Writing in Biology

The aim of this experiment is to test whether or not two species of the same niche can occupy the same space and coexist. This experiment tests whether or not one of two species would outcompete the other when they both rely on the same resources. By using two floating aquatic plants, Lemna minor and Salvina molesta, two species of the same niche are brought together for the experiment. In nature, when two species of the same niche are brought together, possible outcomes include dominance by one of the species, partitioning of the environment and resources, or co-evolution, in which the species diverge from usage of the same resource. With limited time for the experiment, it is unlikely to observe evolution of the two selected species. It is therefore possible that the species may cohabitate and partition the resources so that they both thrive, or one will out-compete the other. In this experiment, we predict that one of the species will outcompete the other due to useage of the same resources.

In the laboratory environment, the two species Lemna minor and Salvina molesta were brought together to show how reliance on the same resources will result in elimination of one of the species. This is an increasing problem in natural ecosystems throughout the globe. As invasive species are brought to new environments, they devastate the local ecosystem and displace the native species. This experiment revealed the potential threats of careless introduction of foreign species to different environments where they pose a threat to species that already occupy the same niche. Although cohibitation is a possibility, it is not typically the case when there is a reliance of the same limited resources.

Not all of the food consumed by humans today were made accessable to all until after the Columbian Exchange. Besides the new people and new land, there were new foods that Europeans have never seen. Some of these crops included corn, tomato, potatos, chili, and chocolate. Corn originated from central and north america. Potatos were originally found in moutainous regions of south america. Tomatos came from Mexico and were orignally thought to be poisonous because of its bright red color. Chocolate also came from central america. Although the initial meeting of the new and old world populations brought about diseases that dimished the population of the new world, overall, the exchange of new crops and livestock greater increased the world human population due to a greater diversity in diet and available staples.

The definition of competitve species is a species whos phenotypes causes a fitness decrease in a competitor species. In bacteria, this is observed in phenotypes such as secretion of digestive enymes and production of antibiotics as a result of biotic competition with other bacteria, as opposed to environmental pressures. Competitor species must also overlap a single resrouce. When this occurs, there are two types of competition, passive and active. In passive competition, one organism outcompetes the other by using the same resource more efficiently. In active competition, the organism may directly harm the other. In the case of bacteria, this may be done by producing chemicals that harm other bacteria of the same niche. Thee possible results of such competition include having one species dominating the other, coexistence over time due to divergence of resource use, or territorial niches are developed. The later is observed in microbial colonies that when initially mixed, separate into patches on the surface of agar. The result of competition is typically a decrease in diversity but increase in ecological stability. The long-term effect depends on selection pressures of the environment.

In the past, ecologists thought there was a negative correlation between species abundance and niche width of a species. However, current ecologists agree that there is a positive correlation between the abundance and niche width of a species due to the increase in a diversity of resrouces consumed, thus an increase in tolerance of various environmental conditions. However, invasive species are therefore successful when they have a wider niche than that of native species, therefore, doing better with competition. A superior competitor can use the same resources of a native species and cause competitive exclusion of the native species. Co-existance of species that rely on the same resources is explained by the abundance of resources for both species and resource partitioning.

          The debate over evolution is divided into two main sides, with detractors of evolutionary theory promoting intelligent design as a counterargument to the Darwinian theory advanced by scientists. Intelligent design is the belief that life, or the universe, did not originate by chance, but rather was designed and created by some intelligent entity, with many of the proponents expressing the belief that the designer is the Christian deity. Intelligent design advocates assert that natural selection could not create the complex biological systems observed in living organisms, because such elaborate and interdependent anatomy must be the deliberate product of an engineer, not random variation and cumulative natural selection as Darwin theorized. In contrast, the biological evolutionary theory describes a gradual change in allele frequency within a population through natural selection and various other mechanisms. In this scientific theory, random mutation results in new variation, the environmental pressures on organisms select for those with the most advantageous traits by allowing them to better survive and reproduce, and this natural selection works alongside other mechanisms to cumulatively cause change in species over time. The key distinction between this and intelligent design is that biological evolution is random and operates blindly, with no foresight or end goal. Meanwhile, intelligent design is entirely based on the idea that an organism’s form follows a deliberate blueprint sketched out by a provident entity who is responsible for the creation of all life.

The article Cancer Disparities by Race/Ethnicity and Socioeconomic Status examines disparities in cancer incidence, mortality, and survival in relation to race, and census data on poverty in the county or census tract of residence. It highlights differences in cancer risk factors, screening, stage at diagnosis, and treatment between population groups that could be reduced or possibly eliminated by applying current knowledge about cancer prevention, early detection, and treatment equally to all segments of the population. The data compiled illustrates that among both men and women, five-year survival for all cancers combined is 10 percentage points lower among persons who live in poorer areas than those who live in more affluent census tracts. Even when census tract poverty rate is accounted for, however, African American, American Indian/Alaskan Native, and Asian/Pacific Islander men and African American and American Indian/Alaskan Native women have lower five-year survival than non-Hispanic Whites.

          Green is the New Black is a speech made by Majora Carter to the Ella Baker Center for Human Rights’ Solutions Salon, on May 19, 2006. She describes how her neighborhood in New York City handled 40 percent of the entire city’s commercial waste, acting as home to a sewage treatment plant, a sewage sludge pelletizing plant, four power plants, the world’s largest food distribution center and other industries which brought in tens of thousands of diesel trucks to the area each week. Carter uses her first-hand knowledge of the rampant pollution of the Bronx to depict how environmental degradation and social and economic divestment go hand in hand, and how these circumstances inevitably produce negative health outcomes for the members of the communities which they affect. She went on to explain how she and her peers employed grass roots activism to fight against the damage being done to their community, and outlines strategies that can be used to improve the environmental, and subsequently medical and economic, conditions of communities like the Bronx

          The debate over nature vs nurture has been going on for at least hundreds of years, and our modern understanding of DNA and the research around behavioral genetics is just another facet of that discussion. We already know human responses to various stimuli are triggered by numerous neurochemicals and molecular signalling pathways, which are in turn regulated by the activation and deactivation of particular genes. The way that I’ve always understood it, though, is that while there are certain sets of genes that, if inherited, may predispose you to be more susceptible to addiction or obesity or whatever else, it is not in any way guarantee that you’ll actually exhibit these traits. In addition, the field of epigenetics has also revealed that environmental factors can impact when and how a gene is activated or deactivated. For instance, in the article by Kathleen Mcauliffe, Jaroslav Flegr’s research into T. gondii did not illustrate human genes driving disordered behavior, but rather external environmental factors which were, in this case, the presence and disruptive influence of the T. gondii parasite. As discussed in Amy Harmon’s article “The DNA Age”, some people see themselves as “hostages” to their genes. I disagree with this attitude, excluding in cases of diagnosed disorders, because I believe it overstates how much individual genes can direct complex and variable human behaviors. I personally think of it as DNA acting as a foundation for what might be possible, and then factors from both the physical environment and the social environment build up from there and result in the formation of what behavioral tendencies are exhibited.

The article (https://neurosciencenews.com/dopamine-cognitive-ability-10788/) mentions that the right amount of dopamine in the brain will improve cognitive function. Tyrosine is a precursor for dopamine. Tyrosine is a polar amino acid.  An experiment was conducted where participants were given tyrosine juice or a placebo. Then the participants were given a memory task where they viewed a bunch of slides and took note of if there were any replicates. The participants who had an increase in dopamine levels with the tyrosine juice performed at a "faster rate with fewer mistakes". In class I learned that dopamine is responsible for attention and motivation. Participants who had the extra dopamine would have a higher level of attention and would pick up on more details. Also their motivation to complete the task would be higher too. Therefore, the level of dopamine in our system to function at a higher level is not always met. My question is if there is an optimal level of dopamine for the brain to function at that level, why is the brain not constantly producing dopamine to reach that level?