Writing in Biology - Section 1

I pulled a strange leaf out of my salad today. The leaf has lost its stiff, crunchy texture became soft, wilted. This altered appearance makes the leaf hard to identify. In this brand of salad, iceberg lettuce is traditionally used. Iceberg lettuce has the appearance of an even light green color with some mild discoloration around the edges of the leaf. The stem of an iceberg lettuce leaf is also quite large and stiff. The leaf specimen I extracted from the salad has a thin, light green stem. The whole leaf is also discolored so that it is a mixture of dark purple and green. The dressing seems to be obstructing important characteristics about the leaf that could have led to an easier identification. From the stem to the opposite end of leaf it appears to be approximately 3 inches long. Again this seems like a strange length for a piece of iceberg lettuce. Perhaps this leaf was trimmed or it has no relation to iceberg lettuce and is instead a smaller leaf.

Stem cells are incredibly fascinating to look at. They possess the ability to turn into absolutely any cell in the body, performing any function. In a recent study done in Kyoto Univeristy, they were able to obtain a ball of pluripotent stem cells and place in a petri dish with liquid that was similar to the environment that a brain cells can grow in. They were able to grow the cerebral part of the brain and use it to assess the brain structures and measure activity in the neurons that were present. However, Yi Zhou from Florida State University said that the research had a long way to go since it only represented a part of the brain and not the whole organoid, and you could only measure the activity in certain neurons indirectly with calcium ion activity. 

I am extremely against unnecessary screening for illness and disease in medicine. In OBGYN offices, it is common practice to begin screening for cervical cancer at the age of 21 once every three years. That means that if a woman reaches the average age of death in America, 81, that is 20 pap smears. Twenty internal investigations into her body and twenty horribly awkward experiences. I recently dived into research regarding the new debate that is arguing pap tests are over performed for their aid in medical treatment. It was found that although in general cervical cancer deaths dropped when pap smears became regularly checked, when case studies of pap smear discovered cervical cancer was looked into, their benefits seemed much less evident. One case in particular involved a woman being diagnosed with stage three cervical cancer after every previous pap result had been cleared negative and she died shortly later. When the family investigated the fault of her death, it was shown that the two or three pap tests prior to the first diagnosis of cancer were both identified as positive for cervical cancer. It wasn't that the results were not properly reported to the patient, it was that the analyst had cleared the images with little attention or care. If this cancer is so dangerous and probable in occurring that it is screened for your whole life after the age of 20, why were the outcomes not treated with that same importance and weight? The answer is allusive, but the problem remains that these tests are rendered useless when the results are quantified appropriately, and it begs the question if the invasiveness is worth the time. A similar yet different argument exists for me and x-rays. I understand that x-rays are extremely usefull in identifying issues in bone structure and teeth that can help solve and treat unknown problems for many patients. I however found myself in the dentist chair and the assistant requested x-rays with the reasoning for performing the x-ray being "Your insurance allows us to every year". I made clear I had no pain in my jaw and did not experience any discomfort that might lead to the suggestion of a cavity, and yet it was requested to be done. Here. the basis of treatment relied on what the insurance was willing to pay for, and the dentist wanted to reach the maximum amount of profit from my dental plan. This was completely besides that fact that x-rays can cause DNA damage and radiation leading to cancer and death. I might sound dramatic for saying a dentist looking at my molars could kill me, but the possibility exists. And yet the safety and wishes of the patient were thrown out the window for profit. I of course refused and the assistant handed me a brochure about x-rays to "help educate" me. No, you are not getting my money to spam the oral cavity next to my brain with DNA damaging rays. 

One of the easiest things to grow in your garden are potatoes. Potatoes grow best in full sun in lightly loose well drained soil. They prefer a pH of about 5-7. Once you find a location, you simply pick the type of potato you would like to grow and leave them out in the sun for a few days. Since planting is generally done in the spring you should not have to worry about overheating your potatoes. After being exposed to the light they should start sprouting. You then make trenches in rows about 6-8” deep. You can cut the potatoes in half and lay them in the trench about 12-15” apart. It is best to only cover the potatoes with about 4” of soil at first to allow them to grow and establish, then as they grow fill in more soil until eventually you have a mound over the potatoes. This will generally happen over the course of a week or more. In most cases, if you just plant the potato halves and just mound them over, they will still grow. You should keep your potatoes well-watered, usually about 1-2 inches of watering a week. The foliage should grow and flower, then in the fall the leaves will start to yellow. Once they start to yellow, discontinue watering. The potatoes can be harvested about 2 weeks after the leaves yellow and die back. To harvest the potatoes, you can use a shovel, pitchfork, etc to dig them up. Be careful not to damage the potatoes when digging.

Today in my genetics class, the professor allowed us to work on practice problems similar to the ones that will be on the exam on Thursday. The topics on the exam include Mendelian genetics, determing chi-square and P values, and finding the probability the offspring or specific offspring will have a specific phenotype. I worked with my friend on the problems today and I have a very good understanding of the material so I should do well. I have been studying this past weekend and today. I also plan on studying up until the exam on Thursday, while having to do other assignments due Tuesday and Wednesday. This exam will be my first of the semester.

Homeostasis is one of those important phenomena that everyone takes for granted. It ensures that several of the conditions in our body are strictly regulated without us realizing. One of the prime examples is the regulation of our body temperature. When our internal temperature rises above the normal, our blood vessels undergo vasodilation, where they dilate so that the blood flows closer to the skin surface. This allows heat from the blood to escape through the skin. Another way to reduce the heat is through sweating. The sweat glands produce sweat, which reaches the surface of the skin and evaporates, taking the latent heat with it. Conversely, a drop in our body temperature causes our blood vessels to undergo vasoconstriction, which is the narrowing of the blood vessels to keep the blood from losing its heat. We also shiver, which generates heat in our body. 

Biome 2

    From the temperature - precipitation data collected by the probe in location 2, I believe the biome to be a temperate shrubland. The average annual temperature is 14.4 °C (even though the line is plotted entirely between 16 °C - 18 °C) and the total annual precipitation is 51.8 cm. Throughout the course of 1 year, the temperature stays steady while the precipitation changes seasonally. The dry seasons are short, span the end-of-March to June and mid-April to the end-of-September, and cause droughts in both occasions. On earth, temperate shrublands, such as Gerona, Spain, tend to have a ~15 °C range of temperatures with one dry season during the summer months. Although there is no temperature variation and two dry seasons this biome still matches a temperate shrubland. One such example on earth is Gerona, Spain. The average yearly temperature is 16.7 °C and the average rainfall is 74.7cm. Only 2 °C and 20 cm away from the novel biome. Similar peaks of high rainfall on both the novel biome and Gerona, Spain are observed throughout the year. For these reasons, I believe this is a temperate shrubland.

    Temperate shrublands have unique characteristics that set them apart from other biomes. The latitude on earth where they are found tends to be between 30 ° - 40 ° North and South of the equator, which is where I would expect this novel biome to be. At this latitude, Ferrell cells are most likely the air pattern present which drives tropical air masses toward the poles and polar air masses towards the equator. These assumptions are based on earth's biomes and climate and therefore may not perfectly describe a novel biome. Two dry seasons are not commonly found. It may be that for this planet revolving around its sun happens quicker and therefore seasonal change could happen more frequently in a years time. This could explain multiple dry seasons. As for plants found here, there are a few possibilities. Sclerophyllous shrubs are most likely present. They thrive in dry/wet climates due to their tough leathery leaves and ability to grow in dry soils. During droughts, they continue to photosynthesize at lower rates in order to preserve water. Evergreen trees may also be found in this biome. They also rely on wet/dry climates and can specifically grow in infertile soils produced by the drought. Their use of evergreen leaves reduces water loss, lowering the nutrient cost of living. Grasses could possibly grow in this region as well. Although they may require a greater amount of rain, water-retentive adaptations could allow them to inhabit this biome. Fires often take place every 30 - 40 years in the shrublands and many kinds of grass could survive this event because of their underground nutrient stores. Sclerophyllous shrubs and evergreens will most definitely be found in this region, with the possibility of grasses.

Vertebrate hearing has been the subject of much study. The anatomy of the vertebrate ear is complex, but can be subdivided into three general regions, the outer ear, the middle ear, and the inner ear. The outer ear consists of the pinna and a duct that leads to the middle ear. The pinna’s primary function is amplification, allowing for sounds dispersed over the large surface area of the ear to be channeled into a small air duct towards the middle ear. The middle ear converts this sound energy into mechanical energy via the tympanic membrane. The distance this membrane is stretched is a function of the sound’s amplitude, the number of times per second the membrane is stretched from crest to trough is a function of the sound’s frequency. The shifts in the tympanic membrane are translated into three ear ossicles that function like a lever, amplifying the sound as it travels to the entrance of the inner ear, the oval window. The oval window is a membrane on the cochlea that vibrates in response to the last ossicle’s movement and translates this mechanical energy into hydraulic energy. The frequency of the sound is translated by how quickly the liquid revolves through the cochlea and sound amplitude is translated by the amount of compression applied to the fluid. Translation of this movement into sound perception is done through the organ of Corti, a series of membranes and special nerve cells called hair cells. The organ of Corti is composed of two membranes, the lower basilar membrane which is flexible, and the upper tectorial membrane which is more rigid. Lodged into the basilar membrane are the bottom ends of the hair cells, whose namesake hair-like protrusions stick out at the top and into the tectorial membrane. The basilar membrane will resonate based on the movement of the fluid, which is passed on to the hair cells through their axonal projections. Sound amplitude is translated by the amount these hair cells move, and hence the amount of neurotransmitter they release into the tectorial membrane, the more neurotransmitter, the louder we perceive that sound. Sound frequency is more complicated. The stiffness of the basilar membrane differs at its base and at its apex. The basilar fibres are shorter and stiffer at the base, while longer and more flexible at the apex. Higher frequency sounds cause the shorter fibres to vibrate and lower frequency sounds cause the longer fibres to vibrate. An animal’s hearing range increases as the difference between basal and apical fibre length increases. The shorter the fibre, the higher the frequency that can be heard, the longer the fibre, the lower the frequency that can be heard.

Based on the temperature - precipitation graph collected in this location I interpret the biome to be most similar to a desert. The probe's measurements report the average annual temperature to be 28.1 °C ranging from 26 °C - 30 °C monthly and the annual precipitation to be 27.8 cm ranging between 2.0 cm - 2.5 cm monthly. Both temp. And precip. show little change throughout the year. My reasoning for this classification has to do with the major drought present year-round. I can infer this because the temperature is consistently higher than the precipitation, which is low and therefore produces a drought. These key factor set a desert apart from all the other biomes. Also, a classic desert on earth would typically experience a large temperature difference from 10 °C - 30+ °C during the year and on average less than a centimeter of rain every month. Although this new biome may seem different, when plotted on the triangle graph containing all 9 biomes, it still falls under the desert section.

     A desert classification narrows the possible latitude and plants of this biome. On earth, deserts are normally found near the 30 ° North and South latitudes from the equator. Assuming the planet is similar to earth the location of this biome should be near or on this coordinate. With little to no water and intense heat, the types of plants that could survive in this environment must be specialized to retain water. Therefore, plants found here are likely succulents, such as cacti and desert shrubs. These plants are able to live off of little water due to their water storage abilities and withstand heat. Succulents on earth are accustomed to hot/cold seasonal shifts and even lesser rain, so the plants found in this biome may have evolutionary differences when compared to earths’ plants. They may transpire more in order to deal with the constant high temperatures throughout the year.