Mutualistic relationship

Nurse plants are larger plants; typically with a canopy, providing other smaller plants with an establishment of shade and protection. These younger and more juvenile plants found in the desert come to rely on such nurse plants for survival (Sternberg and Lowe, 1977 and Sternberg and Lowe, 1983). There are benefits to this mutuality of plants in the desert. Such benefits include protection from seed predators, increased nutrients for the plants, shade and reduced water evaporation (Tally D Dernier, Colleen M.

Gritty (2003) “Saguaro Distribution under Nurse Plants in Arizona Sonora Desert: Directional and Micrometer Influences pig. ). In this study we aim to determine whether (1 ) That the C Gigantic, Forecasts Wizened, and the Ambrosia Deltoid are randomly associated with nurse plants; (2) that these certain species are not randomly associated with the nurse plants. The null hypothesis in this study was rejected therefore the alternative hypothesis was accepted. Methods, The group of three gathered up and decided to pick an area based on where the saguaros were visible in Greenwood Park.

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The group picked an area to walk in a straight line making sure that it would not interfere with any other group’s straight line to prevent collecting the same data. Each member of every group spread out 5 meters from each of their own group members still making sure not to intersect with another group. In a line, the group moved forward in a straight line, counting the numbers of each juvenile C Gigantic, Forecasts Wizened, and Ambrosia Deltoid that were associated with nurse plants and those that were not. We determined whether each species was juvenile or not by measuring each to see whether it was 30′ or under.

For each one found the group members recorded it down tallying them all up as they went along. All the groups came together comparing and sharing data to get total numbers of each species. One group calculated the percent coverage, which would then be used to calculate the chi squared ((bobs. -expo. ) Q/ expo. ) Results- C Gigantic observed in association with nurse plants (53) added to the total number Of C Gigantic observed that were not in association with nurse plants (38) got us the total observed, which is 91.

Performing the chi squared test resulted in that there is not random association among C. Gigantic and nurse plants. Fig 1: In the figure above it shows the results of the chi squared test for the C. Gigantic. Class collected data In figure 1 it shows clearly that the C. Gigantic is 99. Percent not randomly associated with nurse plants (supporting the alternative hypothesis). These results were significant and they also disproved our null hypothesis that stated “random association of desert plants with nurse plants”.

Forecasts Wizened I Observed number Expected number (bobs. -expo. )AH/expo. Associated 55 29. 8 21 . 3 Not associated 47 72. 19 8. 9 XA-30. 2 UDF=l p=. 01 Fig 2: In the figure above it shows the results of the chi squared test for the Forecasts Wizened. Class collected data In figure 2 it shows that Forecasts Wizened is 99. 9 percent not randomly associated with nurse plants, which also supports the alternative hypothesis. These results are significant and they also disprove the null hypothesis. Ambrosia Deltoid (bobs. -expo. PA/expo. 71 148. 4 101 . 3 237 359. 7 41 . 78 Xx-143. 08 Fig 3: In the figure above it shows the results of the chi squared test for the Ambrosia Deltoid. Class collected data In figure 3 it shows that the Ambrosia Deltoid is 99. 9 percent not randomly associated with the nurse plants, supporting the alternative hypothesis. The results are significant and reject the null hypothesis. The C. Gigantic, Forecasts Wizened, and Ambrosia Deltoid species tested by chi squared are 99. Confidence not randomly associated with nurse plants.

Discussion- The results support the hypothesis that desert plants are not randomly associated with nurse plants. In each one of the categories of species you can see clearly that each by performing chi squared end up with 1 degree of freedom and each of the probabilities on the chi squared distribution chart. As each number rises in the degree of freedom and the probability you know that you’re null hypothesis or the random distribution of desert plant animals is becoming less likely to be true. Therefore that means that the evidence is supporting the alternative hypothesis.

This type of mutuality between the C. Gigantic, Forecasts Wizened, Ambrosia Deltoid and the nurse plants like the Palo Verve tree is a perfect example of how an ecosystem works. (Ecology) The distribution of organisms is a defining feature of how and ecosystem actually works. A relationship of this kind provides many benefits such as “increased nutrients, lower summer soil temperatures, reduced photoengraving’s, and protection from animals” (Tally D Dernier, Colleen M. Gritty (2003) “Saguaro Distribution under Nurse Plants in Arizona Sonora Desert: Directional and Micrometer Influences pig. 1).

Many saguaros perish from freezing winter temperatures and from desiccation in the summer when only saguaros under a nurse survive” (T. D. Dernier; Volume 65, Issue 1 , April 2006, Pages 46-?61, Plant facilitation in extreme environments: The non-random distribution of saguaro cacti (Carnegie gigantic) under their nurse associates and the relationship to nurse architecture). What was said by T. D Dernier supports the idea that these younger juvenile plants do accordingly distribute based on nurse plants. The naturalistic relationship of the nurse plants and juvenile desert plants is not randomly distributed throughout the desert.