The Battle for Stripes

Zebras, horses, and donkeys are all closely related, yet zebras are the only one within the species to have stripes; the only African mammal in the region with stripes, too. These species inhabit a wide variety of different niches such as, grasslands, savannas, woodlands, thorny scrublands, mountains, and costal hills. Until recently, limited information was available on the subject, but many hypothesis have been deduced over the years. These theories include, the stripes evolving as a form of camouflage, disrupting predatory attack by visually confusing carnivores, a mechanism of heat management, a social function, and evolving as a defense against ectoparasite attacks, such as biting flies.

Published on April 1^st 2014 2014, in the online journal, Nature Communications, by the University of California- Davis, a new study finds that biting flies, like horseflies (tabanid) and tsetse (glossinid) flies, are a significant influence in the evolution of stripes. A team of researchers mapped and compared geographic distributions for seven different species of horses, zebras, donkeys, and other subspecies measuring different variables such as, the thickness, locations, intensity of their stripes on several parts of their bodies, ranges of large predators, temperature, and the geographic distribution of the biting flies. The researchers found that in areas where zebras had greater stripe density, they also suffered from a greater annoyance of bug biting. Lead author Tim Caro, a UC Davis professor of wildlife biology said, "Again and again, there was greater striping on areas of the body in those parts of the world where there was more annoyance from biting flies." Previous experimentation determined that these species of flies avoid black-and-white stripe patterns. Together, both sets of data suggest that overlapping areas with higher bug density influenced zebras to have greater striping patterns, as a defense. Zebras have shorter hair than most mammals in their region, making them more susceptible to the biting bugs. This study provides logical insight into the evolution of stripes on zebra as a defense against biting bugs.


Evolution is influenced by a magnitude of factors and changing even one can result in major phenotypic or genotypic changes. This is a beautiful example of species interacting, showing how a battle between two species can result in an observable pattern we can study. It cannot be taken as definitive proof as to why stripes evolved, but it suggest that in terms of their geographical distribution a coevolutionary arms race between biting flies and zebra striping has a strong correlation. I believe these other theories hold great value and its possible they all played a major role in the evolution of stripes. However, some factors have a greater influence then others, but as to which is the greater force, is still unknown. 

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Maxwell Liner (B)

A New Perspective to View Alzheimer's

Dr. Alois Alzheimer first described Alzheimer’s disease as a peculiar disease related to memory loss and shrinkage of nerves cells in 1906. Alzheimer’s disease has been recognized for over a century. Yet, cure for this neurodegenerative disease is still waiting for being developed. Since the brain is a very complicated organ, scientists could not study this disease profoundly until the electronic microscope became a common research apparatus after World War II.

Due to the increasing number of Alzheimer’s disease patients were diagnosed, the awareness of Alzheimer’s disease has also been increasing in the United States. Studies and research about Alzheimer’s disease had been going on since then. In 1980s, discoveries of two important proteins were identified as key components of Alzheimer’s disease. Beta-amyloid protein is believed to be the main protein causes plaque formation in Alzheimer’s brains and triggers damage to neurons. And tau protein causes formation of tangles, which degenerates normal neurons into copies of them. However, the first pharmaceutical treatment was not developed until 1993 and it only slows down disease’s symptoms. Fortunately, in 1996, scientists successfully advanced an Alzheimer vaccine in mice. When injecting transgenic mice with beta-amyloid protein, mice show that the vaccine prevents the mice from plague formation.

Diagnosis of Alzheimer’s disease is a lot easier comparing to determine the causes of the disease. Because of the symptom is memory loss, but have trouble with memory loss does not necessary mean that it is because of Alzheimer’s. Depression or drug abuses can both lead to memory loss. Therefore, we need a new mean to study this disease more in depth.
According to ScienceDaily, researchers at Lancaster University had invented a new imaging tool—Ultrasonic Force Microscopy (UFM), which uses a vibrating scanner to show a better quality and high contrast nanometer scale resolution image. This apparatus is better than electronic microscopy, which can only gives the resolution but not the contrast, and optical microscopy, which does not provide enough resolution. With the use of UFM, scientists now can review the causes of Alzheimer’s disease with contrast on a nanometer scale.  Hoping in a few years, scientists can develop the Alzheimer’s vaccine for human use with the help of UFM.

Posted by Yim Hui

Tailor made beer – thanks to science!

We can all rest easy; the future of the beer industry is in good hands. Many of the beers you drink are given their distinctive flavors thanks to the yeast used in fermentation. However up until recently it was impossible for beer brands to maintain perfectly consistent flavor because their yeast would gradually be altered over time. Even reproducing the yeast from the same colony would eventually lead to changes in its genetic makeup as random mutations occurred. Thanks to a team of geneticists from Johns Hopkins University brewers (and brew drinkers) may no longer need to fear the loss of their favorite flavors.

An article in Popular Mechanics explains that a team of scientists led by Jef Boeke are creating the first synthetic yeast chromosome. While it has been possible to make alterations and splice in specific genes to yeast’s genetic code this is the first time that scientists have completed the insertion of a full chromosome for this organism. Their eventual goal is to synthesize an entire genome for the yeast, introducing new segments in an eleven-part process. Given that yeast’s genetic code is made up of approximately 11 million base pairs, this is no small undertaking. What makes this so exciting is the ability to alter and modify the code as they go. The researchers have cut out portions of the basic genetic code they believe to be unnecessary, allowing them to lessen the total number of nucleotides they need to insert. This sort of specificity will allow researchers to tailor organisms to their personal needs in the future.

In the case of beer not only does it mean that the flavor should remain true for years to come, but it also leads to exciting new opportunities for changing the flavor of traditional brews. Your next Hefeweizen might just have been genetically altered to give you that clove and banana smell you’ve come to know and love.

Posted by: Kirk MacKinnon (8)

A Different Form of Medicine

         Thinking about a number of disorders and diseases, the common mode of treatment is medication or drugs prescribed by a physician. What about when the disorder involves social challenges or communication difficulties, which are not always able to be treated most effectively with medication? Autism and autism spectrum disorders are characterized by difficulties in social interaction, with severity and symptoms varying immensely between affected people. Typical treatment has a focus on modification and improvement of behavior and more recently, therapies involving animals have been incorporated including equine therapy.

         Equine therapy has shown to have promising results, especially for those with disorders such as autism. Children learn to ride and interact with the horses in a number of ways. While riding, the rocking, rhythmic motion increases the focus on the movement leading to relaxation. Physically, riding develops motor skills and the bonding with the horse can influence self esteem and confidence which may carry over outside of therapy. Tasks such as grooming the horse, and interacting with the instructor both stimulate the senses and can help the child open up, improving verbal communication with the people around them. 

         A recently conducted study involving the effects of equine assisted therapy on autism spectrum disorders showed a clear improvement in autism spectrum symptoms using equine therapy, the effect increasing as the number of lessons increased. The study found that those with the most severe autistic symptoms benefited the least amount as a result of these patients being harder to reach and communicate with. The largest therapeutic effects were seen for sociability and sensory/cognitive awareness, with 1/3 of the patient’s improvement being clinically significant after the 12 week program. 

         With such positive results associated with equine and other animal related therapies on autism and related disorders, hopefully we will see an increase in their prevalence in treatment plans in the future.

Posted by: Morgan Matuszko (8)

Can the Ocean Really Run Out of Fish?

Ever since humans have fished the oceans we have considered the ocean's resources as infinite as the ocean seems to be. For quite some time, this was the case for the most part. Even the largest fishing fleets couldn't seem to make much of a dent in the stocks of any fish, shellfish, etc. Once industrialization began however, the story changed. The technological advancements of industrialization and the accompanying population boom generated both the demand and capability to drastically increase fishing efforts.
The early stages of overfishing are generally only measured by the gradual decrease in the average size of fish. As more and more are taken the average age that a fish lives to gets lower, meaning less time to grow and develop. If this continues for too long the number of reproductive age individuals will be so low that they can not efficiently find each other. This results in a "Population Collapse", as most mathematical estimations of population growth break down due to the inability of the remaining individuals to even reproduce. The population is not extinct at this point, but it often takes years of active rehabilitation before it returns to healthy levels.
This has happened multiple times within the last 50 years, and the unfortunate trend is to ignore the problem until it actually happens. The North Atlantic Cod fishery collapsed in 1992, several deep sea fish stocks, and even the Oyster fisheries near New York have all experienced collapse with some never recovering. Pressure for fishery regulation reform is always met with intense opposition from fishermen and corporations who would likely not be able to make a living under safe quotas, and refuse to accept the risk of collapse.

Recent activism has started to pay off in terms of smart conservation efforts. Since 2010 the Japanese government had been allowing more than 10,000 whales be taken per year for "Scientific Research". Recently a U.N. court ruled that Japan's "Scientific" whaling practices were illegal and ordered the Japanese Government to immediately halt all such operations. Unfortunately a lot of the world's fishing practices are unsustainable and still unregulated. Fishing that happens in international waters, such as tuna fishing, is one of the biggest concerns. If we don't move to further regulate the harvesting of marine resources we may soon not have anything to harvest at all.

-Stephen O'Brien

Wrongly Striped

In the world of biology, much is done to study and understand many different traits species possess all around the Earth. Traits are a very important part of evolutionary biology since they help us understand how traits help species respond to their environment thus allowing them to pass on those traits to subsequent generations. Most biologists focus on phenotypic traits which are observable traits that are expressed by a gene. For example, a phenotypic trait is the long neck of a giraffe, helping it reach up high for fruits. But not all traits are what they seem; a trait might not be helping in a way one would think. This brings us to the topic I present today, the stripes of a zebra.

Zebras are part of the Equide family, or more commonly known as the horse family. Their distinguishable trait is the fact that they have black and white stripes. Any biologist worth their salt would want to find out why, and the most popular theory put out was that it is for camouflage, but a Discovery News article called “Zebra Stripes Not for Camo, But They Do Something Else” brings to light that maybe that isn't the case. Citing a newly published research in Nature Communications, it gives the evidence that biting fly ranges and zebra ranges overlap and that the zebra are sensitive to the flies. The research claims that the stripes are not used for camo, but instead a sort of bug repellent to prevent these flies from biting the zebras. The average zebra hair is shorter than the mouth parts of the flies so it makes them extremely prone to biting. So what makes the stripes effective against this? Well, flies tend use a number of senses to help land on targets such as temperature, odor and movement, but the most important sense is vision. The stripes of the zebras help to throw off the vision of the flies. In the research, the researchers actually found that in areas of high fly density the zebras exhibited more stripes.

With this new found study the Discovery News article mentions that it will also help us understand why other animals have stripes when they don't actually seem to need them for camouflage. In the human aspect, can striped shirts possible help us avoid fly bites? Time and further research will tell.

Posted by Jacob Geier (Week 8-B)

The Black Death

           

           During the 14^th and 15^th centuries the Black Death killed more than 75 million people

throughout Asia and Europe. The vast spread of the Black Death was caused by a highly contagious strain carried by fleas and rats. However this week in London, Archeologists have found evidence that suggests a different reason for the quickness of its transmission, airborne infection.

            Last year, twenty-five skeletons were dug up from a burial ground in the Clerkenwell London area. After examining the teeth of each skeleton, forensic specialists found Yersinia Pestis, the DNA of the black plague. When scientists compared this strain to one that had recently killed sixty people

in Madagascar, they found that the 14^th century strain was no more virulent than today’s strain. In better terms, the DNA from the skeleton strains was almost an exact match to those strains in Madagascar. It is likely that all twenty-five skeletons who were exposed to the Black Death, died from it.

            According to scientists at Public Health England in Porton Down, the only way for the plague to have spread so quickly and over such a large range was for it to have gotten into the victim’s lungs. By being transmitted through coughs and sneezes rather than rats, the Black Death would actually be a pneumonic plague rather than a bubonic plague. The rate of transmission from household was so fast, that there is now way a rat or flea could be result in the high number of plague cases.

            With the help of modern day antibiotics, scientists can prevent the disease from becoming pneumonic. However, those who do not have access to these medications can still die from the disease.

Posted by: Lindsey Janof (8)