Activity 2.3 – Island Biodiversity Simulation Report
1.0 Introduction
The History of Biogeography
Biogeography is the study of the distribution of animals and plants throughout various biomes and landscapes. Biogeography became of interest during the 1600’s when people began to travel across the globe to search for new lands. “Many ships had naturalists on board who made extensive collections. Collections began to show trends in species distributions and abundance” (“History of Biogeography,” n.d.). Biogeography was in direct conflict with theology because of the belief that at least one of every animal on Earth gathered onto Noah’s ark. Biogeography also began to prove that the Earth was much older than the bible stated. Charles Darwin is one of the most known individuals that set the foundation for Biogeography. Darwin studied species diversity and natural selection, which was a substantial breakthrough for biogeography.
Biodiversity, or the “variability among living organisms from all sources,” is extremely vital for all the inhabitants on Earth (“Biodiversity and Human,” n.d.). When populations of plants and animals are diverse, the environment is less likely to be majorly impacted if a population decreases. High biodiversity means that humans can create/discover medicines easier, food sources are more abundant, and nutrients can be recycled and stored throughout the environment. Biogeography involves researching the movement and abundance of animals and plants, while considering various land features that may impact their dissemination.
2.0 Data Collection and Analysis
Experiment 1- No Manipulation
The first step in this experiment was to observe how each species moved without any manipulation to the islands. In trials 1 and 2, the current number of species was the same. In both trials, island #1 had 10 species and island #2 had 9. The average number of species per island had a slight variation from trial 1 to trial 2. During trial 1, the average number of species for island #1 was 8.9, which decreased slightly to 8 in trial 2. For island #2, the average number of species for trial 1 was 7.8, which increased to 8.1 in trial 2. For island #1 trial 1, the most abundant species were species 2 and 7. In trial 2 island #1, the most abundant number of species changed to species 2,5,6, and 10. For island #2 trial 1, the most abundant number of species was 5 and 2, which changed to species 4 and 6 in trial 2. When taking the mean for island #1 including both trials, the total is 33.5. The mean for island #2 is also 33.5, so the island totals for both islands are exactly the same.
Experiment 2- Distance manipulation
8For the next step in the experiment, one island was moved either further or closer to the mainland. I chose to move island #2 110 km away from the mainland. Island #2 was moved 100 km away from island #1. In trial 1, the current number of species for island #1 was 10, which stayed the same during trial 2. For island #2, the current number of species was 9 in trial 1 and increased to 10 in trial 2. In trial 1, the average number of species for island #1 was 8.3, which slightly decreased to 8.2 in trial 2. For island #2, the average number of species was 8.8 in trial 1, which decreased to 8 in trial 2. For trial 1 island #1, the most abundant number of species were species 1 and 8. This changed to species 2,4,6,7,9, and 10 in trial 2. In trial 1 island #2, the most abundant number of species were species 6 and 10, which changed to species 1,2,4,7, and 8 during trial 2. The mean for island #1 including both trials was 35.3. The mean for island #2 including both trials is 31. The mean for island #1 is greater than the mean for island #2.
Experiment 3- Size Manipulation
During this part of the experiment, the islands were moved back to an equal distance, but one of the islands sizes was manipulated. I increased the size of island #2 to 128 km, which is 128 km smaller than island #1. The current number of species for island #1 during trial 1 was 10, which stayed the same in trial 2. The current number of species for island #2 during trial 2 was 9, which decreased significantly to 3 in trial 2. During trial 1, the average number of species for island #1 was 7.7 and increased to 8.4 in trial 2. The average number of species for island #2 during trial 1 was 6.7 and decreased to 6.3 during trial 2. The most abundant number of species for island #1 in trial 1 were species 4,5,7, and 9, which changed to species 5,7,8, and 9 during trial 2. For island #2 trial 1, the most abundant number of species were species 1,2,8, and 9, which changed to species 7 and 2 during trial 2. When accounting for both trials, the mean for island #1 is 29 and the mean for island #2 is 10.5. The total for island #1 is significantly greater than the total for island #2.
Experiment 4- Size Plus Distance Manipulation
In this part of the experiment, both island's distance and size were manipulated. For island #1, I changed its distance to 130 km and its size to 224 km. For island #2, I changed its distance to 30 km and its size to 96 km. The current number of species for island #1 during trial 1 was 10, which changed to 9 in trial 2. The current number of species for island #2 during trial 1 was 6, which decreased to 2 during trial 2. For island #1 trial 1, the average number of species was 7.2, which increased slightly to 7.7 in trial 2. The average number of species for island #2 trial 1 was 3, which decreased to 2.8 during trial 2. The most abundant number of species for island #1 during trial 1 were species 5 and 6, which changed to species 1,2, and 7 in trial 2. For island #2 during trial 1, the most abundant number of species were species 2,6, and 8, which changed to species 6 and 9. When accounting for both trials, the mean for island #1 is 29 and the mean for island #2 is 3.5. The total for island #2 is significantly lower than the total for island.
Experiment 5- Migration And Mortality Manipulation
In the last step of the experiment, the size and distance were kept the same from the previous step, but the rate of migration and mortality rate were manipulated. I changed the rate of migration to 5 and the mortality rate to 0.03. The current number of species for island #1 trial 1 was 10, which did not change in trial 2. The current number of species for island #2 trial 1 was 8, which increased to 10 during trial 2. The average number of species for island #1 trial 1 was 9, which slightly increased to 9.4 during trial 2. The average number of species for island #2 trial 1 was 7.4, which decreased to 6.4 in trial 2. The most abundant species for island #1 during trial 1 were 2 and 7, which changed to 1 and 10 in trial 2. The most abundant species for island #2 during trial 1 were 3,6, and 10, which changed in trial 2 to species 3,7, and 9. When accounting for both trials, the mean for island #1 is 87.5 and the mean for island #2 is 21. The island total for island #1 is significantly higher than the island total for island #2.
Pie Chart and Bar Graph
For the Abundance of species table and pie graph, the number of each species throughout all the experiments were totaled and recorded. When considering all the experiments, the most abundant species was species 2, which appeared throughout the experiments a total of 10 times. Species 2 accounted for 16.95% of the total number of species. The least abundant species was species 3, which appeared throughout the experiments a total of 2 times. Species 3 accounted for 3.4% of the total number of species. The bar graph labeled Abundance vs Species gives a better idea about how many more times species 2 showed up throughout the experiments compared to species 3.
3.0 Discussion
After looking over the outcome of the experiments, it is apparent that the bigger the island and the closer it is to the mainland, the higher the island total is. The largest difference happens when both the distance and size are manipulated. The average number of species and the current number of species decreases substantially when island #2 was made smaller and moved closer to the mainland. This decrease in the number of species is due to the island having a small surface area. An island with a small surface area is prone to species extinction and is less likely to be seen by various organisms. It can be observed that even if an island is close to the mainland, the size plays a significant role in the number of species it can sustain. The largest similarities happened when both islands #1 and #2 were kept the same exact size and distance from the mainland. This can be expected since there is no difference in land features. Species 2 was the most abundant across both islands and both trials. Species 3 was the least abundant. Manipulation #1 allowed for the most prosperous species survival, but manipulation #2 allowed for more of a variety of species during trial 2. When an island is close to the mainland, varied species can travel to and from the island easily. When an island is far away from the mainland, less species can reach the land due to surrounding conditions, like water. There is a very select type of species that can reach further away islands, which is why islands that are far away from the mainland have less species variation.
4.0 References
Biodiversity & Human Well-being. (n.d.). Retrieved from https://www.greenfacts.org/en/biodiversity/l-3/1-define-biodiversity.htm
History of Biogeography. (n.d.). [PDF Presentation]. Retrieved from https://www.zoology.ubc.ca/~jankowsk/BIO413_2_010814.pdf
