The question of whether or not the tropical foraminiferans have extra-low extinction rates is not clear cut. Based on the graph below, they do seem to have slightly lower extinction rates — but not by much!
Let’s look at some more data relevant to this hypothesis. The pie chart below shows data on bivalves, not foraminiferans. It is fairly easy to understand. The chart shows what percent of bivalve genera living in different parts of the world have gone extinct over the past 16 million years.
Does the graph and pie chart above support the hypothesis that the tropics are a museum — in other words, that extinction rates are lower in the tropics than in other regions of the world? Or can you tell from these data? Explain your answer.