User:Atcovi/The Serengeti Rules

Introduction: Miracles and Wonder
Q: Determine whether the following statement is true or false and explain your reasoning for your choice: Diseases are mostly abnormalities of regulation, where too little or too much of something is made.

A: I perceive the statement by Sean Carroll as the truth and I, thereby, agree to his perception of diseases as mostly "abnormalities in regulation". We can look at several diseases, an example being cancer and meningoencephalitis in listeriosis animals, where too much is being done (so to say).

Malignant tumors depend upon the c-Myc, a regulating gene. An increase in c-Myc levels can amplify tumors in tissues and reduce biological abilities to restrain it. In animals, listeriosis may cause animals to suffer from meningoencephalitis, inflammation of the brain and meninges tissues. The pathogen responsible for this, Listeria monocytogenes, harms its host by increasing the levels of cytokines. With moderation, cytokines accommodate cells in maintaining homeostasis. With a malicious increase, they can cause fluids to build up in the brain, known as cerebral edema.

Part I: Everything Is Regulated
Q: '''When your body gets cold, you shiver. When your body gets hot, you sweat. Why do you think your body resists these changes in temperature? What other changes are resisted by your body?'''

A: The body resists these radical changes in temperature in order to maintain homeostasis, which is the body's way of sustaining stable biological conditions. Without this, our body will not be able to function to its best. Another example of a homeostatic change in the body is when a person exercises. The body heats up, which is detected by the nerve cells who deliver the information to the brain. The brain responds by activating the sweat glands, cooling the body. Other radical bodily changes, such as extreme changes to the glucose and pH concentrations, are also monitored and responded to by our body.

Part II: The Logic of Life
Q: '''Figure 7 above shows the biosynthetic pathway of cholesterol. If you were to try to regulate this series of reactions, even shut them down completely, where do you think would be a good place to intervene? Why?''' A: I would intervene at the HMG-CoA reductase (HGMR), where it's converting HMG-CoA to mevalonate, an organic compound which serves as the precursor in the mevalonate pathway because this is where the main production of cholesterol takes place (producing mevalonate, which leads to cholesterol). Statins, or HMG-CoA reductase inhibitors, such as the drugs Lescol and Zocor, control and inhibit the HMG-CoA reductase to prevent cardiovascular diseases... so this is exactly where I would regulate and change [HMG-CoA reductase] as well.

Part III: The Serengeti Rules
4Q: Study the food chain pyramids shown in Figure 9 below. AQ: For each of the Grass → Prairie Dog → Coyote pyramids, explain why they are shaped the way they are. For Numbers, the number of producers is bigger than consumers because the producers receive readily available energy (sun, water) while the consumers receive a source of energy that isn't readily available at all times (prey goes extinct at times, such as dodos), resulting in a lesser number of consumers than producers. For Energy, half of the energy is lost when energy is transferred from one organism to another, so energy decreases as you move up the pyramid. For Biomass, the less number of organisms at each trophic level results in less biomass. BQ: For each of the Phytoplankton → Zooplankton → Squid → Penguin pyramids, explain why they are shaped the way they are. For Numbers, there is more zooplankton as zooplanktons not only eat phytoplankton, a type of plant (similar to grass), but they also eat other zooplanktons. This causes an increase in numbers as not only do zooplanktons have to produce for other organisms, such as the squid, but also for themselves. For Energy, energy decreases as you move up the pyramid. For Biomass, the less number of organisms results in less number of biomass.

CQ: '''Imagine that squid is the primary consumers of zooplankton and are also the primary food for penguins. Describe what might happen to the pyramid of numbers if the squid began disappearing from this marine ecosystem.''' If squids were to disappear, the zooplankton's population would increase exponentially while the population of squids would decrease. The pyramid would look abnormal.

DQ: '''Often trophic pyramids like these are drawn as triangles with smooth sides. Why might blocks like the ones shown in Figure 9 be more representative of the actual relationships between trophic levels?''' I feel that blocks that are shown above are more realistic to the actual ecosystemic relationships because the blocks are more specific, in terms of size, then the pyramids, in which the size is adjusted to make a pyramid look perfect.

Part IV: Figure 11 (Wilbur Figure)
5Q: Study Figure 11 below and answer the items listed below. AQ: Write the prediction Wilbur likely made given the experimental methods he used to test his hypothesis. If the number of individual tadpoles per meter squared increases, the average body mass of the tadpoles decrease.

BQ: Why do you think it was important for Wilbur to replicate his experiment four times? Wilbur felt it was necessary to do his experiment 4 times because he wanted consistency (density ↑ body mass ↓).

CQ: Identify what you see in the graph. The graph shows that as the density of the tadpoles increase, the average body mass of the tadpoles decreased. There is an inverted relationship between the larvae population density and the mean body mass of each of the 4 tadpole replicates.

DQ: From what you see in the graph, interpret the effect you think higher tadpole densities have on their final body masses. The higher the tadpole density, the smaller the final body mass is.

EQ: Propose an explanatory hypothesis for the results Wilbur observed in his experiment. The body mass of the tadpoles decreases as the density increases because the tadpoles are adapting to their surrounding area. As the population increases, food availability will decrease. As a result, the body will, over time, adapt to the loss of food by making their bodies smaller, resulting in less food consumption.

Part V: Serengeti Rules
6Q. List and explain the Serengeti Rules.
 * 1) Keystones: Not all species are equal: Some exceptional species in an ecosystem produce effects on the living standards of their neighbors, thus having more of an influence on the ecosystem than other species. When the starfish is removed from the tidepools, the mussels grow and expand in numbers and feast on the other species, causing a decline in their numbers. The wildebeests' influences on the Serengeti allows for the Serengeti to even exist by regulating and affecting the lifestyles of the other animals.
 * 2) Some species mediate strong indirect effects through trophic cascades: If one animal is removed/added, it may produce great effects on the food web in that area. Starfish removed from tidepools allowed mussels to grow, which caused a decline in other species, such as barnacles and limpets.
 * 3) Competition: Some species compete for common resources: Different animals compete with their neighbors for basic, survival resources. Wildebeests compete against the gazelles and grasshoppers for grass, which affect the food supply of the other animals because it allows for the grass to grow quicker and produce more food, increasing the food supply for the other animals.
 * 4) Body size affects the mode of regulation: Small animals are controlled by predators while big animals are controlled by the availability of prey.
 * 5) Density: The regulation of some species depends on their density: Some animals are controlled by how much a certain item is there/available. An example is predators on prey. Predators decrease the prey population. Once the predator finds a new source of food, the origin prey population can expand in numbers again while the new prey population will decrease in numbers.
 * 6) Migration increases animal numbers: When a prey migrates to a new location, it escapes its predators. This allows them to expand and grow as they don't have predators to come and reduce their numbers. They also find a new food supply.
 * General Rules of Regulation
 * Positive regulation - A increases B (reductases/enzymes)
 * Negative regulation - A decreases B (predators)
 * Double negative - A decreases B which allows C to increase. (predator --> prey/predator --> prey)
 * Feedback - C grows, which goes back to negatively regulating A and, as a result, B. (childbirth)