Individuals of the roughly 2,000 species in the family Lampyridae include those insects capable of producing bioluminescent light through a specific metabolic process. Though commonly referred to as fireflies or lightning bugs, these idiosyncratic creatures are more accurately categorized as winged beetles. Like their amphibian predators, most fireflies are crepuscular and are thus largely reliant on their bioluminescence to attract mates, find food, and warn predators of their potential poisonousness. Fireflies are known not to be desirable prey animals for most predators due to the presence of potentially harmful substances in their blood and bitter taste. During their larval stage, bioluminescence serves as the primary defense mechanism to fend off those predators. The diet of most fireflies includes a mixture of nectar, pollen, fireflies, and other insects. It has been shown that different species of fireflies exhibit unique bioluminescence patterns when attracting mates. For example, males of the species P. pyralis (the state insect of Tennessee) use flashing patterns during courtship to attract potential mates. If a female elects to mate with the male, she will respond by reciprocating with a flash of her own. However, the males must beware, as females of other species such as P. pensylvanica can mimic these patterns to deceive, attract, and eat the males.

The biochemical reaction by which fireflies produce light occurs inside a specialized organ in their lower abdomen. This light-emitting organ utilizes the molecule luciferin, which is responsible for the production of visible light. In the presence of oxygen, magnesium ions, and the energy-rich molecule adenosine triphosphate (ATP), the enzyme luciferase converts luciferin into oxyluciferin, which emits light due to being in an electronically excited state. Upon emitting light, oxyluciferin is recycled and reconverted to luciferin so the process may continue. As with any biochemical process, the rate and capacity for bioluminescence in fireflies is dictated by the concentration of inputs as well as the rate at which byproducts are recycled. Scientists still do not fully understand how fireflies are able to produce bioluminescence with upwards of 80-90% energy efficiency. In comparison, the average incandescent light bulbs and LED lights emit only about 10% and 20% of their total electrical energy input as light, respectively. Since the first law of thermodynamics states that the total energy of the universe is constant and energy can neither be created nor destroyed, heat is the major byproduct in the reactions mentioned above.

To further study the interaction of firefly luciferase with its substrate, a student designs an experiment testing the rate at which the molecules involved are recycled. The student gathers 100 fireflies and separates them randomly into five equal experimental groups. Group A is not given any treatment and each subsequent group of fireflies is administered increasing concentrations of luciferin. Each group of fireflies is then released into separate pitch-black rooms that mimic the fireflies’ natural habitat. These rooms also contain light meters that measure the intensity of light emitted by the group of 20 fireflies as a whole. The results of this experiment are shown in Table 1.

Table 1

Gentrification is a social phenomenon that is characterized by community developments that, at times, displace lower income residents and small businesses. This process is often characterized by urban renewal or urban planning projects that are initiated by increased interest in a particular community. For example, low-income artisans such as artists and musicians may move into a lower income urban sector and utilize their talents to enhance its aesthetics. These early gentrifiers increase the community’s appearance and desirability, which attracts the attention of others who wish to further develop the area. Once urban development begins, it is common for these areas to experience an influx in wealthier inhabitants, which are often accompanied by upper-class business enterprises and increased property values. Once the gentrification process has reached this point, some of the earlier inhabitants or locals of the area may not be able to afford the increased cost of living in the community. This may result in population migration out of the community. As a result, the area’s social demographics change, which may be accompanied by conflict and controversy between immigrating and emigrating groups. A case study in Chicago’s Hyde Park will help to illustrate this process.

In the wake of WWII, labor-hungry war industries coupled with white out-migration (“white flight”) from Chicago’s inner city to the suburbs resulted in a dramatic shift in the city’s racial demographics between the years 1920 to 1950. In the early 1900s, the migration of southern blacks to Chicago’s south side south of 55^th Street created what became known as the Black Belt. This shift in racial demographics resulted in an increase of Chicago’s black population, from only 4 percent of the city’s population in 1920 to 23 percent in 1960. 

In the early 1950’s, the traditional Cottage Grove Avenue barrier that separated the Hyde Park-Kenwood area from the Black Belt was traversed by further black migrations, which resulted—in part—from the demolition of the nearby Lake Meadows Housing Development. The University of Chicago used political power to revitalize neighborhood areas that had deteriorated due to the construction of low-income housing developments nearby. Specifically, they sought to keep public housing out of the neighborhoods surrounding the University. The creation of the citizen-oriented Hyde Park-Kenwood Community Conference (HPKCC) in 1949 and the University of Chicago’s establishment of the Southeast Chicago Commission (SECC) in 1952 resulted in the implementation of a plan disguised as urban renewal, which attempted to slow the racial transformation of the area. In 1958, the Chicago City Council approved the Hyde Park-Kenwood Renewal Plan that racially segregated the area. The University sought to maintain a compatible environment for its operations and to preserve the racial homogeneity of the community; thus, the University, through the SECC, attempted to create an economically upgraded and predominantly white neighborhood. In other words, if the racial composition of the area could not be maintained, then upgraded class and socioeconomic statuses could prevent demographic changes by making it unaffordable to lower income groups. It is important to note that this contention and “renewal” of Hyde Park’s racial structure was not contained within this time span between the post war period and the Civil Rights Era in the 1960s. The 1970s brought similar racial strife and tension to Hyde Park in the wake of gentrifying forces.

A group of researchers observed gentrification in the Chicago suburbs. These researchers paid close attention to neighborhoods that were described as “up and coming.” They decided to use census data to look at two factors in these regions: population and median home values between the years of 2010 and 2015. The researchers planned to observe the changes contained in four census tracts: 8412, 6706, 6715, and 7107. The researchers hypothesized that they would observe population out-migrations and increased property values in areas that have been gentrified. The results of this data were tabulated in the following two figures.

Figure 1: Changes in population of observed census tracts between 2000 and 2015.

Figure 2: Changes in median home value of observed census tracts between 2000 and 2015.