mtracy's blog

The Paddlefish is classified into Actinopterygii, or ray finned fishes. More specifically, it is placed in the Acipensiformes order. This fish has an elongated snout, supported by a matrix of tiny thin bones. While individually the bones are very fragile, together they form a sturdy yet lightweight structure. This long snout contains electroreceptors, a trait previously lost in bony fishes, and allows the paddlefish to detect plankton in its direct pathway. Once a large enough group of plankton is detected, the paddlefish will open its mouth, drawing in the water and engulfing the plankton. Water will flow through the gills and gill rakers, which filter out the plankton to be directed into the Paddlefishes stomach. Water safely passes through the gill slits as is normal, exchanging gases extraordinarily efficiently.

Modern sharks, rays and skates are united under the Chondrichthyes class. All Chondrichthians have cartilaginous skeletons. The males have intromittent organs called claspers, which are derived from the pelvic fins of the fish. All fertilization occurs internally and females my be either oviparous or viviparous. All Chondrichthians have no swim bladder. Sharks in particular rely on their large pectoral fins and oily livers to maintain bouncy. This also comes with the benefit of being able to traverse a variety of depths without expanding or compressing as much as a fish with a swim bladder would. Another interesting characteristic of Chondrichthians is the presence of placoid scales, teeth like structures which produce a sand-paper like skin.

A subclass of Chondrichthyes is the Elasmobranchs, which means plated gills. This class may be further seperated into Selachians, the sharks, or Batoids, the rays and skates. Seleachians have their plated gills on the side of their head while the gills of Batoids are located ventrally. A Batoids pectoral fins will be fused to the side of the head, in place of the gills location. Rays and skates differ by their means of reproduction. A ray is viviparous, giving live birth, while a skate is oviparous and will lay eggs.

I am currently taking statistics 240. We have covered topics such as descriptive statistics, simple linear regression and we have just started probability. We have also discussed the difference between qualitative and quantitative statistics, and whether or not they are discrete or continuous. Statistics may be represented in many ways, such as graphs and tables. There may be bar graphs, line graphs, and pie charts. Histograms and boxplots also provide details on the distribution of the data. Range, median, mode, mean and standard deviation are useful measures of the data and provide a variety of details about it, such as its general distribution. Chi-Square tests may be used, along with p-value, in order to determine whether there is a relationship between two sets of data. Simple linear regression may be used to determine whether or not two sets of date are correlated. By looking at the regression line and "r" it may be determined if there is a positive, negative, strong or weak correlation. Of course it is important to remember that correlation does not equal causation and there be a number of lurking variables which may effect the data, and make the correlation exist.

Enzymes are regulated in a variety of Reversible inhibition, which are forms of noncovalent mechanisms. These reversible inhibition methods come in Competitive, uncompetitive, noncompetitive and mixed forms. Competitive inhibition competes for the active site of the enzyme. When the inhibitor binds to the site, it blocks subtrate binding and thus activation of the enzyme activity. This may be overcome with a higher concentration of substrate. the Vmax of the enzyme is unchanged by this, though this increases the Km. Uncompetitive inhibition is when an inhibitor binds to a spot other than the active site. This only occurs when a substrate is already bound to the enzyme, but it will block further enzyme activity. This method lowers both Vmax and Km. Noncompetitive inhibition and mixed inhibition both bind whether there is a substrate bound to the enzyme or not. Thus, this cannot be overcame with a higher substrate concentration. What seperates these two methods is that during noncompetitive inhibition, Vmax will decrease, but Km will be uneffected. Mixed inhibition will decrease the Vmax as well but Km may either rase or lower depending on certain conditions.

Both Selachains and batoids are considered Elasmobranchs, a subclass of the Chondrochtyes. Both of these fishes have cartilaginous skeletons and plated gills. Additionally both have placoid scales, which are similar in strucutre to teeth, giving them a rough sand-paper like skin. Since these groups are a subclass of elasmobranchs, they also have polydenton dentitions. That is to say there are many rows of replacable teeth.

Selachians include sharks. All sharks have 5-7 gill slits on the side of their head. These also have no swimbladder. Rather they rely on their large pectoral fins and oily livers to maintain bounency. Some sharks have the ability to osmoregulate, and can occupy a large range of ecosystems, marine or otherwise.

Batoids are fish such as rays and skates. These are dorsal ventrally flatened fish with pectoral fins fused to the side of their heads. Rather than having their gills on the side of their head, their gills are on located ventrally. Rays are viviporous and give birth to live young, while skaes are oviparous and lay eggs.

The kingdom of animalia may be seperated into protostomes and deuterostomes. Protostomes includes animals such as annelids, molluscs, and insects, while deuterostomes includes organisms such as the echinoderms, hemichordates, chordaes and verebrates. There are 5 main characteristics which separate the protostomes and deuterostomes. During protostome development, the first opening to appear in the blastopore becomes the mouth of the organism. This pore deepens, eventually reaching through the organism, forming the gut and exiting at the anus. In contrast, during deuterostome development, the anus will form first, followed by the mouth. Protostomes cell layers develop slightly offset from one and other. This produces a spiral cleavage pattern. This is unlike deuterostome development, which has a radial cleavage, where the cells are stacked on top of each other. Furthermore cell role is determined very early on in protostome development, while deuterostome cell role is indeterminate. Lastly, the method of coelom development differs between protostome and deterostomes. Protostome coelom development proceeds through a process called schizocoely. During this method masses of the mesoderm migrate and form the coelom. However, deuterostomes perform enterocoely, where the mesoderm folds and pinches off to form the coelom.

During Fall 2018, as part of the Writing in Biology course at the University of Massachusetts Amherst, I conducted a project which simulated a research report. This project was designed to demonstrate the importance of a clear, concise methods section, the importance of variable control, and the difference between an observation and an inference. A spiderweb was located under a short lighpost between the Morrill buildings. A close up photograph was taken of the spiderweb, a photograph of the general area surrounding the spiderweb and a map of the area in which the web was found were compiled into a multi-panel figure using inkscape image editing software. Once figures were completed, a detailed methods section was written for another student to follow in an attempt to replicate the original figure. The original and replicate figures were compared. Differences were observed in the presence or absence of background or foreground structures and objects, font sizes used, general labeling differences, the presence or lack of light and the presence of water on the ground. Weather and time of day, angling and distance at which photographs are taken, labeling consistency, image resolution, device used to take the image, and the object used to provide scale are factors which were identified as being responsible for these differences.

There are a total of 11 differences visible when comparing panel A of the two figures. In Figure 1:A the lamp of the lightpost is on, shining light down onto the spiderweb. This light is absent in Figure 2:A. In Figure 1:A there is a ruler held to the left of the lightpost. This ruler is absent in Figure 2:A, however a student ID card is held beneath the spiderweb with a purple flower visible to the left in the background behind the lightpost. There is also a rockwall visible to the left of the lightpost in Figure 2:A. Less of the top jutting portion of the lightpost, which houses the lamp, is visible in Figure 1:A. This portion of the lightpost is wet in Figure 2:A. Figure 2:A also shows more of the sidewalk to the right of the lightpost, has the door to Morrill 1 visible in the background, and the brick wall of Morrill 1 visible to the left of the lightpost. Overall Figure 1:A is darker than Figure 2:A.

A total of 12 differences were observed between Panel B of the two figures. The lightpost present in Figure 1:B has its lamp turned on while it is off in Figure 2:B. The curb and sidewalk in front of the lightpost is visible in Figure 1:B. Nearly all of the tree behind the lightpost is visible in Figure 2:B while the top half is absent in Figure 1:B. Furthermore, the brick wall of Morrill 1 is visible behind the lightpost, including windows. Figure 1:B has the lower right of the door, but with the addition of a portion of brick wall which is absent in Figure 2:B. There is also a purple flower in Figure 2:B which is absent in Figure 1:B. There is a grey rectangluar structure imbeded in the ground present in each figure, however in Figure 1:B, the lightpost occludes this structure. Lastly, the ground and the top portion of the lamp is wet in Figure 2:B

When comparing the labeling present in either figure a total of 7 differences are noticable. The labeling has differences when it comes to font size. In Figure 2, font size when labeling the images “A – B – C” looks to be larger than in Figure 1, which has a font size of 72. The font size of the “Web location” label in Figure 1:C is 28. However in Figure 2:C this font size is notably larger; with the addition of an absence of capitals at the beginning of each word. Rather than facing upward and pointing towards Morrill 1, as is the case in Figure 1, the arrow which sits above this “Web Location” label is facing the downward direction in Figure 2:C. The line width of the arrow is not set to a width of 3.0mm as indicated in the methods either. The arrow head of this arrow is significantly wider than in Figure 1, which had used a more narrow arrow head. The arrow itself is also pointing to a different location in the two figures, with Figure 2:C having its arrow more to the left

Protostomes includes organisms such as annelids, molluscs and insects. During protostome development the first opening to appear in a blastopore becomes the mouth of the organism. This pore deepens, forming the gut and eventually the anus. Protostomes exhibit spiral clevage in their cells, since each layer is offest slightly. Additionally the cells roles (ie: this cell will be a neuron) are determined very early on in development. The role is chosen, and stays as such in the organisms adult form. The coelom of the organism develops through a process called schizocoely, in which masses from the mesoderm migrate and form the coelom.

Deuterostomes include organisms such as echinoderms, hemichordates, chordates and vertebrates. Unlike the protostome, rather than forming the mouth furst during blastulation, the anus forms first. Furthermore, deuterostomes exhibit a radial clevage, as cells are not offset with each layer. These cells fate and role are also indeterminate. Rather the cells role in the body of an adult will be determined at a later time, usually though stem cells. The coelom of a deuterostome is developed through a process called enterocoely, where the mesoderm folds and pinches to form the coelom.