Precipitation Effect on Evolution
Introduction
Precipitation can have rapid and lasting effects on an ecosystem and evolution of the life forms throughout the region. Too much precipitation can cause flooding, eroding shorelines, and rising sea levels. The effects of such activity wash away food sources and ultimately changes the way the various life forms will behave and survive. If weather patterns change and eliminate or drastically reduce food sources and habitats, it can bring various elements of the ecosystem to extinction. The route chosen for this lab was to change precipitation patterns and land size moderately for both islands to evaluate how this would affect the finch population and see if either island would be able to sustain a population of finch with excessive rain or a lack of rain. These types of climate changes are happening throughout the world and result in dramatic behavioral adaptation to adjust to the environment.
Materials
The materials used for this lab were a computer and access to the Evolution Lab that is found on the student website of the University of Phoenix.
Methods and Procedures
Using the scientific method the research provided background information that two islands have similar variables pertaining to the ecosystem, finch characteristics, and finch population. The question is will a change in the current precipitation pattern have a lasting effect on the finch population? The hypothesis is if the precipitation increases it will erode the shorelines, create rising seas and decrease the population of finch on either island. Another hypothesis was if the precipitation decreases it will cause the finch to change behavior in finding food sources but will not dramatically affect the population.
Data
The below chart reflects the data collected.
Precipitation Chart
Neutral data, based on no change to ecosystem
Adverse effects of change on population
Moderate effects of change on population
Positive effects to change on population
Increase Precip. Of Darwin Increased Precip. of Wallace Darwin Wallace Darwin Wallace
Year Neutral Change Neutral Change Year Neutral Change Neutral Change
1997 200 200 200 200 1997 200 200 200 200
2007 362 225 347 280 2007 362 288 347 232
2017 269 260 376 396 2017 269 341 376 195
2027 343 223 361 350 2027 343 455 361 266
2037 316 270 344 412 2037 316 387 344 255
2047 287 304 387 424 2047 287 315 387 279
2057 375 309 412 451 2057 375 438 412 241
2067 439 267 390 521 2067 439 468 390 285
2077 463 309 437 509 2077 463 459 437 290
2087 407 261 456 505 2087 407 585 456 311
2096 520 328 538 588 2096 520 506 538 348 -37% +9% -3% -35%
Decrease Precip. Of Darwin Decrease Precip. of Wallace Darwin Wallace Darwin Wallace
Year Neutral Change Neutral Change Year Neutral Change Neutral Change
1997 200 200 200 200 1997 200 200 200 200
2007 362 130 347 272 2007 362 133 347 301
2017 269 257 376 335 2017 269 216 376 220
2027 343 290 361 313 2027 343 410 361 259
2037 316 337 344 390 2037 316 466 344 278
2047 287 298 387 320 2047 287 383 387 357
2057 375 438 412 382 2057 375 464 412 362
2067 439 467 390 415 2067 439 440 390 471
2077 463 435 437 416 2077 463 463 437 489
2087 407 508 456 428 2087 407 492 456 499
2096 520 478 538 503 2096 520 507 538 640 -8% -7% -2% +19%

The lab reflected that with an increase in precipitation there was a slight change of the seed types from hard to medium and soft. The lab provided information on the change of hard seed type with a decreased of 15% while medium seed increased 11% and soft seed increased 5%. The changes in the seed type were not necessarily enough to affect the overall population of the finch as much as the loss of total seeds due to the precipitation washing into the surrounding ocean. On the opposite side of the table it reflects far less of a change in population related to the decrease in precipitation. The exact difference was a 17% drop in hard seed that transferred to an increase of 15% medium seeds and 3 % soft seeds.
Discussion and Results
The chart above shows that over 100 year period an ecosystem will be affected by an increase in precipitation. In both cases involving Darwin and Wallace Islands there was an average drop of 35% in the finch population to the directly affected ecosystem. This same chart has to completely different outcomes as to the direct affect of decreased precipitation over a 100 year span, which resulted in a mild drop in population to the Darwin Island but a substantial increase in population of 19% to the Wallace Island.
Conclusion
It is difficult to determine the exact reasons for the results provided by the Evolution Lab. With minimal data to research there are many variables that could have affected the outcome of the research such as loss of food sources or habitats, or simply adapting to the environment. Although the seed composition changed slightly in either case it is apparent that there were situations where positive reactions happened to increase or decrease in precipitation. In either case the results reflect that excess precipitation definitely adversely affect the finch population whereas the decrease in precipitation simple encouraged the population to change in one environment and not in the other. Providing more variables such as types of food sources and habitats would enable a better analysis and conclusion to the research of how the finch is affected on both Darwin and Wallace Islands with the change in precipitation.

References
University of Phoenix. (2012). Evolution Lab. Retrieved from University of Phoenix, BIO101 website.