Drafts

The simple pendulum experiment measured the amount of time ten periods of rotation took place when varying angles of displacement.  Each angle was increased by twenty-five degrees the rotation responded by increasing the amount of time ten rotations took place with an average of 7.6 seconds/10 rotation. Though only the first two rotations were observed to be gradually increasing the last two measured angles increased by more than three seconds. The big difference in time is troubling because each increase should have been less than a second. In my observations, I thought that the increase of angle affected the amount of air friction the pendulum went against. The experiment was interesting because it made me think what if a wrecking ball was used to crash a building the wrecking ball would have to be angled at a smaller degree to cause less disturbance when there is only one target.

                There a numerous methods of reproduction. For instance, many organisms reproduce through a method known as ovipary. This simply means that the organism lays their eggs. The eggs may be fertilized before or after laying. A secondy method is known is vivipary. In organisms that reproduce by vivipary, they will hold their eggs until hatching. Vivipary comes in two forms, Lecithotropy and Matrotrophy, which is defined by the method of nutrients given to the embryo. During Lecithotrophy, the embryo is sustained by lecithin found in the yolk of the egg. Matrotrophy adds additional methods of sustaining the embryo. These methods include: Oophagy, Adelphophagy, Placentation, Epithliotrophy, and Dermatotrophy. During Oophagy, the mother will produce additional eggs, which may or may not be fertilized, which the current embryo will feed on. Adelphophagy is very similar in that an embryo will feed on other embryos within the mother. Placentation simply connects the embryo to the mother’s circulatory system, allowing it to gain nutrients from the mother more directly. During Epithliotrophy, the mother produces a lining within her womb, which the embryo may ingest for further nutrients. This too is similar to Dermatotrophy, in which the embryo will ingest parts of the mother’s outer skin for nutrients. These methods will allow for an offspring to be larger and thus more viable, however it requires a substantial energy sacrifice for the mother.

           Animals communicate through four major modalities. The first is via auditory signals. These are the calls, whines, and noises that each animal makes in order to communicate. Each noise has its own meaning behind it and context is extremely important. For example, during mating season, black-back gulls make a mew sound which is a sign of hunger and the desire to nuptually feed. This same sound is made outside of mating season in order to call in back up for territorial disputes. Another modality would be visual cues such as body position, colorations, and even dance or other ritualistic movements which can indicate a number of things as well. The third modality is the animals chemical signals. As we all know, each organism has a set of pheremones which elicit a response in a partner. This chemical signal is used to signify the beginning of mating season and the organisms ability to mate. Lastly are tactile signals. Organisms may touch or poke or pro at each other in order to send a signal. An example of this once again comes from the black back gulls who's females often rub their heads on a mates neck to beg for food and/or sex. Each modality has unique characteristics and all send different signals to members of the species. Therefore, it is important to analyze the situation in order to try and decipher the message being broadcasted.

In comparing the hilly area to the flat area, the results portrayed that the hypothesis that there would be less diversity on a hilly area compared to a flat area because it would be very hard for the plants to absorb the nutrients was correct. Though it seems as if a hill would help to spread nutrients over a broader area of plants, the water would run down too quickly resulting in only a minimal amount of nutrients able to be absorbed. However, the nutrients would most likely be too little of an amount to fully saturate the roots of the plants. However, on a flat area, the nutrients can fully sink into the ground, providing much more room for diversity. In Table 2 of the hilly area, the data showed that species 6 dominated the area. From this, it can be assumed that this species is more suited for survival on a sloped area than most species of plants. This may be due to the plant having shorter roots or the plant being more self-sufficient and only requiring a small amount of nutrients to survive. It can further be presumed that on hilly areas specific types of plants will be found.

Birdsong is used to communicate with other birds, similar to the way humans communicate. Birdsong is taught the same way humans learn language: they learn from their parents and it is passed down. In addition, there are different dialects for different regions. Also, children birds and humans both hear their mistakes as their learn their languages. Depending on the environment in which a bird lives, the pitch and type of song the bird sings may be different. A bird’s song is meant to be heard for as far as possible so the recipient can hear it clearly. As a result, some birds may have high pitched songs while others may have low pitched songs, depending on their environment and who they are trying to communicate with. For example, deserts are much more open than forests, so birds in the desert usually use “the buzz” while birds in the forest may use low pitched songs so it won’t be lost amongst the trees and ground. Males try to show off their skill and compete for mates through their songs. Males will usually create much more complex songs in hopes of impressing a female and making them their mate.

It is often wondered how visual and sensory stimuli affect a child’s development. While ‘nature versus nurture’ is an extensive and prolonged debate, it is a relevant topic when trying to understand child development and growth. In a recent experiment, rats were split up and placed into three scenario cages: a cage with adequate resources and space, a cage without adequate resources and space, and a cage with an excessive amount of resources and space. After weeks of living in these the scenarios, the scientists collected the rats and measured each rat’s brain radius and brain activity. As a result, the rats living in the cage with excessive amounts of resources and space had a very different brain chemical make-up and size then the rats living under impoverish circumstances. More specifically, the cerebral cortex of the brains in the rats living in great conditions were larger and more developed; this indicates that brain development is dependent on outside experience or ‘nurturing’ factors.  This is significant in proving that brain development is affected by living experiences; and now the nurture side of the ‘nature versus nurture’ debate has a solid piece of evidence to back it up. 

In this lab, the diversity of plant species in different types of environments was observed. In this case, the diversity of plant species were collected on a hill and a flatland. Depending on the slope of the environment the plant was growing on, the diversity of species were examined. Diversity is good in an environment because it makes it more stable and suitable for diseases and other changes to its surroundings. An environment is healthy when it is very rich. Richness is the number of species in a community. The most common way to determine whether an environment is diverse or not is through the Shannon diversity index. The Shannon diversity index is a way to mathematically measure a community’s diversity (Beals). This is important to biologists in order to observe how rare or common a species is in an environment (Beals). In this lab, the types of environments were observed to see if they make a difference on the diversity of plants in the given area. On a hill the nutrients and soil will run down to the bottom, preventing plants from using them. The assumption can be made that there will be less diversity on a hill than there would be on a flatland because of the decreased amount of nutrients on a hill due to its slope.

I believe the second biome to be a temperate deciduous forest, which could be found between 30º and 50º N. In this area it is also important to note that this is limited to “on the eastern and western edges of Eurasia, and on the eastern edges of North America” (Bowman 65) this is because the further inland you go, the more precipitation is lost. The main factor that led me to believe that it is a temperate deciduous forest are the periods of sub-freezing temperatures (under 0 º C) that occur between the months of December, January, and mid-February. In addition, I also noticed that there were no periods of time where it was insufficient for plant growth which supports the idea of tree growth. The mystery biome is described as having an annual precipitation rate of 1562 mm. If this biome is like the other biomes we have studied, I’d assume it contains trees such as oak trees which are deciduous and lose their leaves, which is important for the freezing temperatures. In addition, deciduous trees are well suited for the seasonality of the cool/ cold temperatures and the dry/ wet precipitation. 

A sodium potassium pumps is used in the active transport of sodium and potassium ions across a cell membrane. The pumps moves 3 sodium ions out of the cell for every 2 potassium ions that it brings into the cell. The movement of these ions is against their concentration gradients, which means the pump needs energy in order to transport these ions. In a cell, most of the Na+ exists outside of the cell and the K+ is inside the cell. Charge is measured at the membrane and in a neutral cell, the inner layer is negative where the outside is positive. Cells move torward the membrane potential of the ion it's most permeable to, so if a cell has more leakage channels for K+ then the membrane potential for K+ is what is desired. 

Extracellular potassium will result in a less negative membrane potential because an addition of extracellular potassium results in a decrease in the concentration gradient. There is more potassium inside of the cell to begin with so an increase in extracellular potassium decreses the chemical gradient, creating a less negative membrance potential. 

Decreasing extracellular sodium will not have a similar impact on the membrane potential. This actually has little effect on the membrane potential since the membrane is not very permeable to sodium. Leakage potassium channels exist so the membrane is more permeable to potassium than to sodium. So potassium has more movement available. An increase in extracellular potassium would then decrease the amount of potassium leaving the cell through these leakage channels since the gradient is less steep. This results in a less negative (more positive) membrane potential. Becasuse sodium is not as permeable, reduction of extracellular sodium would not have a similar effect because active transport is required regardless. 

I believe mystery Biome 1 to be a temperate shrubland + woodland area. Most likely falling between 30º and 40º N and S. One of the main reasons that made me believe this, was because there is seasonal precipitation. In this first biome, there is a rainy winter season. For example, the month where it hits the peak in October and then continues to stay high throughout the winter. I also noticed that the precipitation drops in April and continues to drop until July where it starts to get wetter again. During the months of mid-June and mid-August, the conditions are insufficient for plant growth. This factor is in line with what we already know about shrubland and woodland areas. If this biome behaves the same way, we can assume that it is going to contain mostly evergreen shrubs and trees. The plants here have to make it through the months where it is insufficient for plant growth so many of them will probably contain sclerophyllous leaves, which are able to survive hot, dry summers.