As children we wondered, “Why don’t we see living dinosaurs?” “Because they are extinct,” a parent or teacher told us. And we learned that “extinct” is an adjective meaning “of a species, family, or other larger group having no living members.” (oxforddictionaries.com)
We might further learn such facts as: “Species become extinct for many reasons, including climate change, disease, destruction of habitat, local or worldwide natural disasters, and development into new species (speciation). The great majority of species that have ever lived—probably more than 99 percent—are now extinct.” (dictionary.com)
But do we ever know what extinction looks like? Here on Lake Michigan’s Left Coast, the beach is lined with stones of many types. Sometimes the Lake reveals the limestone, chert, or quartz skulls of creatures who lived in the Paleozoic Era (541.0–252.17 million years ago). By the Permian Period (298.9–252.17 million years ago), life on Earth had evolved into amphibians and reptiles whose skulls were large enough to be easily recognizable even now. Though highly eroded by time and water, these rocks are the faces of extinction.