1. How does the availability of water to a plant constrain the rate of photosynthesis?
● Photosynthesis turns C molecules from CO2 into high energy organic molecules
● 6 CO2 + 6 H2O → C6H12O6 + 6O2
Photosynthesis has 2 parts:
1. Light reactions
○ Membrane bound
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After light is captured in chloroplasts (during the light reaction), the energy is stored in
high energy chemical bonds: ATP and NADPH
○ Energy stored in ATP and NADPH is moved to another part of the chloroplast →
incorporated into bonds of carbon compounds in Calvin-Benson cycle
2. Calvin - Benson cycle
● CO2 is captured and “fixed” into organic C compounds; energy captured from
light reaction is stored in C bonds
● => C3 photosynthesis
○ First, most common, most simple kind
● Limitations:
○ Maxes out way below full sunlight
○ More limited with increased temperature
○ Requires a lot of rubisco (protein) to achieve high photosynthetic rates
■ Rubisco is not a good carboxylase
■ Second function : photorespiration
● Photorespiration = rubisco takes up O2 instead of CO2
○ Occurs when: CO2 is low, O2 is high, Temperature is warm
○ No energy captured, no carbon fixed
○ Reduces photosynthesis carried out
○ May reduce damage from intense sun
C4
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4-C organic acids
C4 step comes first & costs extra energy
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Calvin cycle fixes C the same way, but deeper inside leaf, away from O2
No rubisco
No photorespiration
C4 plants
○ High maximum photosynthetic rates
○ Warm, dry, bright environments
○ Grassland grases, weeds, corn, sugar cane
2. What are some of the definitions of ecology and how do they vary depending on what a
particular ecologist might study? If an ecologist studied the effects of a particular gene, describe
how the emphasis of that work might differ from that of a geneticist or a cell biologist.
● Interactions between organisms and their environments / relationships among
organisms and their interaction with the environment / patterns and causes of
abundance and distribution of organisms
● An ecologist may study the evolutionary effects of this gene or how this gene affects a
species in terms of their environment and relationships with other organisms- a
geneticist or cell biologist would study more about the science of the gene on a
molecular level
3. What are the major patterns of atmospheric circulation on Earth? How do those patterns
contribute to global patterns of precipitation?
● Hadley cells, ferrel cells, polar cells
● Coriolis effect
● El nino southern oscillation
4. Explain the difference between climate and weather. What can you learn from a climate
diagram of a particular location?
● weather
○ Specific place and time
● Climate
○ Long term average patterns
● Climate diagrams: long term average temperature and precipitation patterns throughout
the year
5. What is the difference between heat and temperature? If the temperature of two solid objects
is exactly the same, but one feels cool to your touch and the other feels much warmer, how can
that be possible? Explain. (2-3 sentences)
● Temperature = average random kinetic energy of molecules in substance
● Heat = total kinetic energy of molecules in substance
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6. How can regional geography influence local climates? Give two examples.
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7. What causes the seasonal patterns we experience as we move from winter, spring, summer
to fall?
● The angle of sun rays hitting earth changes throughout the year
● ITCZ moves from
8. What are the major terrestrial biomes? Why do ecologists tend to categorize them by the
dominate plant growth forms?
● Tropical rainforest: broadleaved evergreen and deciduous trees
● Temperate evergreen forests:
● Temperate deciduous first; oaks, maples, beeches
● Temperate grasslands: grasses
● savannas/tropical seasonal forests: shorter trees, deciduous in dry seasons, more
grasses and shrubs
● Temperate shrublands and woodlands: evergreen shrubs and trees
● Desert: sparse vegetation
● Boreal forest: conifers
● Tundra: low growing shrubs, lichens mosses
● Dominant plant growth forms reflect the climate of the biome
9. What abiotic factors set the geographic distribution of terrestrial biomes?
● Temperature
● Precipitation
10. What abiotic factors are used to categorize freshwater and marine biomes?
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11. What are some of the benefits that humans obtain from each of the major biomes? What are
some examples of how human activities can threaten each of the major biomes?
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Tropical rainforest: plant/animal harvesting- trees for paper,
○ Land clearing, tree harvesting, hunting animals, habitat destruction
Temperate evergreen forests: trees; threatened by logging
Temperate deciduous forest: wood; clear cutting
Temperate grasslands: farming- nutrient rich soil; threatened by over use of land for
agriculture and hunting ex. Bison
savannas/tropical seasonal forests:
Temperate shrublands and woodlands:
Desert:
taiga/ Boreal forest: huge carbon reservoir, threatened by resource extraction and
climate change
Tundra: threatened by climate change
12. How do organisms exchange heat energy with the environment?
● Radiant heat, sensible heat, latent heat, metabolic heat
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13. What adaptations can help plants and animals modify their heat energy balance?
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14. What adaptations can help plants and animals modify their water balance? How does the
CAM photosynthetic pathway influence water loss from plants? The C4 pathway?
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15. What are the major ways by which organisms obtain energy?
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16. Spruce Knob (latitude 38.625°N) in eastern West Virginia is named for the spruce trees that
dominate the forests at this site. Spruce trees are typically found in the colder forests of the
more northern latitudes (northeastern United States and Canada). What does the presence of
spruce trees at Spruce Knob tell you about this site?
17. In the Rocky Mountains, one species of chipmunk, Eutamias umbrinus, lives in coniferous
forests at high elevations and a second species, E. dorsalis, lives in open woodlands at
lower elevations. They meet at the transition between the habitats, but overlap very little.
Propose two alternative hypotheses that could explain why E. umbrinus does not live at
lower elevations. Describe the experiments you would carry out to test each of these
hypotheses. Discuss the possible results of each experiment and how they would support
or contradict each hypothesis.
18. What abiotic factors influence primary productivity in terrestrial ecosystems? Freshwater and
marine ecosystems?
19. What factors influence the efficiency of secondary production? (e.g. ingestion, assimilation,
etc.)
20. Compare the relative importance of grazing and detrital food chains in terrestrial and aquatic
ecosystems.
21. Why does decomposition play a fundamental role in nutrient cycling?