Tag Archives: Extinction

Extinction of the Old, Evolution of the New: What really happened to the dinosaurs?

ResearchBlogging.orgMany years ago, a sudden event occurred that changed everything. Or at least, that is what we think now. But in truth, the event took longer than many today believe, and many of the specific details, the exact order of events, the actual meaning of each detail, are not fully understood. Indeed, in the process of describing this event today, we find considerable disagreement, or at least, it is clear that one person’s version is different than another’s. I’d be happy to give you my version of it. What qualifies me to do that? Well, for one thing, I was there when it happened…
Continue reading Extinction of the Old, Evolution of the New: What really happened to the dinosaurs?

The Fantastic Mystery of the Younger Dryas

One of the most interesting and exciting stories in science is that of the Younger Dryas. The Younger Dryas was a climate event that had important effects on human history, and that has been reasonably linked to some of our most important cultural changes, and ultimately some evolutionary changes as well. That is one reason why it is interesting. In addition, the Younger Dryas was a pretty big deal … a climate change or something like a climate change that caused massive changes all around the earth, and fairly recently. But the cause of the Younger Dryas is at present unknown, although a series of explanations have been advanced, each as convincing as the next depending on one’s point of view. The Younger Dryas itself is interesting, and the story of how scientists have studied it and the changing explanations emerging from that research is just as interesting.

The latest science is beginning to suggest that it is all even more interesting and exciting (and scary) than previously thought.

Continue reading The Fantastic Mystery of the Younger Dryas

New in Paperback Book on Permian Mass Extinction

i-10092cedc7be5d8a5cb3f10bec59f6b5-lifedied.jpgWhen Life Nearly Died: The Greatest Mass Extinction of All Time is a book by Michael Benton on the Permian Extinction now out in paperback. From the press release:

Today it is common knowledge that the dinosaurs were wiped out by a meteorite impact sixty-five million years ago, which killed half of all species then living.Far less well-known is a much bigger catastrophe – the greatest mass extinction of all time – which occurred 251 million years ago, at the end of the Permian period. In this cataclysm, at least ninety per cent of life was destroyed, both on land, including sabre-toothed reptiles and their rhinoceros-sized prey, and in the sea.After the event the Earth was a cold, airless place, with only one or two species eking out a poor existence. What caused destruction on such an unimaginable scale, and how did life recover?Michael Benton’s book about this catastrophe – When Life Nearly Died: the greatest mass extinction of all time – has been published in paperback this week. Michael Benton is Professor of Vertebrate Palaeontology at the University of Bristol.James Lovelock said of the book: “Michael Benton’s book brings back to Earth Science a sense of adventure … it is both a wonderfully good read and a valued reference”.When Life Nearly Died documents not only what happened 251 million years ago, but also the recent rekindling of the idea of catastrophism, after it was seemingly extinguished in a great battle of ideas in the early nineteenth century. Scientists have at last come to accept that the world has been subject to huge cataclysms in the past. For the end-Permian event the killing models are controversial – was the agent the impact of a huge meteorite or comet over ten kilometres in diameter, or prolonged volcanic eruption in Siberia? The evidence has been accumulating through the 1990s and into the new millennium, and Michael Benton gives his verdict at the very end of this book.

Did sexist white males cause the extinction of the woolly mammoth, or was it climate change?

i-df0d572725cb6610419e63e698f12a2f-mammoth.jpgEver since 3,599 years ago humans have been asking the question “Why did our furry elephant go extinct?”What caused the woolly mammoth’s (not to be confused with the also-woolly mastodon) extinction? Climate warming in the Holocene might have driven the extinction of this cold-adapted species, yet the species had survived previous warming periods, suggesting that the more-plausible cause was human expansion.The woolly mammoth went extinct less than four thousand years ago. The bones of miniaturized woolly mammoths have been found in Siberia dating to about 3,600 years ago. Indeed, woolly mammoths, the furry elephant of the north, was around recently enough that it overlaps with the invention of writing by humans, and is depicted in a drawing on the wall of at least one example of a dynastic Egyptian building, along with a number of other unusual (for Egypt) but perfectly real animals. Continue reading Did sexist white males cause the extinction of the woolly mammoth, or was it climate change?

Mammals and the KT Event

A very important and truly wonderful paper in Nature described a tour-de-force analysis of the Mammalian Evolutionary Record, and draws the following two important conclusions:

  1. The diversification of the major groups of mammals occurred millions of years prior to the KT boundary event; and
  2. The further diversification of these groups into the modern pattern of mammalian diversity occurred millions of years later than the KT boundary event.

Continue reading Mammals and the KT Event

Darwin and the Voyage: 11 ~ Elephants and Horses

In 1833, Darwin spent a fair amount of time on the East Coast of South America, including in the Pampas, where he had access to abundant fossil material. Here I’d like to examine his writings about some of the megafauna, including Toxodon, Mastodon, and horses, and his further considerations of biogeography and evolution. Continue reading Darwin and the Voyage: 11 ~ Elephants and Horses

Are We In The Anthropocene? No.

ResearchBlogging.orgProposals to give the latter part of the present geological period (the Holocene) a new name … the Anthropocene … are misguided, scientifically invalid, and obnoxious. However, there is a use for a term that is closely related to “Anthropocene” and I propose that we adopt that term instead. Continue reading Are We In The Anthropocene? No.

Did Humans or Climate Change Cause the Extinctions of Pleistocene Eurasian Megafauna?

Blogging on Peer-Reviewed ResearchDid humans wipe out the Pleistocene megafauna? This is a question that can be asked separately for each area of the world colonized by Homo sapiens. It is also a question that engenders sometimes heated debate. A new paper coming out in the Journal of Human Evolution concludes that many Pleistocene megafauna managed to go extinct by themselves, but that humans were not entirely uninvolved.

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