Writing in Biology - Section 1

During TLC, the starting material is less polar than the product and will be the highest spot on silica gel plate because the presence of the double bounded oxygen decreases the polarity of the substance because it more evenly distributes the electrons on the keytone as compared to an alcohol.  The less polar substance has a less interaction with the silica gel plate and will travel up the silica gel plate more.  Therefore, the product will be lower on silica gel plate because the starting material’s double bonded oxygen was reduced to an alcohol group via nucleophilic addition reaction.  The other two spots seen on the crude material and co-spot TLC plate are the products of the nucleophilic addition of a hydride.  Nucleophilic addition can attack the oxygen from either side and as a result, a mixture of diastereomers could be the product (refer to the image below as the possible diastereomer mix that could be formed from the nucleophilic addition of benzoin).

The other method of identification and purification is through TLC.  Two plates were run, one with a comparison of the crude product with the starting material and another with the final, pure product compared to the starting material.  Because the starting material is less polar, than the expected product as it is a keytone, it will have a larger Rf value because it travels farther up the silica gel plate as it has less interactions with the plate.  The product of the reduction has an alcohol group and therefore more polarity.  As a result, the product is expected to have a smaller Rf value.  In the TLC of the crude 1,2-diphenylethane-1,2-diol, the filter paper of the TLC chamber was likely in contact with the right side of the plate causing the co-spot of starting material and crude product to travel inward. Despite this factor, the results of the TLC were still conclusive.  The spot of just the crude product’s Rf is 0.7708 and there no spot above it indicating there is no remnant starting material.  The Rf of the crude product is also similar to the Rf (0.7917) found in the co-spot of the starting material and the crude product.  In the TLC of the second plate comparing the starting material and the recrystallized pure product, 1,2-diphenylethane-1,2-diol, the results showed a slightly lower Rf value of 0.6808 of just the pure product and 0.7021 of co-spot.  Based on these lower numbers, the recrystallization process must have removed some nonpolar impurities from the solvent.  It also revealed the presence of some of the starting material in the pure product as seen by second higher spot with the Rf of 0.8936 which is consistent with the other starting material spots of the first lane (Rf= 0.8936) and the co-spot (Rf= 0.9149).  Based on the TLC, the final product is 1,2-diphenylethane-1,2-diol with some residual starting material in it causing the lower melting point as well as the second, higher spot of starting material.   

To understand what lead to my sister’s disease and treatment, one has to look at the structure of the hospital.  Biomedicine often tries to find a specific cause to the disease.  For my sister, she was looking for an event which would have caused a UTI which having gone untreated would lead to pyelonephritis. Although she was asymptomatic for a UTI, she recalled a shift she came in early at 11a.m. to cover for understaffing.  Her shift had been so busy that she did not realize until she left the hospital at 11p.m. that she had not gone to the bathroom all day. Likely, this was a the cause of her UTI and she diagnosed it as urinary infrequency, something she consistently suffers from. When she got treated, the ED had been understaffed as well which resulted in her long wait time.  Although the hospital has adequate supplies, the one resource that seemed to be lacking in both these cases were nurses.  Often times, nurses in the ED of her hospital have anywhere from 8-10 patients from critical to stable condition.  For any capable nurse, this patient load would be overwhelming.  There is a flaw to the structure of her hospital which lead to her illness as well as the inadequate care and treatment when she sought out medical care.  Not only did her illness affect her quality of work before she was diagnosed but her disease impaired her from working for a week. My sister’s illness narrative revealed a flaw in the structure of her hospital which perpetuated harm, not only to her but her patients as well as her fellow nurses.  

When she was first admitted, she had her vitals taken as well as blood work and a UA (urinalysis).  With clinical proficiency, she was able to recall her vitals from her stay as all being well above average from her normal baseline.  Her blood work showed a white blood cell count of 22 (above normal).  When my sister told me about her UA results, she said the physician only stated they were “grossly positive.” When I asked her to elaborate on the results, she didn't know precisely the results as she didn't go into much detail with the physician but would assume that meant white blood cells, bacteria, glucose, and blood were all present in her urine.  With these result in hand, the physician started her on IV antibiotics as well as Toradol (IV ibuprofen).  A CT scan revealed her diagnosis to be pyelonephritis (kidney infection) as well as urosepsis.  For most patients, treatment would mean a night in the hospital for monitoring while they administered IV antibiotics.  My sister, unwilling to spend a night in the hospital as a patient, knew exactly what to tell the doctor to make sure she went home.  Although her condition is something that should not be taken lightly, she knew because of her age the physicians would expect her to bounce back relatively quickly upon treatment.  From there, she would just have to inform them she had an appetite and was not in a lot of pain, both things she had become conditioned to over the past week.  She was released from the hospital that night with a prescription for antibiotics in hand.

The fitness of a trait expressed an individual in a population is determined by a few factors. In broad sense heritablilty, the proportion is measured by genetic variation to genetic variation and environmental variation. The greater the environmental factors, the less likely that the trait is influenced by genetics and less likely that the trait can be passed down. In terms of narrow sense heritability, other genetic factors are measured to determine if internal/external environmental conditions contribute. If a trait has high fitness, relatively high survivial rate and produce a large number of offspring, then traits with high heritability will likely be passed to offspring. This will result in a selection differential between the mean of the general population and the population of breeders, creating a directional slection pattern if the traits are graphed. The reaction to selection may also be quantified by multiply the heritability of a trait with the selection differential. Fitness does not necessesarily correlate with high frequency. Sometimes traits with low frequency express a higher fitness which is known as negative frequency dependent selection. 

Climate change is one of the biggest threats to the planet today. One of the results of climate change is altered levels of CO2 in the atmosphere, land, and oceans. Buildup of CO2 in certain environments and different amounts can have drastic effects on the ecosystem. Continued use of fossil fuels has contributed greatly to this increase in CO2. In recent years, scientists have done research into the use of seaweed (macroalgae) as a method of carbon mitigation. Wild seaweed has great potential to sequester carbon, and an increase in agriculture of seaweed (particularly in aquaculture farms close to heavily populated land) would provide a barrier of carbon mitigation between human carbon waste and the ocean. Macroalgae can inhabit a range of aquatic habitats spanning the globe, and some species are adapted for the acidic, high-carbon environments that carbon pollution has produced. Aquaculture is a growing industry but has yet to take hold in most of the countries across the world. Seaweed aquaculture is primarily used for food, medicine, and cosmetics. Increasing seaweed production for food markets appears to be the best course in order to increase seaweed cultivation and subsequently it’s beneficial carbon-sequestering effects. Seaweed aquaculture is not an end-all solution to climate change and carbon buildup. There would need to be significant increases in aquaculture alongside reductions and reforms of the biggest CO2 production industries and locations for seaweed aquaculture to have a significant benefit. Currently, this method of carbon sequestering has gone relatively undeveloped and should be implemented world-wide where growth conditions are right as an ecologically- beneficial method of reducing carbon and CO2 buildup in the environment.  

With evidence that 43 species in Massachusetts are flowering earlier due to rising temperatures, other regions throughout the United States or globally may see similar results. A meta analysis was conducted to determine the effects of climate change on both flowering plants and animals. This analysis also showed that there was a shift in phenological process that mirrors the expected outcome predicted using prior knowledge of ecological constraints on individual species (Root, Price, Hall, et al. 2003). This information can be used to understand the results of the study done on the 43 species in Massachusetts and the global implications it indicates.

Climate change can create a cascade of effects throughout entire ecosystems. In marine life, communities that rely heavily on biotic and abiotic factors have experienced the effects of rising temperatures in the ocean. Warming of the sea can be detrimental to life in the future, especially for migrants like beluga whales whose habitat is surrounded by seasonally-ice covered waters. This is why researchers have conducted a study spanning over 30 years to collect data and determine if the ever changing sea ice has had an impact on their migrational behavior. From 1974-2014, scientists followed four traditional migratory routes in beluga whales between wintering and summer  areas of the Alaskan and Canadian arctic.

The methods used to monitor the population included genetic data and harvesting data from whale sightings. Tissue samples from a total of 978 whales were collected and DNA was extracted from each sample and screened. Ariel surveys were taken by native hunters and field biologists which determined the annual arrival times during migration. Lastly, ice conditions were examined through passive microwave-derived sea-ice concentration (SIC). Based on the reports, it was revealed that beluga whales migrated to the Chukchi Sea each summer with its peak population in June at Kotzebue Sound, located in the Arctic.

The results from the SIC demonstrated that the varying sea ice conditions, (5.2% in 1997 vs. 83.7% in 2006), did not affect the times that the distinct populations arrived. However, after the year 1983, the occurrence of beluga whales at this location diminished quite dramatically despite two exceptions in 1996 and 2007. Genetic analysis determined that at one point, in 2007, 90% of the whale migrants to Kotzebue sound had been males, thus, suggesting a link between sea ice conditions and migratory behavior which caused them to alter their course. This phenomena also suggests that changes in the ecosystem may affect gender differently. During the years where sea-ice levels were low, orca whales were able to easily maneuver themselves into the Chukchi Sea. This resulted in an increase in predation, which may have been a contributing factor for evasive shifts in beluga migratory patterns.

The data collected from this study indeed proposed a relationship between ice levels and beluga whale migration, though the research may have been flawed. There most definitely are variables that could have skewed the results that was determined. For example, relying on whale sightings alone does not seem to be a strong enough resource for tracking. There should have been another method used to monitor movement: like attaching a gps tracking device to the mammal. In addition to this, it can be difficult to consistently measure sea-ice conditions that vary considerably throughout the year especially if they are due to underlying factors, which may need more research in the future to eliminate these possibilities.

This study was specifically chosen because of its relation to climate change and as an effort to shine some light on future conservation efforts. If the ocean temperature continues to rise and potentially even affect prey availability for beluga whales, it can pose a huge threat for them in the future. Hopefully soon they receive the rightful attention and action will be taken to conserve, and protect this species.

One important difference between allopolyploidy and autopolyploidy is how they come to be. Meaning, an allopolyploid individual is made when two parent individuals come together with a different number of their pairs of chromosomes (one gamete has 3, the other 2) to form a hybrid that cannot produce viable gametes. An autopolyploid individual happens when the chromosomes of the diploid parent individual go through a meiotic error which causes the chromosomes to divide incorrectly, resulting in gametes having a full set of chromosomes as well (2n). Another major difference between allo- and autopolyploidy is the fact that one could have the opportunity to produce viable gametes with another in its species, while the other self-fertilizes. Allopolyploid hybrids can go through a duplication event and ‘accidentally’ double the number of the chromosomes they have, which allows them to produce sexually again, and meiosis can proceed normally.

Allopolyploid individuals cannot reproduce easily with the two species that made it (similar to autopolyploidy) but can mate and produce viable gametes with another of its species, unlike autopolyploidy, where there is just one parent involved. A third important difference between allo- and autopolyploidy is the amount of genetic variation in each. Because there is only one parent involved for autopolyploidization, there is a small amount of genetic variance within the offspring. But, this is not the case for allopolyploidization. Two species can create a large amount of the allopolyploid hybrids, which can then interbreed between each other. This different origins of the hybrid creates more genetic variation, which allows for natural selection to create more fit hybrids as the generations continue. 

Autopolyploidy occurs when there are additional sets of chromosomes in a cell. The chromosomes in the parent individual with 3 sets of homologous chromosomes (2n=6) go through a meiotic error which results in an unreduced gamete with 6 chromosomes (rather than 3) that self fertilize and create a tetraploid zygote. However, the polyploid offspring is unable to reproduce sexually. Normally, the 2n offspring would mate with another 2n offspring. Then the 1n gametes produced combine with the other and produces another 2n offspring in the parent generation. However, what reproductively isolates this example from its diploid parent species is the fact that through the meiotic error, 4n cells in the the adult occurs.

They are then unable to produce fertile offspring with the parent species. When the 3n offspring results, (or any uneven numbered offspring), mitosis would work just fine because the homologous chromosomes don’t have to match up, BUT, meiosis is faltered because the 3n offspring trying to produce gametes through this genetic mechanism will fail because the cell will not be able to divide. The result is impaired meiosis of unpaired chromosomes. This is a postzygotic isolating barrier.