Download 2.1 Energy Flow in Ecosystems Student Notes

Name:_____________________________ Date:___________________ 2.1 Energy Flow in Ecosystems Student Notes
General Information
Biomass is ___________________________________________________________
______________________________________________________________________
•
•
Biomass is also sometimes used to measure the mass of organic materials that are
used to produce biofuels such as biogas.
Biomass is generally measured in g/m2 or kg/m2
Within an organism’s niche, the organism interacts with the ecosystem by:
1._______________________________________________________________
2._______________________________________________________________
• Plants are called “producers” because they produce carbohydrates from carbon
dioxide, water and the sun’s energy, a process called photosynthesis.
• “_____________________________” get their energy by feeding on producers or
other consumers.
• ______________________________ is the break-down of wastes and dead
organisms, by organisms called “decomposers”, through the process of
biodegradation.
Energy Flow
Scientists use different methods to represent energy moving through ecosystems.
• Food chains
• Food webs
• Food pyramids
Name:_____________________________ Date:___________________ Food chains show the flow of energy in an
ecosystem
• Each step is a __________________________
Feeding & niche relationship
• _______________________ = 1st trophic level
• _______________________ = 2nd trophic
level
• _______________________ = 3rd trophic level
•
____________________________________ =
4th trophic level
Energy Flow and Types of Consumers
Consumers in a food chain can be classified as:
1. __________________________ - consumers that obtain
energy and nutrients from dead organisms and waste matter
and includes small insects, earthworms, bacteria and fungi
Detrivores feed at___________________ trophic level
• Detrivores have their own, separate food chains, and
are ___________________________
2. _________________________- primary consumers
• herbivores eat plants (producers) only
3. _________________________ - secondary or tertiary
consumers
• Secondary consumers eat non-producers, such as
herbivores
• Tertiary consumers eat secondary consumers
o Aka top consumers, top carnivores or top consumers
4. _________________________ - consumers that eat both plants and animals
• Examples include humans and bears
Energy Flow - Food Webs
Most organisms are part of many food chains. A food web is used to represent
_____________________________________________________.
Name:_____________________________ •
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Date:___________________ Food webs are models of the
feeding relationship in an
ecosystem.
Arrows in a food web
represent the
_______________________
_________________________
and nutrients.
•
Following the arrows _______
_________________________
_________________________
This food web represents a terrestrial
ecosystem that could be found in
British Columbia
Energy Flow - Food Pyramids
Food pyramids show the ____________________________________________ from
one trophic level to another in a food chain.
• Energy enters at the first tropic level (producers), where there is
a_________________ amount of biomass, and therefore
_____________________energy
• It takes large quantities of organisms in one tropic level to meet the energy needs
of the next trophic level because:
o Each level loses large amounts of
the energy it gathers through
basic processes of living.
o __________________ of energy
taken in by consumers (at
each level) is used in
chemical reactions in the
body, and is lost as heat energy.
o
There is
_____________________
energy if left over for growth or
increase in biomass.
Name:_____________________________ Date:___________________ Food pyramids are also known as ecological pyramids.
• Ecological pyramids may show
___________________________________________
________________________________.
• The amount of life an ecosystem can contain is
_______________________________
_____________________________ of the ecological pyramid, where producers
capture energy from the sun.
• Each level in the energy pyramid = a loss of ______________ of total energy
available
o Lower trophic levels have much larger populations than upper levels.
o This shows the importance of maintaining large, biodiverse populations at
the lowest levels of the food pyramid
Practice Assignments: Complete crossword, quiz and Check your understanding
questions at the end of the online notes.
Name:_____________________________ Date:___________________ 2.2 – Nutrient Cycles in Ecosystems Student Notes
General Information
Nutrients are __________________________________________________________
_____________________________________________________________________.
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Nutrients move through the biosphere in __________________________, or
exchanges.
Nutrients often accumulate in areas called ______________________.
Without interference, generally the amount of nutrients flowing into a store
___________________ the amount of nutrients flowing out.
Human activities can _______________________________ of nutrient cycles.
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Land clearing, agriculture, urban expansion, mining, industry and motorized
transportation can all increase the levels of nutrients more quickly than the stores
can absorb them.
Excess nutrients in the biosphere can have unexpected consequences.
There are five chemical elements required for life.
•
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________________________________________________ cycle between living
things and the atmosphere.
Phosphorous cycles in from _______________________________.
The Carbon Cycle
Carbon atoms are a fundamental unit in cells of all living things.
•
Carbon is also an essential part of chemical processes that sustain life.
Carbon can be stored in many different locations.
•
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_____________________________ is found in aquatic and terrestrial organisms,
and in CO2 in the atmosphere and top layers of the ocean.
_______________________________ is found in middle and lower ocean layers
as dissolved CO2, and in coal, oil and gas deposits in land and ocean sediments.
o Sedimentation traps many long-term stores of carbon
o Layers of soil and decomposing organic matter become buried on land and
under the oceans.
Name:_____________________________ o
o
Date:___________________ Slowly, under great pressure over many years, _______________
________________________________ form.
Layers of shells also are deposited in sediments on the ocean floor, forming
_____________________ rocks like limestone over long periods of time.
Carbon stores are also known as carbon sinks
Carbon is cycled through ecosystems in a variety of ways.
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Photosynthesis: energy from the sun allows CO2 and H2O to react
Carbon in the _____________________ is transformed by plants into
carbohydrates.
Photosynthesis also occurs in cyanobacteria and algae in oceans.
Cellular respiration: ______________________________________________ in
consumers. (opposite of photosynthesis)
The energy _____________________ is used for growth, repair and other life
processes. Decomposition: decomposers break down large quantities of cellulose
o Cellulose is a carbohydrate most other organisms
_______________________________________________________
Ocean Processes: CO2 dissolves in cold, northern waters and sinks
Ocean currents flow to the tropics, the water rises and releases CO2
o This process is called ocean mixing.
Eruptions and fires: volcanic eruptions can _________________________
o
Forest fires also release CO2
Name:_____________________________ Date:___________________ Many human activities can influence the carbon cycle
Since the start of the Industrial Revolution (160 years ago), CO2 levels have
_______________________________ from the increased burning of fossil fuels.
•
The increase in CO2 levels in the previous 160 000 years was 1% - 3%
• Carbon is being ___________________________________________ more
quickly than it naturally would as we mine coal and drill for oil and gas.
• CO2 is also a ___________________________, which traps heat in the
atmosphere.
•
Nitrogen Cycle
Nitrogen is very important in the structure of ______________________________.
•
In animals, proteins are vital for______________________ function.
•
In plants, nitrogen is important for ________________________.
The largest store of nitrogen is in the atmosphere in the form N2.
Name:_____________________________ •
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Date:___________________ Approximately ______________of the Earth’s atmosphere is N2 gas.
Nitrogen is also stored in oceans, and as organic matter in soil.
Smaller nitrogen stores are found in terrestrial ecosystems and waterways.
Nitrogen is cycled through processes involving plants
1. _______________________
2. _______________________
3. _______________________
______________________ - is the conversion of N2 gas into compounds containing
nitrate (NO3–) and ammonium (NH4+)
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Both nitrate and ammonium compounds are usable by plants.
Nitrogen fixation occurs in one of three ways
1. ______________________ - lightning provides the energy for N2 gas to react with O2
gas to form nitrate and ammonium ions.
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Compounds formed by these ions then enter the soil via precipitation
This only provides a small amount of nitrogen fixation.
2. ___________________- nitrogen-fixing bacteria like Rhizobium in the soil convert N2
gas into ammonium ions
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These bacteria grow on the root nodules of legumes like peas.
The plants provide sugars, while bacteria provide nitrogen ions.
3. _____________________ - some species of cyanobacteria also convert N2 into
ammonium during the process of photosynthesis.
___________________ - occurs when certain soil bacteria convert ammonium.
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Ammonium is converted into nitrates (NO3–) by nitrifying bacteria.
Ammonium is converted to nitrite (NO2–), which is then converted to nitrate.
Name:_____________________________ Date:___________________ ______________________ - enter plant roots via uptake
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These nitrogen compounds compose plant proteins.
Herbivores then eat plants, and use nitrogen for DNA and protein synthesis.
Nitrogen is returned to the atmosphere via ___________________________.
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Nitrates are converted back to N2 by denitrifying bacteria.
N2 is also returned to the atmosphere through volcanic eruptions.
Excess nitrogen __________________________, enters the waterways, and washes
into lakes and oceans.
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The nitrogen compounds eventually become trapped in sedimentary rocks, and
will not be released again until the rocks weather.
Name:_____________________________ Date:___________________ Human activities can also affect the nitrogen cycle.
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Due to human activities, the amount of nitrogen in the ecosystem
has____________________ in the last 50 years.
Burning fossil fuels and treating sewage releases nitrogen oxide (NO) and
nitrogen dioxide (NO2).
o Burning also releases nitrogen compounds that increase
____________________________________ in the form of nitric acid
(HNO3).
o Agricultural practices often use large amounts of _________________
_________________________________________.
o Excess nitrogen is washed away, or________________, into the
waterways.
 This promotes huge growth in aquatic algae =
___________________________________
 These algal blooms use up all __________________________
________________________________, killing many aquatic
organisms.
 The algal blooms can also produce neurotoxins that poison animals.
Clearing land for agriculture and urban development __________________ plants
that can absorb and convert CO2.
o Farmed land __________________________________ CO2 as natural
vegetation does.
Phosphorous Cycle
Phosphorous is essential for life processes in plants and animals.
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Phosphorous is a part of the molecule that carries energy in living cells.
Phosphorous promotes root growth, stem strength and seed production.
In animals, phosphorous and calcium are important for strong bones.
Phosphorous is not stored in the atmosphere.
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Instead, it is trapped in phosphates (PO43–, HPO42–, H2PO4–) found in rocks and in
the sediments on the ocean floor.
Weathering releases phosphates from rocks.
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Chemical weathering, via acid precipitation or lichens, releases phosphates.
Name:_____________________________ •
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Date:___________________ Physical weathering, where wind, water and freezing release the phosphates.
o Phosphates are then absorbed by plants, which are then eaten by animals.
Weathering doesn’t occur until there is geologic uplift, exposing the rock to
chemical and physical weathering.
Humans add excess phosphorous to the environment through ________________
______________________ components.
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Extra phosphorous, often along with potassium, then enters the ecosystems faster
than methods can replenish the natural stores.
Humans can also reduce phosphorous supplies.
•
_________________________________ of forests removes phosphorous from
trees, and it then is deposited as ash in waterways.
Name:_____________________________ Date:___________________ Nutrient Cycles and Biodiversity
Any significant changes to any of these nutrients (_______________________) can
greatly impact biodiversity.
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Carbon cycle changes are adding to climate change and global warming.
o Slight temperature fluctuations and changes in water levels can drastically
change ecosystems.
o Changes influence every other organism in those food webs.
_______________ levels of nitrogen can allow certain plant species to outcompete other species, decreasing resources for every species in those food webs.
________________ levels of phosphorous can inhibit the growth of algal species
which are very important producers in many food chains.
Review Assignments: Complete the crossword, 2.2 quiz and the 2.2 Check your
Understanding questions at the end of the lesson.
Required Assignment: Complete 2.2 Assignment B - Case Study of Nitrogen
Loading pg 88-89 in your textbook and then upload it to the appropriate drop box.
2.3 Bioaccumulation Student Notes
Introduction
Amphibians (like frogs) are valuable indicators of ___________________________.
• They are also ___________________ to
chemicals changes in the environment.
• Since the 1980s, much of the world’s
amphibian species have suffered declines
in population.
• There has also been alarming increases in
amphibian birth deformities in that time.
• Many theories attempt to explain these
changes, including drought, increased UV
rays, pollution, habitat loss, parasites and
diseases.
Amphibians, like this frog, have exhibited drastic changes since the 1980s.
Name:_____________________________ Date:___________________ Bioaccumulation
Bioaccumulation refers to an organism slowly _______________________________
the amount of chemicals in their bodies.
• Many harmful chemicals ______________________ be decomposed naturally.
• These chemicals can be eaten or absorbed, and sometimes cannot be removed
from the body of the organism effectively.
• If a keystone species suffers a chemical bioaccumulation, it can
_______________________________ organism in its far reaching niches.
o A keystone species is a vital part of an ecosystem.
Biomagnification refers to the animals at the ________________________________
receiving huge doses of accumulated chemicals.
• At each level of the food pyramid, chemicals that do not get broken down
________________________________________________ in organisms.
• When the consumer in the next trophic level eats organisms with a chemical
accumulation, they receive a huge dose of the chemical(s).
An example of bioaccumulation in BC is the effect of PCBs on the Orca.
• ________________ are a chemical that were used for many industrial and
electrical applications in the mid 20th century.
• PCBs were ________________ in 1977 because of fears of their environmental
impact.
• PCBs bioaccumulate, and also have a long-half life
(______________________________________________________).
• PCBs will affect the reproductive cycles of Orcas until at least 2030.
Name:_____________________________ Date:___________________ The bioaccumulation of PCBs begins with the absorption of the chemicals by
microscopic plants and algae.
Chemicals like PCBs and DDT are called ____________________________ (POPs)
• POPs contain carbon, like all organic compounds, and remain in water and soil for
many years.
• Many POPs are insecticides, used to control pest populations.
o DDT was introduced in 1941 to control mosquito populations, and is still
used in some places in the world.
o Like PCBs, DDT also bioaccumulates and has a long half life.
o At even low levels (5 ppm), DDT in animals can cause
__________________________________________________________.
 ppm = parts per million
___________________________ also bioaccumulate.
• Lead, mercury and cadmium are the most polluting heavy metals.
o Lead is found naturally at low levels, but levels have increased.
 Lead is _______________________________________________.
 Many electronics contain lead, and must be recycled carefully.
 Lead can _______________________________________________
damage.
o Cadmium is also found in low levels naturally.
 Cadmium is used in the manufacturing of plastics and nickelcadmium batteries.
 It is toxic to earthworms, and causes many health problems in fish.
 In humans, the main source of cadmium exposure is _____________
_____________________________________.
 Cadmium causes lung diseases, cancer, nervous and immune system
damage.
o Mercury also is found naturally.
 Much more has entered ecosystems through the burning of fossil
fuels, waste incineration, mining and the manufacture of items like
batteries.
 Coal burning adds ______________of of the mercury released into
the atmosphere.
 Mercury bioaccumulates in ________________________________
of many animals.
 Fish bioaccumulate mercury compounds, adding risk for any
organisms eating fish.
Name:_____________________________ Date:___________________ Reducing the effects of chemical pollution can be accomplished in several ways.
• By trapping chemicals in the soil, they cannot enter the food chains as easily.
• Bioremediation is also used, ___________________________________ are used
to help clean up, and are then removed from the ecosystem.
o The oil industry will often use bacteria to “eat” oil spills.
o Certain natural species are also excellent at bioremediation.