kruzzoli's blog

Our research could be further improved by developing a more standard method of silk measurements. Within each cluster of silk we obtained from the three webs, there were multiple individual strands of various thicknesses. Different strands of silk could represent different types of silk, such as silk used for web production to catch food or silk that is made as a byproduct of spider function. Identifying different types of web produced by the spiders and only quantifying the same type of web would potentially give more solid data that would better indicate if a correlation between weight and silk thickness existed. We also had to move the spiders around to different locations because we had to bring them to the lab in order to use a scale and the microscope. This means the spiders may have been in states of distress that could cause disruptions in silk production. To better future research, keeping the spiders in the same location throughout the experiment might yield better results because the spiders would be in a constant controlled environment.

If we were to continue research, we could take web samples from more than just three spiders and standardize the measurements.

Our data displays a negative trend between the weight of the spiders and the thickness of their silk. The heaviest spider had an average silk thickness of .758 μm which is the smallest average thickness of silk. Due to the negative trend between weight and thickness, our hypothesis is not supported because heavier spiders do not produce a thicker silk. Our results had inconsistent web thicknesses so in some cases the average is not representative of the entirety of the silk.

Our research could be improved by developing a more standard method of silk measurements, Within each cluster of silk we obtained from the three webs, there were multiple individual strands of various thicknesses. Different strands of silk could represent different types of silk, such as silk used for web production to catch food or silk that is made as a byproduct of spider function. Identifying different types of web produced by the spiders and only quantifying the same type of web would potentially give more solid data that would better indicate if a correlation between weight and silk thickness existed. We also had to move the spiders around to different locations because we had to bring them to the lab in order to use a scale and the microscope. This means the spiders may have been in states of distress that could cause disruptions in silk production. To better future research, keeping the spiders in the same location throughout the experiment might yield better results because the spiders would be in a constant controlled environment.

In the United States, energy generation emits most of the Co2. It emits more than transportation and industry and electricity is a needed resource in this day and age. Nuclear power is currently the largest source of carbon free electricity so using nuclear power would greatly reduce the amount carbon dioxide released. This is beneficial because Co2 is one of the major greenhouse gases that is destroying our environment, so if we can potentially find an electricity source that reduces CO2 emission, we would be taking a huge step towards creating a healthier environment.

2. There is a large push for both wind and solar power which are great environmentally friendly ways of producing electricity but they are poorly suited for large scale use because of their intermittent and variable supply. They depend upon the weather to create good supplies of energy and this is something that we cannot control, so their effectiveness cannot be guaranteed to run whenever needed and to produce as much energy as needed all the time. Nuclear power, however, does not rely on the weather to generate electricity and is therefore more reliable and better suited for mass production of electricity.

We decided to analyze the energy expenditure of Ursus maritimus, commonly known as the polar bear. We were curious about how polar bears budget there time so we asked the question: What proportion of time is spent preforming high energy versus low energy behaviors by Ursus maritimus individuals. We wanted to know if they conserved their energy and how they spend there time. We hypothesized that Ursus maritimus individuals will spend a larger proportion of time performing low energy behaviors in order to conserve energy while active. 

Background Info:

Polar bears are a carnivorous maritime bear that resides on the arctic sea ice. They hunt primarily ringed and bearded seals because they require a high fat energy diet to survive. Polar bears have a thick layer of fur around their entire body in order to keep them warm and they also have a thick layer of blubber under their fur to provide insulation and buoyancy. They are currently listed as a threatened species due to declining populations of polar bears as a result of melting sea ice. There main food source is seals and in the summer they are in a physiological state of hibernation even though they remain active. This means they require less food because there body is feeding of the fat storages. 

We watched 5 minutes of videos of polar bears, Ursus maritimus, from the Macaulay Library database to observe behaviors and we identified certain behaviors that the polar bears did. We identified a list of behaviors and divided this list into four categories based on how much energy each behavior takes. The four levels of energy were minimal energy, low energy, mid energy, and high energy. We identified minimal energy behaviors as lying down and standing still. Low energy behaviors were walking around with the nose up or nose down. We identified mid energy behaviors as walking quickly and swimming. Running, digging, diving, and shaking were high energy behaviors. We watched 30 additional minutes of videos of polar bears from the Macaulay Library database and using Jwatcher, recorded how much time each behavior occurred. We took a screenshot of each behavior and put the images into a table based on the energy level and added a description of each behavior. Each behavior in the table appears chronologically. To determine how much energy the polar bears have, we identified the location and season of when the videos were taken and we identified the food source of these particular polar bears.

• Six spiders of the Pholcus-pholcidae species were collected and placed into  six separate clear containers. The weight of each spider was recorded using an analytical scale. Each spider was placed on a plate, weighed, and then we subtracted the weight of the plate from the weight of the plate with the spider to get the weight of each spider.

• The spiders were given one mosquito at the beginning of the trial after being weighed and allowed to spin their web for three days at a constant environment of 20 degrees celsius.

• A strand of silk was removed from three of the spiders containers because not all 6 spiders produced enough silk to be measured. Using tweezers, the silk from each sample was placed onto a microscope slide and a cover was placed on top.

• We used a Nikon Inverted Microscope Eclipse microscope to take pictures of the samples. For each sample, we took two images of the web from different areas of the sample.

• We used Fiji to analyze the images of the webs. For each image, there was .108 microns per pixel. We used this ratio to determine the ratio to measure silk thickness. The known distance for each thickness was determined using Fiji to draw a line from one end of the silk to the other, and the number of pixels was divided by .108 to give the length of the silk in micrometers.

One thin strand of silk and one thick strand of silk was measured in each image. We measured the thickness of five different points on a 28 μm width of the silk. The average of these five measurements was calculated to determine the average thickness of the silk.

The aim of this study is to determine if there is a relationship present between spider body weight and spider silk thickness among Pholcus-pholcidae,commonly known as cellar spiders. This experiment tested the effect of spider weight on the thickness of spider silk. Discovering the various factors that contribute to differences in spider web characteristics, such as thickness, could help us learn more about the factors that contribute to their extreme elasticity and could be useful for material engineering of a material that is both strong and soft . Previous studies have shown that there is some variation in spider silk diameters, as well as the mechanical characterization of spider silk . Light-microscopy is a proven method to study the differences between objects that are small, such as spider silk, and will be used in this study to measure the diameter differences. In this experiment, six spiders were weighed at the beginning of the experiment and they spun webs for 3 days after being weighed. After the third day, the thickness of an individual strand of silk from each web was measured using a microscope and micrometer. The measurements of weight and silk thickness were compared to determine if a relationship existed between the two factors.

• We collected 6 spiders of the same species and recorded the weight of each individual spider. We placed each spider in their own, clean, clear  plastic container.

• We allowed the spiders to spin web for 5 days, all spiders were kept under the same conditions.

• We removed silk from the six containers and using a  microscope, measured them for the thickness of each silk and recorded the data so that we had the weight of each spider and the thickness of the silk from their web.

• We compared the weight of the spider with the thickness of the silk by creating a graph that measured weight in grams on the X axis and the silk thickness on the y axis.

• We analyzed the data to find any significant relationships.

We choose to observe the presence of wing bars, if the bird had a short or long beak, the color of the throat, eye ring color, belly color, feet color, the presence of yellow feathers, the presence of bright colored feathers, rump coloration, the presence of a curved beak, if the bird had more than two feather colors, and if the crown was a different color than the body. We observed the photographs and the skin museum to observe each species and categorize the plumage characteristics. We wrote the color of each plumage feature in the table and we used “1” and “0” for traits that didn’t specify a color. The presence of wing bars, yellow feathers, bright colored feathers, more than two feather colors, and a matching crown were indicated by a 1 for yes and a 0 indicated no. A short beak was categorized by a 0 and a long beak was categorized by a 1. After evaluating each of the 33 species of Warblers for the set of characteristics determined, four of the patterns were chosen to apply to a phylogenetic tree. We choose the presence of wingbars, the presence of yellow feathers, foot coloration, and the presence of a matching crown color. We indicated the absence of wing bars with a black line on the taxa of the phylogenetic tree.

Sexual selection, is the selection of certain traits based on sexual preference by one of the sexes. This is typically seen as female choice driving the evolution of ornate plumage and elaborate songs used by males during courtship. Sexually selected traits are often very costly for males and can lower survorship, however they increase fitness. Traits can be costly due to the energy required to have them, or they can attract predators. Brightly colored feathers can be a sexually selected trait that lowers survivorship because it makes the bird more peceptible to preadators. However, colorful wings increases fitness because females are attracted to colorful wings so the male is more likely to attract mates and therefore produce more offspring. In some cases, sexual selection can result in "run-away" sexual selection in which the males evolve very elaborate forms of ornamentation that keep evolving as female preference evolves to prefer more elaborate traits.