, clouds and volcanic ash increase
albedo = increase reflection/decrease
temperature (nuclear winter).
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The levels of carbon and oxygen can be
determined using stromatolites- limestone
rock with fossilized bacteria.
Originally methane levels were higher,
creating a haze around the planet that
deflected the sun and allowed more
temperate conditions on earth.
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Includes 4 Processes: Nitrogen fixation,
ammonification, nitrification and
denitrification.
Nitrogen is an important component of all
proteins and nucleic acids.
Most organisms can’t use Nitrogen directly; it
must be put into soli by:
 Volcanic action.
 Lightening.
 Nitrogen- fixing bacteria.
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Nitrogen fixation: bacteria (90%)/lightening
(10%) convert atmospheric nitrogen into
roots of plants (legumes).
Fertilizers increase this amount.
Ammonification: Decomposers convert
nitrogen products (from tissues) into
ammonia (NH3).
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Nitrification: process changing ammonium
ions into nitrates (NO3), performed by
nitrifying bacteria.
Absorbed by plants, used to make a.a’s:
absorbed by consumer when eaten.
Denitrification: Bacteria convert ammonia
into Nitrogen, which returns to atmosphere.
fertilizer - chemicals that contain nitrogen and
phosphorus natural fertilizer
Manure: contains N which is ammonified first in the
soil, then nitrified to provide useful nitrates
Commercial Fertilizers: 3 numbers:
 The first number is the % nitrogen (by weight)
 The second number is the % phosphorus (by weight)

The third number is the % potassium (by weight).
Agriculture and the Nitrogen and
Phosphorus cycles:
Fertilizer - chemicals that contain nitrogen and
phosphorus natural fertilizer
Manure; contains N which is ammonified first in
soil, then nitrified to provide useful nitrates
Commercial Fertilizers:
 First # is % nitrogen (by weight)
 Second # is the % phosphorus (by weight)
 Third # is the % potassium (by weight)
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Found in ATP, cell membranes and animal
bones.
Phosphate is found in rock (reservoir);
phosphorus leeches out into the water table.
Is a limiting factor in terrestrial and aquatic
ecosystems (Phosphorous isn’t useable).
As Phosphorous becomes available, it is
quickly taken up.
Phosphorus Cycle
FAST TRACK…
Phosphates remain in the Soil
Animals eat plants to obtain P
Decomposers work to and
plants break down animals
P returned to soil
SLOW TRACK…
Phosphates Washed into the Ocean
P becomes part of shellfish
Shellfish die and P settles in sediment
Over millions of years, this sediment is
pressed into rock that is thrust upward
Agriculture and Nutrient Cycles
•Harvesting of crops removes N and P from soil
•Interrupts natural cycles
•Fertilizing soil restores nutrients and increases food
production
•Irresponsible fertilizing can produce soil that is 10 X more
acidic
•Destruction of crops as well as acid deposition
•Eutrophication and Algal Blooms
•Spring runoff of N and P, from fertilized soils, into lakes
promotes aquatic growth (blooms)  which decreases O2
levels in lakes  decomposing bacteria use O2  lake O2
levels decrease and fish begin to die
Algae Bloom – prevent light from reaching
bottom of lake or pond
•Nitrites in drinking water
•Adult humans and animals have bacteria in large
intestines to convert NO3 1- into NO2 1•Bacteria cannot live in human stomach
•However, in young humans, bacteria can travel from
large intestines to stomach (less acidic)
•Convert NO3 1- into NO2 1•Can attach to hemoglobin of blood, thus, less O2
in body
Complete the N-cycle worksheet
(workbook)
 Label and color N-cycle and P-Cycle
coloring book diagram
 Section 3.3 Questions page 66 Text

Review nitrogen cycle
http://bcs.whfreeman.com/thelifewire/content/chp58/5802004.html
Review N and C Cycles
http://www.nslc.wustl.edu/courses/Bio381/movies/processes/C&Ncycles
96
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An ecotone = transition area between
ecosystems.
Each organism has a niche = it’s role in the
ecosystem (place in food web, habitat,
breeding area).
Niches help reduce competition for resources
and stabilize the ecosystem.
Why does an exotic species cause disruption?
Ecological niche benefits:
•Helps reduce competition between species
•Ex: owls and hawks
•Different time of day to hunt
•Different adaptations to habitat (grassland vs.
forest)
•Different nesting sites
•Ex: different species of warblers prefer a different
section of trees
Competition for Niches
•New or “exotic” species that enters an ecosystem
causes a disturbance
•They compete with one or more species
“indigenous” to an area
•How are species introduced?
•Animals move
•Plant seeds are carried by wind or animals
Introduction of Exotic Species
•Human introduction of species causes species
extinction (2nd to habitat loss)
•Reason:
•Ecosystem may lack natural predators or diseases
•Many types of prey available
•Settle in nesting sites before indigenous species
•Examples: starlings, purple loosestrife, thistle
1) Interactions within Ecosystems
Nelson pages 86 – 93
•Ecologists study interactions between biotic and abiotic
factors
•Study how biosphere operates by investigating various
levels of organization
Organism
(biologist)
Biosphere
(ecologist)
Cell
Organism
Tissue
Population
Organ
Community
Organ system
Ecosystem
Complete organism
Biosphere

There are 4 biomes in Canada,
each with abiotic and biotic
factors:
a.Tundra/Muskeg:
- abiotic- arctic, short growing
season, permafrost layer, low
temperatures, low precipitation.
- biotic: caribou, mosses/lichens,
polar bears, seals, rapidly
flowering plants.
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
Abiotic: south of
tundra, 35-40cm/year
precipitation, change in
weather patterns,
acidic, watery soil.
Biotic: Coniferous
forest, moose,
Goldenrod, caribou.


Abiotic: South of boreal,
increased sunlight,
precipitation (100 cm/year),
rich, fertile soil.
Biotic: Deciduous trees,
moose, weasels, many
shrubs, woodpeckers.


Abiotic: Same latitude as
mixed woodland, less
precipitation than woodland,
soils holds more water.
Biotic: Hawks, rattlesnakes,
Plains bison.
107

Abiotic factors are non-living components of an ecosystem
 Affect type and # of organisms that can live there

Describe abiotic components that cause the two terrestrial
ecosystems below
Abiotic factors are called limiting factors
Why?
They restrict or limit # and types of organisms able
to survive in a particular environment
Belts of climate determine result in distinct vegetation
patterns
Vegetation of a region determines which consumers can
and will continue to exist there
Zones are called biomes

109

Physical features of a geographical area
a) Latitude - higher latitudes: less solar energy input, varied
day lengths with seasons
b) Altitude - higher altitudes: cooler temps, more wind,
poorer soil
c) Topography - physical features of land (ex: mountains,
river valleys)
▪ May affect precipitation
a)
Terrestrial (land) abiotic factors:
1. Soil: Known as Edaphic factors.
- 4 layers: Litter (partially decomposed matter), Topsoil (rock and
humus), Subsoil (lighter color and less organic material) and
bedrock (layer beneath the soil).
- pH of soil determined by plants and rock that forms is; basic =
alkaline or acidic.
2. Available water: determined by amount and type of precipitation.
- groundwater = precipitation that stays in the soil, determines
depth of water table.
3. Temperature: can vary greatly- dependant on climate.
- organisms adapt to temperature changes; examples?
4. Sunlight: varies with altitude and latitude.
Ecosystem
Taiga
Muskeg
Type of Soil
•Well – drained,
acidic
•Poor drainage
and low amounts
of O2
1) Chemical environment – type of water, dissolved oxygen,
pH.
2) Temperature/Light – varies with seasons and water depth.
3) Water Pressure – adapted to live near surface or at greater
depths.
113
1. Oxygen
Lakes and ponds get some O2
from atmosphere, but most
from photosynthetic plants
 Fast flowing rivers get major
source of O2 from aeration
 Lowest acceptable limit is 5
ppm (5 parts of O2 per million
parts water)
 Conc. of O2 in water decreases
as temperature increases

2. Carbon Dioxide
 Respiration by living organisms is major source
 Surface contains very little but bottom has
higher levels due to respiration by
decomposers; mostly bacteria
3. pH
 Healthy range is usually between 6.7 to 8.6
 Acid rain can cause pH levels to drop, making
aquatic environment unable to support life
114
4. Temperature
Each species has a preferred temp.
With most species, an increase by 5OC is harmful
As water temp goes up, ability to hold O2 goes down, yet
animal needs more O2 --------> or dies
5. Light
Increased light means increased P/S and higher plant
productivity
6. Water Pressure
Water is 800 X denser than air
Pressure increases by 100 kPa for every 10 m of depth
Ave. depth of ocean is 4000 m
116

Read pages 99-100 and make notes: define the 3 general
zones of lakes, describe the typical biota of the zone and
abiotic factors of the zone, define epilimnion, hypolimnion,
thermocline (see index).
Lakes during the Winter
•Temp. of ice is slightly above 00C ; light can penetrate
transparent ice for Ps to occur
Lakes during Spring
•O2 becomes dissolved from air
•Winds and storms increase rate of dissolved O2
oxygen
•As temp. of surface water approaches 40C, it
sinks through less dense water
•Carries O2 throughout all depths
•Process is spring overturn
120
Bogs are usually located in regions where temp.’s are
cool for much of year
Marshes and swamps are usually located near coastal
areas in warmer climates
A variety of waterfowl and shorebirds live in swamps
and marshes
• Also provide shelter to animals
▪ Muskrats, frogs, turtles, snakes, alligators, fish, and
raccoons
Type of Vegetation
Marshes
•Small plants
•Reeds, cattails, and
grasses
Swamps
•Large plants
•Cypress trees and
Spanish moss, as well
as shrubs and water
lilies
Bogs
• Large # of insects
• Beetles, dragonflies, and mosquitoes, are common in bogs
• Bogs also have a variety of plants that grow well in the
organically rich, partially decayed plant material called peat
• Peat forms much of bog soil
• One of the most unusual bog plants is the pitcher plant
122
123
Pages 108-112
124

Field mice can reproduce every 6 weeks and can have
litters of 6 or more. A population of 20 mice could become
5120 mice in six months! What factors prevent a
population explosion of mice?
Biotic potential is maximum # of offspring that a species
could produce if resources are unlimited
Regulated by 4 factors:
Birth potential (max #/birth)
Capacity for survival (# reach reproductive age)
Breeding frequency
Length of reproductive life (age of sexual maturity and
# of fertile years)

126

Limiting factors are factors that restrict or limit # and
types of organisms able to survive in a particular
environment
 Prevent populations from obtaining their biotic potential

Carrying capacity is maximum # of individuals that can
be supported by an ecosystem
At what level do the deer
reach their CARRYING
CAPACITY?
Factors that causes a
population to increase
Factors that cause a
population to
decrease
Abiotic
•Favorable light, temp.,
chemical env.
•Too much or too little
light, too cold or too
warm, unfavorable
chemical env.
Biotic
•Sufficient food, low # or
low effectiveness of
predators, few or weak
diseases and parasites,
ability to compete for
resources
•Insufficient food, high #
or high effectiveness of
predators, many or
strong diseases and
parasites, inability to
compete successfully
for resources

Law of Minimum –
 The nutrient that is in
least supply is the one
that limits growth
(proposed by Justus
von Liebig (mid1850’s)

Victor Shelford (1913)
added on to the Law of
minimum by proposing
the Law of Tolerance
 An organism can
survive within a
particular range of an
abiotic factor
129


Density-Independent factors affect a population
regardless of population density
Density-Dependent Factors affect size of a
population as a result of population density
Factors that Cause Changes in
Populations
Density –
independent factors
Density – dependent factors
•Flood
•Fire
•Pesticides
•Change in climate or temp.
•Destruction of habitat
•Drought
•Food shortage
•Competition for mates, breeding areas
(habitat)
•Disease caused by a microorganism or
parasite
•Introduction of an exotic species
•Increased predation
•Competition for water and other
resources
131
Pages 113 -122 Nelson
I. Changes in Terrestrial Ecosystems
•33 % of Earth’s forests have been cleared for agricultural or urban
land purposes
•Significance of forests:
•Recycle H2O and CO2
•Thus, affect climate
•Affect physical environment
•Control H2O runoff, hold groundwater, and prevent soil
erosion
•Provide shelters and nesting sites for wildlife, as well as food
Forestry Practices
• 3 categories of deforestation:
1. Slash and burn
• Used in tropical areas
• Agriculture
• Vegetation is bulldozed and burned in a pile
Forestry Practices
2. Clear – cutting
• Removal of all trees in an area for use in timber or pulp
• Followed by replanting the dominant species
3. Selective cutting
• Only certain trees are harvested from an area
• Other trees are left to regenerate the area
• Softwoods (spruce and fir) are considered more valuable
than hardwoods (grow slowly)
• 2 – 3 years after cutting, herbicides are used to prevent
softwoods from being overcrowded by hardwoods
• 10 years – underbrush is removed
• 35 years – trees are checked for diseases, as
monocultures are more susceptible
• 80 – 90 years, softwoods can be harvested
Effects of Clear - Cutting
Positive Effects
Negative Effects
•Less expensive than selective
cutting
•If pests exists in an area, this
method eliminates pests without
infecting surrounding areas
•Permits replacement of less
valuable trees with ones more
valuable
•Moose benefits; fruit – bearing
shrubs provide stable food
source
•Soil erosion and runoff into streams
increase
•NO3 1- and other nutrients increase
algal growth in streams
•Sediment carried into streams affect
fish spawning
•Dark soils are exposed; water loss
of soils increases
•Replanting with a monoculture
decreases biodiversity
•Owls are negatively affected;
nesting sites are destroyed
2) Effects of Fire
•Fires in Elk Island National Park
•Create and maintain a mosaic of vegetation types
•Prescribed burns
•Fires set intentionally in defined areas of a park
•Fire is carefully put out
•Reduces amount of dry timber
•Discourages expansion of forests and maintains
food supply for bison
E) Ecological Succession
Process of Succession
•Ecological succession - a community change in which new
populations of organisms gradually replace existing ones
• Succession occurs from natural causes (competition, fire,
earthquakes, etc) or due to humans (logging, mining,
farming etc)
138
1) Primary Succession
• Succession that begins in an area where there is no existing
community
• Causes: volcanic eruption, glacier retreat
• Pioneer community: 1st group of organisms to occupy an area
undergoing
• Pioneer organisms must be hardy and able to live on minimal
resources
• Lichens are pioneer organisms
Primary Succession Animation
139
140
Glacier Retreats
exposing Parent rock
Increased soil =
shallow rooted
trees (pine)
Pioneer community
(lichens, mosses)
Grasses die = more
soil = shrubs and
weeds take over
Increased pine = more shade =
favorable for deeply rooted plant
(maple/ birch)
Soil formation
(lichens die/
break up rock)
Enough soil =
grasses out
compete lichens
Climax Community
Primary Succession:
Primary Succession Animation
141
2) Secondary Succession
•Occurs in an area where an existing community has been
partially destroyed
• Examples: Fires, logging, farming
•Occurs more rapidly than primary succession
•Climax community
• A community that achieves relative stability
• Tend to have greater species diversity than the
communities that precede them
142
1.143Indicator (index) Species
When water becomes polluted, there tends
to be a shift from MANY species of
moderate population density to a FEW
species of high population density ------>
indicator species
 This decrease in diversity of species present
is best indicator of pollution
2. Eutrophication
 Natural process of SLOWLY aging or
increasing productivity of a body of water




Pollution increases the natural eutrophication process of
water. Why?
Unnatural Eutrophication: a process in which nutrient runoff
from agricultural lands or livestock operations causes
photosynthetic organisms in ponds and lakes to multiply
rapidly
Human-caused eutrophication wiped out fisheries in Lake Erie in the 1950s
and 1960s
144
LAKE EUTROPHICATION
High levels of P
and N containing
compounds
(fertilizers/
detergents)
Low oxygen = other
organisms die out
Algal
Bloom
Algae die = food
for decomposers =
population grows
Decomposers break down material
and use up oxygen in lake
• Water in which oxygen becomes too low to support animal life is
called eutrophic
• To protect Canadian lakes, ponds, and streams from becoming
eutrophic, some provinces no longer allow the sale of detergents
145
containing phosphorus compounds
Eutrophic vs. Oligotrophic Lakes:
• Classification of lakes by the nutrient input, which in turn determines
primary producers --- 2 types:
• Oligotrophic lakes: Nutrient-poor, photosynthesis-limited, clear water,
O2 rich, deeper and colder than eutrophic lakes
• Eutrophic lakes: Nutrient-rich, high photosynthesis, murky water, O2
poor.
146
•Eutrophication of a lake depends on natural and human
factors:
•From oligotrophic to eutrophic
a.) Oligotrophic – deep, cool, hold a lot of O2
b.) Soil sediment and organic material fall to lake
bottom
• Lake becomes shallow  profundal zone disappears
 sunlight reaches lake bed
•Water temp. and plant growth increase, O2 levels drop,
which reduces # of aquatic animals
c.) Lake continues to become shallower and warmer
•More matter and nutrients accumulate
•Submerged and emergent plants accumulate
•Too many producers and decomposers deprive lake with O2
•Reduces # of fish spp. (e.g., trout and salmon)
•Plankton, insect larvae, worms, leeches, and mollusks thrive
•Slug worms are indicator spp. of aquatic ecosystems to
identify lakes with lower levels of oxygen
3) Sources of Water Pollution
•Organic solid waste
•Includes sewage and waste from food processing
•Decomposed by bacteria, which uses up O2
•Disease – causing organisms
•From sewage and animal wastes that runoff into aquatic
ecosystems
•Trigger water – borne diseases (ex: typhoid)
•Inorganic solids and dissolved nutrients
•Waste from mining, fertilizers, salts from roads and runoff
•Thermal energy
•From electricity generating plants and other industries
•Decreases solubility of O2 in water
•Organic compounds
•Oil from roads, pesticides, and detergents (organic
phosphates)
•Toxic, accumulate through food chain, promote algal
bloom, respectively
4) Indicators of Water Quality
• 3 main indicators
1.Bacteria count
• Detect coliform bacteria
• Found in intestines of humans and other animals
• Presence indicates fecal contamination in water
• Process:
• Agar medium, with nutrients, is used to grow
bacteria
• The greater the # of bacteria colonies, the more
polluted the water sample
2.Dissolved Oxygen
• Solutions can be used to test for D.O.
• Change color when they react with oxygen
• Cool lakes, with few pollutants have a D.O. of 8 – 14 mg/L
• Examine living things in the water
• Healthy trout – high oxygen level
• Carp and catfish – low level
• Absence of fish – low oxygen level; possible toxins in the
water
3.Biological Oxygen Demand
• A measure of amount of dissolved O2 needed by
decomposers to break down organic matter in a sample of
water over a 5 day period at 20 OC
• Cold, less productive lakes
• BOD near 2 mg of O2/L
• Warm, more productive lakes
• BOD near 20 mg of O2/L
• As # of organisms , BOD increases, more organisms use
O2, thus, DO 
• Humans releasing sewage or nutrients promotes algal bloom,
which  decaying matter, which  decomposition
4) Changes in Alberta’s Lakes
•Receding shore lines
•Changes in water shed
•Area of land that drains towards a lake or body of
water
•Drop in lake levels
•Increase in salinity
•Reduced O2 levels and biodiversity
•Increase in erosion at shoreline
•Eutrophication by sewage, phosphorus, and fertilizer runoff
•Change in odor and taste of water