bio lab

Observance of Artificial Selection: Technical Study of Wisconsin Fast Plants

5th and 6th period AP Biology
Due: 12/16/13
Abstract
This experiment was used to explore the Theory of Evolution created by Charles Darwin. The use of natural selection was apparent in the artificial modification of an organism 's traits which aided in this investigation. Through this experiment the Wisconsin Fast Plant was used. It is a fast-growing organism developed to improve the resistance to disease in cruciferous plants. This plant aids scientist in the exploration of environmental effects on population due to the speed to which is matures and reproduces. Artificial selection was stimulated by the selection against plants with few hairs (trichomes). Trichomes create a wider variation meaning it is polygenic. The plants that had only a few trichomes were exterminated and the rest were pollinated to create an F2 generation. This was done in an attempt to increase the number of plants with many hairs in the next generation. It turned out to be a successful use of natural selection due to the decreased amount of bald plants from the F1 generation to the F2 generation. Concerning how the experiment is actually performed, five Wisconsin fast seeds are planted into a cup full of soil and six fertilizer seeds. The seeds are then covered with more dirt and connected to a cup full of water through a wick. The soon to be plant is then placed under light for 24 hours. After this the plants with the highest amount of trichome numbers are found and kept. When flowers are present, the selected plants are cross pollinated with a pollinating stick and from there the plants are monitored and recorded.

Introduction
In this experiment, two rounds of artificial selection on a population of Wisconsin Fast Plants, also known as “Brassica rapa” were performed. Artificial Selection is when humans decide which organism can reproduce. What is being tested is if there would be a different amount of trichomes in the two generations. Trichomes are small hairs on the epidermis of a plant. The process would be done through a mechanism known as evolution. Evolution is the change in characteristics of living organisms over generations. Before the second generation, artificial selection occurs by cross pollinating the selected plants, collecting the seed pods and planting them. Seedpods are connected to the plant, they hold the seeds. As this experiment is performed, differences between the two generations of plants are observed. During the experiment all plants with fewer than 15 trichomes were thinned and not allowed to reproduce in the next generation. The purpose of this experiment was to observe the effects of artificial selection over three generations (P, F1, and F2) of Wisconsin Fast Plants. The P generation functions as a control for the number of trichomes present in the absence of evolution or artificial selection. The independent variable is the plants able to reproduce in the next generation on the basis of trichome number. The dependent variable is the number of trichomes present in the following generation. The life cycle was closely monitored for any changes in plant growth or development. Through each successive generation a significant increase in the number of trichomes present is expected. Thus the hypothesis of this experiment is that if Fast Plants with fewer than 15 trichomes are removed from the population, the number of trichomes will increase significantly from generation to generation because of artificial selection will inhibit the plants with fewer than 15 trichomes from contributing that phenotype to the next generation.

Results As the graph clearly shows, there are many more plants with higher amounts of trichomes in the 2nd generation.
Discussion
Analysis After looking at the results over the two generations, the data shows their differences. The point of the experiment was to artificially select a certain plant that had the most trichomes and then pass down that trait to see if the second generation would have more trichomes. Through Chi-Square results ( a statistical analytical method used to determine whether the observed results varied significantly from the expected values), it was concluded that artificial selection is successful if the number of trichomes in the two generations could not have merely happened by chance. This is because the number of observed phenotype should remain relatively constant from generation to generation if evolution is not occurring. The null hypothesis was rejected which concludes that the number of trichomes did vary significantly from generation to generation.

Conclusion The observed effect of natural selection is that the observed number of trichomes in the F1 generation varied significantly from the number of trichomes in the P generation. This was proven by a Chi-Square statistical analysis, which revealed that the variance between the two filial generations had a less than .05% chance of occurring merely due to chance. Because the number of trichomes increased significantly from generation to generation the hypothesis is supported and artificial selection is in favor of greater trichome number was proven successful. This experiment allows researchers not only to gain insight into the effects of artificial selection, but macroevolution is occurring within the laboratory. Invaluable information is gained about evolution and artificial selection in addition to the reproductive systems and life cycles of angiosperms. The information can also be applied to the future if an organism with a certain trait is better of use than the rest, then it will pass down these traits and will be seen in the second generation. If this experiment was to be continued, the best option would be to continue discarding plants with low trichomes and reproduce the plants with high amounts of trichomes. The offspring would then be examined to see if they continue the pattern.

Materials
Dirt
Twine/ Wick
Six Wisconsin Fast Seeds (6 in each)
Fertilizer (five in each)
Four plastic cups
Water
Light Source

Methods
1). The home the plant will be living in for the next few weeks was prepared.
2).Two cups were placed on top of each other, the smaller one was on top and had a hole in it.
3).Soil was placed on open top, Fertilizer was mixed, and soil was wet until it drips from the wicks.
4).Seeds were planted carefully about six to a bottle and spaced out.
5).Each day plants were checked and made sure the bottom of the cups were filled with water. Observations were recorded as the plant grew.
8).Plants with the most trichomes were found and marked.
9).Data was recorded for population of plants. These plants were then isolated.
10). When flowers were present, selected plants were pollinated.
11).Observations were recorded as this process was done over a few days.
12). Once the seed pods turned yellow, the seed pods were harvested from the selected population.
13).Plants were monitored, pollinated, and maintained for the rest of their life cycle.
14).Seeds of plants were taken to grow the second generation of plants under the same conditions the first generation was under.
15).Over a few days, plants were reexamined and trichomes were counted

Works Cited
"Artificial selection - Understanding Evolution." 2005. 5 Dec. 2012

Cited: "Artificial selection - Understanding Evolution." 2005. 5 Dec. 2012