Data Activity - Graph Skills - Topic 3.1 - Disappearing butterflies (Answers)
Exploring the Data 1. At the top of the graph the following sentence appears: "Changes in butterfly populations are measured as an index relative to populations in their start year (1976 or 1990 depending on the species group)." Outline what this means and explain why the person who drew the graph has done this. A relatively simple way to make such comparisons about how the populations of butterflies have varied over...