jhussaini's blog

Asking people to take pictures of me in my neighborhood was a learning experience. Although it may not be considered “deviant behavior” in some eyes, it did in fact deviate from the social norm by taking people out of their comfort zone to act in a way they normally wouldn’t. The variety of reactions that I encountered shows that everyone is different. Some groups of people are more reluctant to break the social norm whereas other groups of people are completely unfazed by it. I suppose the right response depends on the situation at hand. In any case, I now realize that it takes a conscious effort to go against the social norm because of the social pressures that come with being seen as a deviant.

The visual system of most deep sea organisms is able to detect short-wave blue wavelengths. Loosejaw dragonfish are able to detect longer wavelengths of light and emit these wavelengths as the color red through bioluminescence. Because red light does not penetrate deep into the ocean, the red visual system allows organisms with the adaptation to communicate with each other specifically, and in addition, it allows predators to catch unsuspecting prey by surprise using bioluminescence. This paper focuses on uncovering the evolutionary history of this phenotype in the family of Stomiidae. The authors sought to understand the timing of the evolution, the number of times the trait evolved, and whether it arose due to positive selection. The findings for the evolution of the red visual system were more complex than expected. The red visual system was found to have evolved once as a single evolutionary event within loosejaws. They found that at approximately 15.4 Ma, far red visual systems evolved and at 11.2 Ma the primitive blue visual system re-appeared in the most recent common ancestor of dragonfish. The authors also investigate the phylogenetic relationships between Stomiidae and found that the relationship between this family and loosejaws is paraphyletic. The significance of this study in the context of spectral tuning in deep sea organisms is that it provides a phylogenetic approach to analyzing the evolution of the red visual system.

The visual system of most deep sea organisms is able to detect short-wave blue wavelengths. Loosejaw dragonfish are able to detect longer wavelengths of light and emit these wavelengths as the color red through bioluminescence. The authors sought to understand the timing of the evolution, the number of times the trait evolved, and whether it arose due to positive selection. The findings for the evolution of the red visual system were more complex than expected. The red visual system was found to have evolved once as a single evolutionary event within loosejaws. They found that at approximately 15.4 Ma, far red visual systems evolved and at 11.2 Ma the primitive blue visual system re-appeared in the most recent common ancestor of dragonfish. The authors also investigate the phylogenetic relationships between Stomiidae and found that the relationship between this family and loosejaws is paraphyletic. The significance of this study in the context of spectral tuning in deep sea organisms is that it provides a phylogenetic approach to analyzing the evolution of the red visual system.

German Shepards should be saved with the vaccine. Like many other breeds, they can be household companions that are known for their loyalty to their owner. Many german shepards love their owners so much that they might have separation anxiety after being away from them. The devotion of german shepards to their owners makes it easy for them to make a valuable, inseparable bond to their owner. For this reason, I think we should choose German Shepherds to save. They possess qualities that make humans feel more loved and less lonely. Not only are German Shepards a man’s best friend, but they also have valuable skills that can be exploited to assist humans. Their vigilance, obedience, and ability to focus makes them a good candidate as service dogs. In addition, they are often used by the police to sniff out drugs or human remains.

The article “Four new DNA letters double life’s alphabet,” describes how synthetic bases are used to form a DNA structure. The ability to generate synthetic DNA that even slightly resembles how biological DNA functions is truly phenomenal. However, from a standpoint that defines life in terms of purpose and function, if the synthetic bases are unable to give rise to the molecules necessary for survival or unable to replicate, then I would consider the DNA as non-living. Even if the DNA looks similar in structure and shares a few of the functions of biological DNA, it would be unable to preserve its identity. This demonstrates my initial point that even if something shares some characteristics with a living thing, that does not make it alive.

The article “Four new DNA letters double life’s alphabet,” describes how synthetic bases are used to form a DNA structure. The ability to generate synthetic DNA that even slightly resembles how biological DNA functions is truly phenomenal. However, from a standpoint that defines life in terms of purpose and function, if the synthetic bases are unable to give rise to the molecules necessary for survival or unable to replicate, then I would consider the DNA as non-living. Even if the DNA looks similar in structure and shares a few of the functions of biological DNA, it would be unable to preserve its identity. This demonstrates my initial point that even if something shares some characteristics with a living thing, that does not make it alive.

The warming climate has a known bleaching effect on coral reefs. This paper highlights the significant effects of the climate on coral bleaching at deep, mesophotic depths. These bleaching results demonstrate the limitation of deep coral reefs as thermal refuges as the climate continues to warm. The study collected data on the temperature and severity of bleaching at different sites along the Great Barrier Reef and the Western Coral. In 2016, a mass bleaching event in this area caused the death of 30% of shallow-water corals. Results showed more severe bleaching for shallow-water corals in relation to deep corals. Although the severity of bleaching was significantly less for deep corals, the impact is still substantial and is predicted to worsen in the future. This result is devastating because bleaching effects are not only harmful to the coral, but also to all of the millions of animals that depend on the reefs for survival. 

This paper focuses on how interstitial annelids evolved to live in interstitial spaces. Three hypotheses on how this evolution occurred include progenesis, miniaturization, and that the interstitial space was originally an ancestral home to Bilateria. Progenesis is the retention of juvenile characteristics in the adult form, and miniaturization is the evolution of a small body size. Progenesis is the commonly accepted hypothesis for interstitial annelid evolution, though it has not been fully explored, which is a reason this study was conducted. The authors of the study applied a phylogenomic approach by generating transcriptome sequencing data. They found relationships and similarities between clades to figure out how different annelids evolved in interstitial spaces. Progenetic evolution was found in Orbiniida, Eunicida, and Hesionidae. Evolution through miniaturization was found in Protodriliformia, Pisionidae, and other interstitial species. One of the conclusions they found was that the simple body organization and interstitial habitat of annelids are not ancestral traits of annelida. This result led them to reject the “Archiannelida” hypothesis. The authors also found that progenesis and miniaturization were equal in terms of significance as factors that caused annelids to evolve in interstitial spaces.

In contrast to snakes, anoles (a type of lizard) possess more limb structures such as the tibia and fibula. The presence of more limb structures is partially due to different expression patterns of the Sonic Hedgehog gene. A team of researchers (led by Leal and Cohn) found that in anole leg buds, expression is more sustained and in pythons’ expression is transient. The ZRS domain in anoles was also found to bind more strongly to transcription factors than the python’s ZRS domain. The differences between enhancer elements for the Sonic Hedgehog gene indicate how the gene was able to evolve over time. Mutations that have lowered enhancer binding could have down-regulated the Sonic Hedgehog pathway, leading to limb reduction in snakes. In many vertebrates from anoles to humans, the amount of limb development shows a direct relationship with the activity of the Sonic Hedgehog enhancer. 

The Hedgehog signaling pathway plays a role in the loss of limbs in snakes. According to the fossil record, ancestral snakes had limbs, which became reduced over the course of evolution. Some species of snakes such as boas and pythons still have a rudimentary femur and claw, while in other species such as cobras, limbs have disappeared completely. This phenotypic difference suggests that limbs were lost over time. The Sonic Hedgehog gene is regulated by a limb-specific enhancer called the zone of polarizing activity regulatory sequence (ZRS). This enhancer is conserved in all invertebrates and accounts for differences in limb development in vertebrates. A team of researchers led by a genomicist named Visel found that by substituting the ZRS of mice with the ZRS of snakes caused truncated limbs. In contrast, substituting mice with human and fish enhancers caused legs to grow normally. Sequence analysis of the ZRS in snakes showed deletions, which resulted in weak expression of Sonic Hedgehog and truncated limbs. The varying degrees of expression of Sonic Hedgehog is a possible cause of limb reduction in snakes.