Writing in Biology

This species has developed certain adaptations that allow it to succesfully enter the water at a high speed when diving. Its unusual beak-shaped mouth provides streamlining, which minimizes the impact against the surface and increases the chances of a successful hunt by avoiding excessive splashing that may scare away fish. Unlike most mammals, which have seven cervical vertebrae, this species has five cervical vertebrae and they are surrounded by thick layers of soft tissue. This gives the bat a shorter neck with a shock absorbing mechanism that greatly reduces the risk of injury when penetrating the water.

Adaptive radiation is an evolutionary process that explains how organisms can rapidly evolve and diversify from one common ancestor into many different species. This is especially effective when the environment changes and creates new niche spaces for the once common ancestor to fill. The change in environment could be a physical boundary between the common ancestor group that separates them to change, but it could also be the introduction of a different food supply or new predator species. These forces act on the common ancestor and it fills different niche spaces and as they adapt to fill these new spaces, they also diversify enough to be different species. A well-known example of adaptive radiation is in Darwin’s finches. Although they present as different species on the outset, it is possible to trace them back to the same common ancestor. Their evolution occurred over a short period of time and their evolutionary adaptative difference can be explained by the island that the finches inhabit. Once the common ancestor was spread to the different islands of the Galapagos, different environmental pressures presented themselves, such as different food sources which would change the beak shape of the birds.

Adaptive radiation is an evolutionary process that explains how organisms can rapidly evolve and diversify from one common ancestor into many different species. This is especially effective when the environment changes and creates new niche spaces for the once common ancestor to fill. The change in environment could be a physical boundary between the common ancestor group that separates them to change, but it could also be the introduction of a different food supply or new predator species. These forces act on the common ancestor and it fills different niche spaces and as they adapt to fill these new spaces, they also diversify enough to be different species. A well-known example of adaptive radiation is in Darwin’s finches. Although they present as different species on the outset, it is possible to trace them back to the same common ancestor. Their evolution occurred over a short period of time and their evolutionary adaptative difference can be explained by the island that the finches inhabit. Once the common ancestor was spread to the different islands of the Galapagos, different environmental pressures presented themselves, such as different food sources which would change the beak shape of the birds.

Crab spiders are ambush hunters that prey on pollinator insects by lurking in the flowers they visit. Due to the nature of their hunting strategies, we hypothesized that crab spiders prefer to hide in flowers that more closely resemble their body coloration. In order to test this, we set up an arena divided into two colors and recorded the location of the spider prior to being displaced and after being moved to the center of the stage.
The data for the cyan versus green trials suggests that Mecaphesa celer shows an initial preference towards cyan, but when placed in the center of the arena it will move towards the green background. Meanwhile, in the white and yellow trials Mecaphesa initially shows no particular preference between the backgrounds, but when placed in the center of the arena it will move towards the white side. The results agree with our hypothesis that crab spiders prefer backgrounds that match their current body coloration, although further trials with a larger sample size and a refined protocol should be performed in the future to confirm these findings. Despite being a pilot study, this line of investigation could shed light on multiple aspects of the ecology and evolution of cryptic coloration in predator-prey relationships.

Geckos are able to adhere to surfaces thanks to a combination of their physical structures and behaviors. The fingertips of a gecko's hand are made up of lamellae, which are modified scales that contain special hairs called setae. These hairs are tiny, which allow for making better contact with surfaces via Van der Waals forces. As well, geckos have tendons in their hands that allow them to "peel off" their fingers when climbing, and their motions follow a complex set of behaviors that maximize their grip to surfaces.

Sea lampreys are anadromous. From their lake or sea habitats, they migrate up rivers to spawn (followed by
the death of the spawning adults); females deposit a large number of eggs in nests made by males in the
substrate of streams with moderately strong current. Larvae (ammocoete larvae) burrow in sand and silt
bottom in quiet water downstream from spawning areas and filter-feed on plankton and detritus.
After 7 years in freshwater habitats, the ammoecoete larvae undergo a metamorphosis that allows young
post metamorphic lampreys to migrate to the sea or lakes and start feeding on blood.
The lamprey uses its suction cup-like mouth to attach itself to the skin of a fish and rasps away tissue with
its sharp, probing tongue and keratinized teeth. After one year of hematophagous feeding, lampreys return
to the river to spawn and die, a year and a half after the completion of metamorphosis.

Like other crab spiders, Mecaphesa celer is an ambush hunter and it preys on pollinator insects by lurking in the flowers they visit. We hypothesized that in order to successfully capture its prey, Mecaphesa would choose to hide in flowers that more closely resemble its actual body coloration. In order to test our hypothesis, we designed an arena split into two different colors based in the RGB color model, and recorded to which side the spider moved after being placed in the center.

We chose to test the colors white versus yellow and cyan versus green in our experiment. Some species of crab spiders are able to change their color from white to yellow, and yellow to white. We decided to use white and yellow as a control in our experiment and see which side the spiders would prefer. The color white is made up of red, green and blue all at their highest intensities which is 255 in the RGB color model. Yellow is made up of red and green both at their highest intensities of 255, with no blue is added. The next set-up contained cyan and green. Cyan is made up of green and blue both at their highest intensities of 255, and no addition of red. Green is made up of only green at its highest intensity of 255.

The results of our experiment testing whether or not a relationship exists between the body weight and the average web thickness of a spider indicated a negative correlation, but likely were unreflective of reality. We hypothesized that spider body weight would be positively correlated with web thickness, speculating that a heavier spider would need a thicker web to support its weight. Before we began our experiment, we found another study that investigated this same subject and found that there was no correlation. We wanted to see if our results would be the same, or if they would be different. We photographed 3 spider webs under a microscope, and for each spider we measured and averaged 10 different threads of its web, then compared them to its body weight. The spider with the lowest weight (Spider 1) had the highest average web thickness, whereas the spider with the highest weight (Spider 3) had the lowest average web thickness. Both measurements of weight and average web thickness of Spider 2 were in between Spiders 1 and 3. However, our results are unlikely to be representative of reality for two main reasons. First, our sample size was very small since only 3 of the spiders we selected for our study produced webs in the experiment time. A small sample size leaves the differences between the measurements up to chance. Second, there was a high standard deviation within each spiders ten individual web strand width measurements; they varied greatly from the “average.” Thus, the average, which was used to identify the trend of negative correlation, is unreflective of the full data scope and thus not a meaningful measurement when plotted against spider body weight. To further this point, one can see in our graph that Spider 2 had a web width average that was in between the averages of spiders 1 and 3. However, looking at all of the individual web strand measurements of Spider 2 that went into the average, one of it’s values is the highest value of all 3 spiders, and another one of it’s values is the lowest of all 3 spiders. It is the spider with the most moderate weight, but it has the largest range of web widths. Since the measurements based on Spider 3 are from the same spider, they are all have the same weight, yet their width varies so largely, so it must be highly influenced by some other factor external to weight.  In conclusion after reanalyzing the data, it is unlikely that spider weight has an effect of spider web thickness.

In our research project, we analyzed the correlation between body weight of a spider and the thickness of its web. We were only able to obtain 3 spider webs from our population of six spiders. To get a fuller picture of weight vs thickness, we also compared our results to the results of another study which examined the same hypothesis, but had a greater sample size and used multiple species whereas we used one species. Our results of the average web thicknesses of each spider plotted against their weight were a negative nonlinear correlation. The results of the other study showed no correlation. Our results probably did not show the full picture of reality. We only had a sample size of three, which is a very small number. Also, although the average widths plotted against the weights showed a negative correlation, there was a high standard deviation in the individual measurements, so the average probably does not mean that much. Spider number 2 that we measured had a weight that was in the middle of spider 1 and 3, as well as an “average” width that was in between 1 and 3. However, as our graph shows, looking at the individual data points spider number 2 actually had both the highest and the lowest observed single strand diameter, with individual points scattered on both the very high and the very low points of the plot. Thus, the average is not a very effective measurement. The spider’s body weight is constant, yet its strands have a large variation. It is likely that in reality, spider body weight does not play a role in determining web thickness, but rather other factors, such as the type of the web itself and its purpose.