Drafts

Across many land plants, similar cells and cell structures relating to similar functions can be identified. One of which being vascular components. A plant's vascular system can be broken down into two major groups, xylem, and phloem. Xylem are plant cells designed to transport water from the roots to the shoots via a suction pump of sorts. As the plant uses its water at a sink, place where water is used, it creates a low-pressure zone which in turn creates a pressure gradient. This gradient of high to low is what ultimately runs the movement of water in a plant. Xylem can be found near the inside of plants and in woody plants, they are actually dead. As a part of their development, they die so the plant doesn't need to spend much energy on them and it can gain structure from having many tightly packed xylem.

Phloem are the food transport cells of a plant. These are living cells whose main purpose is to facilitate the transport of sugars and foodstuffs from the leaves where sugars are created to sinks, where sugars are used, such as shoot apical meristems, root meristems, and cambial meristems. As a side, meristems are undifferentiated cells who create mature cells to replace older ones. Phloem are entirely hollow, to allow for efficient transport, however, still require 'helper' cells connected by plasmodesmata to house the necessary organelles for them to survive. Xylem and phloem work together to form the vascular system found in all vascular plants.

Tropical jungles are found, as the name suggests, in the tropics between 10 degrees north and south of the equator. At these latitudes, precipitation rates are consistent, exceeding 2,000 mm or 79 inches annually with two peaks based on the intertropical convergence zone or ITCZ. The ITCZ is a region in the tropics with low average pressures due to the high uplift of warm air.  Temperatures don't vary much here, staying relatively stable around 25 degrees Celsius or 80 degrees Fahrenheit year-round. Given this very stable environment, with little change in both precipitation and temperature, species have been able to thrive with little to no stress or disturbance. Approximately 50% of the earth's species are present here, even though it covers only 11% of earths vegetation. 

The plant forms that grow here include broad-leaved evergreen and deciduous trees. These trees are able to photosynthesize all year long so instead of losing all their leaves, such as deciduous trees in Massachusetts, they can maintain the leaf year-round and expel it to immediately renew it. The abundance of plant life creates 5 layers of jungle known as the emergent layer, canopy, understorey, shrub layer, and forest floor. The forest floor, in particular, creates a paradox. It appears the soil here is very low in nutrients, so how could it support so much life? Unsurprisingly, the abundance of life is the reason why the soil is so nutrient-poor. Plants take in nutrients from the soil to grow, and if enough plants are growing then the soil gets leeched of all nutrients. 

The tomatoes we eat today were almost 10 times smaller years ago. So how did the size and thickness just increase over time? It was just by random chance. It is as simple as that – one day a farmer had found a tomato slight bigger than what he had been cultivating – technically an anomaly – and he grew that tomato over and over again. Domestication of tomatoes has led to us getting the fruit we take for granted so easily. The process may have been simple, but the mechanism was much more complex. The paper “A cascade of arabinosyltransferases controls shoot meristem size in tomato” (Xu, Cao, et al 2015) breaks down the mechanism through which we ended up with the mutation that gave us our tomatoes. Growing plants have shoots containing meristems which contain stem cells. Stem cells have the ability to become absolutely any cell they want. As they multiply, the meristem grows bigger and bigger, allowing more flowers and fruits etc. However, that is not what happened with these tomato plants originally. An original pathway looked something like this: a gene expressed a protein name WUSCHEL (WUS). This protein is in charge of causing the meristem to grow in size, but it also activates its repressor CLAVATA3 (CLV3). CLV3, being a ligand, attaches to the receptor protein, CLAVATA1 (CLV1). This is allows the activity of WUS to be deactivated and so the meristem cannot grow in size. 

The organization present in the different forms of life on Earth is astounding. In a plant physiology class that I took last semester, we looked at a lot of different processes that plants use to survive. As multicellular organisms, a lot goes into a plant in order for it to survive. From photosynthesis to maintaining homeostasis, many processes are going on at once to keep the plant alive. Examining the cell pathways and interactions in and outside of the plant, it is easy to get lost because of how many steps are usually involved with these processes. With how complicated these processes are, it is easy not to get lost in awe of how organized these processes are. Certain things only happen depending on the completion of other events, and other things require the presence of so many things in a particular order. The same can be said about mostly every organism. Every organism has tightly regulated processes that try to ensure survival and the level of organization that goes into the different cell pathways, etc. is mind-blowing and it makes me think of how miraculous it really is that all this life can exist on Earth.

In plants, actin dynamics are regulated by actin-associated proteins. There are multiple processes in the plants that are carried out due to these proteins. Some of the processes include growing filaments, capping the filaments at either end so new monomers cannot be added or removed, severing actin filaments, and budnling together several actin filaments. Myosin are motors that are able to walk along the actin filaments towards the plus end promoting growth of the filament. Dyneins are able to walk towards the minus ends, but this motor protein only appears in animals cells, not plant cells.

For Male infantile aggression in mice, scientists used a technique called the knockout method, by removing the receptor for the hormone progesterone. Males without the ability to sense the hormone in their system did not attack infants as opposed to unaltered males who regularly attacked infants. Blood tests showed similar levels of the hormone in this group of males and the control that did not endure the knockout of the receptor. The advantage to this method is that you can directly tell if a behavior is hormone controlled by removing the ability to detect the hormone in the specimen as opposed to only measuring hormone levels.

The less invasive method of only measuring hormone levels would not be beneficial for this type of experiment. This is because of the fact both groups had similar concentrations of it, which does not show a direct cause for why one set of males was aggressive and the other was not. By using the knockout method you can find the cause.

If i am a comparative psychologist, I am working in a lab setting with controlled experiments. I am generally interested in the “how’s” of learning, in other words, proximate questions based on the genetics and development which influence behavior in animals. The type of experiment I might be conducting would be with rats and pigeons in the lab. I would be testing their learning abilities and working with BF Skinner. I believe that animals are born with a blank slate based on my studies

If I am an ethologist, I am in a field setting observing nature. I am interested in the evolutionary history and the “why’s” of behavior, in other words, ultimate questions wondering about their evolutionary history and adaptive value. I might be in the field observing why spiders live in groups and trying to understand the value of that behavior with Konrad Lorenz and Niko Tinbergen.

Flu shots are a widely used source of artificial long-term active immunity. Why then, is it just now becoming known as a threat to your child's safety when it's purpose is to improve health? The answer lies in the medical field's history of doctor-patient relationships. The underlying statues that constitutes the AMA purpose involve very specific wording that paints the doctors in an omnipotent and god-like fashion, whereas the patients are refered to in terms deeming them the obidients to the doctors willing to help them. Patients were at the will of the doctor, and the doctor determined the pertinent information of a patient's own medical record in treatment. It was true that even in the 1950s patients would die without knowing the cause of their illness in its true definition because the doctors would flirt around the topic never to fully unviel how doomed their health was. This aspect of medicine that gives the doctor the right to know and right to hide the complete truth, and therefore decieve a patient, has combined with the modern way of life that is obtaining seemingly all realms of knowledge from the interenet. Patients can now begin to control their own treatment by researching symptoms, discovering solutions, and bringing plans to their doctor's office for check-ups all without a physician involved. Now patients are learning more about their health for themselves and peaking behind the proverbial curtain. This threatens doctors who like to be the head chief in deciding things for patients. A doctor that cannot serve a patient in need of emotional counceling instead of medicial treatments will not survive in this shifting method of patient care. Patients need less medical options and more advice on what will best fulfill their needs for sustaining a life they are happy with, be it through medicial intervention. Now let us come full circle back to the classical flu shot. People have always simply been told to take the flu shot, the flu shot is good for you, it will increase your long-term active immunity. With the view of the public on high up medical practitioners shifting, the low likelyhood of detrimental effects from the flu shot, up to and including mild retardation of children, now becomes a widespread worry for parents because doctors have forever wilthheld that information from the patients. Trust in the medical field is at an all time low thanks to the availability of self-help on the interenet, and doctors did not position themselves in a place to maintain it. 

Vision is a complex mechanism that exists in many forms across the animal kingdom. Planaria have very simple eyes, consisting of just a few light sensitive cells, detect whether light is present and allow them to perform phototaxis. More complex eyes have a retina with rods and cones as well as a lens which can be bent for vision at different focal lengths. These complex eyes have the capacity to produce fully formed images of the environment that appear different based on the rods and cones in an animal’s retina. Rods and cones are the visual cells that allow eyes to see different wavelengths of light. As the name suggests, rods have rod-like endings filled with opsins that can perceive more light under darker conditions than cones can, and are often found in the peripheral area of the retina. Nocturnal animals often have a preponderance of these in their retina in order to better see at night. Cones have cone-shaped endings that are also filled with opsins, however they can possess opsins of many different conformations. Opsins are a group of proteins that allow for light detection, with different opsin conformations allowing for the detection of different wavelengths of light. For example, humans have red, green, and blue cones, each with opsins keyed to those wavelengths of visible light. Our eyes receive light information from the environment and then our brain relates that to known ideas about colour, brightness, and other visual information. Different animals have different opsins, often those that best serve their survival. For example, rats can’t see red light. As nocturnal animals, rats have no need for red light since it’s longer wavelength and isn’t present at night, unlike blue light or UV. In their evolutionary past, rats no longer needed to see red, and so the opsin was free to mutate and disappear, but they did need to see UV, leading to selection for a UV-detecting opsin. Very rarely, humans will develop a mutation that leads to the development of a fourth opsin, and hence a new type of cone, that allows them to see more colours than non-mutant humans.

Coral reefs may only span less than 0.01% of the ocean floor, but they house nearly a quarter of all known marine species. They are built using limestone produced by coral polyps in the warm shallow oceans near the tropics and are very complex and unique structures. Over the course of 1 year, a massive coral can expect to grow 2 cm, making the creation of such habitats incredibly slow. Smaller species of marine life use the densely populated corals as homes while predators such as cuttlefish and octopus use specialized techniques to draw them out. 

One particularly interesting mutualism is the clownfish and sea anemones. Found near the reefs, anemones are half-plant half animals that sting their prey such as fish and mussels. However, they seem to allow clownfish to inhabit the same space. It happens that clownfish clean the anemone of dirt and debris so keeping these kinds of fish around is actually very beneficial. Likewise, clownfish gain a home and a place to lay their eggs. The anemone provides protection to clownfish natural predators while clownfish do the same for anemones. Clownfish are normally eaten by larger fish, eels, and sharks, but having an anemone shelter can provide a secluded hiding spot. Anemones are eaten by starfish, eels, and other fish, which clownfish have the ability to ward off. They not only protect their home, but also the anemone.