What was the Cambrian explosion? How can the sudden appearance of so many new species be explained?<\/p>\n\n\n\n
The fossil record shows something intriguing: A ton of new species suddenly appeared about 540 million years ago. Author Bill Bryson explores what this might mean.<\/p>\n\n\n\n
Keep reading for a brief overview of the Cambrian explosion.<\/p>\n\n\n\n\n\n\n\n
What was the Cambrian explosion? In the fossil record, a large number and diversity of multicellular organisms appear relatively abruptly about 540 million years ago. These organisms were all aquatic and included both plants and animals. As Bryson discusses, scientists refer to this sudden appearance of new species as the Cambrian explosion. <\/p>\n\n\n\n
But, he notes, their sudden appearance in the fossil record doesn\u2019t necessarily mean that they appeared suddenly on Earth. Scientists conjecture that many of the Cambrian creatures existed long before the presumed Cambrian explosion and became larger over time, making their fossilized remains progressively more discernible. Furthermore, the fossil record provides only sporadic glimpses of what life looked like in the past because fossils form only under certain conditions that occur only occasionally. Scientists estimate that only about one out of every 10,000 species that have ever lived on Earth is preserved in the fossil record.<\/p>\n\n\n\n