3.4 Workbook Review
*Vocab
*Key Questions (at top of wkbk)
*What is important about each cycle?
Recycling in the Biosphere
• *1. The four elements that make up over 95% of the
body in most organisms are oxygen, sulfur, nitrogen
and hydrogen
• False – CARBON
• 2. Matter moves through an ecosystem in cycles
• True
• 3. Chemical and physical processes include the
formation of clouds and precipitation, “burning
food”, and the flow of running water
• False - LIGHTNING
• 4. The illustration draws an analogy between the way
energy drives matter to cycle in an ecosystem and
the way water causes a waterwheel to turn. Give an
example of another analogy that could be used to
show the relationship between energy and the cycles
of matter.
• Ex: wind causing windmill to turn; car engine
causing wheels to turn; foot pushing bicycle pedal
around and around…
• *5. Explain why Earth is considered a closed system
• Matter does not enter or escape the earth. They are
recycled through organisms.
• *6. How might building a new highway affect the cycles
of matter?
• Building a highway means clearing out trees, plants,
and habitats of organisms, which limits nutrient
availability. This prevents the nutrients from being
recycled
THE WATER CYCLE:
• *7. What role do plants play in the water cycle?
• Absorb groundwater through roots
• *Transpiration - plants lose water through leaves
(evaporation through tiny pores)
• *8. Draw a diagram explaining the water cycle. LABEL the
processes involved as biological or physical/chemical
• *9. Complete the chart about the carbon cycle
PROCESSES THAT CAUSE CARBON TO
MOVE INTO THE ATMOSPHERE
PROCESSES THAT CAUSE CARBON TO MOVE
OUT OF THE ATMOSPHERE
PROCESS
DESCRIPTION
PROCESS
Respiration
Organisms eat and
break down food,
releasing CO2 through
cellular respiration
Photosynthesis
Volcanic Activity
Release of CO2 and
other gases into the
atmosphere through
vents in Earth’s crust
Ex: Dissolving,
fossil fuels,
others?
DESCRIPTION
Plants use of
sunlight, water and
CO2 to produce
carbohydrates
CO2 dissolves in
rainwater; animals
are decomposed,
pressurized and
converted to fossil
fuels over time
• *10. The carbon in coal, oil, and natural gas came from
A. combustion of fossil fuels
B. remains of dead organisms
C. carbon-fixing bacteria in swamp soil
D. carbon dioxide dissolved in ocean water
• B. remains of dead organisms
• *11. How does most of the carbon in an organism’s body return to the
environment after the organism dies?
A. decomposers break down into simpler compounds
B. heat from the sun causes carbon in the body to evaporate
C. geological processes cause it to turn into fossil fuel
D. rainwater dissolves carbon in body and carries to the ocean
• A. decomposers break down into simpler compounds
• *12. Human processes mainly contribute to
A. release of carbon dioxide (CO2) into the atmosphere
B. decrease of total amount of carbon found on earth
C. depletion of carbon dioxide reserves in atmosphere
D. increase in carbon contained in rock material
• A. release of carbon dioxide (CO2) into the atmosphere
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13 – 16 about Nitrogen Cycle!
13. Nitrogen in the form of ammonia, nitrate, and nitrite is
found in the soil
True
*14. Nitrogen fixation is the process in which certain bacteria
convert nitrogen gas into nitrates
False- Ammonia
*15. Denitrification is the process by which some soil bacteria
convert nitrates into nitrogen gas
TRUE
*16. All organisms require nitrogen to make amino acids,
which in turn are used to build carbohydrates
False – proteins
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17 – 22 about Phosphorus cycle!
*17. Phosphate is released as rocks and sediment wear down
True
*18. Plants absorb phosphate from the soil or water.
True
*19. Phosphorus is the most abundant gas in the atmosphere
False – nitrogen (about 75%!! More than oxygen…)
*20. Organic phosphate is taken up by producers during photosynthesis
and released by cellular respiration
False – carbon dioxide
*21. Phosphorus forms part of the important life-sustaining molecules
such as DNA and RNA
True (So does nitrogen…)
*22. Plants absorb phosphorus from the atmosphere or water
False - soil
• 23. List and describe the biological steps in the nitrogen cycle
• *Nitrogen fixation – bacteria take nitrogen gas from
atmosphere and fix (make it stick) it into soil
• Once in soil, plants absorb it into their roots
• Consumers eat producers and reuse the nitrogen to make
compounds
• Decomposers release nitrogen from dead organisms into soil
• Bacteria convert it back to a gas - *denitrification
• 24. What is atmospheric nitrogen fixation, and how
does it affect organisms
• When lightning strikes, some atmospheric nitrogen
is converted to usable compounds in soil to be used
by organisms (wow!)
• *25. How do humans add nitrogen to the biosphere?
• Fertilizers!! (good or bad…)
• 26. Which parts of the phosphorus cycle are
geological processes?
• Geological activity- marine sediment turned into
rock and washes phosphates from rock to ocean
• 27. The visual analogy compares interlocking gears to the
major nutrients – potassium, phosphorus, and nitrogen. What
other “gears” would be affected if these stopped working?
• Plants and organisms could be added to the analogy
• Plants cannot live without these vital nutrients, thus…
• Consumers would not have oxygen produced by plants
• Consumers would not get their food sources
• 28. If a nutrient were in short supply in an ecosystem, how
might it affect an organism?
• Limit organism’s growth, or even survival
• *29. When is a substance a limiting nutrient?
• When it is scarce or cycles very slowly and limits an
ecosystem’s growth
• 30. Compare and contrast the flow of energy through an
environment with the flow of matter through that same
environment
• Matter moves differently than energy.
• Energy is captured by producers and passes from one trophic
level to the next, and some energy is lost at each step.
• Matter is recycled within and between ecosystems.
Elements pass from one organism to another and through
nonliving things in the environment – these loops are called
**biogeochemical cycles
• The End! Whew!
• Focus on your vocabulary terms, and the “key questions”
found at the beginning of the section