Food webs — the network of trophic (eating) interaction among the many species sharing a habitat or biome — is a much studied aspect of ecology. Food web and other similar phenomena such as dispersal syndromes are epiphenomena of evolution, resulting from the negotiation of competitive and cooperative interactions among many individuals. Indeed, the food web is the gross-level movement of energy within the ebb and flow of entropy and life-based energy capture. This flow of energy is fundamental to all life systems.
The delicacy or vulnerability of a particular habitat … the potential susceptibility or resistance to perturbation … may depend on the details of this network of interactions. If everything ultimately depends on a basal food type that goes extinct, for example, there could be big trouble.So, just as understanding any aspect of life requires that we examine historically ancient, no longer extant systems, we need to understand ancient food webs. But, a valid study of food webs requires a certain level of detail that is often absent from the data available for ancient systems.Moments ago, a study of Cambrian food webs came out in PLoS Biology. Continue reading Cambrian Food Webs
Tag Archives: Paleontology
Ancient Soft Parts: Dinosaur and Elephant Tales
Some of my colleagues are downplaying the recent paper in science showing a: that mastodons are elephants and b: that birds and dinosaurs … in particular Tyrannosaurus rex and turkeys … are related. (See here and here, for instance)Yes, it is true that these phylogenetic findings are wholly uninteresting, being exactly what we expected. But that is WHY these particular phylogenies were carried out.You see, the research is being done with organic material that is very very old, and is amazingly, remarkably, unexpectedly and astoundingly preserved. The point of using this material to test a phylogeny that we already know is actually to test the material … the organic stuff in the ‘fossils’ … to see if it is for real.And yes, indeed, it is. Bits of rotted flesh from a mastodon and an old dinosaur exist. Ick.Here are the ancient elephant and the dinosaur resting comfortably on their phylogenetic laurels: Continue reading Ancient Soft Parts: Dinosaur and Elephant Tales
Elephants Were Aquatic
That elephants have an aquatic ancestry has been suspected for some time now. Moreover, the idea of elephant aquatic origins and elephant origins in general is part of a growing realization that many of the world’s aquatic mammals originated in a couple of regions of Africa that were for a very long time enormous inland seas (but that is another story I won’t cover here).
The earlier evidence came from observation of the ontogeny of the kidneys in elephants, during which the kidneys take on the characteristics that are found in aquatic mammals generally. That research was published in 1999, and is summarized here: Continue reading Elephants Were Aquatic
New in Paperback Book on Permian Mass Extinction
When Life Nearly Died: The Greatest Mass Extinction of All Time
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?
Ever 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?
The Smithsonian Institution Is Not Smarter Than a Fifth Grader
Fifth grader Kenton Stufflebeam is smarter than the Smithsonian Institution. Since 1981, the Tower of Time exhibit has indicated that the Precambrian is an “era” … when in fact it is not an actual era.The student informed the museum, and now the Smithsonian is working on plans to paint over the word “era.”[source]
The Boneyard XIII
Grrrrrrrrrrrrr….
Welcome to the Lucky 13th Edition of The Boneyard … the Web Carnival about Bones and Stuff.
“The Boneyard is a blog carnival covering all things paleo, from dinosaurs to pollen to hominids and everywhere in between. It’s held every two weeks (the 1st and 3rd Saturday of the month), traveling around to a different blog for each installment, connecting some of the best blogging on ancient life.”
The previous edition of The Boneyard is here, at Dragon’s Tales. The next edition of The Boneyard will be Here at Archaeozoology. If you would like to submit an entry to the next edition, you may do so here. As always, thanks to Brian for originating and managing this carnival.
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:
- The diversification of the major groups of mammals occurred millions of years prior to the KT boundary event; and
- The further diversification of these groups into the modern pattern of mammalian diversity occurred millions of years later than the KT boundary 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
Darwin and the Voyage: 09 ~ Fossil Quadrupeds
Charles Darwin wrote a book called Geological Observations on South America. Since Fitzroy needed to carry out intensive and extensive coastal mapping in South America, and Darwin was, at heart, a geologist more than anything else (at least during the Beagle’s voyage), this meant that Darwin would become the world’s expert on South American geology. Much of The Voyage is about his expeditions and observations. Part of this, of course, was figuring out the paleontology of the region. Continue reading Darwin and the Voyage: 09 ~ Fossil Quadrupeds
The Boneyard Lucky 13
<-- If you can tell me what this thing is, I'd be much obliged.
The Boneyard. This is approximately the 13th installment of The Boneyard Web Carnival, dated February 9th, plus or minus a week or so. In paleontology, we do not concern ourselves with trifles such as exact dates.
The Boneyard web carnival is about fossils, and bones, paleontology and taphonomy. It is about anything boney except actual boneyards, although actual boneyards would be of interest as well because we are a morbid, bone loving bunch.
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:
- The diversification of the major groups of mammals occurred millions of years prior to the KT boundary event; and
- The further diversification of these groups into the modern pattern of mammalian diversity occurred millions of years later than the KT boundary event.
Whale Evolution
Are We In The Anthropocene? No.
Proposals 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?
Did 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.