Writing in Biology

    Recently on youtube, I was watching some BBC videos featuring David Attenborough. One video that I watched was about beavers. Beavers have a much more sophisticated system of engineering than they are given credit for. In the video, it is shown the tiny stream that they used to turn into a giant pond system that enables them to traverse through their environment and not be attacked by a bear or a mountain lion. They also extend their territory by digging tunnels that lead them to sources of food. For food, the beavers ingest wood from terrestrial plants and also aquatic plants. One interesting behavior they have is how they will bring back wood and keep it in a storage area underwater. Scientists call this their “fridge” and it allows them to be active throughout the winter, instead of having to hibernate. The beavers live in a structure that is built with such strength that it is impenetrable by a bear. During the winter, hot air can be seen flowing out the top of the snow covered lodge, just showing the insulative properties of the lodge.

In the two chemical tests, the product was proven to be cyclohexene based on the results. In the bromine test cyclohexene remained colorless while the cyclohexane became a brownish orange color. In the potassium permanganate test cyclohexene formed a brown precipitate while cyclohexane remained clear on the top with purple color on the bottom. 

During distillation, the temperature at which the first drop was recorded was at 66^oC and plateaued at 70^oC. Although cyclohexene has a boiling point of 83^oC, the decrease in the boiling point could have been to the impurities of the mixture, which was later washed out. Although human error in the placement if the thermometer could have been the reason of the lower temperature recorded. The initial mass was 2.013g with a final mass after distillation was 0.722 g. The percent yield was 35.9%, which was caused by the removal of the alcohol into water. The water was then removed from the cyclohexene via washing. 

In this lab, cyclohexanol was distilled with a phosphoric acid catalyst, giving a 35.9 % yield of cyclohexene. After the GC, the product I produced was in fact cyclohexene. The standard GC graph shows a retention time at 0.205. The GC graph obtained from the cyclohexene product showed a retention time of 0.175, which is not much difference than the standard. The IR analysis showed the results have a major dip between 3200 and 2800 l/cm. The standard IR analysis shows a dip from 3061.03 to 2837.29 l/cm. The results obtained are a clear indicator that the product was cyclohexene. There is a dip at 1635.00 l/cm indicates that there is a double bond in the product. Since there is no presence of a dip between 3400 to 3200, there is no alcohol present in the product. After these two methods of analysis, the results can confirm that the product was indeed cyclohexene.

After the synthesis of cyclohexene, a work-up was done. In a small test tube, add 0.5 mL of cyclohexane. In another small test tube add 0.5 mL of the cyclohexene product produced. Three drops of 3% bromine solution in dichloromethane are added to each test tube, and note any color change. Then in a small test tube add 0.3 mL of cyclohexane, and in another small test tube add 0.3 mL of the cyclohexene product. Then add 1% potassium permanganate and 10% sulfuric acid solution to each test tube. Record any color change and manganese dioxide precipitate formation. Finally, perform a GC/IR analysis of the cyclohexene product.

In the fume hood, turn on the sand bath onto 40. In a small 10 ml round-bottomed flask add about 2 grams of cycloexanol (2.013 g used). Then add to the same flask 85% phosphoric acid (0.5 mL) and boiling chips. Using the distillation setup, distill the reagents into a collection vial at the rate of 20 to 30 seconds per drop. At the first drop write down the temperature ( 66^oC), and stop distillation when there is only 10% of liquid left in the flask. In the collection vial there will be two layers (water and cyclohexene). Using a pipet, the contents of the collection vial are transferred into a test tube. Then add about 1 ml of distilled water into the test tube. After remove the lower aqueous layer via pipet. After, add 1 mL of 1 M sodium hydroxide (NaOH), and again remove the lower aqueous layer. Add 1-2 ml of saturated aqueous sodium chloride, brine, to the test tube. For the third time remove the lower aqueous layer. The organic layer is left in the test tube, transfer the layer into a new vial. After, add CaCl₂ to the new vial until the CaCl₂ does not clump together. The vial should be capped and left to dry for at least five minutes. After the drying process, transfer the product into a new tared vial. The weight of the product was .722 g. Then calculate the percent yield, which was 35.9 %.

Distill cyclohexene and phosphoric acid, work up the collection vial, and analyze the dried product through infrared spectroscopy and gas chromatography. Do a chemical analysis to test for alkenes and then determine the percent yield. 

The methodological approach used was the expression of Channelrhodopsin-2 in mice

neurons that produce dopamine. Channelrhodopsin-2 is a light-sensitive cation channel that responds to light when stimulated. The stimulation by light causes dopamine release from synaptic terminals in the nucleus accumbens and the dorsal striatum. In order to find out whether glutamate will still be released along with dopamine when dopamine is released, VGLUT2 in a mouse was removed. The stimulation was also done on the mouse that lacked the vesicular glutamate transporter known to be needed for releasing glutamate into synaptic terminals. This was to determine whether glutamate would still be released with dopamine even without VGLUT2 and only on dopamine stimulation alone.

Agonistic Behavior: Interactions between 2 individuals are inherently selfish however, their desire to succeed can lead to aggressive or cooperative interactions. Questions concerning the morality and truthfulness of these interactions as well as the presence of “cheating” the system. The behavior between rivals, i.e aggressive (attack or threaten) as well as passive (flee or submit) are known as agonistic behaviors. Conflict typically peaks at threatening gestures due to the risk of injury when fighting. This includes use of wings, bills and claws as potential weapons that will eventually lead to actual battle if one does not give. To avoid higher frequencies of injury, communication of aggressive and submissive behavior is a large part in social structure. This has lead to submissive behavior and an advanced, ranked social structure to mitigate the stress of a social system.  

Territorial Behavior: This is a pattern of aggressive behavior or spacing. A territory is typically a  fixed area that is defended in both breeding and non breeding season, however, a range can gradually shift locations if the resource that is being defended is mobile. To defend this territory, acts of dominance, songs, or aggressive pursuit discourage other from entering or using the space that is being guarded. The primary use of the territory’s resources are the defender, its mate, and occasionally its progeny.

While a simple territory may solely focus on simple food supplies; more all purpose nesting grounds serve to reduce predation and competition for mates as well. Although the benefits are apparent, there are certain costs associated with territoriality as well. Resources must be spatially and temporally viable in order for the territory’s maintenance to be beneficial.. Birds spend a large amount of calories defending their zones and this expenditure linearly increases with territory size. Furthermore, an abundance of resources can attract an overwhelming amount of outsiders that are unable to be driven away.