aprisby's blog

Predators are an important part of a healthy ecosystem. By controlling the size of prey populations, predators help slow down the spread of disease. Predators catch healthy prey when they can, but catching sick or injured animals helps in natural selection and the establishment of healthier prey populations as the fittest animals are left to survive and reproduce. Predators such as the wolves from the Yellowstone were essential for all other life to function together and grow. The presence of the wolves decreased the deer population which in turn allowed more vegetation and forests to grow back and prosper, which ultimately lead to more diversity and stabilized the rivers. Maasailand Preservation Trust (MPT) is an example of one predator compensation programme working in response to the threat of local lion extinction in African plains. It not only aims to prevent lion extinction but also provides coverage for other persecuted species, such as hyena, cheetah, leopard, wild dog and jackal. In areas such as Maasailand these animals are under threat from livestock owners who see them as a danger to their livestock and kill them in trade for livestock losses. From this project, within a decade people who were once killing these predators by the hundreds are now working to protect them and reduce the killing of lions.

Ecology investigates the interactions between organisms and their environment. One branch of ecology looks more specifically how the environment can lead to physiological effects in individuals and populations of species. Physiological ecology studies organisms coping with environmental variation. A particular species cannot live everywhere due to energy resource limitations, physiological tolerance limitations, and interactions between resources and tolerance. These determine effects on growth, survival, and reproduction. For example, Quaking aspen (populus tremuloides) is a broadly tolerant species with northern range limits including frost effects (permafrost) and a southern range limit of drought effects. Specific physiological functions are inhibited by drought and frost. Species ranges reflect environmental constraints on energy gain and physiological tolerance. Populations respond to environmental variation through adaptation (natural selection). Populations differ across a species range. Genetic variation allows for many traits, an when new conditions occur, certain mutations may be beneficial for that species. Individuals respond to environmental variation through acclimation. They adjust their phenotype to reduce effects of environmental change.

After reading the chapters in Writing in Biological Sciences by Angelika Hofmann as well as The One Right Way to Talk Science by Jay Lemke, I learned and was surprised by a few things. I found it interesting in the reading by Lemke that he seemed to oppose the use of formality in scientific writing, or rather, encouraged the fact that science is a very “human” activity. Lemke lists even the ways that scientific writing can be too correct and too serious, which ultimately drives the attention of the reader away. He says that “these rules are a recipe for dull, alienating language. They mainly serve to create a strong contrast between the language of human experience and the language of science” (Lemke 134). I found this quote to be particular interesting because from I have always been taught in school about scientific writing, it should be as formal and serious and complexly worded as possible. However even I feel at times, even reading the scientific review article (from this week’s readings), Describing and quantifying interspecific interactions: a commentary on recent approaches by Peter A Abrams, that it fit this serious and “alienated” language description exactly as Lemke describes in his chapter. I felt that the constant use of complex wording actually made it harder to follow (without having to re-read a few times) in certain paragraphs because it was so serious. Another point I learned came from Hofmann, where she provides the difference between a scientific research paper and a lab report. Previously I had considered them to be found within the same category because they both include introduction, methods, results, and conclusion sections, however there is a difference. Both are based upon original sources of data, however lab reports focus on one particular study while research papers investigate a whole “family” of related experiments performed perhaps over a period of time. As she continues her description of lab report tips, I liked how Hofmann gives samples of good and bad types of titles (even a title page), tables, abstracts, and provides structure formats for introductions and the big picture.

Tetrahymena is a genus of free-living ciliates, a freshwater organism that can inhabit lakes, streams, and ponds and can be found almost everywhere and in a variety of climates. Their main food source is bacteria. Tetrahymena feed by the process of phagocytosis, where is the engulfing of other cells or particles. The membrane of a phagocyte surrounds a cell to be engulfed and then pinches off to create a phagosome inside of itself that contains the engulfed material. The resulting phagosome may be merged with lysosomes to form a phagolysosome for the digestion and release of nutrients for use in other metabolic processes (Phagocytosis Process). Phagocytosis can be quantitated by counting the number of vacuoles that form in a defined time period. Tetrahymena were selected in this experiment to study food vacuole appearance. This was done by taking five samples of cells as follows: one immediately when the India ink was added, one at ten minutes, one at twenty minutes, one at thirty minutes, and one at forty minutes. Samples were taken in small test tubes, and inside a mixture of 100 µL sample of the Tetrahymena and India Ink (which was used to be able to visually observe number of vacuoles formed) and 20 µL of dilute glutaraldehyde to fix the cells was added at each interval of time. After all of the samples were taken, they were studied under a microscope at the 10X objective. The number of marked vacuoles formed for ten different Tetrahymena cells were recorded for each of the time intervals, then graphed using a line graph.

Tetrahymena is a genus of free-living ciliates, a freshwater organism that can inhabit lakes, streams, and ponds and can be found almost everywhere and in a variety of climates and their main food source is bacteria. Tetrahymena were selected in this experiment to study food vacuole appearance. This was done by taking 5 samples of cells: one immediately when the India ink was added, 10, 20, 30, and one at 40 minutes. Samples were taken in small test tubes, and inside a mixture of 100 µL sample of the Tetrahymena and India Ink and 20 µL of dilute glutaraldehyde to fix the cells was added at each interval of time. After all of the samples were taken, they were studied under a microscope at the 10X objective, then the number of marked vacuoles formed for ten different cells were recorded for each of the time intervals, then graphed. Tetrahymena feed by the process of phagocytosis, where is the engulfing of other cells or particles. Phagocytosis can be quantitated by counting the number of vacuoles that form in a defined time period.

Jaguar population continues to decline and suffer as a direct result of human impact. As seen in several instances, the removal of just one species can cause the entire ecosystem to change rapidly or deplete within years. Jaguars are the top predators in their environment, so they play an important role in controlling the populations of other species. This helps keep a balance in the food chain, and a healthy environment. Since their forest homes have continued to be destroyed, jaguar populations now occupy only a small fraction of their original territory, and are so exclusive that we cannot even determine how many are left in the wild. As the cause for this issue, it is our job that we protect and conserve designated habitat patches and corridors so that jaguars may be allowed space and ability to survive and grow. Providing protection for the connectivity between different landscapes will allow the jaguars to be able to expand their population gene pool, which will then in turn create a healthier, more stable population. The corridors would also allow for jaguars to move unnoticed amongst human development while maintaining the ability to migrate and create their own territory.

Based on these two articles I noticed a difference in tone; they both were written formally however the review article used more complex language and a persuasive tone, while the research article used a more factual tone. The review article analyzes research already done in primary sources, while the research article is itself a primary source of original research. The review article referred to many more external sources, while the research article referred mostly to its own sources. In text citations for both were cited in parentheses with the author and date of publication stated. For the research article citations only seemed to be used in the introductory and methods sections. The review article used citations in the form of paraphrasing of references to other scientific articles and were used to further support their argument with real facts provided from primary sources. What I learned was the difference between the two types: before I had heard and written a scientific research type article before in labs, however I had never even heard of a review article. It was also interesting to see how each varies as far as formatting and how they use in text citations professionally. What surprised me was how formal the review article was because I had expected that one to be the more simplified, easier read considering it is most likely geared for a broader audience than the research article would be.  

In ecology I am interested in a deeper perspective into the different levels of ecology. I would like to further investigate individual organisms, populations, communities, ecosystems, and biospheres and the relationships between each one. Ecology focuses on the relationships between organisms and their environments, so I look forward to studying topics such as mutualism, commensalism, parasitism, as well as looking at a single organism’s role within its environment. Similarly, I want to investigate further predation and competition between organisms and how these affect their niches within the ecosystem. Within the topic of populations, I believe it would be interesting to see how populations change and adapt overtime and how they are able to respond to different environmental pressures. It would also be interesting to look at how different types of ecosystems function systematically, and their abiotic and biotic factors, as well as specifically how humans have impacted these ecosystems. In a more broad spectrum, I am interested in the many levels of ecology because in order to reduce the problems the earth faces as a direct result of humans, we need to better understand the relationship between our ecosystems and the impact that certain human actions (deforestation, species endangerment, pollution, etc) have in causing our ecosystems to decline rapidly today.

Birds have evolved to come in a variety of shapes and sizes that allow them to exploit niches in different ecosystems. Certain species may have developed different shaped wings for faster flight or sharper talons with a locking mechanism that allows them to firmly grasp their prey as they soar through the air. However birds have also adapted different visual abilities and color schemes that allow for more birds to exist within an ecosystem. Field marks are distinctive spots, colors, shapes, patterns birds have developed in a variety of forms. It is believed that they developed these in order to identify different species from one another, and recognize members of their own species. They are also used today as a means for humans to identify birds of different species. They can be found on the head in the form of an eyebrow stripe (striper over the eye), eyeline (line through the eye), a crown stripe (stripe along the midline of the head), an eyering (ring of color around the eye), and a throat patch. Field marks can also be identified on the wings of a bird through the various feather patterns, as well as in the shapes of wings (long and slender, rounded and short). Field marks then allow us to be certain of identification.

Observations of the Spike-Worm

As the object was placed upon the desk for observation, initially the object has a worm, caterpillar-like resemblance. It is alive and attempts to escape its slippery, plastic chamber by carefully crawling its way around the outer ring of the clear plastic cup, keeping to the very edges. It’s solid body is segmented into several sections (twelve approximately), and is a faint brown in color. On the anterior end of the organism. the head appears more rigid and is darker than the rest of the body. There also appear to be several black spots as well as black hair-like structures along the side of the body. The body is materialized into a diamond-like shape, laterally symmetrical. The organism has several legs; the anterior legs are pointed in shape while the posterior legs flatter, stubbier, and have the appearance of suction cups. Perhaps this is to better grip surfaces for climbing branches or leaves in its natural environment. On the opposing hand, its worm-like appearance may also suggest that it burrows underground.    

Upon closer observation of the behavior of the organism, the body moves very fluidly, each of the segments moving in a wave-like fashion to propel itself forward, as well as if it needs to move backwards. The anterior side continues to rear up on its hind legs, perhaps to gain a better glimpse of its surroundings. Similarly, it has large eyes in the front of the head, which most likely suggest it uses its visual sense primarily. Judging by its body movements, the organism does not move quickly, meaning it must serve as easy prey for predators. The organism also has field markings on the posterior side of its head, as to ward off predators. The body does not respond to stimuli well. The anterior head and posterior segment of the organism appear to move independently of one another. It only moves along the outer ring of the cup.