Here’s a good gig

Selbourne Surveys in California is a novel idea by a couple of naturalists. They survey a property, such as a resort or ranch, and provide an attractive and accurate report on its natural ecology, including

• Prehistory and history
• Geology and soil
• Weather and its influences
• Plants, native and otherwise
• Wildlife, resident and visiting
• Planting suggestions to welcome wildlife
• References for further reading

It’s a lovely idea for planning, encouraging or deterring development, and attracting ecotourists.

At the same time, it’s a way for the naturalists to be paid for doing research and finding new places to do it.

Polio vaccine: why we could—and should—build a better one

ERV on Scienceblogs (short for Endogenous Retrovirus) revisits the argument for building a better polio vaccine.

Briefly, polio is an RNA virus, thus has an error-prone RNA-RNA polymerase, thus acts like a quasispecies like HIV-1. Now, a live attenuated polio vaccine is the ‘best’ because you activate lots of branches of your immune system, which ‘remember’ the polio virus for a really long time. But because of polio’s potential genetic diversity, the attenuated vaccine variant can revert back to the wild-type variant, which is ‘more fit’.

This doesn’t matter to you, because you’ve been vaccinated. But if you shed wild-type virus…

Well, you could make someone else sick. ERV then describes the new polio viruses that have been created and that would make a safer and more reliable vaccine:

Vignuzzi et al found they could generate polio viruses that:

• Had a higher-fidelity RNA-RNA polymerase, cutting mutation rates by half or more
• Were almost equally ‘fit’ to wild-type virus, reducing selective pressure to revert
• Did not infect the brain/central nervous system
• Were still susceptible to anti-polio antivirals
• Provided better protective immunity to wild-type polio than even the current ‘live’ polio vaccine

All of these are important, especially in countries where vaccination is spotty and supplies of clean water are less reliable. People die while we sit by and say, “I’m all right, Jack.”

The paper she refers to, Vignuzzi et al., is described here: “Building a better polio vaccine.”

The current post goes on to discuss that concept in relation to a larger parasite: disease-carrying mosquitoes.

Strange and wonderful birds

I caught a bit of a nature show on birds: The Life of Birds, with David Attenborough narrating. Some of the birds of New Zealand really caught my eye.

Flightless birds: kiwi, rhea, cassowary, ostrich & chick

Perhaps it’s just as well that the elephant bird or the terror bird are no longer around to dine on us; but it’s a shame that the giant coots, flightless parrots, kiwis, and other birds are so close to extinction.

Skeleton of giant, flightless bird

The kakapo is a ground-living parrot of New Zealand. It survives only on one or two islands, and even there up in the hills where climate is harsh. The birds eat the juicy bases of grass stems and it takes an adult bird at least a year to teach its single young how to forage. Consequently, they don’t mate every year.

The kakapo, a flightless parrot that eats grass

And the hoatzin! I’d heard vaguely of a bird that had claws on its wings. But I never pictured the way the nestlings climb around on branches.

Hoatzin chick using clawed wings to climb

They look very much like prehistoric birds just getting ready to use their feathers for the first time. Gliding from tree to tree has evolved much more often and in more animal taxa than pure flying.

Hoatzin chick climbing

The hoatzin is so adapted to eating masses of low-energy vegetation that it flies poorly. But its wings are well developed. The claws are a juvenile evolutionary trace.

Updated from 2 July 2008 because I finally inserted the pictures.

What makes locusts swarm?

I saw something on Daily Planet tonight about locusts. They look like grasshoppers. They have a solitary, weakly flying or non-flying form. And when they get crowded, they develop into a new form that is brightly coloured, social to other locusts, and a strong flyer. That encourages them to leave their dwindling food sources and find new ones.

A Dr. Steve Rogers of Cambridge University has discovered that what makes locusts change is serotonin, which is produced when the locusts rub their legs together (rub up against each other?), see or smell one another, or are tickled. If serotonin is inhibited, they don’t change and become sociable. If serotonin is injected, they change. A mystery solved!

Taung child was eagle’s prey

Darren Naish points to evidence that the famous African hominid fossil called the Taung child was killed by an eagle—or at least eaten by one.

This is the famous juvenile australopithecine specimen described by [Raymond] Dart in 1925, and thought to have been a 3 or 4 yr old. Following up on Brain’s observations of 1981 that the Taung assemblage represented an accumulation produced by a large carnivore, probably a leopard, Lee R. Berger and Ronald J. Clarke (1995) showed in Journal of Human Evolution that a large eagle was the most likely killer of the juvenile. The case was good: the assemblage consists of smallish mammals (like mole rats, spring hares and small antelopes), evidence for carnivorous mammals is absent, nick marks corresponding to those produced by eagle beaks and talons are present on some of the bones, and eggshell was also discovered at the site. The new discovery is that nick marks around the orbital margins of the Taung child demonstrate once and for all that an eagle really was the killer. Great stuff – I look forward to the paper.

And elsewhere, there are limericks about it.