This is a lite version of a ‘science round-up’.
I’ve done a bit of detective work in amongst my current lab work, and have come up with the following:
- development of large size in mammals;
- discovery of new species in jungles; and
- adaptation to pollution is fascinating, yet slightly disturbing
Whales and development of size in mammals.
From the ABC news, I saw that blue whales are getting larger. Big deal, you say. Well, it was published in PNAS, so apparently it is a big deal. Pun intended? I don’t know. Anyway, this research provides some interesting information on the evolution of mammal size. The scientists found that it took approximately 20 million generations for mammals to get from the size of a mouse to the size of an elephant. Interestingly, it took only 5 million generations for whales to go from 25kg to 190 tonnes – such is the wonderful buoyancy of salt water. Blue whales haven’t finished though, apparently they are continuing to increase in size with subsequent generations.
Fun new species found in Suriname
Conservation International, an organisation dedicated to conservation and biodiversity activities, has just released the results of a field survey in the rainforests of Suriname, held in 2010. The new species found include a little frog with (extremely small) fringes on its legs that led it to be called a ‘cowboy’ frog, a catfish covered in spines like a mofo, and a selection of insects and other invertebrates. The researchers actually discovered between 37 and 51 new species of insects, compared with 8 new species of fish and one new species of herptile, but let’s not forget that a frog that you can call a cowboy is clearly of perceived greater interest to the public than a whole stack of invertebrates.
And my favourite for the week:
Fish adapt to toxic chemical pollution
(thanks to Terry H for inadvertently letting me know about this one)
From National Geographic, we have a report on research done on fish to determine who the hell they manage to survive in areas heavily polluted by polychlorinated biphenyls (PCBs). PCBs are nasty chemicals that have been banned for about 50 years, but do not degrade and are still found in abundance in parts of nature. Studies were conducted on a species of fish, tomcod, that appeared to suffer no ill-effects from levels of PCBs that were dangerous to other fish. The tomcods in high-pollution areas have a ridiculously high level of PCBs in their livers. The researchers found that the high-pollution tomcods have a mutation that confers a kind of immunity to the chemicals (to quote the Nat Geo site: “…the fish sport a handy modification to a gene…” as though the mutation is this season’s must-have accessory). This is achieved because the proteins coded for certain receptors and the mutant form of the receptors bind poorly to PCBs, thus decreasing the effects of the chemical on the body of the fish. The mutation was found at lower prevalence in areas of low pollution, which indicates that it was a pre-existing mutation, but was under high selection pressure after the widespread use and release of PCBs from the early 1900s.