A cane toad, living in an evolutionary “Olympic village”? Photo by tubagooba.
This week at Nothing in Biology Makes Sense!, Devin Drown explains the population dynamics that crop up near the edge of a species’s geographic range:
One famous example of this phenomenon is found among invasive cane toads (Rinella marina) in Australia. In 2006, Phillips et al found that the toads at the leading edge of the expansion had longer legs making them primary candidates for high dispersal capabilities. Later, Lindstrom et al (2013) found (via radio collar measurements) that those toads at the front of the range were more likely to disperse than those at the encamped within the population.
To find out why biologists have compared life on the range edge to living in the athletes’ dormitory at the Olympics, go the whole thing.◼
A wilderness firefighting crew of conscientious objectors in 1945, who were clearly doing it all wrong. (WikiMedia Commons)
There’s an emerging strain of thought in contemporary, politicized U.S. Christianity, which holds that freedom of religion logically must permit pharmacists to refuse to fill prescriptions for birth control pills if they believe that birth control is wrong; or, more lately, for people who provide wedding-related services to refuse to serve gay or lesbian couples if they oppose same-sex marriage. These refusals of service are an expression of conscience, the reasoning goes, and you can’t just force someone to violate their conscience, even if it’s in the course of doing their job.
This thinking would have come as quite the surprise to the Christian tradition in which I was raised. Mennonites know something about conscientious objection, since they’re pacifists—so, rather than take up arms, my grandparents’ generation spent the Second World War doing alternative, nonviolent service in forestry and soil conservation, in public health and psychiatric care, as wilderness fire fighters, and even as human guinea pigs. That is to say, they felt it was wrong to kill, so they opted to do hard, unpleasant, even quite dangerous things rather than take a job that required them to kill.
But clearly what those COs should actually have done was sign right up for the draft, work their ways through boot camp, ship out to the front—and then lay down their arms. From what I can tell, the current generation of “dissenters” would say it was only a free exercise of their Constitutional rights.◼
One of the most popular items at The Molecular Ecologist isn’t a blog post—it’s Travis Glenn’s “Field Guide” to the capabilities and costs of the many next-generation sequencing technologies currently available. Today we’re pleased to release the 2014 update to the Guide, this time with some new personal insight from Travis in the form of both an introductory blog post and a new table rating the overall quality of each technology:
Overall, if you are in the market for a next generation DNA sequencer in early 2014, the data indicate one clear inexorable trend – think Illumina. For fans of the Brady Bunch – Illumina, Illumina, Illumina! For fans of Star Trek – Prepare to be assimilated by one of Illumina’s Borg-like cubes. For fans of Henry Ford – You can have any NSG instrument you want, so long as it’s an Illumina.
A huge diversity of flowering plants rely on animals to carry pollen from one flower to another, ensuring healthy, more genetically diverse offpsring. These animal-pollinated species are in a somewhat unique position, from an evolutionary perspective: they can become reproductively isolated, and form new species, as a result of evolutionary or ecological change in an entirely different species.
Evolutionary biologists have had good reason to think that pollinators often play a role in the formation of new plant species since at least the middle of the 20th century, when Verne Grant observed that animal-pollinated plant species are more likely to differ in their floral characteristics than plants that move pollen around via wind. More recently, biologists have gone as far as to dissect the genetic basis of traits that determine which pollinator species are attracted to a flower—and thus, which flowers can trade pollen.
However, while it’s very well established that pollinators can maintain isolation between plant populations, we have much less evidence that interactions with pollinators help to create that isolation in the first place. One likely candidate for such pollinator-mediated speciation is Joshua tree, the iconic plant of the Mojave Desert.