Writing in Biology

A lack of zoom on a camera may explain the image quality differences between the original and replicate figures. Perhaps there was not enough time to borrow a camera and SD kit from the Digital Media Lab or perhaps all the cameras were already checked out at the time of replication. Ducks and geese are also mobile, unpredictable creatures. It is impossible to ensure the ducks and geese will be in the exact location they were at the time of initial imagery, or that the weather conditions will be the same. This can explain the differences in the backgrounds of each image for both the original and replicate figures.

In this experiment, we explored the phenomenon of genetic complementation in yeast cells, saccharomyces cerevisiae, through mating. Within the procedure, we observed the yeasts’ entire life cycle- including the development of diploids and haploids, the process of gene complementation by mating and the impact of mutations due to specific external environments. In this experiment, exposure to UV radiation was used as a method to produce mutations in haploid yeast cells. The collected data include a simple cross between different mating yeast cells on a YED plate and then an MV plate through replication. In addition, the growth of meiosis and sporulation occur as we designed and performed a complementation test. The results further demonstrate the various genotypes and phenotypes of each parent and each offspring yeast cell.

Repetitive transcranial magnetic stimulation (rTMS) is the use of magnetic coils on the prefrontal cortex to suppress depression. The magnetics are placed on the prefrontal cortex and is non invasive, which means it does not pierce the skin. The magnets target the neurons in the prefrontal cortex and depolarizes them. Which causes those neurons to fire. When those neurons fire it causes more regulation of emotion and depressive symptoms. Which can have an effect on depression as a whole. There are many shapes the coil can be. A figure 8 coil resulted in a 24 % success rate with a 17% remission rate. While a H-1 coil results in a 37% success rate and a 30% remission rate. Though testing has only been done on adults, it is not available and not advised for children and or pregnant women. The procedure is expensive ranging from $6000-$12,000.

This is the observed results and conclusion for my bacterial motility experiment.

Observed Results:

For the motility agar test the agar inoculated with P. mirabilis was entirely purple. This demonstrated that tetrazolium salt had been reduced by bacterial cells, in order for this to happen the bacteria must be motile showing that P. mirabilis is motile. For the motility agar inoculated with S. aureus only the area of inoculation was purple meaning only S. aureus was only able to reduce the tetrazolium salt in its immediate vicinity showing that it is non-motile. The results for the chemotaxis plates were not as expected. The plates inoculated with E. faecalis (plated by Liam Potter) showed no growth on either the control or test plate. The plates inoculated with S. marcescens (plated by Christina Fruciano) showed growth but not motility. On the control plate colonies of S. marcescens grew on both halves of the GYE agar. On the test plate S. marcescens grew on the GYE agar but not on the water agar, it did not move from the inoculated water agar to GYE agar as expected.   

Conclusion:

The organisms tested on motility agar behaved as expected. S. aureus did not reduce all of the tetrazolium salt in the agar because it is non-motile. P. mirabilis did reduce all of the tetrazolium salt in the agar because it is motile. The organisms tested on the chemotaxis plates did not behave as expected. E. faecalis did not grow on either the test plate or control plate. This may have been due to cells in the inoculum being dead or due to a plating error. The results couldn’t confirm that E. faecalis was either motile or non-motile because there was no cell growth. S. marcescens did not travel across the filter paper after being inoculated on the water agar, nor did it form any colony on the water agar. This may have been due to nutrients not being properly absorbed by the filter paper causing no chemical signal to be present for S. marcescens. Another possibility is that the inoculated cells may have died on the water agar due to lack of nutrients. Based of the observed results S. marcescens is non-motile contrary to the expected results.

There are three main evolutionary processes that are responsible for evolution. The first one is phyletic evolution, which refers to a gradual change of lineages and relates one specie to another. The second one is speciation, the separation of phyletic lineage into multiple ones. Lastly extinction, the end of a lineage. However, extinction erased relationships among related species because species need other species to connect with otherwise it cannot happen if there is no species left. Species are the fundamental units for classification. There are numerous number of birds species due to different shape, color, habitat, songs and niches. Species are refer to how a single organism can reproduce and creates one or more offspring. Birds have a great amount of advantages when it comes to reproduction because they can migrate in a larger range than terrestrial animals, which makes them diverse.

 

Pursuing de-extinction will limit the time and resources that we could be spending on protecting current endangered species. As conservationists it would be our responsibility to handle the consequences of the released de-extinct species being integrated into the biosystems under conservation protection. The preservation of wildlife itself is composed primarily of non-profit organizations, meaning that the majority of funding comes from private donors who choose to donate to the cause. We must use these funds resourcefully to gain the best possible results for the ecosystems at stake since we are relying upon the non-hunting profit. If the wildlife conservation world already receives little financial backing, so does it truly make sense to divert the majority of necessary funding towards resurrecting species that have already past their time? De-extinction is extremely resource-intensive as it would require the use of technologies that have only recently been introduced and developed, not to mention additional conservation funds to monitor released species as well as protect their native environments. Managing healthy populations and rebuilding damaged ecosystems all require heavy funding. Pappas explains that “in almost every case, reviving an extinct species and asking the government to pay to conserve it would require deprioritizing a greater number of still-living species, the researchers found. The money used to conserve all five New South Wales species, for example, could go to keep 42 not-yet-extinct species from vanishing.” Each day that we don’t protect a current species, hundreds will go extinct each year. Spending millions to bring back one species will not compensate for the thousands lost to humanity. Conservation itself receives little funding, so we will be forced then to make a decision: do we focus all our efforts on bringing back that have disappeared? Given limited conservation dollars, bringing back one lost species would essentially cost the extinction of more alive endangered species. “For example, if New Zealand resurrected 11 of its extinct species, the government would have to sacrifice the conservation of 33 living species to pay to keep the revived species alive” (Pappas, 2017). If it is our responsibility to atone for causing hundreds of species to go extinct, is it then right to neglect the still-alive animals headed toward extinction if not supported by humans?

Delayed density dependence are delays in the effect that density has on population size. They can contribute to population fluctuations and lead to time lags. When the time lag is small, the population shows logistic growth (with no fluctuations). When the time lag is intermediate, populations show damped oscillations (fluctuations become smaller over time). When the time lag is large, the population shows stable limit cycles (regular fluctuations around the carrying capacity). A.J. Nicholson in his experiments, showed that delayed density dependence was a cause of fluctuations in blowfly populations. Additionally, these fluctuations can increase the risk of extinction. Small populations are especially at higher risk due to a number of factors: Chance events are unpredictable events, and can be environmental conditions such as temperature and rainfall. Genetic drift are chance events influence the alleles passed on to the next generation, and can cause allele frequencies to change at random. Finally inbreeding, which is mating between relatives, can make individuals too closely related, and increase the frequency of homozygotes, including harmful alleles.

In all realms of our biosphere, interspecific interactions occur. These interactions may involve mobile and/or stationary species. Some interactions may also be easily observable while others may not be but the ubiquitousness of such interactions is undisputed. Here, I observed the interaction between tree roots and green lichens before generating images of the interaction. I pass on the steps I followed, to obtain the images, to a peer to replicate the procedure and generate an image. This study reveals how common this interspecific interaction is here at the University of Massachusetts Amherst. It also shows the importance of detail in reporting scientific methods and how different outcomes may arise from slight variations in reporting. Detail is essential for accurate replication of experiments.