BSC 326 Ecology, Assignment 5, Chapter 5 (31 pts)

BSC 326 Ecology, Assignment 5, Chapter 5 (31 pts [[[COMMENT BY Diana Curiel (2018-09-14T02:31:23Z)]]] i have already submitted the document [[[---]]] ) Kyle: 1, 4, 7, 10, 13, 16, 19 Diana: 2, 5, 8, 11, 14, 17, 20 Lupita: 3, 6, 9, 12, 15, 18 1. (1 pt) Concept Review, p. 103, no. 5.1.1, What advantages might the warm microenvironments of Dryas flowers offer to the insects attracted to them? The Dryas flower is able to reposition its flower so that it is constantly facing the sun. Because of this the flower has a constant heat source while the sun is out. Insects are then able to sit within the flower to absorb some of the warmth that the flower is storing, raising the insect's body temperature. 2. (1 pt) Concept Review, p. 103, no. 5.1.3, Contrast the microclimates of the aboveground parts of desert plants to that of their roots. The northern and southern mountain valley areas allow organisms to live in contrasting microclimates that provide various forms of vegetation. Crust forming mosses are common in the Northern and Southern dune within the Negev Desert. Plants are able to create microclimates due to the shade that they provide to the landscape. In fact, trees and shrubs manufacture significant microclimates within the deserts. These desert landscapes are comprised of vegetation and are also a source of conflicting thermal habitats. 3. (1 pt) Concept Review, p. 104, no. 5.2.1, If growing lines of Escherichia coli at 20 °C for 2,000 generations increased their fitness at 20 °C without reducing their fitness at 40 °C, how would the distribution of points in Fig. 5.7 change? If the growing lines of Escherichia coli at 20 °C for 2,000 generations increased their fitness at 20 °C without without the reduction of fitness at 40 °C, the distribution points in the figure 5.7 would be in the first quadrant, the quadrant on the upper right. The distribution would occur at this quadrant due both temperatures having a positive fitness, so it would be where the increased coordinates intersected. 4. (1 pt) Learning Outcomes, p. 105, no. 5.1, Explain why the process of acclimation to temperature is not an evolutionary process. The process of acclimation is the physiological changes that an organism makes to adjust for the temperature, however, these changes that are made are reversible. For example, Robert Pearcy was able to take a plant from Death Valley and grow the plant in two different environments using cuttings from the bush. One environment was a hot temperature, while the other was cold. After letting the bushes grow, the photosynthetic rates were observed. The maximum rates observed, from both hot and cold environments, were seen at 40? and 32? respectively. This being the results shows that the same plant with the same genes was able to acclimate to different temperatures. 5. (2 pts) Learning Outcomes, p. 105, no. 5.11, Discuss how evidence that organisms are adapted to a restricted range of temperatures supports the principle of allocation. Once organisms have adapted to their environments conditions, the fitness of the organisms becomes lessened towards other possible habitations. Due to limitations on energy, organisms are forced to adapt to very few environmental conditions. The consequences of such disadvantages are called principles of allocations, and a consequence of energy allocation to a necessary life function will decrease capabilities for other functions. Utilizing this reasoning, Levins was able to deduce that adaptation to a particular environmental conditions leads to an overall decrease in other life functions. 6. (1 pt) Critiquing the Evidence, p. 106, no. 5.2, Why do ecologists generally supplement information resulting from laboratory experiments with field observations or experiments? Or: What is the value of following laboratory experiments with field observations/experiments? Laboratory experiments and field experiments are used by researchers to test a hypothesis Although both may be similar in their purpose, laboratory experiments are carried out in a controlled setting where all factors are kept constant except one, which is the variable. In a field experiment, ongoing behavior is observed, consequently less is controlled. These experiments are conducted in a more natural environment which allows for better results in the perspective of an ecologist [[[COMMENT BY Guadalupe Roman (2018-09-13T19:50:50Z)]]] Rusty, I was hoping you can take a look at question #6. I was confused by the question so I wasn't sure if that's what Dr. Alexander is looking for. [[[---]]] . 7. (1 pt) Concept Review, p. 109, no. 5.3.1, Signs of thermal stress in fish include swimming on their sides and swimming in spirals. Using what you know about temperature and acetylcholinesterase, explain. Given that the is swimming on its side or in spirals, the fish could be experiencing lack of neural function. Enzymes work most efficiently within a certain temperature range. If that the temperature of the environment the fish is in is outside of the enzymes range, the efficiency of the enzyme declines, including the enzyme acetylcholinesterase. This enzyme is responsible for the breakdown of neurotransmitters, a critical process in neural functions. With the temperature out of the range of this enzyme, neural function and communication would decline, making the fish swim on its side or in spirals. 8. (1 pt) Concept Review, p. 109, no. 5.3.2, How can we be sure that the two distinctive responses to temperature shown by Atriplex lentiformis (Fig. 5.12) were due to acclimation rather than genetic differences? Acclimation is associated by physiological, not genetic changes in response to temperature;thus, acclimation is reversible once there is an alteration within environmental conditions. A. lentiformis constructed physiological adjustments to understand the plants’ annual cycle. The physiological adjustments suggested that acclimation has an ability to shift its temperature for photosynthesis to match seasonal changes in environmental temperature. 9. (1 pt) Learning Outcomes, p. 109, no. 5.17, Explain the difficulty of being an endotherm in an aquatic environment. It is more difficult to be an endotherm in an aquatic environment because this type of environment makes it harder for the organisms to regulate their body temperatures. Aquatic organisms find it more difficult to fluctuate their body temperature because more heat energy is needed to be absorbed by water to change the temperature compared to air and the loss of conductive and convective heat are more greater than air as well. Due to this type of environment, it is much more easier to be an endotherm on land where their respiratory surface is not surrounded by water. 10. (2 pts) Concept Review, p. 119, no. 5.4.1, Why would it be a disadvantage for Encelia farinosa (p. 110) to produce highly reflective, pubescent leaves in both hot and cool seasons? While the highly reflective and hairy leaves are beneficial in the hotter seasons, they would do the opposite in the cooler seasons. In the hotter seasons the reflective properties and hair reduced the amount of heat gain that the plant is absorbing. This property is beneficial in the hotter seasons because the amount of heat gain without these features would be to much for the plant. During the cooler seasons the plant is going to want more heat gain than compared to the hotter seasons. If the plant still had the reflective and hairy leaves, the heat that would be reflected away is now heat that the plant would want to absorb, leaving the plant now too cold. 11. (1 pt) Concept Review, p. 119, no. 5.4.3, Why are all endothermic fish relatively large? All endothermic fish have large sizes due to the amount of muscle, and the amount of swimming procedures their bodies need to roam around freely. Also, they contain blood vessels that function as countercurrent heat exchangers. The potential for heat loss is very high;therefore, gill-breathing species that must be exposed to a large respiratory surface in order to take oxygen molecules from the water. 12. (1 pt) Concept Review, p. 121, no. 5.5.1, Why don’t hummingbirds save energy by going into torpor at night even when food supplies are abundant? In other words, what would be a possible disadvantage of routine, nightly torpor? Torpor is a short term state of reduction in an organism's metabolism and body temperature. Hummingbirds go into this state at night when their body temperatures drop to 12°C- 17°C and nectar availability is scarce or inadequate. Hummingbirds go into torpor to save energy but do not establish a routine of nightly torpor because when they’re in this state, their physical and mental activity decreases due to the reduced metabolic rate. Thus, making it harder for hummingbirds to react to their environment in the case of predators. 13. (2 pts) Concept Review, p. 121, no. 5.5.2, Why might the frequency of torpor and hibernation be more common among animals in tropical dry forest compared to those living in tropical rainforests? Within the tropical dry forest there is a wet and a dry season. During the wet season of this forest there is a large amount of fruits and flowers that can be consumed by the animals in the area. However, during the dry seasons, the lack of these foods cause some animals within the area to enter torpor or hibernation. Compared to the tropical rainforests, these forest are able to produce fruit and flowers for a majority of the year, allowing the animals to have a constant food source that doesn't rely on the seasons. With the constant intake of nutrients, there is no need for these animals to enter hibernation. 14. (1 pt) Learning Outcomes, p. 122, no. 5.23, Review (outline or describe) the evidence that temperature changes around the city of Basel are responsible for local extinctions of the snail A. arbustorum. The snail species Arianta arbustorum, had disappeared from several of the sites near the city of Basel. These species tend to reside in meadows, forests, and other moist habitats within the altitudes up to 2,700 m in the northwestern and central parts of Europe. A. arbustorum, are able to mate, but prefer to fertilize their own eggs. Unfortunately, the hatching of eggs depends highly on temperature, for any fluxating in hatching could determine whether the egg is able to hatch. The species A. arbustorum has been found to inhabit the southern Scandinavia to the Iberian peninsula, yet Baurs was unable to locate remains of the A. arbustorum at any of the sites. This may be due to the altitude difference between Site A with an altitude of 274 m versus the survival sites of 420 m. These survival sites were often much colder with temperatures that measured up to 22 degrees Celsius. However, sites that had reached 25 degrees caused the species to go extinct. In fact, these sites were often hot and escalated to 29 degrees Celsius. This data allowed Baurs to concluded that the high temperatures from eight sites caused the A. arbustorum to go extinct by thermal radiation given by urbanized cities. Several researchers were able to conclude that greater thermal sensitivity is responsible for the extinction of A. arbustorum at some sites. 15. (1 pt) Review Questions, p. 124, no. 2, Imagine a desert beetle that uses behavior to regulate its body temperature above 35 °C. How might this beetle’s use of microclimates created by shrubs, burrows, and bare ground change with the season? As the seasons change, beatles use microclimates to help regulate their body temperatures. Physical features that can influence microclimates are the presence of boulders, vegetation and color variation of the ground. During the summer, when temperatures tend to be much more higher, beetles can take shelter in the burrows underground. The animal burrows tend to be much cooler since they are more secluded from sunlight. However during the winter, beetles can take advantage of the bare ground that allows them to be exposed to warmer temperatures. The color variation of the ground is correlated with different temperatures, that being black sand has higher temperatures than lighter sand. Lastly, in the course of seasons that are cooler than the summer but also warmer than winter, beetles can use shrubs as shade since the regulation of their body temperatures won’t be as drastic as in other seasons. 16. (3 pts) Review Questions, p. 124, no. 5, Baur and Baur (1993) documented local extinctions of the land snail A. arbustorum, and shows that these extinctions may be due to reduced egg hatching at higher temperatures. Do these results show conclusively that the direct effect of higher temperatures on hatching success is responsible for the local extinctions? Propose and justify one or more alternative hypotheses. Consider all of the observations of the Baurs. The results do show conclusively that the higher temperatures affected the success of the egg hatching success. The experiment conducted that took eggs of two species and observed if they hatched at different temperatures suggest that as the temperatures rising in the area did not allow for the eggs of the next generation of snails to hatch. Another hypothesis that could be made is that the urbanization of the area was a significant role in the extinction of A. arbustorum. Viewing the heat map that the Baur’s measured, it can be seen that a majority of the sites that became extinct with the snail are close to the urbanized sites. These urbanized site could be a source of heat or possible pollution that the snails could not handle. 17. (2 pts) Review Questions, p. 124, no. 6, Butterflies, which are ectothermic and diurnal, are found from the tropics to the Arctic. They can elevate their body temperatures by basking in sunlight. How would the percentage of time spent basking vs. flying change with latitude? Would the amount of time butterflies spend basking change with daily changes in temperature? Explain. The positions in latitude correlates directly with temperature. As the altitude continues to increase, butterflies time for sun basking rises also. Higher latitudes often produce low temperatures;therefore, butterflies are require the butterflies to bask in the sun in order to raise in order to raise body temperatures before flight. As we draw near equator, the time spent basking in the sun would drastically decrease due to the air temperature becoming moderate enough to keep the butterflies warm for flight throughout the day and night. When temperatures drop, the butterflies will utilize the sun before flying in order to gather hear from the environment. Once they are exposed to cold air during flight, they begin to release body heat due to being ectotherms. 18. (3 pts) Review Questions, p. 124, no. 8, The section on avoiding temperature extremes focused mainly on animals. What are some ways (at least three) that plants avoid temperature extremes? Some of the natural history from chp. 2 may be helpful. Plants can avoid temperature extremes in cold environments by increasing their rate of radiative heating and reducing the rate of convective cooling. Plants in colder climates tend to be a darker pigment allowing them to absorb more light and increase their radiative heating. These plants can also change the orientation of their leaves to be perpendicular to sunlight. Plants can also gain cushion growth form to reduce their convection heat loss by being closer to the ground resulting in a decrease of exposure to wind. In hot environments, plants avoid temperature extremes by modifying the radiative heat gain they are exposed to. One of the plant adaptations in this climate is the dense covering of plant hairs on their leaves, which reduces water losses and prevents dehydration. They also evolved reflective surfaces that reflect solar radiation and adjust the direction of theirs leaves to be parallel to the sun or fold them. Plants in biomes such as deserts are able to remain dormant in the soil as seeds and grow once their environment is adequate for germination. 19. (3 pts) Review Questions, p. 124, no. 9, Some plants and grasshoppers in hot environments have reflective body surfaces that reduce their radiative heat gain, Hr. If you were to design a tiger beetle that could best cope with thermal conditions on black beaches (Fig. 5.4), what color would it be? The beetles on the black beaches of New Zealand are black, and the beetles on the white beaches are white. What do the matches between the color of these beetles and their beaches suggest about the relative roles of thermoregulation and predation in determining beetle color? What does this example imply about the ability of natural selection to optimize the characteristics of organisms? A beetle designed to best cope with a black beaches thermal conditions would be a white beetle. Black beaches absorb more heat energy than other beaches and a white beetle would be able to reflect most of the heat energy absorbed by the sand and from the sun. The matching of colors on the respective beaches suggest that predation plays a larger role in the beetles color. With the colors of the beetles matching the surrounding environment, the beetles are able to stay hidden or camouflaged from the predator that may be within the area. This example implies that natural selection will optimize the characteristics of a population to best survive in the given environment. If natural selection would have chosen to fit the color of beetle to have the best thermoregulation, the beetles would not be camouflaged and be easy prey for the predators. However, with the beetles matching the color to the beaches, they are able to hide from predators and deal with thermoregulation in another way. 20. (2 pts) Review Questions, p. 124, no. 10, In most of the examples discussed in chp. 5, we saw a close match between the characteristics of organisms and their environments. However, natural selection does not always produce an optimal, or even a good, fit of organism to environment. To verify this you need only reflect that most of the species that have existed are now extinct. What are some reasons (at least two) for a mismatch between an organism and its environment? Consider the environment, organism characteristics, and the nature of natural selection. Natural selection is differential methods of survival and reproduction among several phenotypic organisms. Darwin noted that the characteristics of phenotypes with individuals would be greater in rates than other individuals with different phenotypic characteristics. Therefore, certain organisms with different phenotypic qualities would be able to adapt better to an environment while others can not. Stabilizing selection, leads a population to maintain a particular phenotype over long periods of time. Stabilizing selection can occur when organisms within a population have completely adapted their their environment. Stabilizing selection sustains environmental conditions and the dominant phenotype within a population, but can often become difficult if met with environmental change.