Climate Change

Submitted by bthoole on Fri, 11/16/2018 - 09:03

Years of industrialization and little to no regulation on what can be emitted into the atmosphere has led to a changing climate which will only grow worse with time. The current shared opinion among scientists is that humans need to limit the rise in temperature to only two degrees Celsius above preindustrial levels in order to avoid a point where the increase in temperature reaches a point where it would no longer be able to be controlled or averted. Currently, climate change is occurring because of the presence of “greenhouse” gases in the atmosphere, mostly methane and carbon dioxide. These gases act as a blanket of sorts for the earth and trap incoming radiation from the sun, thus heating the planet. This process drives other factors that then contribute to the increased temperatures as well. With the increase in temperature, glaciers and other land bound ice are melting and raising sea levels. This affects global temperature in two ways. The first is that the ice normally serves as a source of albedo that stops the sunlight from being absorbed by the darker colored earth and reflects it back into the atmosphere. The second is that as sea levels rise, it provides more water to absorb heat, again raising temperatures. These are just two examples of how climate change has the potential to reach a tipping point that, if reached, will not be able to be stopped.

Esterification Conclusion

Submitted by bthoole on Fri, 11/16/2018 - 09:02

A one to one mixture of alcohol and carboxylic acid will usually yield an equilibrium mixture that is about 70% ester. The experiment carried out did not use a one to one ratio and instead used 13 mmol of carboxylic acid to 11 mmol of alcohol. This was in an attempt to react all the alcohol and not limit it, but the reaction of 1-propanol and propionic acid produced a percent yield of 19.81%. The final product of ester after the drying work up was 0.253 g when the theoretical put the grams of 1-propyl propionate ester at 1.255 g. The final percent yield may be the result of an incomplete separation during the reflux between the water and organic layers. The reflux filled the side arm quickly and required the top layer to be dumped back into the round-bottom flask multiple times during the 15 min heating period. A higher ester yield may have been possible if the separation occurred at a slower rate so that the side arm did not fill so quickly, or if the side arm were larger. If the side arm were larger, it would allow for more catchment and a more defined layer to distinguish the organic from the water. The better distinction would also allow for only the organic layer to be removed after the 15 min reflux. Given that the reflux did not completely separate the organic product from the water, some of the ester may have been removed as the aqueous layer during the work up which would have lowered the final volume and therefore the percent yield. Still, the IR analysis confirmed the existence of an ester based on the peaks seen, so the esterification reaction between 1-propanol and propionic acid was successful in producing 1-propyl propionate.

Avian gonads

Submitted by jmalloldiaz on Fri, 11/16/2018 - 08:52

Gonad enlargement and ovarian development are driven by proximate factors, which are the external conditions that actually induce reproduction. Temperature is probably the most important modifier of annual gonadal cycles. Other factors such as habitat, vegetation, abundance of resources, or social stimulation help consummate the final stages of gonad enlargement and ovarian development.

New Caledonian Crows

Submitted by jmalloldiaz on Fri, 11/16/2018 - 08:33

New Caledonian Crows craft tools for probing and prying food. They make a variety of hooked tools by first selecting the raw material, then trimming it, and finally sculpting it into a hook. They also craft a second kind of tool from the leaves of a screw pipe by alternating angled cuts with horizontal rips to create a serrated edge. They use the tools for extracting insect prey from crevices.

Zugunruhe

Submitted by jmalloldiaz on Fri, 11/16/2018 - 08:30

Zugunruhe or migratory restlessness is determined by the circadian clock in response to the annual cycle. In a study of the orientation of Zugunruhe in Common Starlings, the birds were placed in cages in a room where they could see the sun, including its change of position as the day progressed. As long as they could see the sun, they focused their attention towards the northeast, the correct direction for spring migration. On overcast days, however, the starlings showed no directional tendency.

Intro

Submitted by jmalloldiaz on Fri, 11/16/2018 - 08:28

Following up on my work on sensory priming during the past semester and this summer, I will continue running arena trials with a new generation of P. princeps in order to study the behavioral responses of jumping spiders towards visual and acoustic stimuli. My experiments consisted of introducing a jumping spider in an arena so that it walked into a viewing chamber were pictures suddenly appeared in an iPod screen. The pictures were of a wasp (a potential predator), a cricket (a preferred prey), and a beetle (a neutral stimulus). Each spider was shown one image per trial and during the sound trials a speaker played a wasp buzzing sound for 5 seconds every 2 minutes.  Since the trials were run between the end of the Spring semester and this summer, it is possible that the effect of age influenced the spider’s response towards the stimuli, because jumping spiders are very visual and still they showed little response towards the pictures.

Gravity essay Intro -PP

Submitted by eehardy on Thu, 11/15/2018 - 23:58

 

You certainly do not have to be a physicist to know of gravity. Gravity is not some obscure concept mentioned only in the lingo of die-hard astronomy fans, like a “quasar" or a "red giant." Gravity is a concept known by toddlers and astrophysicists alike. From a young age, we learn that when we throw a ball up, it must come back down. We learn that if we slip on the monkey bars, gravity will bring us hurtling toward the ground. And sadly, we learn that we cannot fly. These lessons are all thanks to gravity.  But while anyone and everyone recognizes that gravity exists, it is likely that far fewer people have pondered where gravity comes from. Few have likely asked themselves, “what really IS gravity?" That is where physicists come into play, and the answer is not quite as simple as the concept itself. 

Gravity essay

Submitted by eehardy on Thu, 11/15/2018 - 23:16

One of the most prominent great thinkers of Ancient Greece, philosopher Aristotle, took a stab at theorizing the nature of gravity in the 4th century B.C. Aristotle believed that different elements gravitated toward different sources based on their own internal nature, rather than an external compelling force. The consensus at that time was that the earth was the center of the universe, supported by the complex diagrams constructed by the Roman Ptolemy which could be used to predict the motion of the visible planets. Thus, Aristotle believed that heavy elements were trying to seek their "correct" place at the center of the universe (the center of the earth).  For this reason rocks would fall to the ground, but lighter elements like steam would rise to their own natural and "correct" place in the sky. This led Aristotle to the conclusion that heavier elements fall faster.

What is gravity? Intro Draft

Submitted by eehardy on Thu, 11/15/2018 - 23:12

You certainly do not have to be a physicist to know of gravity. Gravity is not some obscure concept mentioned only in the lingo of die-hard astronomy fans, like a quasar or a red giant. Gravity is a concept known by toddlers and astrophysicists alike. From a young age, we learn that when we throw a ball up, it must come back down. We learn that if we slip on the money bars, gravity will bring us hurtling toward the ground. And sadly, we learn that we cannot fly. These lessons are all thanks to gravity. And it doesn’t stop there. We all feel gravity constantly, pulling us to the ground when we are sitting, standing, running, skipping, and jumping. John Mayer even wrote a song about it. We all know of gravity’s existence just like we all know the sky is blue. But while anyone and everyone can recognize that gravity exists, not many people have probably sat down and really asked themselves, from what source does gravity originate? What really IS gravity? And that is where physicists come into play, and the answer is not quite as simple as the concept itself. 

Gobiifromes

Submitted by mtracy on Thu, 11/15/2018 - 22:21

Gobiiformes is an order of fish containing about 210 genera and 1700 species. Gobies are marine fish which occasionally wander into adjacent freshwater areas. Their pelvic and medial fins unite and form a sucker, which they may use to adhere to objects such as plants and rocks. Some sand dwelling gobies have a symbiotic relationship with shrimp. The shrimp will dig a burrow in the soft sand substrate in which the two organisms live. The goby will then alert the shrimp to danger and they will both burrow deeper. There are also reef dwelling gobies. Some species of reef dwelling gobies exhibit a bidirectional sex change. Generally these go from female to male (protogynus), though under lab conditions the opposite direction has been induced by removing the female. When this occurs the largest male will become a female. If two males are ever placed in the same area, one will change to form a matching pair of male and female. Of course this may only work in lab conditions as in the wild, the gobies will likely simply migrate to a new area.

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