Writing in Biology - Section 1

Due to the increased use of capsaicinoid and tolerance of capsicums in the human diet, other health benefits emerged as a consequence.  In Tsuchiya’s study of the effects of capsaicinoids on membrane fluidity, bacterial growth and platelet aggregation were the two subjects (2001).  The lipid form of capsaicinoids were able to interact with the membrane in bacterial cells, inhibiting their growth (Tsuchiya, 2001). This effect on bacteria could result in capsaicinoids being essential in maintaining a healthy gut biome for an individual who was raised in an environment with a high spicy food tolerance.  Gastrointestinal disease has been reported to be decreased with capsaicin consumption (Deng et. al., 2016). In platelets of humans, rabbits, and rats, capsaicinoids were shown to decrease their aggregation (Truchiya, 2001). Capsaicin has already been proven in other studies to decrease cardiovascular disease (Deng et. al., 2016).  The effects of membrane fluidity could be one of the physiological changes within the body which decreased cardiovascular disease. In China, a study was conducted to determine if chili intake and capsaicin had any effect on the obesity of the population (Shi, Riley, Taylor, & Page, 2017). Although this was one of the first conclusive studies done involving obesity, there was conclusive evidence that chili intake had an inverse effect on obesity and might provide a low cost solution to obesity problems in China (Shi, Riley, Taylor, & Page, 2017).  Through the decrease of obesity, there is a multitude of other health complications that can be relieved. One of the flaws with the studies on the health benefits of capsaicinoid consumption is the lack of physiological understanding within the body of how it alters the health of the individual. Until these pathways are fully understood, there will be a slew of health benefits that are not maximized.   

Within mammals, humans are one of the few species which cater to their taste preferences using spices.  One of the spices used in cooking contains the active ingredient capsaicin which causes a burning or spicy sensation when eating.   Of the mammals, humans and tree shrews are two of the few species who have been documented to consume plants containing capsicumoids as part of their diet (“Tree shrews can tolerate hot peppers,” 2018).  Chili peppers are one of the most common cooking plants containing capsaicin, a type of capsaicinoid (Tsuchiya, 2001).  Other mammals avoid the Capsicum plant species due to the spicy burning sensation caused by their consumption.  Within tree shrews, they have a mutation on the reception TRPV1 which decreased the effects of capsaicin on the receptor (Han, Li, Yin, Xu, Ombati, Luo, & Lai, 2018).  From this mutation, tree shrews were able to expand their diet due to their tolerance of capsicumoids in a similar pattern of convergent evolution. With humans, the burning sensation is variable depending on food preference of the individual but humans are the only species known to actively seek out the consumption of very spicy foods (Han et. al., 2018).  TRPV1 receptors are apparent throughout mammals in their avoidance of spicy foods but only humans and tree shrews have evolved to utilize capsaicinoids in their diet. Of other vertebrates species, birds are one of the only other species to have no response to eating Capsicum plants (Han et. al., 2018).  Birds are often used by plants to spread their seeds and it is likely that mammals do not do this job as well leading to the plant’s possible evolution to prevent their consumption by mammals.

Nutrient cycles in an ecosystem move the key components organisms need to survive. Nutrients generally enter a system through 2 channels. Either the weathering of abiotic materials that release the nutrients from its previous form or atmospheric inputs such as deposition and fixation. These nutrients are then soluble and can be absorbed by plants and microorganisms. Plants and microorganisms end up as detritus after their life cycles are terminated. Before becoming detritus some of these individuals will be consumed by heterotrophs which also inevitably become detritus. After time is allowed to pass the detritus decomposes and the nutrients mineralize and enter the soluble pool again. During this process, some of the nutrients are lost. The nutrients can become leached into the soil or be released into the atmosphere as a gaseous loss. This process repeats as long as nutrients are present in the active pools. If the nutrients stop cycling the ecosystem could experience catastrophic loss in biodiversity.

In order to visualize the available energy and biomass at each trophic level, ecologists use the pyramid model. At each trophic level, beginning with the primary producers on the bottom, a rectangle is made proportional to its value in that ecosystem. In terrestrial ecosystems, the energy and biomass pyramids decrease as each trophic level progresses. The primary producers have the most of both and the tertiary consumers are at the top with the least of both values. Aquatic ecosystems share a similar energy pyramid where the primary producers have the greatest amount and the tertiary consumers have the least. However, the biomass pyramid shows a different pattern. At the lowest trophic level, the primary producers, there is the least amount of biomass and as the trophic levels increase the biomass increases. This is known as an inverted pyramid. A pyramid such as this one occurs in aquatic ecosystems because the turnover rates of the primary producers are much higher. In terrestrial ecosystems, a lot of the biomass is inedible so the turnover rates are slower. 

In my physics class, we are learning about magnetic fields. One of the most interesting things I find about magnets is the inability to separate north and south poles, unlike the ability to separate positive and negative charges. No matter how small you go, even down to the atom, a magnetized object will always have a magnetic north pole and a magnetic south pole. For example, if you cut a bar magnet with a north and south magnetic pole in half, the two halves would both then form a north and south pole. Scientists have never observed a magnetic monopole, which is a particle that has just one magnetic pole whether that be north or south; however, scientists don't know why this is the case and are trying to figure out why this happens if a magnetic monopole cannot be observed.

Based on the premise that since all living things have the same DNA, that DNA from one organism can still be read and expressed when transferred to another organism (genetic engineering). Monsanto is a company that produces genetically modified organisms. They have made plants such that round up, a herbicide and carcinogen, would not be effective against vegetation. This is concerning because we are consuming dangerous compounds. An interesting topic to think about is the ruling of GMOs. GMOs are not considered GMOs if they are produced via CRISPR-Cas9, versus a product produced by a "gene gun" which is considered a GMO because we are taking DNA from one organism and inserting it into another. One example in which genetic engineering can be seen as a positive result is the modification of fast food potatoes. McDonald's takes advantage of genetic engineering to get rid of formaldehyde that can synthesize in potatoes when cooked at a high temperature. This lets us consume fast food safely, while letting companies mass-produce safe food for consumption.

Based on the premise that since all living things have the same DNA, that DNA from one organism can still be read and expressed when transferred to another organism (genetic engineering). Monsanto is a company that produces genetically modified organisms. They have made plants such that round up, a herbicide and carcinogen, would not be effective against vegetation. This is concerning because we are consuming dangerous compounds. An interesting topic to think about is the ruling of GMOs. GMOs are not considered GMOs if they are produced via CRISPR-Cas9, versus a product produced by a "gene gun" which is considered a GMO because we are taking DNA from one organism and inserting it into another. One example in which genetic engineering can be seen as a positive result is the modification of fast food potatoes. McDonald's takes advantage of genetic engineering to get rid of formaldehyde that can synthesize in potatoes when cooked at a high temperature. This lets us consume fast food safely, while letting companies mass-produce safe food for consumption.

in the novel Nadia’s doctor cousin is “blown to bits, literally to bits, the largest of which … were a head and two-thirds of an arm”. The man who sells Nadia and Saeed magic mushrooms is beheaded, then “strung up by one ankle from an electricity pylon where [his body] swayed legs akimbo until the shoelaces his executioners used instead of rope rotted and gave way”. Saeed’s own mother dies while looking in her car for a lost earring, “a stray heavy-calibre round passing through the windscreen … and taking with it a quarter of her head”. These examples of individual terrorism could be easily compared to many cases I have personal experienced with involving my Coptic Otthodox community. The EgyptAir Airbus A320 flying overnight from Paris to Cairo crashed into the eastern Mediterranean Sea on 19 May 2016. All 66 passengers and crew on board Flight MS804 died. My friend, Mariem Tanious’ father passed away during this flight, and they are Coptic Orthodox as well. Nevertheless, my direct cousin who is also my religion and is a famous drummer in Egypt, was held to gunpoint by a terrorist, asking him for all his money. Luckily, the wallet was given and the terrorist had fled.  

Theories for invasive species and why they occur have been hypothesized in ecological research. Some such theories are the enemy escape hypothesis, EICA hypothesis, EDCA hypothesis, Novel Weapons hypothesis, Missed Mutualism hypothesis, Invasional Meltdown hypothesis, Biotic Resistance hypothesis, unusual refuge hypothesis, global competition hypothesis, introduction pressure hypothesis, unintentional screening hypothesis, intentional screening hypothesis and biological control corollary. The enemy escape hypothesis states that species are less subject to specialized predators and pathogens where they are introduced than where they are native. This is due to the lack of selection for a specialized predator where the organism was not existing. The EICA (Evolution of Increased Competetive Ability) hypothesis is where plants evolve to grow faster than other plants. EDCA  (Evolution of Decreased Competitve Ability) hypothesis is where plants evolve to reproduce faster than other plants, but have no competetive ability. Novel Weapons Hypothesis explains how native species have not evolved to be selected for defenses against introduced species. This means that the introduced species defense mechanisms are more likely to target and harm the native species. Missed Mutualism Hypothesis states that the invading species will be less likely to take over it if is introduced without its native mutualists because it no longer benefits from the relationship with them. The opposite is true of the Invasional Meltdown Hypothesis which discusses the idea that if the mutualists of an introduced species are brought with it, the species will be highly invasive and almost always win out. The Biotic Resistance Hypothesis states that introduced species are less likely to be invasive because the presence of native predators, pathogens, and competitors will limit their spread. The idea that specific location yield species that are highly specialized to live there and only there comes into play in the Unusual Refuge Hypothesis, where it is thought that lack of adaption to local stresses limits invasive-ness, then locations with unusual stresses are less invasible. Global Competition Hypothesis simply states that it is more likely that some species elsewhere is a better competitor in a single niche than the local species because of the opportunity for better plants to be located and adapted to any other location on the planet. The introduction pressure hypothesis believes that the greater the number of individuals of a species are introduced and the more times that species arrives, the more likely it is to take hold in the introduced environment. That is because increasing the number of individuals reduces the limitations on the genetic pool of the migrated population and decreases the affects of genetic drift, and interbreeding between previously separate species populations increases fitness. Intentional screening causes certain traits that are more likely to yield an invasive species to be artifically selected for when people pick plants to bring. The unintentional invasion hypothesis deals with the traits that a plant species is likely to have to have survived travel and dispersal to become invasive. Plants that cling to boats and crops and survive travel are likely to be more drought tolerant, more fecund, parasitic to plants that were intentionally brought, and from places disturbed by people and therefore disturbance tolerant. The biological control corollary is the idea that a specialized predator from the native location of an invasive plant can be brought to reduce the invasive-ness of that plant. 

Both between and within populations, human taste preference varies between every individual.  Within humans, an assemblage of factors affect food preference like genetics, environmental conditions, and culture (Robino, Concas, Catamo, & Gasparini, 2019).  Due to advancements in molecular genetics, the understanding of food preference as it relates to sensory perceptions is being uncovered. Not only does genes coding for the taste and olfactory receptors have an effect on food preference but novel genes also have an influence as well (Robino, Concas, Catamo, & Gasparini, 2019).  The connection of novel genes to direct genes shows the complexity of food perception in the body. Through heritability studies, there is conclusive evidence that food preference is heritable but there is another variable that also has an effect on food preference (Robino, Concas, Catamo, & Gasparini, 2019). If there is any advantage to specific foods being consumed, then these food preferences would be selected for and passed down to the next generation.  At the genetic level, DNA polymorphisms are responsible for taste and smell variations between individuals. For example, the TAS2R38 receptor detects bitter taste and just a single nucleotide mutation can lead to a variable taste perception (Robino, Concas, Catamo, & Gasparini, 2019). Within the body, there is a complex system of gene expression interacting with cultural and environmental influences which determine an individual’s food preferences.