A new take on the evolutionary history of the moa was published in PNAS this week. Mike Bunce from Murdoch University in Perth and researchers from Alan Cooper’s lab at University of Adelaide have combined genetic data from over 260 moa bones with anatomical, geological and ecological information, to revise species relationships among moa and suggest a timeframe and origin for their evolution.
Most New Zealanders can name at least a dozen or so species of native bird, but how many can do the same for our native reptiles? If you starting counting and only got as far as 1. tuatara, you’re probably not alone. Although we are missing some of the major groups of reptiles (like snakes and alligators), we do have a diverse array of lizards. In fact New Zealand has around 80 different lizard species in two major groups – geckos and skinks (tuatara are not lizards, they are Sphenodontids).
Around half of our lizard species are skinks. These are the most commonly encountered native reptiles, being the species most likely to be spotted disappearing under rocks or into long grass on a hot day, and generally being favoured by the domestic moggy. Now new research is improving our understanding of the origins and evolution of our skink fauna, with some exciting fossil finds and the publication of a comprehensive genetic study. Read the rest of this entry »
A publication in Plos One this week heralded the discovery of a 47 million year old primate fossil, named Darwinius masillae (or Ida to her friends). The fossil is extremely well preserved and complete, which in itself makes it an important find. Ida is an early example of a lemur-like group of primates called adapids, which the authors suggest could be a common ancestor of all present-day monkeys, apes and humans (although it appears that the jury is still out on this point).
News reports all over the world including this one that I saw last night on TV3 have heralded this discovery as THE missing link, the proof that scientists have been seeking that Darwin was right!!!
But lets not get carried away here. First of all, there are already plenty of transitional fossils (not to mention lots of molecular evidence) that give credence to Darwin’s theory of evolution. This is just another one of those fossils, albeit an extremely well-preserved and complete one. This sort of talk plays into the idea that creationists would have us believe that evolution is still an extremely controversial, dodgy theory, and that up until now we evolutionary biologists haven’t had any good proof of Darwin’s theory.
Secondly, the idea that there is one “missing link” that once found, will “prove” the theory of evolution just shows how little most journalists and the general public understand evolution. As John Wilkins has pointed out in his blog, the idea of a missing link in evolution implies evolution is a chain, rather than a tree or a network where species diverge, branch, hybridise and sometimes go extinct. When evolution is viewed more correctly as a tree or a network, there are an almost infinite number of “missing links”. In fact virtually every fossil found could be regarded as a link of some sort, and most of these are not direct ancestors of modern species, but members of extinct lineages. PZ Myers has it right when he says:
let’s not forget that there are lots of transitional forms found all the time. She’s unique as a representative of a new species, but she isn’t at all unique as a representative of the complex history of life on earth.
I think I’ll give Ed Yong the final word on this one…