Category: Natural Sciences

Some links: 35

The occasion of Nature‘s publication of 15 Evolutionary Gems, synopses of recent research from its pages that deepens our understanding of the process of evolution, prompted some pruning and dusting of my bookmark files. So here let us take note of

The papers summarized in the Nature document examine evidence collected by field observation, at the molecular level in the lab, and from the fossil record. Of particular note to “no transitional forms” deniers is the discussion of newly-described specimens found in China.

In the 1980s, deposits from the early Cretaceous period (about 125 million years ago) in the Liaoning Province in northern China vindicated these speculations in the most dramatic fashion, with discoveries of primitive birds in abundance — alongside dinosaurs with feathers, and feather-like plumage. Starting with the discovery of the small theropod Sinosauropteryx by Pei-ji Chen from China’s Nanjing Institute of Geology and Palaeontology and his colleagues, a variety of feather-clad forms have been found. Many of these feathered dinosaurs could not possibly have flown, showing that feathers first evolved for reasons other than flight, possibly for sexual display or thermal insulation, for instance. In 2008, Fucheng Zhang and his colleagues from the Chinese Academy of Sciences in Beijing announced the bizarre creature Epidexipteryx, a small dinosaur clad in downy plumage, and sporting four long plumes from its tail. Palaeontologists are now beginning to think that their speculations weren’t nearly wild enough, and that feathers were indeed quite common in dinosaurs.

The discovery of feathered dinosaurs not only vindicated the idea of transitional forms, but also showed that evolution has a way of coming up with a dazzling variety of solutions when we had no idea that there were even problems. Flight could have been no more than an additional opportunity that presented itself to creatures already clothed in feathers.

One more good reason

Newly-published research by Shalene Jha and Christopher W. Dick indicates that traditional shade-grown coffee farms provide yet another ecosystem service: maintenance of genetic diversity of trees in the landscape. The paper studies Miconia affinis in Chiapas state, Mexico. The inference is that natural seed dispersers (birds and bats), harbored by shade-grown plantations, promote the needed gene flow, and that the farms knit together fragmented forest patches.

Loss of pressure

A recent paper by Erin F. Baerwald et al. as summarized in Science Daily, suggests the cause of many bat fatalities near wind turbines: rather than direct collisions with turbine blades, bats die from barotrauma, internal injuries caused by sudden changes in air pressure. Unfortunately, the researchers don’t have ready suggestions to mitigate the pressure changes and hence reduce the kills.

Forthright

Amy Harmon profiles David Campbell, a contributor to new Florida state science education standards.

“Faith is not based on science,” Mr. Campbell said [to his class of 10th-grade biology students]. “And science is not based on faith. I don’t expect you to ‘believe’ the scientific explanation of evolution that we’re going to talk about over the next few weeks.”

“But I do,” he added, “expect you to understand it.”

Once around the block

Napier Shelton walks an eight-mile nature loop around Northwest D.C. for the current issue of Audubon Naturalist News. (Alas, Audubon Naturalist Society has moved its web site into a new URL- and page title-mangling content management system.)

Since the days of my childhood, some tropical migrant birds have been lost, but barred owls and red-shouldered hawks still live in Glover-Archbold; black-crowned night herons still roost by day along Rock Creek; and deer, beavers, and coyotes have moved in. A big difference from the past, however, is the lack of kids (and adults) exploring the woods by themselves like I did.

Better boarding

One more thing to look out for in the park: a weathered sheet of plywood lying on the ground might be a snake board, sheltering small mammals and the herps who eat them, reports the Winter 2008 number of the Fairfax County Park Authority’s newsletter, ResOURces. Tony Bulmer’s checklist for boards at Ellanor C. Lawrence Park (he’s a naturalist and interpreter there) includes nine species of snake, as well as skinks, salamanders, and toads. Caution: if you find a board, don’t disturb it. If you flip it over without knowing what you’re doing, you may find yourself nose-to-nose with a copperhead.

More than a cappucino

Starbucks is making strides in areas beyond finding creative, entertaining ways to separate you from your cash in its stores. Continuing to deepen its involvement with the agricultural sources of its drinks, the company is in the middle of a three-year partnership with the Earthwatch Institute supporting research into aspects of sustainable coffee production. The current project sends volunteers to member fincas of Coope Tarrazú, a co-op in Costa Rica. Using GIS technology, field workers are establishing baseline maps of resources (soil condition, water quality, etc.).

The volunteer effort supports the research of Karen Holl of the University of California, Santa Cruz. Holl’s research interests in Costa Rica include strategies for re-establishing forests in land that has been cleared for pasture.

…we have established 16, 1-ha sites in southern Costa Rica. We are testing questions about “applied nucleation” by planting islands of native tree seedlings to facilitate recovery and studying the effect of the amount of surrounding forest cover on ecosystem recovery. We are collecting extensive data on seed dispersal, seed fate, vegetation establishment, and seedling dynamics.

Also involved in the Costa Rica projects is Catherine Lindell of Michigan State University, who has published studies of habitat use by various bird species in Costa Rica.

That which we call a rose

bit-player laments the confusing system of names used to identify complexity classes.

The letter P generally stands for “polynomial” (except where it’s “probabilistic”). N usually denotes “nondeterministic” (but NC is “Nick’s Class”). Likewise the prefix D is for “deterministic” (except that it’s usually omitted, and sometimes it means “difference” or “dynamical” instead). B stands for “bounded-error” (except that BH is “Boolean hierarchy” and “BPd(P)” is “Polynomial Size d-Times-Only Branching Program”). Q is for “quantum” (except “QH” is the “query hierarchy” and “QP” is “quasi-polynomial time”).

The sad truth is, the naming conventions for furniture at Ikea make for a more consistent language than those of complexity theory.

Hmm. Maybe the math and CS guys should talk to the bioinformaticians that gave us Pokemon as the name of an oncogene, until (under threat of legal action) it was renamed Zbtb7.

Imprinting

Phllip Ball reviews a special number of the journal Homeopathy (published by Elsevier, a competitor) devoted to papers on “the memory of water.” He keeps the expected snarkiness in check, for the most part.

The procedures and protocols on display here are often unusual, if not bizarre, because it seems the one thing you must not do on any account is the simplest experiment that would probe any alleged ‘memory’ effect: to look for the persistent activity of a single, well-defined agent in a simple reaction—say an enzyme or an inorganic catalyst—as dilution clears the solution of any active ingredient.

Bottle it up

Luís Gil explains why cork is a better choice for stoppering wine bottles than its synthetic alternatives. Some of his arguments are not persuasive, and amount to “we’ve always done it this way,” but consider:

6) Cork is a renewable resource and cork oak forests are one of the most sustainable natural systems, providing the habitat of several endangered species and supporting one of the highest levels of biodiversity among European forests. Cork comes from the bark of the cork oak [Quercus suber], and is harvested only once every nine or ten years, without detriment to the tree.

* * *

10) Cork production is based in poor rural areas where it provides much needed jobs. About 150,000 people around the world work with cork, and it is an important part of Southern Europe and North African economies.

* * *

13) Cork sequesters carbon from the atmosphere; a cork stopper sequesters about twice is weight of CO2; all the cork stoppers produced in one year represent the CO2 pollution of about 49,000 automobiles each year.

Bring it up again

A leader from the traditionally eco-skeptic Economist admits that recycling is “mostly worthwhile,” and proposes three steps to encourage the practice. Relying on mechanisms technological, political, and economic, the magazine recommends

  1. a single stream from the consumer, with automated conveyor belts at the processing facility to separate items;
  2. selling recycled waste to emerging markets; and
  3. monetary rewards to consumers based on how much they recycle.

I haven’t yet read the magazine’s current Technology Quarterly, which features recycling and other environmental issues; I’m interested in how the writers handle the question of streaming recyclables into the third world.