Assignment 4

Effect of Island Size: The size of the living area for any population can strongly influence population numbers for organisms that live within that environment. The maximum number of organisms from a given population that an environment can support is known as the carrying capacity of that environment. Island size is one factor that can determine the carrying capacity of finches on each island. For the purposes of this simulation, the islands are assumed to be roughly circular and island size is represented as the radius of the island in kilometers. The size of each island remains constant throughout the simulation unless you choose to change this parameter. Although changing the entire size of an island is not something that could easily be done in real life, habitat changes and reducing the living environment for a population are real changes that occur through processes such as land development, and pollution. Working within EvolutionLab, answer the questions below.


1 .		Develop a testable hypothesis to predict what effect an increase in island size will have on beak size and finch populations. Test your hypothesis as follows: Begin your experiment by leaving all other parameters at their default values. Select the Island Size input and use the sliders to increase the size of either Darwin or Wallace Island. As you move the slider, the island image will change to reflect the values you have chosen.

2 .		What effect did changing the island size have on finch population? What effect did this change in island size have on beak size? Are the results what you expected? Explain your answers. Perform a new experiment to learn about the effects of a decrease in island size on beak size and finch populations.

3 .		Based on the previous experiments, consider possible parameters that you could manipulate which would prevent the changes in population size and beak size that you observed from occurring. Test the effect of these parameters to influence population size and beak size by designing and running experiments to confirm or refute your answers.