Drafts

Reed warblers are night migrants, known for their incredible instinct which allows them to calculate their east-west position during the breeding season. Even in the case of displacement, these songbirds have the ability to correct their orientation. Previous research has revealed that a tiny magnetic compass is possessed by the songbirds in each eye. However, this information is not enough to explain which sensory mechanisms and cues warblers use in determining longitude. Fortunately, a key to solving this phenomena lies in a second magnetic sense, involving the ophthalmic branch of the trigeminal nerve (V1). It is speculated that V1 channels magnetic information into the brain, which has lead researchers at the University of Oldenburg to a strong hypothesis in which V1 may serve as a magnetic map and is necessary in determining a reed warbler’s east-west position.

The methods in this double blind experiment included capturing 57 Eurasian reed warblers in Rybachy and separating them into groups. Some underwent a procedure involving the severing of V1 while the other birds participated in a sham surgery. The songbirds were then displaced 1,000km eastward in Zvenigorod, and their orientation was compared before displacement in Rybachy.

The results revealed that sham sectioned bird’s orientation shifted by 49 degrees counterclockwise compared to non operated birds in Rybachy, though they did in fact correct for displacement. The V1 sectioned birds however, did not adjust for the displacement. Their orientation was considerably different in comparison. Based on these results, it was evident that V1 plays an important role in detecting longitude in the magnetic field and therefore a reed warblers sensory ability to provide map related information. This information has lead researchers closer to determining the biological function of V1 including the possibility of transmitting information through magnetoreceptors and olfactory receptors.

These implications match with the evidence that was found from this study. However, there are quite a few restrictions with this study. For example, these results cannot be applied to all birds. Migratory homing pigeons are still able to navigate despite sectioning the V1 nerve, contradictory to the results from this study with reed warblers. Thus, navigational ability involving V1 may be species dependant. In addition to this, other research involving V1 in birds is virtually useless to compare this experiment to, due to the fact that many have not been able to be replicated, resulting in a very low reliability factor. Without this, it becomes increasingly harder to find out more about the function of this nerve in birds. In addition, there may be other cues which help songbirds to correct their displacement, for example: smell.

Thankfully, unknowns and complications from this experiment like the one mentioned above serve to be quite helpful because they can always be experimented with. The possibility of olfactory senses being a major contributing factor in bird migration can be tested to determine if transmitting odor is a function of V1. Therefore one can observe whether it has impact during bird migration. Most research isn’t perfect, so these kinks in studies provide a layout for future research to take place because there is always information to be found.

Bird flight is not as simple as wing-flapping and hovering above the trees. This primary mode of locomotion has evolved to possess many intricacies involving movement. Despite several studies covering migrational behavior in birds, there is little information about the aerodynamic principles and forces behind flight. This is precisely why researchers at the Department of Biology in the University of Portland have studied the mechanical power output of the pectoralis muscle in magpies, cockatiels, and doves. They hypothesized that a number of factors could contribute to the overall shape of a power curve such as morphology, wing kinematics, and ultimately flight style.

Cockatiels and doves were subjected to a variable-speed wind tunnel to measure velocity and any potential change of the pectoralis. Bone strain recordings and sonomicrometry were used to monitor tension and length of the pectoralis muscle, while work output per wing beat was calculated. 3D kinematic data was also used for analysis of mechanical movement. The data from the velocity of birds in power curves were plotted for comparison. The results revealed a significant difference in pectoralis power output and speed. The doves were found to have a higher minimum (7ms-1) and maximum (17ms-1) power output and mass specific power output compared to the cockatiels (5ms-1, 14ms-1) for most speeds. However, there was an exception at 14ms-1, which was most likely due to a trade-off in the dove’s larger wing size relative to body size. Therefore, the doves would require more power in comparison to the cockatiel’s to account for reduced maneuverability at that speed.

Nonetheless, both species exhibited a U shaped curve for their power curves. In comparison, the mechanical power curve for magpies was relatively flat. This was likely due to morphological differences. Unlike cockatiels and doves, the broad wings and long tails in magpies constrain power output, greatly increasing drag while decreasing thrust. Overall, these implications are consistent with the hypothesis of this study. Wing morphology and flight style indeed significantly alter the shape of the power curve. However, this study does have restrictions. For example, these results are species dependent. There are evident physiological and behavioral differences in birds because they have evolved to be the most fit in distinct habitats. Some species, like galliformes, do not rely much on mass specific pectoralis power output because they use flight specifically to elude from predators. In addition, the researchers failed to take into account the possibility that more than just the pectoralis muscle is responsible for power output. This study also assumed that wings are the primary source of reducing power requirements. They did not consider that the tail could also aid in work. Due to these flaws, this field of study requires more research to conclude which components are important for locomotion in birds.

In the future, any similar experiments should include a more diverse sample size, and the biologists should measure potential variables to prevent any holes or discrepancies in data. Regardless of any mistakes, the data extracted from this study will serve as a helpful guide for improving the structure of experimentation as well as getting a better look into the relationship between mechanical power output and forward velocity in birds.

There are many different ways to study the locomotion of animals and humans alike; for birds, there are wind tunnels, for humans, there are treadmills, and for fish, there are swim tunnels. Jeanine M. Donley, Chugey A. Sepulveda, Peter Konstantinidis, Sven Gemballa & Robert E. Shadwick wanted to look further into the locomotion of sea animals, specifically tunas and lamnid sharks (examples would be both mako and white). The reason for their study was to determine if the morphological similarities between these two sea animals meant that their mechanical and functional design had also converged. To do this, they studied the musculature and structure of the mako shark. The scientists examined Isurus oxyrinchus, a species of shortfin mako shark. The lamnid sharks used in this study ranged from 80 to 112 cm in size. While observing the shortfin mako in a swim tunnel, the scientists were able to determine where the dorsal midline was located using digital images. The position on the midline is important because swimming modes in fishes are explained based on the proportion of the body that is used during movement of the tail, which is also known as thrust-producing movements. These modes are distinguished by different patterns of displacement. Tunas fall under the least undulatory mode, meaning the body is very rigid and the tail is the source of most movement. When studying the mako shark, it was found that they have a similar mode to the tuna due to the degree of lateral motion along the shark’s form, which was from 0.4 L to 0.8 L (L meaning total body length). Past 0.8 L, the amount of movement in the tail increases substantially. After noting the similarity between the two species, the scientists wondered if the shortening the red muscle found in the mako shark would result in a functional property found in tunas. This functional property is when the tuna uses its red muscle fiber found in the midsection/upper region of the body to propel and create thunniform kinematics in the posterior region of the body, mostly the tail. There are long tendons that link to their tail so that even the red muscle is build more interior, they can use the tendons and the tail to create the movement of the tail while keeping the rest of their body very rigid. If the shortening of the red muscles happens at the same time as the white muscle, the mako shark would swim the way most fish do; if they are not synchronized, it means the mako shark swims and propels itself in the same way a tuna fish does. Sonomicrometry and electromyography used to measure muscles lengths instantaneously during swimming sessions, both active and passive. The results showed that the shortening of red muscles was uncoupled from the other tissues, similar to tunas. The results from their study also show that mako sharks possess the same tendon structure which aids in producing thrust. The findings of this study confirm that lamnid sharks and tunas have converged on both mechanical design, as well as morphological, concluding in selection for fast and continuous locomotion. The study itself reveals more data than previously known about lamnid sharks, but because these types of sharks are large and aggressive predators, they are difficult to handle and leaves dynamic properties about their individual locomotor system unknown. Future studies could look into the reasons behind this morphological and functional conversion; the usage of certain muscles, the placement of fins, the size of fish, etc. all deserve further research.

Design

What instantly drew me into this poster other than my interest for whales was its display of the whale sighting app they were advertising inside the screen of a smartphone. Not only was there a layout of a poster, but there was a layout inside of that layout, that being, the way the app looked on the smartphone photos they provided. It added even more of a dynamic to the poster. The design of the poster was very organized and clear, with nothing too distracting other than the neon colors of the bar graph on the right side of the poster. The colors used were mostly consistent and were not hard on the eyes other than that. The color of the design had a theme and were mostly neutral colors like blue and gray theme to match the photographs of the ocean and maps they provided. The text was plain and fitting; it did not distract me. The only fault was the lack of white space. They fit a lot of information into one poster, so there was not much breathing room for space between sections.

There are multiple ways an animal can find its way around an environment. It is very common for animals to navigate via the use of landmarks and beacons, which they sometimes use to generate cognitive maps. A landmark is defined as an object or structure distinguishable from the background environment that gives information about the position of and direction to a goal. A beacon is defined as an object or structure distinguishable from the background environment that is near a goal and marks its location. A cognitive map is defined as an image of the environment stored in the animal’s memory and is considered present when an animal can generate a novel route to a goal. The use of landmarks has been demonstrated in animals as different as wasps and birds. Concerning wasps, a test was done where a circle of pinecones was placed around the wasp’s nest and once the wasp left, the circle was moved. When the wasp returned, it looked for its nest in the circle of pinecones rather than at the nest’s actual location, which evidenced its use of landmarks. Birds are not only able to use landmarks, as was shown in hummingbirds when poles were used to demarcate flower location and that when the landmarks were moved they followed the landmarks rather than the flower’s actual location, but also the use of cognitive maps. Clark’s nutcrackers have been shown to be able to recognise the relative location of objects, which has been considered evidence of cognitive mapping. In a test where seeds were buried halfway between two landmarks, the nutcrackers managed to consistently locate the seeds even as the landmarks were pushed closer to one another or pulled further apart. In each trial, the birds found the seeds by going to the halfway point between the landmarks rather than looking for the seeds using absolute distance as would be the case if they were solely employing landmarks as indicators of distance.

There is a relationship between the texture of the soil and hydraulic conductivity. That relationship revolves around matric potential. At saturated conditions, hydraulic conductivity is much higher than potentials that are in unsaturated conditions. When there is a high moisture content, the hydraulic conductivity is higher in the sand than in the clay. At low moisture contents hydraulic conductivity is higher in the clay rather than sand. This phenomena occurs because sand has many more macropores and this allows moisture to move readily through the soil. That is why the graph shows the sandy loam soil’s curve dropping faster than the clay. Saturated flow takes place near zero ksat. This can be seen on the graph just before the sandy loam’s line starts to curve downward. In unsaturated conditions, the sandy loam ksat decreases. For the clay soil, the ksat is high in unsaturated conditions. This most likely has to do with the many more small pores that clay has versus sandy loams with macropores.

In ecological terms, succession is the process by which a community's composition changes over time. Succession begins in an environment where there is no life present. In such an area, a species hearty enough to survive extreme conditions must be introduced first. Once a species takes hold in this harsh environment, it becomes known as a pioneer species which launches the the area into the pioneer stage. These first species usually create changes in the area through their existence by simply carrying out their natural functions. Eventually, once pioneer species have molded the environment enough, other species begin to inhabit the area even though they may not have been able to beforehand. Overtime species will be added and removed from the community putting it in an intermediate stage. Through enough trial and error via natural selection, amongst other factors, a community may reach what is known as the climax stage. In this stage, a community is thought to be a stable endpoint where the ecosystem is harmoniously functioning. At any one of the three major stages disturbances such as fires, storms, eruptions, etc, could send the community back to any one of the earlier stages.

After a plant has taken in sunlight and water to produce ATP and NADPH, it has the necessary ingredients to produce a sugar molecule. First, a plant must take in CO2 to be fixed using the 5 carbon molecule Rubisco or RuBP. Carbon fixing is the process by which gaseous carbon is converted to a non-gaseous molecule. Exactly 3 CO2's and 3 RuBP's are used to produce 6 3-PGA's. The 6 3-PGA's are then are reduced using 6 ATP's and 6 NADPH's into 6 G3P molecules. One of these G3P molecules is set aside as a sugar product and the remaining 5 are used to regenerate RuBP. The product, G3P, is composed of 3 carbons, oxygen, hydrogen, and phosphorus. Regenerating RuBP requires an additional 3 ATP and the 5 leftover G3P's. Once RuBP has been regenerated it can be used to fix more CO2 and continue the dark reaction cycle.

As I have an exam tomorrow, while I was studying, I have realized a lot of predators have broad diets. Most predators eat prey in relation to their availability without showing a preference for any particular prey species. A predator, like a lynx will be specific if it eats tat species more often than would be expected based on that prey's availibility. That is why it will choose the snow hare bunny. They are considered specialists. Same goes with the coyote. This constitutes 60-80% of the coyotes diet. Some predators concentrate teir foraging on what ever prey is most plentiful, which to me makes the most sense. The more they fill you up the better! In a research conducted, guppies were given fruit flies that float on the water surface or worms that sink, and they chose the one that is more abundant. They will switch to either, whichever is most abundant. 

ATP itself does not give energy directly to a process that may need it, rather it is the breaking down of ATP that gives a reaction the energy it needs to proceed. The energy that ATP gives comes from energy released by breaking the bonds in its structure. The three phosphate groups attached to each other all have the same charge, and like charges prefer not to be close to one another. Given this relationship, a lot of energy is required to bond these phosphate groups together. When a reaction needs energy, the bond between the second and third phosphate group of the ATP molecule is broken, which releases a large amount of energy that can be used by reactants. Because mitochondria produce the cell’s major energy source, ATP, mitochondria are referred to as “the powerhouse of the cell”.