A Community of Woody Shrubs, Essay Example

In this experiment, algae growth will be the dependent variable that is used to determine the effect of falling leaves on net primary production in a pond (independent variable). Two ponds will be identified that have different levels of falling leaves in the pond. One pond will be selected that has no falling leaves or very few, while the second pond that will be selected for observation will have many fallen leaves. The amount of leaves in each pond will be quantified by determining the average number of leaves in a 0.5 meter radius. Five different measurements will be conducted in different parts of the pond to generate this value. The total algae in each of these radii will then be extracted and weighed separately. The average weight of the algae in grams will be calculated. After this experiment is performed for both the pond with no leaves (control) and the pond with many leaves, the amount of algae in grams will be compared. If there is more algae in the pond with no leaves, then a lack of leaves enhances primary production in ponds. If there is more algae in the pond with leaves, then leaves enhance primary production in ponds.

To test whether the leaves of chaparral shrubs release harmful, water- soluble chemicals that keep the grass seeds from germinating in the adjacent soil, it would be helpful to plant chaparral seeds in a controlled area with just this chemical present and compare their growth to chaparral seedsplanted in a controlled area with none of this chemical present. To determine whether that small mammals living in the dense cover provided by chaparral consumethe grass seeds before they germinate, they can be planted in their native environment surrounded by a cage that keeps these animals out. The growth of these plants should then be compared to chaparral plants that have not been provided with the same level of protection.

In order to test this second hypothesis, it will be first necessary to define what animals live in the surrounding area and could potentially be consuming the chaparral seeds. Netting should be placed around the plant to keep the smallest potential animal out. If these plants continue to grow, it can be concluded that animals are impacting the chaparral growth.

Darwinian fitness is the relationship between surviving progeny of a particular genotype compared with average number of surviving progeny of competing genotypes after a single generation. To measure this experimentally without DNA sequencing, it would be necessary to measure a genotype that has a directly observable phenotype. In this particular situation, it would be possible to measure the survivability of cacti that have needles compared to those without needles. To do so, it would be essential to identify a population of cacti that have a mixed population of those with and without needles. If these belong to different genera and species, it would be necessary to correctly identify members of each group in a mile radius. After this initial counting, the site should be revisited to determine the new ratio between the cacti. A comparison of the ratio at the beginning of the year to the ratio at the end of the year will indicate the Darwinian fitness of the population. It is possible to repeat this experiment with other plants that have a similar genotype/phenotype relationship.