Surface Area to Volume Ratios in Plants (Arid vs. Moist Environments)
The ability of plants to survive in certain environments depends on many abiotic factors such as the amount of water or light available. It is important to look at how these factors affect the growth and survival of plants in order to determine their future success. In today's day and age, with the environment under constant pressures such as pollution and global warming it is crucial to investigate aspects such as how much water loss or water intake a plant can withstand. A plant in an area with large amounts of precipitation for example, is expected to have a high surface area to volume ratio. If weather patterns were to suddenly change due to a global warming trend, how would this affect the plant's growth and ability to photosynthesize? These are the questions that lie at the basis of the following experiment.
Objective:
To determine how the presence or absence of water in the environment affects the surface area to volume ratios in plants. It is observed that plants in moist environments have more lush, larger foliage, while plants inhabiting desert conditions are generally smaller and have less photosynthetic surface areas.

Hypothesis:

Alternative Hypothesis: states the hypothesis being tested in this experiment. Photosynthetic structures of plants adapted to arid environments have a lower surface area to volume ratio than plants adapted to less dry or moist environments.
Null hypothesis: there are no differences between the wet and dry habitat plants and observed differences are purely a result of chance. The null hypothesis is formulated to be rejected.

Methods:

The methods used to gather data for this experiment were fairly simple. Three plants from an arid environment and three from a moist environment were gathered randomly from the UCLA botany garden. Three photosynthetic structures from each plant were then chosen to be measured. If the stems along with leaves were photosynthetic they too were measured. The length, width, and height of each structure was then recorded in order to use for later calculations.

Statistics Method:

After gathering the data, using the dimensions measured, each group calculated the surface areas and volumes of their plants. Four groups, each with three plants gave a total of twelve plants from each environment. This is important for sample sizes lower than six or eight are not useful for statistical purposes. Then the sample mean was calculated for the data in each category. The variances were then calculated in order to determine which t-test would be used to analyze the data. It was found that the Fs value was greater than the Fcritical value and therefore the null hypothesis was rejected. After performing the Ftest and determining that the variances were assumed unequal, the Ttest was then used in order to verify that there is indeed a difference in surface area to volume ratios of plants in wet and dry habitats. This was done by first calculating the degrees of freedom and then looking at the given table and comparing the t value calculated with the t-critical value.

Results:

(Calculations and statistics shown on attached sheet of paper)

Discussion:

As seen from the calculations, the t-value for this experiment was larger than the t-critical value for an alpha of 0.05. This immediately shows that there is indeed a difference between the surface area to volume ratios of plants ...