Explain how the range of ecosystems in North America helps to increase biodiversity.
The diversity of some beetle species that feed on animal dung (faeces) was studied at two kinds of grassland site in North America. One grassland site type was grazed by cattle, whereas the other site type was not grazed. Dung beetles were collected, identified and counted from two areas with the same total size. Some of the findings are given in Table 8.1.
State the null hypothesis for a statistical test that compares the data from the two site types.
State how many genera and how many species of beetle are shown in Table 8.1.
Simpson’s Index of Diversity for the beetles on the grassland grazed by cattle was found to be $0.521$ using the formula: $D = 1 - \sum \left( \frac{n}{N} \right)^2$ where $n$ is the number of individuals of each species in the sample and $N$ is the total number of individuals of all species. Calculate Simpson’s Index of Diversity for the beetles on the grassland that was not grazed. Complete Table 8.2 to show your working. Show all working to three decimal places. Write your final answer on the dotted line.
Describe what the results in Table 8.1 and both figures for Simpson’s Index of Diversity reveal about how grazing affects the diversity of dung beetles.
State the null hypothesis for a statistical test comparing the data from the two types of site.
State how many genera and how many species of beetle are shown in Table 8.1.
Simpson’s Index of Diversity for the beetles on the grassland grazed by cattle was found to be 0.521 using the formula $D = 1 - \sum\left(\frac{n}{N}\right)^2$, where $n$ is the number of individuals of each species in the sample and $N$ is the total number of all individuals of all species. Calculate Simpson’s Index of Diversity for the beetles on the grassland that was not grazed. Complete Table 8.2 to show your working. Show all working to three decimal places. Write your final answer on the dotted line.
Describe what the results in Table 8.1 and both figures for Simpson’s Index of Diversity reveal about how grazing affects the diversity of dung beetles.