You are here

afeltrin's blog

Epigenetics

Submitted by afeltrin on Tue, 04/16/2019 - 17:49

In “Trauma Permanently Affecting DNA?,” I found it so intriguing that trauma, regardless of it being short-lived or continual, can permanently alter your DNA. Epigenetic gene expression is different from other kinds of inheritance due to it being solely a change in the phenotype of the gene, not the genotype. So, the underlying gene sequence is not affected; molecules will sit on the DNA and change the way in which RNA is made from DNA. This, in turn, changes the way proteins are made, leading to change in mood, behavior, and stress responses. A common example of an epigenetic change is methylation, which is the addition of a methyl group onto DNA. Other forms of inheritance directly alter the DNA gene sequence, in contrast with epigenetics.

Macroevolutionary Changes Among Crinoids

Submitted by afeltrin on Tue, 04/16/2019 - 16:16

This article aims to search for macroevolutionary consequences from the predation of crinoids. It is hypothesized that sea urchins preyed on crinoids, leading to evolutionary change. The scientists observed Mesozoic skeletons of crinoids in search of bite marks from echinoids. These bite marks would show up as trace fossils remaining on the skeletons long after death. Their results showed that as the Mesozoic period gradually progressed, the occurrence of bite marks on crinoids increased. Additionally, there were more bites present on sessile crinoids than motile crinoids. Their data showcased a strong positive correlation between increasing sea urchin diversity and the frequency of bite marks. Scientists hypothesize a potential arms race between predation pressure and defenses displayed in prey. As predation increases, prey are left to develop stronger defenses for survival. So, it is plausible that crinoids increased defenses involving their motile abilities.

The Impact of the Pyramids of Giza on Egypt’s State Society

Submitted by afeltrin on Tue, 04/16/2019 - 13:11

Ultimately, the four factors that were imperative to Egypt’s success as a state society are the intensified agricultural production, the creation of writing and systems of record-keeping, the rise of monumental architecture, and the organization of hierarchy into discrete social and political classes. The agricultural production soared being near the Mediterranean Sea, leading to labor specialization and, as a result, a more complex state society in Egypt. The introduction of writing and a record-keeping system led to an increase in trading and the ability to track an individual’s hours worked, if they got paid, and if they were scheduled to work or perform labor. The physical building of the pyramid built the social and political hierarchies, with the lower class working on building the pyramid, while the highest class would not actually work on it; they would just be buried inside it. Without these four factors, Egypt would not have flourished as such an important city, and we may not have ever had the formation of the pyramids.

Comparison of Humans to Primates

Submitted by afeltrin on Mon, 04/15/2019 - 21:54

Studying contemporary populations of primates is a good analog for studying ancient hominids and hominins because they are the closest living relative we have. Not an actual ancestor, primates are viewed as our closest living cousins. We are able to study their sociality and behaviors to see how our ancestors might have interacted with one another, how they reared their young, and how they secured food. A big factor that separates us, hominins, from primates is sociality. Their interactions are far different from ours, and that can limit what we are able to apply and the comparison may skew what we already believe.

Deep Sea Vision Summary PP

Submitted by afeltrin on Thu, 04/11/2019 - 10:52

The purpose of this study is to predict the evolutionary history of far-red sensitivity in the Stomiidae family of deep-sea dragonfish. This entailed examining the proteins within rhodopsin. Additionally, the researchers wanted to determine when this evolution occurred and how many times. They achieved this through extracting DNA and performing PCR on each sample. Of the 28 genera, they were able to obtain samples from at least one species from 25 genera. From these procedures, the researchers were able to predict divergence times, identify tuning sites, and attempt to determine why far-red visual systems developed. It was concluded that the far-red sensitivity evolved once within the Stomiidae family, in a singly evolutionary event. The species Photostomious and Eustomias were determined to have evolved far-red visual systems and then eventually re-evolved blue visual systems. Currently, only four species of Stomiidae have sensitivities to far-red wavelengths, giving them advantages concerning predation and communication.

Sea Urchin Errors and Future Work

Submitted by afeltrin on Wed, 04/10/2019 - 20:24

Possible inconsistencies that may have been experienced during this experiment are the lack of equal amounts of eggs in each gathered sample. Though the samples were stirred beforehand, the amount of eggs pipetted out onto a slide have very little chance of being exactly the same. This could have attributed to our results showing that a lower proportion of diesel to seawater somehow garnered more lysed eggs than the higher proportion of diesel to seawater. Possible sources of error are generally due to human error. Perhaps the ratio of diesel to seawater was miscalculated at any point, or the trial samples were mixed up. Future work that may be conducted in relation to this experiment may include testing out different pollutants and their effects on sea urchin larval development and fertilization success.

Adolescents and the Competency to Stand Trial

Submitted by afeltrin on Wed, 04/10/2019 - 17:57

In the famous case of Lionel Tate, there was great controversy regarding whether the twelve-year-old possessed enough competence to stand trial. He was twelve when he was accused of murdering his younger sister, Tiffany. When autopsied, the results showed that six-year-old Tiffany endured more than 35 injuries, including a cracked skull, cracked ribs, brain injuries, and vast internal bleeding. Due to the extent of the crime, they transferred him to an adult court room. Lionel tried to say he accidentally killed her while trying to imitate professional wrestling, popularly deemed the ‘wrestling defense.’ Professionals argued that there was no way it could have been a wrestling accident due to the severity of her injuries. Ultimately, he was convicted of 1st degree murder and was sent to life in jail with no parole. His lawyer then went to the federal appeals court and Lionel ended up getting a new trial because his competency wasn’t evaluated before trial. His new trial offered him a plea bargain for 2nd degree murder and Lionel accepted it.

Sea Urchin Discussion

Submitted by afeltrin on Wed, 04/10/2019 - 12:50

Our hypothesis was determined to be validated. The results displayed the high number of lysed eggs seen in both condition groups, while there were no lysed eggs seen in the control samples. This can be due to the detrimental pollutant negatively impacting their gametes. Like the study previously mentioned, although there is no physical abnormalities displayed in the egg or sperm cells, there are clear repercussions shown once fertilization has initiated. It has been studied that pollutants significantly decrease the success rate of fertilization, as well as increased abnormal larval development (Vashchenko 1980). There should not really be lysed eggs occurring in pure seawater, as that is the most optimal of conditions for eggs and larvae to develop into adults.

Deep Sea Vision Summary

Submitted by afeltrin on Wed, 04/10/2019 - 11:39

The purpose of this discussed study is to predict the evolutionary history of far-red sensitivity in the Stomiidae family. This entailed examining the proteins within rhodopsin. Additionally, the researchers wanted to determine when this evolution occurred and how many times. They achieved this through extracting DNA and performing PCR on each sample. Of the 28 genera, they were able to obtain samples from at least one species from 25 genera. From these procedures, the researchers were able to predict divergence times, identify tuning sites, and attempt to determine why far-red visual systems developed. It was concluded that the far-red sensitivity evolved once within the Stomiidae family, in a singly evolutionary event. The species Photostomious and Eustomias were determined to have evolved far-red visual systems and then eventually re-evolved blue visual systems. Currently, only four species of Stomiidae have sensitivities to far-red wavelengths, giving them advantages concerning predation and communication.

The Arms Race in the Deep Sea

Submitted by afeltrin on Tue, 04/09/2019 - 20:44

In the deep sea, light is unable to penetrate. Most of the organisms living there have the ability to produce bioluminescence. This is essentially advantageous to these organisms due to its ability to attract prey. They are able to deter predators by turning off their bioluminescence and, instead, producing a red pigment. In the ocean, blue light is the only wavelength that can penetrate, so when organisms choose to release red pigment, they essentially look grey to other organisms and are able to camouflage. But now, species of fish are now evolving sensitivities to far-red light, allowing them to visualize prey. There are alterations in their rhodopsins that enhance their low light vision levels, making them a prime predator in the deep sea.

Pages

Subscribe to RSS - afeltrin's blog