Life Sciences
laelaps | January 6, 2010
Tiktaalik is practically a household name. Since its description in 2006 the flat-headed "fishapod" has appeared in books, on t-shirts, and has even starred in its own music video. Hailed as a "missing link", Tiktaalik has become a poster child fossil for evolution, but it is hardly the first such creature to be given this honor.
Way back in the 1840's, well over a decade before Charles Darwin's On the Origin of Species was published, the Victorian anatomist Richard Owen was mulling over the concept of transitional forms. He was not so much thinking about actual fossils as the way anatomical…
edyong | January 6, 2010
Around 395 million years ago, a group of four-legged animals strode across a Polish coast. These large, amphibious creatures were among the first invaders of the land, the first animals with true legs that could walk across solid ground. With sprawling gaits and tails held high, they took pioneering footsteps. Their tracks eventually fossilised and their recent discovery yields a big surprise that could rewrite what we know about the invasion of land. These animals were walking around 18 million years earlier than expected.
The evolution of four-legged creatures - tetrapods - is one of…
clock | January 6, 2010There are 27 new articles in PLoS ONE today. As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers. You can now also easily place articles on various social services (CiteULike, Mendeley, Connotea, Stumbleupon, Facebook and Digg) with just one click. Here are my own picks for the week - you go and look for your own favourites:
Global versus Local Conservation Focus of U.S. State Agency Endangered Bird Species Lists:
The development of species priorities for conservation at local or regional scales (for example, within a state or…
laelaps | January 5, 2010
A restoration of Mammalodon by Brian Choo (published in Fitzgerald, 2009).
In the introduction to his 1883 lecture on whales, the English anatomist William Henry Flower said;
Few natural groups present so many remarkable, very obvious, and easily appreciated illustrations of several of the most important general laws which appear to have determined the structure of animal bodies, as that selected for my lecture this evening. We shall find the effects of the two opposing forces--that of heredity or conformation to ancestral characters, and that of adaptation to changed environment, whether…
tetrapodzoology | January 4, 2010
South America has a diverse and well-studied toad fauna. The continent's toads include some decidedly untoad-like taxa, such as the brightly coloured stubfoot toads or harlequin frogs. These remarkable little animals are superficially similar to the better known poison-dart frogs. What makes South America's toads particularly interesting is that several of them occupy a basal position within bufonid phylogeny: in the phylogeny generated by Frost et al. (2006), Melanophryniscus, an Atelopus + Osornophryne clade, and Dendrophryniscus are all at the base of Bufonidae, while in Pramuk et al.'s (…
gregladen | January 4, 2010I had mentioned earlier that the volcanoes of the Virugna region in the Western Rift Valley (as well as other highland spots) have often been islands of rain forest separated from each other by different habitats, including grasslands and wooded savannas. this has produced an island effect that has been a laboratory for evolution, and it is likely that these forest islands (and others in the greater region of east Central Africa and western East Africa) have been the loci of evolution of many endemic species. (See Island Africa: The Evolution of Africa's Rare Animals and Plants by Kingdon…
jjacquet | January 3, 2010Need a New Year's resolution? Consider signing this seafood boycott.
It's that time of year where we welcome changes and commitment to ideals. New gym memberships. Re-committing to flossing every day. Giving up seafood...
My New Year's resolution was to finally write this blogpost compile a list of people that will boycott seafood (all farmed and wild caught marine and freshwater animals) for 2010 to:
1.demonstrate serious admonition for current fisheries practices (on the whole; we know there are a few localized examples of good management);
2.demonstrate strong support for seafood…
edyong | January 3, 2010
This is the last animal we saw on our South African safari, and we found it sitting on top of our conditioner. Thank goodness it wasn't a leopard.
I reckon it's a foamy nest frog, so named for its tendency to lay its eggs into a nest of foamy bubbles overhanging a body of water. I always thought this species had a darker colour but apparently, they become almost white in bright sunlight. Charming little tyke, isn't it?
jchosy | January 3, 2010There's a really good point that has been brought up many times about scientists. We suck at sharing our results with the public. Or sometimes we share, but in a way that very few people (scientists included) could understand. One of the problems may be a lack of emphasis on the big "So what?" People are much more interested if they understand the relevance of the findings to normal life. I find it helps to relate the concepts to more familiar things in my life.
For example, fish researchers from the University of New South Wales recently published a paper on the effects of small…
edyong | December 30, 2009I don't really like end-of-the-year lists. They seem a bit too self-knowing and forced, and there are just so many of them, particularly because we're heralding the end of a decade too. I half-expect someone to create a Top Ten Years of the Decade list (and Time Out would probably put 1977 in there just to be edgy).
This might seem like a funny way of introducing an end-of-the-year list, but I've tried to make this one a bit different. This is not a collection of the "top" scientific discoveries of the year. I'm not calling them "breakthroughs". I'm not judging them on such abstract and…
Once You've Got the Chickens, You'll Hardly Notice the Yaks: Re-Inventing the Diversified Small Farm
sastyk | December 29, 2009Over at ye olde blogge, on one of my Independence Days updates, a reader commented on something that I'd posted. I'd mentioned that we are having trouble with goat parasites - most specifically, meningeal worm. Meningeal worm is a parasite is hosted by snails and transmitted by the feces of white tailed deer. It is worst in camelids like llamas and alpacas, but goats are a secondary host, and two of does, Selene and Mina, have it. It is most common after a wet summer and warm fall - this past summer was the wettest in living memory here - we had almost 20 inches of rain in June alone, and…
sastyk | December 28, 2009Energy Bulletin ran this excellent piece from the New York Times on a crisis facing Mongolian Goat Herders who are attempting to deal with unstable world markets, climate change and overgrazing. I was fascinated by the clear way that the author of the piece lays out the vicious circle that they've entered into, and I was struck by how useful an example it is of the kind of ecological vicious circle that we face all the time:
To compensate for low prices, herders have been increasing supply by breeding more goats -- a classic vicious circle. Mongolia's goat population is now approaching 20…
clock | December 24, 2009Is Our Self Nothing but Reward? Neuronal Overlap and Distinction between Reward and Personal Relevance and Its Relation to Human Personality:
The attribution of personal relevance, i.e. relating internal and external stimuli to establish a sense of belonging, is a common phenomenon in daily life. Although previous research demonstrated a relationship between reward and personal relevance, their exact neuronal relationship including the impact of personality traits remains unclear. Using functional magnetic resonance imaging, we applied an experimental paradigm that allowed us to explore the…
edyong | December 22, 2009Patricia Brennan from Yale University is trying to encourage male Muscovy ducks to launch their ballistic penises into test tubes.
Normally, the duck keeps its penis inside-out within a sac in its body. When the time for mating arrives, the penis explodes outwards to a fully-erect 20cm, around a quarter of the animal's total body length. The whole process takes just a third of a second and Brennan captures it all on high-speed camera. This isn't just bizarre voyeurism. Duck penises are a wonderful example of the strange things that happen when sexual conflict shapes the evolution of animal…
laelaps | December 22, 2009
One of Charles R. Knight's wonderful paintings of woolly mammoths walking through the snow of ancient Europe. On display at the Field Museum in Chicago.
When did the last woolly mammoths die?
There is no easy answer to the question. In its heyday the woolly mammoth (Mammuthus primigenius) was distributed across much of the northern hemisphere, from southern Spain to the eastern United States, and the entire species did not simply lay down and die at one particular moment. Some populations (such as the "dwarf" mammoths of Wrangel Island) survived until about 4,000 years ago, but most of…
tetrapodzoology | December 22, 2009
Long-time readers might have noticed that I tend not to cover new dinosaur stories here at Tet Zoo. Partly this is because I like to be novel: I can't help but feel slightly disappointed when the subject I'm blogging about gets covered on a hundred other blogs and news-sites. It's also partly because dinosaurs get way too much coverage as it is: my aim here is to reflect tetrapod diversity as a whole, and not to focus on the attention-grabbing taxa alone. And I've done dinosaurs quite a lot already. So, sorry Aardonyx, Tawa, the proposal of venomosity in dromaeosaurs, and all those million…
milhayser | December 21, 2009
Darren Naish inspects "trace fossils" on Tetrapod Zoology, geologic records of footprints and other indentations left behind by animals. Although these telltale signs can "provide excellent information on behaviour and lifestyle," it can sometimes be hard to tell what kind of creature made them in the first place. Such is the case with a set of mysterious parallel grooves preserved in a Jurassic sandbar, which may have been formed by the snouts of ancient sea monsters trolling for snacks. On Laelaps, Brian Switek reconsiders unilinear assumptions of cetacean evolution, citing "a…
clock | December 14, 2009There are 54 new articles in PLoS ONE today. As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers. You can now also easily place articles on various social services (CiteULike, Mendeley, Connotea, Stumbleupon, Facebook and Digg) with just one click. Here are my own picks for the week - you go and look for your own favourites:
Tropical Mosquito Assemblages Demonstrate 'Textbook' Annual Cycles:
Annual biological rhythms are often depicted as predictably cyclic, but quantitative evaluations are few and rarely both cyclic and…
tetrapodzoology | December 14, 2009
Over the past couple of months I've been reading John MacKinnon's In Search of the Red Ape (Collins, 1974) - one of the first books anyone reads whenever they want to learn about orangutans. The book is stuffed full of anecdotes and other natural history tales about Borneo and Sumatra, and it seems that MacKinnon (who, these days, is best known for his association with the discovery of the Saola Pseudoryx nghetinensis in Vietnam (MacKinnon 2000, Van Dung et al. 1993, 1994)) encountered just about every creature you could hope to encounter in the tropical jungles of the region... yes, even…
tetrapodzoology | December 11, 2009
More thoughts on the ZSL meeting 'The Secret World of Naked Snakes', held on Monday 7th December. In the previous article I discussed Mark Wilkinson and David Gower's presentations [for relevance of pic used above, read on].
Alexander Kupfer was up next, and provided an excellent overview of reproductive diversity, viviparity and parental care in caecilians (his talk was titled 'Yummy mummy: skin feeding and caecilian reproductive biology') [images above, from Wilkinson et al. (2008), show mother Siphonops annulatus looking after, and feeding, babies]. Caecilians exhibit five different…