Ecology 2003 Exam 1 Key - Fairfield University



Ecology 2003 Exam 1 Key

General tips for next time: Just answer the question. If you put in extraneous material and it is wrong, I’m going to grade it as wrong. Likewise, if you write down a bunch of stuff about the topic but don’t answer the question, that is wrong as well.

For the short answer and essay, italics are my comments and regular text are examples of full-credit answers from your peers.

Multiple Choice:

1.d. 2. c. 3. a. 4. e. 5. b. 6. d. 7. a. 8. d. 9. c. 10. a. 11. c. 12. a. 13. d. 14. c. 15. d.

16. energy, water, nutrients.

17. autotrophs

18. niche

19. evolution

20. Hadley cells or air

21. Check book for correct placement. 9 possible correct. 1-2 wrong = -1, 3-4 wrong=-2, 5-6 wrong = -3, 1-8 wrong = -4.

22. For this question, I was looking for mention of both the importance of energy and oxygen in this coupling and evidence that you understood where the energy comes from.

The coupling of the oxidation/reduction of carbon and oxygen in photosynthesis and respiration is important to all living things because this series of reactions encompass the nutrients, energy, and water that are needed by all living organisms. These reactions produce the products of photosynthesis, such as glucose and oxygen, that are essential to both the autotrophs that conduct these reactions and the heterotrophs that also indirectly receive these products. The production of glucose through these oxidations/reductions produce the energy (in the bonds of glucose) that every organism utilizes. The oxygen production is important to the aerobic organisms that utilize this element for metabolism and respiration themselves.

Good for energy part.

The oxidation of oxygen allows for the organic molecules necessary for gaining the energy to carry out metabolic processes to form during photosynthesis through reduction of carbon. Then, during respiration, the energy held in the bonds of organic molecules are broken and energy is released to be used for metabolic processes.

Good for oxygen part.

The coupling of the oxidation/reduction of carbon and oxygen are fundamental important to all living things because through reduction of C in photosynthesis, oxygen is released which recycles the oxygen uptake in respiration.

23. For this question, you needed to say that the nutrients came from decomposing organic matter and also say where the organic matter comes from.

Organisms from the pelagic zone die and fall to the bottom of the ocean. The decaying organic matter makes the deep ocean nutrient-rich. The existence of a thermocline, separating the warm top layer from the colder deep water, keeps this nutrient-rich water from mixing (usually) except where upwelling occurs. Also, many organisms (e.g. ,photosynthetic) cannot live in the deep sea without sunlight, so the nutrients are not getting used up.

Upwelling water is nutrient-rich because when organisms die, they tend to sink to the bottom of the ocean where they decay and begin to release nutrients. The upwelled water carries the nutrients up into the pelagic zone.

24. For this question, the plant is capable of acclimating to lower light intensity but does not photosynthesize as well as it does when acclimated to high light. Also, when acclimated to low light, it loses the ability to photosynthesize at higher light.

The capabilities of the plant show that it is able to acclimate and live in less light intensity. However, there are limitations, the 800 group is never able to produces a photosynthetic rate as highs as the 1500 group. Also, once grown at 800 foot candles, the group was not able to withstand the high light intensities it once used to strive in. The 1500 groups on the other hand, produces a higher optimal photosynthetic rate, but it could withstand less diverse light intensities than the more diverse 800 foot candle group.

My results show both the capabilities and limitations of acclimation in F.S. It is easily observed that the plants grown at 80-0 f.c. have higher photosynthetic rates at lower light intensities. This exhibits the capabilities. However, the limitations are also apparent. By acclimation to a lower light intensity, the plants sacrificed their maximum photosynthetic rate of 6.5 at 1700 f.c. The other plants only had a maximum of 4.3 at 900 f.c. This clearly depicts the limitations of acclimation of F.S.

25. Many people struggled with this one. For full credit, you should have explained what factor varied at each spatial scale and explained how you respond to the variability. The two examples below do this very well.

One the 1 meter scale, spatial variability can be seen when a person walks from a heater building to the cold outside. Although the distance is small, the temperature change is significant and a person must change their dress appropriately (hopefully by bundling up). An example of spatial variability on a 100 meter scale might be moving from the quiet library to the noisy dining hall. A person would have to adjust their own voice in order to be heard and listen more perceptively in order to understand others.

An example of spatial variability on a 1 meter scale could be amount of UV radiation exposed to. For example, moving under an umbrella at the beach could keep one way from harmful sun rays or moving to the shade. An example of spatial variability on the 100 meter scale could be climate. For example the climate on the microscale of 100 meters under lots of trees would be cooler than that exposed to direct sunlight. Spatially, temperature changes on scales of 100 meters. A response to this variability could be wearing another layer of clothes or removing one.

26. This essay is a good example of a question where people shot themselves in the foot by adding extraneous information. The question asks for 1 example of a plant adaptation, and 1 example of an animal adaptation. Many people lost points because they listed a bunch of adaptations without describing any of them. Or they described several and some of them were wrong. Stick to the question and make sure you answer all parts. For full credit, you needed to give the overall climate and seasonality of both temperature and precipitation. For the description of the adaptation, you needed to describe the adaptation and state what is adaptive about it.

In the tundra, the climate is extremely cold in the winter and mild in the short summer months. There is not a lot of precipitation. The factors that are most limiting to plant growth is the permafrost, which is permanently frozen soil below that limits the plants rood system, and another limiting factor is the short growing season as well as the shallow snow cover in the cold months. For these reasons, plants in the tundra are short. This adaptation allows the plant to be sheltered by the shallow snow cover when it is too cold and windy and they have very short root systems so they are not inhibited by the permafrost. A physiological adaptation that a fox has is that its coat is thicker during the winter months so to better insulated it from the cold environment.

The tundra has long, very cold winters with short, mild summers and moderate precipitation. The growing season is only about 4 months long. Plant growth is limited by the permafrost (permanently frozen soil due to the lengthy winters), by the short growing season, and by the extreme cold and harsh winters. Plants in the tundra have adapted by being very low to the ground. This allows the snow to cover them and protect them from the cold and wind. They also have shallow root systems that are above the permafrost during the growing season allowing them to absorb more nutrients and allows them to grown and reproduce for the entirety of the growing season. Animals in the tundra have developed physiological adaptations in order to survive and reproduce such as changing colors from brown during the growing season and white during the winter. This allows them to blend with their environment and protect them from predation.

In the temperate seasonal forest, the climate is moist and warm with great seasonal variability. The summer months experience warm to hot weather with a fair amount of precipitation. The winters are cold with lower precipitation. Factors that are most limiting to plant growth are the seasonal changes in temperature and moisture. Plants must be frost resistant as well as conserves water for the winter months. An example of this are trees losing their leaves in the fall and basically shutting down metabolic processes for the winter. A behavioral adaptation for animals in this biome is a collection of winter food supply. For example, squirrels collecting and storing nuts to use over the winter months when food is scarce.

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