Passage Summary: Two different biological markers were used to date the end of the ice age: beetles and trees. The beetles showed up half a millennium earlier than the trees.

Reasoning: Warmth-adapted beetles appeared in the sediment record 500 years before spruce forests appeared in those same samples.

Analysis: We have two different biological responses to the same warming trend. The fact that the beetles showed up 500 years before the spruce trees suggests a difference in how quickly these organisms react to climate change. Insects can migrate and reproduce very quickly, whereas a forest takes a long time to establish itself. We should look for an answer that concludes that different biological indicators can provide different timelines for the same environmental shift, or that some species respond to warming much faster than others.