New study finds no evidence for theory that humans wiped out Australian megafauna
Most species of gigantic animals that once roamed Australia had disappeared by the time people arrived, a major review of the available evidence has concluded.
The research challenges the claim that humans were primarily responsible for the demise of the megafauna in a proposed “extinction window” between 40,000 and 50,000 years ago, and points the finger instead at climate change.An international team led by the University of New South Wales, and including researchers at the University of Queensland, the University of New England, and the University of Washington, carried out the study. It is published in the Proceedings of the National Academy of Sciences…
(read more: PhysOrg)
(image: This is a reconstruction of an extinct marsupial lion — Thylacoleo carnifex. Artwork: Peter Schouten)More information: Climate change frames debate over the extinction of megafauna in Sahul (Pleistocene Australia-New Guinea) www.pnas.org/cgi/doi/10.1073/pnas.1302698110
HASTINGS NATURAL RESERVE, CALIFORNIA
University of California has long been known as an innovative institution. The 1939 WPA guide to California referred to the university as a “home of celebrated scholars and a brilliant center of research,” and today, that tradition of research continues at UCLA, UC Berkeley and the other campuses across the state.
One of the university’s invaluable resources is its nature reserve system - a network of protected land throughout the state where researchers and graduate students can conduct field studies. Hastings Natural Reserve is the oldest in the system. Its rich and unique history as a research station dates back to the 1930s when former farming land was offered to the University for biological fieldwork. The forward-thinking landowner and University staff and faculty allowed the 2700 acres of land to return to a natural state, and 80 years later, it’s become a great place for scientists to investigate anything from geology to phenology - the study of seasonal or periodic events in biology - with a focus on long term patterns in the environment.
We visited the reserve to interview Brian Haggerty, a UC Santa Barbara graduate student. He’s one of the researchers working on the The California Phenology Project, an effort to track and keep record of plants as a way to monitor climate change. He conducted a workshop with thirty scientists from central California to talk about creating a statewide database for phenological events… or as he calls it “Facebook for plants.” Brian and Vince Voegeli, the reserve manager, took some time to show us around Hastings and tell us a little bit about current research going on here along with the other reserves at UC.
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UC Research tells the stories of the innovative research emerging from the University of California. You can follow them on Facebook, Twitter and at ucresearch.tumblr.com, and find their website here.
Beyond their pretty remarkable ability to “think” and problem-solve, slime molds are just plain beautiful.
John Bonner, a professor emeritus at Princeton, has been studying them for seventy years. He’s been fascinated by the ability of this “bag of amoebae encased in a thin slime sheath” to operate like a simple brain, despite its biological simplicity. He’s used the gooey little guys to further the study of evolution and development for over half a century, and some of the images he’s collected are stunning.
The GIFs above are from this collection of half-century-old film clips captured by a young Bonner, showing the life cycle of a slime mold. Lastly, you absolutely do not want to miss this gorgeous new collection of close-up slime mold photos SciAm’s Alex Wild.
Old and new, these little creatures are as beautiful in form as they are amazing in biology.
Good old Dicty.
Really just goes to show how we can learn so much about our own complex biology from organisms that are distantly related.
So, Tremors or Dune? I suppose it depends on how much camp you can handle in your science fiction. Hydnora africana, while boasting the mien of a sandworm, is actually a smelly, parasitic little oddity that sprouts on the roots of plants in the spurge family.
As its name suggests, it’s native to southern regions of Africa, outfitting itself with the perfume of a latrine in mid-summer. But how else would it attract the dung beetles it needs to pollinate? Three cheers for the weird and weirder, Tumblr. —MN
Hydnora Africana. Possibly the most bizarre looking parasitic plant in the world.
The Date of Interbreeding between Neandertals and Modern Humans
Comparisons of DNA sequences between Neandertals and present-day humans have shown that Neandertals share more genetic variants with non-Africans than with Africans. This could be due to interbreeding between Neandertals and modern humans when the two groups met subsequent to the emergence of modern humans outside Africa. However, it could also be due to population structure that antedates the origin of Neandertal ancestors in Africa. We measure the extent of linkage disequilibrium (LD) in the genomes of present-day Europeans and find that the last gene flow from Neandertals (or their relatives) into Europeans likely occurred 37,000–86,000 years before the present (BP), and most likely 47,000–65,000 years ago. This supports the recent interbreeding hypothesis and suggests that interbreeding may have occurred when modern humans carrying Upper Paleolithic technologies encountered Neandertals as they expanded out of Africa.
This is the kind of thing that makes/made me want to get a Ph.D.
(Of course, as one of the commenters pointed out, what if the scientific community has gotten better at detecting fraud? Can we know if that’s the case?)