Interesting News Items (with commentary)

Bats; Signaling in the Rain Forest; Sumatran Tiger Body Parts; Humans in the New World 20,000 years ago.

Bats are funny. Funny strange, not funny ha ha. There are two kinds of bats, microchiroptera and megachiroptera. The micros are smaller, the megas larger, by and large. and the micros have bat-sonar, while the mega's don't The micros tend to eat insects, the megas tend to eat fruit. Micros are more global in their dsitribution, mega's are more tropical.

It is not the case that all of the evidence regarding bat evolution clearly indicates that the common ancestor of both kinds of bats was bat-like in all the usual respects. It is possible that many bat-features, even flight, are convergences, or at least more convergent than homologic, in the two groups of bats. There are many other evolutionary questions about bats as well, and one is when the sonar evolved in the micros.

This story indicates that we have new evidence:

Bats Could Fly Before They Had 'Radar' from PhysOrg.com

(AP) -- A fossil found in Wyoming has apparently resolved a long-standing question about when bats gained their radar-like ability to navigate and locate airborne insects at night. The answer: after they started flying.

[...]

This is published in Nature, so only special people can read the story. I'm special, but I have not looked at it yet. It's in the in box.

Bird song is usually a signal of individual quality, and is used either by territorial males in the age-old territorial conflict (among males) or it is used by males who signal their qualities to females out to pick a mate. A new study explores the ways in which the song of a particular bird, the Brazillian white-browed warbler, is adapted to the acoustic particular to the forest in which it lives.

Understanding the evolution of acoustic communication systems in animals is a hot topic in evolutionary biology and one of the main challenges is to understand how environmental pressures drive this evolution. Mathevon and his colleagues show that the song of the white-browed warbler, a species living in the Brazilian Atlantic rainforest is particularly well-tailored to the acoustic properties of the environment, with its dense vegetation and can vary in its acoustic properties depending on whether the message is "public" or "private."

[source]

This paper is available on line in the Open Access Journal PLoS One. Here.

Another one for the Inbox!

Sumatran Tigers are just about extinct. One of the main reasons is because crazy people with untenable beliefs like to use their body parts for various purposes.

Tiger body parts, including canine teeth, claws, skin pieces, whiskers and bones, were on sale in 10 percent of the 326 retail outlets surveyed during 2006 in 28 cities and towns across Sumatra. Outlets included goldsmiths, souvenir and traditional Chinese medicine shops, and shops selling antique and precious stones.

The survey conservatively estimates that 23 tigers were killed to supply the products seen, based on the number of canine teeth on sale.
[sourcehttp://www.physorg.com/news122101908.html]

Considering how few Sumatran Tigers there are, that is a very large number.

Also from PLoS one, a paper titled A Three-Stage Colonization Model for the Peopling of the Americas in which the authors argue that the data from DNA, archaeology, and elsewhere ...

support a model for the peopling of the New World in which Amerind ancestors diverged from the Asian gene pool prior to 40,000 years ago and experienced a gradual population expansion as they moved into Beringia. After a long period of little change in population size in greater Beringia, Amerinds rapidly expanded into the Americas â15,000 years ago either through an interior ice-free corridor or along the coast. This rapid colonization of the New World was achieved by a founder group with an effective population size of â1,000-5,400 individuals. Our model presents a detailed scenario for the timing and scale of the initial migration to the Americas, substantially refines the estimate of New World founders, and provides a unified theory for testing with future datasets and analytic methods.

You can reads the paper here. Me? I'm putting it in my Inbox.

Damn, I may need a bigger inbox....