cambrian explosion

Example Sentences

• "Alternatively, if animals had a relatively long Precambrian history, why do so many kinds appear abruptly and more or less synchronously in the fossil record during Early Cambran time? Was there an external environmental factor that either prevented animals from becoming fossilizable (i.e., large muscular, and/or mineralized) prior to the beginning of the Cambrian, or did some biological or environmental event trigger the metazoan radiation? Hypotheses that have been advanced to explain these questions tend to focus on either an external environmental control on, or an internal property of, the organisms that participated in the Cambrian explosion."
• "A major adaptive radiation took place during the Cambrian Period that resulted in the evolution of most of the known phyla (broad groupings of organisms) as well as other phyla that have since become extinct. This geologically rapid appearance of diverse multicellular life is referred to as the Cambrian explosion, and is best documented in the fauna of the Burgess Shale (Middle Cambrian-age Stephan Formation) of British Columbia."
• "Evidence of transitional stages is missing both in the living world and in the "Cambrian explosions" at Burgess Shale in the Canadian Rockies and at the Chengjiang site in China. It is only proper at this point that we demand hard evidence of transitional stages. To wait millions of years for it to appear is simply a scientism of the gaps."
• "A few worlds may have made this giant leap, invented sex (or some equivalent), and produced planets with sponge-like organisms to filter-clean their seas as a precedent to the evolution of more complex life. Here and there, and likely very rarely, a few planets may have undergone their own Cambrian explosions."
• "[T]hese cliffs, cut over the millennia by the Kotuikan as it winds toward the Arctic Ocean, record one of Earth history's great turning points. As well as any rocks known anywhere, they document the remarkable diversification of animal life popularly known as the Cambrian Explosion. In the broadest possible sense, the Kotuikan cliffs record the beginnings of the modern world, a world in which animals swim, crawl, or walk beneath an atmosphere of breathable air. That's really what brought us here."
• "Brocks said the new study suggested the Ediacaran biota “already contained some of the creatures that gave rise to the [Cambrian] explosion, to the rise of modern animals”. The Cambrian explosion, also called the biological big bang, was a period about 538.8m years ago when almost all major animal groups started to appear in the fossil record."