Kelsey Williams Professor Reiner
March 29, 2016 BIOL-108

Island Biogeography Lab Write-Up

Purpose of lab: Calculating how many species were migrating to different islands
Hypotheses: The main factors are island size and distance from the island. We hypothesized that islands close to a source area should have a higher number of species than islands further from the source area for islands of equivalent areas. Larger islands should have more species than smaller islands for islands located at similar distances from the source area.
Data table—compiled with other groups* Table 1: Island Biogeography Lab Data (fill this in) | Close (2m) | Middle (3m) | Far (4m) | Small (0.25 m2) | 1 | 3 | NA | Medium (.5m2) | 10 | 10 | 6 | Large (1.0 m2) | 15 | 16 | 16 |
Graph for ONE simulation—for YOUR GROUPDATA---include title, label axes, write legend (i.e.-medium island at 3M supports 12 species)

Legend: The linear trend lines did not intersect. Therefore, data is not available.

Questions
Based on your data and personal observations, answer the following questions. 1. Does your data support the basic theory of island biogeography? Explain why or why not. * When increasing the island size, the data supports the basic theory of island biogeography. With regards to the distance factor, the data does not support this theory because there is not a steady increase of distance; the distance measurements are very scattered. 2. How does competition affect number of species present on an island? * Competition affects the number of species present on an island because they are constantly competing for food and resources in order to survive. In general, competition leads to a high number of one species over other species who are competing for the same resources. 3. Do you think (hypothesize) that these bird species would occupy the same trophic level? Why or why not? * Yes, the trophic level is the position a species lies on the food chain. Because the bird species rely on the same organisms for energy and are in the same position of succession with regards to feeding, they are on the same trophic level. 4. What mechanism(s) of evolution may affect the Galapagos finches? * The mechanisms of evolution that may affect the Galapagos finches include mutation, natural selection, migration, genetic drift, and non-random mating. 5. Do the finches of Galapagos show convergent or divergent evolution? Why? * The finches of Galapagos show divergent evolution because different species of finches evolve, adapt, and develop new physical characteristics, which enable them to survive in new environments. 6. Relate the “competitive exclusion principle” to the Galapagos finches. * The competitive exclusion principle states that two species competing for the same resource cannot exist at constant population values due to competition, resource depletion, and other contributing factors. Therefore, the finches with superior characteristics and evolutionary traits will thrive whereas the other species will not; this is based on the natural selection. 7. Relate the concepts of “biological provinces” and “biomes” to the Galapagos finches and island biogeography. * The biological provinces would be considered each individual island whereas the biome would be all the islands as a whole. By definition, biomes are defined “large terrestrial ecosystems, which exhibit climatic similarity.” 8. Would diverse biomes in the Galapagos Islands support high or low biodiversity? Why? * Diverse biomes in the Galapagos Islands would support high biodiversity because all of the biomes provide a wide range of resources and have different characteristics. Thus, this supports that there would be high biodiversity over time. 9. Do you think it would make a difference in the species composition if an island is part of a chain extending out from the mainland instead of a single, solitary island? * Yes. I think it would make a huge difference in the species composition if an island is part of a chain extending out from the mainland instead of a single, solitary island because there would be more species in an island chain competing for the same resources instead of on a single, solitary island. 10. What would you hypothesize would occur if habitats on the Galapagos Islands caused physiological stress to a population of finches? * I would hypothesize that if this were to occur, the finch population would struggle to survive. The presence of this stressor would generate conflict in the habitats of the finches whether it be from competition for food and resources or other relating factors.