A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. The graph below shows some of the data for the major arthropod groups collected. Notice that the scale on the y-axis is logarithmic to make both small and large numbers legible on the same graph. For example, there are about 400 species of spiders but only 40 species of bees.
About how many arthropods were found in total?
About what percentage of these were beetles?

Verified step by step guidance

1. Step 1: Analyze the graph labeled 'Number of species' to determine the total number of arthropod species. The black bar labeled 'All arthropods' represents the total number of species surveyed. Use the logarithmic scale on the y-axis to estimate the total number of species.
2. Step 2: Identify the number of beetle species from the graph. The beetle category includes several subgroups such as predators, scavengers, fungus eaters, and herbivores. Sum the values for these subgroups to find the total number of beetle species.
3. Step 3: Calculate the percentage of beetle species relative to the total number of arthropod species. Use the formula: $\mathrm{Percentage}=\frac{\mathrm{Number} \mathrm{of} \mathrm{beetle} \mathrm{species}}{\mathrm{Total}}\times 100$
4. Step 4: Verify the logarithmic scale interpretation. Since the y-axis is logarithmic, ensure that the values for each arthropod group are correctly read and summed.
5. Step 5: Summarize the findings by stating the total number of arthropod species and the percentage of beetles among them, based on the calculations from the previous steps.

Key Concepts

Biodiversity

Biodiversity refers to the variety of life forms within a given ecosystem, including the number of species, genetic diversity, and the ecological roles they play. In the context of the San Lorenzo rain forest, understanding biodiversity is crucial for assessing the health of the ecosystem and the interactions among species, particularly arthropods, which are vital for pollination, decomposition, and as food sources for other animals.

Logarithmic Scale

A logarithmic scale is a nonlinear scale used for a large range of values, where each unit increase on the scale represents a tenfold increase in quantity. In the provided graph, the y-axis is logarithmic, allowing for the visualization of both small and large numbers of arthropod species, making it easier to compare the relative abundance of different groups, such as spiders and bees.

Species Richness and Abundance

Species richness refers to the number of different species present in an ecosystem, while abundance indicates the number of individuals of each species. In the context of the arthropod survey, calculating the total number of arthropods and determining the percentage of beetles involves understanding both concepts, as they provide insights into the ecological dynamics and health of the rain forest ecosystem.