Have you ever experienced a freezing sensation after eating an ice cream cone? You’re with a group of friends eating the dessert, and suddenly you have a severe headache that lasts for a brief amount of time. You’re not alone because billions of individuals have endured this common reaction called sphenopalatine ganglioneuralgia. It’s also known as brain freeze or ice cream evoked headache. Why does even the simplest discomfort get a scientific name? But in all seriousness, what exactly happens to the body when one experiences a brain freeze?
I’m going to break one of the supposed blogging rules – I’m going to feed a troll. In the comments thread to the bird evolution post I wrote recently, one commenter brought up the supposedly intractable evolutionary problem of the “sudden” appearance of flowering plants. I briefly responded to this comment at the time, but I thought the question is an interesting enough one to deserve further investigation. So here is my presentation on why the “sudden” appearance of flowers was not so sudden.
The International Union for Conservation of Nature (IUCN) released a report in 2007 indicating that more than 16,000 animal species worldwide are threatened with extinction. These numbers translate into one in four mammal species, one in eight bird species and one in three amphibian species that are included on the IUCN’s “Red List” of endangered species. However, a paper was just published suggesting that the risk of extinction for many animals and plants has been underestimated by as much as 100-fold. According to the paper’s lead author, assistant professor Brett Melbourne of University of Colorado at Boulder’s ecology and evolutionary biology department, this underestimation was the result of a mathematical “misdiagnosis.”
Spider silk is a most amazing and versatile material, and spiders put it to all sorts of uses. It helps them to climb, to travel from place to place and most famously, to ensnare their prey. But one group of spiders, the uloborids, use their silk in a unique way – as a murderous garbage-compactor.
Time for more borhyaenoids. Finally, we get round to the taxa that you might have seen or read about in prehistoric animal books: the sabre-toothed thylacosmilids, the supposedly bear-like borhyaenids, and the gigantic and even more bear-like proborhyaenids. We previously looked at basal borhyaenoids here, and at the mostly scansorial, mustelid-like hathlyacinids and prothylacinids here. Here we go…
Thomas Jefferson had an axe to grind when he wrote his Notes on the State of Virginia in 1781. Twenty years earlier the French naturalist Buffon had published the 9th volume of his epic series Histoire naturelle in which he compared the great, ferocious beasts of the Old World with the pitiful creatures found in the New World;