Writing in Biology

          The documentary emphasized the importance of water to both human society and natural ecosystems, outlined the normal water cycle, absent human interference, and went on to describe the ways governments and private companies try to control water, as well as the ways grassroots activists organize in defense of water rights. All of these components of the video offered context for the overarching theme, which was water scarcity. I found the ecology of overcompensation interesting, as the video explained that overpumping of groundwater supplies leads to desertification of the surrounding area, and that when the land can no longer absorb moisture, precipitation runs off into the ocean, contributing to more severe storms. In regards to water management policy, I was somewhat surprised to learn that international organizations like the UN defined water as a commodity, not a right. The example offered of the World Bank refusing to finance a water co-op in Bolivia, and subsequently trying to force Bolivia to privatize their national water system, leading to an actual civil war, was shocking. Furthermore, the way the private sector unsustainably exploits water supplies elsewhere around the world for short-term profits, even going so far as to bribe government officials, was frustrating to hear about.

Dominance of an allele does not predict the outcome of allelic frequencies. Dominance simply refers to the outcome of a phenotype. The common misconception in terms of dominance is that dominance determines which of two alleles will persist. It is misconceived that a dominant allele will go into fixation, and cause the recessive allele to disappear in the population. In fact, dominance cannot determine whether or not alleles go into fixation. It is through selection that determines the outcome of allelic frequencies. If the dominant allele was selected for, in that case, the allele frequency of the dominant allele will increase, otherwise, if there is no positive selection for that allele, it will remain at a constant frequency. Likewise, recessive alleles may also be selected for and its frequency may also increase. To reiterate, dominance only determines the outcome of the phenotype, and if acted upon by negative selection, could potentially disappear from the population.

We will compare the damaged plants (mechanical and jasmonic acid spray) with a regular amount of fertilizer and the non-damaged plants with a regular amount of fertilizer in order to analyze the effect of spraying jasmonic acid onto plants. We will compare them by measuring how tall the plants grow, the rate they grow, the surface area of the leaves before and after, and if there are any signs of chlorosis or necrosis. By doing so, we will be able to see how mechanical and jasmonic acid damage affects new versus old growth on the plant.

120 tomato plants will be used in the study. 100 of the plants will receive a form of damage to their leaves by caterpillars eating bits of leaves off of each plant, the remaining 20 will serve as a baseline. The caterpillars will be left on the plants for enough time to do a measurable/visible amount of damage to the plant. 75 tomato plants will receive JA, there will be three groups receiving treatment and one group will receive no treatment (this will be our control). 25 will receive five sprays of JA, 25 will receive three sprays of JA, 25 will receive one spray of JA, and 25 will receive no treatment of JA (this way, we can see if too much JA hurts the plants, if any amount of JA hurts the plants, or if more JA applied to plants then the plants will repair themselves faster or better than they would have without the extra spray). The responses could be measured by weighing the plants before and after to see if there is a change in biomass. They could also be measured visually by analyzing the plants to see which ones look healthier or if their leaves grew back entirely and then some.

In the bumble bee (Bombus impatiens), the gut parasite Crithidia bombiis related to the causes of Chagas disease and Leishmaniasis in the bumble bee. The parasite is transmitted via ingestion of cells in feces of infected bees, and is present in 80 percent of the Bombus impatienspopulation in New England. In the lab, we will be infecting bumble bees with the gut parasite through a nectar feeder and randomly assign which bees get the treatment. We will then leave them alone for a week, dissect their guts, and count the amount of Crithidia bombicells.

Plant defense mediate tri-trophic interactions. A plant’s response to a threat can influence herbivore mutations and eventually predator mutations. Plant defenses directly reduce herbivore performance, but they can also indirectly benefit herbivores because they can acquire new traits from the new chemicals made by the plant they are consuming. Since pollinators are herbivores (they consume nectar and pollen from plants), they also can acquire new traits from the nectar and pollen containing new plant defenses.

Since 1990, there has been a 25% decline in the United States in vertebrate pollinators and 200 vertebrate pollinator species are near extinction . The majority of our staple crops are wind-pollinated and don’t require vertebrate pollinators, but roughly a third of our crops would not exist without vertebrate pollinators (many types of berries, nuts, vegetables, cotton, coffee, around 90 major crops). Vertebrate pollinators provide 30 billion USD of pollination services in the United States alone, and 200 billion USD globally. The impact of the loss of pollinators to the global agricultural system would be great as well as the to plant species that we do not cultivate.

DDT, or dichlorodiphenyltrichloroethane, is a colorless and tasteless chemical compound developed as an insecticide and its use was banned because of its role in the increased risk of serious health conditions in humans and animals alike. DDT was at the height of its popularity during the second World War. During this time, DDT was used to prevent diseases such as malaria and typhus. Though it was an effective insecticide, it was cause for concern when the chemical would also kill beneficial insects as well as birds and fish. Not only did DDT kill birds, but it also caused egg-shell thinning in Perregrine Falcons. This egg-shell thinning would make it much more difficult for the falcons' young to be born. The egg-shell thinning was not the extent of the damage done by DDT. This harmful compound is thought to be a carcinogen as well as an endocrine disruptor. An endocrine disruptor is a chemical that interupts an endocrine system. In this case, a chemical called DDE is formed from DDE when it loses hydrogen chloride. DDE is an androgen receptor antagonist, meaning it will bind to the same receptor that male sex hormones bind to, decreasing the effect of certain hormones such as testosterone. The deleterious human and animal effects caused by DDT were far too prevalent to allow it to continue being used and it was banned in the United States in 1972.

We will be doing an experiment which involves spraying jasmonic acid onto damaged tomato plants (Solanum lycopersicum). This tomato plant species belongs to the Solanacaefamily, which includes eggplants, potatoes, and tomatoes. The reason this species of tomato will be used is because it has well characterized chemical defenses. However, the nectar-less flowers will require pollination by bees. In order to provide the mechanical damage we want to apply to the plants, we will use the tobacco hornworm (Manduca sexta). This worm is native to New England and is a well-known crop pest on tobacco and tomato plants.

Once I took my 3 photographs, I pasted them on a word document in the order I took them on a Mac laptop. I clicked on each picture and changed the text wrap layot to square by clicking layout>arrange>warp text> square. I made each photo a width of 2.13" and a height of 2.84" and had the edges overlapping to form a smooth rectangular edge. Then I made 3 textboxes and filled them all in black. I centered the text and changed the font to calibri (body) size 16 and color to white for all 3 textboxes. I wrote a in one box and dragged it to the top left corner of the first photograph. Then I wrote b in another box and dragged it to the top left corner of the second picture, and then I wrote c in the last text box and dragged it to the top left corner of the last picture. Then I took a screenshot of the figure by pressing comand, shift, and 4 at the same time.