For 10 points, name this event in which an entire species dies.
A concentration of iridium corresponds to one of these events that took place at the K-T boundary, and which was likely due to the Chicxulub [CHEEK-shoo-loob] impact. The coelacanth [SEE-lih-kant] is an example of a Lazarus taxon which experiences this event but then reappears in the fossil record. More recently, this event occurred to the (*) passenger pigeon and dodo. Dinosaurs experienced this about 65 million years ago. For 10 points, name this event in which an entire species dies.
A concentration of iridium corresponds to one of these events that took place at the K-T boundary, and which was likely due to the Chicxulub [CHEEK-shoo-loob] impact.
(mass) extinction event(s) (prompt on dying or similar answers; accept asteroid impact or logical equivalent until "Chicxulub" is read)