Essay about ecosystems

Submitted By swagman69444
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Pages: 5

Name _______________________
Ecosystems and the Physical Environment Scavenger Hunt Quiz
Chapter 6 (Raven & Berg)
1. What is the Gaia Hypothesis?
A series of hypotheses that suggest that living organisms adjust the environment to keep the earth habitable.
2. What is a negative feedback loop?
Processes that work to restore the normal values of a variable, stabilizing the system.
3. What is the term that refers to all of the nutrient cycles? What are 5 examples of these cycles identified by the book?
Biogeochemical cycles – 1) Carbon 2) Water 3) Nitrogen 4) Sulfur 5) Phosphorus
4. Where is most of the carbon in the world stored? What percentage of the earth’s atmosphere is CO2?
Sedimentary rock and fossil fuels; 0.037%
5. What process converts carbon from the atmosphere into biological molecules? What is the chemical formula for this process?
Photosynthesis; 6CO2 + 6H20 -> C6H12O6 + 602
6. What biological process returns carbon to the atmosphere? What human activity has released vast amounts of carbon to the atmosphere?
Cellular respiration; Burning of fossil fuels
7. Where is most nitrogen stored? What organisms are responsible for most of the transformations of nitrogen?
Why do most organisms rely on these transformations?
Atmosphere; Bacteria; Organisms get use atmospheric nitrogen
8. Identify and describe 3 problems concerning nitrogen created by human activities?
1) Groundwater pollution 2) Photochemical smog 3) Acid deposition (rain)
9. Where is most phosphorus found? What is it used for? How have humans altered the phosphorus cycle?
Rock; Fertilizer; Export of agricultural products resulting in depleted soil
10. What are natural sources of sulfur? What are human caused sources of sulfur? What are human caused problems created by the use of sulfur?
Rock; Burning of coal; Acid deposition
11. What is transpiration? What tis the difference between a watershed and an estuary?
Evaporation from plants; Watershed is area that drains to a common body of water, while an estuary is an area that is partially enclosed where fresh and salt water mix
12. Identify 4 reasons why we alter the hydrological cycle when we build damns and levees?
1) Obtain water for domestic and industrial use 2) irrigate crops 3) Produce hydroelectricity 4) Reduce flood damage
13. What portion of the sun’s radiation actually reached the earth’s surface? Identify 2 factors that prevent the radiation from reaching the earth? (be specific)
49%; Light energy is reflected and absorbed by the atmosphere
14. What is albedo? Give 2 examples of things that have high albedo and 2 examples of low albedo?
Proportional reflectivity of the earth’s surface; High – Glaciers and ice sheets; Low – asphalt pavement and buildings
15. Explain how the angle that the sun’s rays strike the earth affects temperatures at different latitudes.
More direct light concentrates the light energy in smaller areas causing higher temperatures; Light that strikes the earth at an angle spreads the same energy over a greater area causing lower temperatures

16. What causes the season and how are the Northern and Southern hemispheres different? The tilt of the earth’s axis; They are opposites, the Northern Hemisphere’s summer is the Southern Hemisphere’s winter
17. Identify the 5 layers of the atmosphere and the trend for how the temperatures change in each layer.
Troposphere cooler as altitude increases, Stratosphere warmer as altitude increases, Mesosphere cooler as altitude increases, Thermosphere as altitude increases, Exosphere cooler as altitude increases,
18. What is the Coriolis effect and what is it caused by?
The deflection of flowing air and water to the right in the Northern Hemisphere and to the left in the Southern Hemisphere; the rotation of the earth
19. What are the three types of prevailing winds and how are they distributes?
Trade winds in lower (0o-30o) latitudes;…