biogeography
gregladen | July 28, 2010
The Triassic is old. This book is new. That is a hard to beat combination.
Let's see ... The Triassic is about here:
(You can also look it up in this PDF file supplied by the USGS.
It is situated between two major extinction events, and is especially interesting because it is during this period that modern day ecological systems and major animal groups took a recognizable form. The preceding Permian, if contrasted with modern day, would form a very stark contrast while the Triassic would be at least somewhat more recognizable.
But of course the Triassic was in many ways distinct,…
gregladen | July 5, 2010Does your back yard slope up, away from your house, or does it slope down?
The likelihood that your yard slopes one way or the other ... statistically ... depends in large part on what region you live in. (Here I'll be speaking mainly of the US, but the principle applies broadly.) If you live in New England, your yard is more likely to slope up. If you live in the Midwest/Plains, your yard is more likely to slope down
This is because in New England, we humans build our settlements around rocks. Because there are rocks. (If you don't believe me, note that all the famous rock farms are in…
grrlscientist | June 24, 2010tags: evolution, biogeography, phylogeography, animals, Here Be Dragons, How the Study of Animal and Plant Distributions Revolutionized Our Views of Life and Earth, Dennis McCarthy, book review
I'm happy: another book review of mine was just published, this time, by Science magazine. This book, Here Be Dragons: How the Study of Animal and Plant Distributions Revolutionized Our Views of Life and Earth (Oxford University Press: Oxford; 2009), is by Dennis McCarthy, a researcher at the Buffalo Museum of Science in Buffalo, New York. In short, I liked the book and I thought it was generally well-…
laelaps | June 10, 2010
"Dinah", a young female gorilla kept at the Bronx Zoo in 1914. From the Zoological Society Bulletin.
Frustrated by the failure of gorillas to thrive in captivity, in 1914 the Bronx Zoo's director William Hornaday lamented "There is not the slightest reason to hope that an adult gorilla, either male or female, ever will be seen living in a zoological park or garden." Whereas wild adult gorillas were "savage" and "implacable" beasts which could not be captured (a photo of a sculpture included in Hornaday's article depicts a gorilla strangling one man, brandishing another about with its other…
grrlscientist | April 25, 2010tags: Parrots the Universe and Everything, biogeography, lemurs, twig technology, conservation, endangered species, evolution, komodo dragons, kakapo, baiji, comedy, Douglas Adams, streaming video
Douglas Adams was the best-selling British author and satirist who created The Hitchhiker's Guide to the Galaxy [DVD]. In this talk at UCSB recorded shortly before his tragic and untimely death, Adams shares hilarious accounts of some of the apparently absurd lifestyles of the world's creatures, and gleans from them extraordinary perceptions about the future of humanity.
grrlscientist | April 19, 2010tags: evolutionary biology, evolutionary biogeography, molecular biology, medicine, ectoparasite, orificial hirudiniasis, mucosal leech infestation, hirudinoids, leech, Tyrannobdella rex, public health, zoology, PLoS ONE, anatomy, phylogenetic analysis, taxonomy, researchblogging.org,peer-reviewed research, journal club
Figure 1. Mucosally invasive hirudinoid leeches. Known from a wide variety of anatomical sites including eyes (A) as in this case involving Dinobdella ferox (B), mucosal leech species, as in a case involving Myxobdella annandalei (C), more frequently feed from the…
laelaps | January 20, 2010
A ring-tailed lemur (Lemur catta), photographed at the Bronx Zoo.
Who doesn't love lemurs? The strepsirrhine primates, or wet-nosed cousins of ours, are favorite documentary subjects and extremely popular zoo attractions. And, in one of those bits of zoological trivia that everyone knows, lemurs only live on the island of Madagascar off Africa's southeastern coast. The question is how they got there.
Documenting the paths of animals during geological history is not an easy task. In the days before scientists understood plate tectonics, land bridges, now sunk beneath the ocean, were often…
grrlscientist | May 21, 2009tags: book review, Why Evolution is True, evolution, creationism, religion, scientific method, Jerry Coyne
Considering the plethora of books about evolution out there, is it really necessary to publish yet another one? What can another book about evolution have to offer that previous books have not provided? This new book not only presents the latest information about evolution to come to light, but it also responds to the most recent attacks made upon this branch of scientific knowledge. The book, Why Evolution is True (NYC: Viking; 2009) by Jerry Coyne, is the most up-to-date and one of the…
awild | May 5, 2009
Benoit Guenard has been hard at work the past couple years compiling broad-scale distribution data for all the world's ants, and his efforts are now online. Here they are- global range maps for all the ant genera:
http://www.antmacroecology.org/ant_genera/index.html
These maps will be a very useful resource, especially if the myrmecological community participates to add new records and vet the occasional error.
One thought, though, is that large umbrella strategies such as this will eventually be redundant with antweb.org. Â Antweb's distributions are built from accumulated individual…
grrlscientist | April 8, 2009tags: lories, Loriinae, Loriidae, ornithology, molecular biology, natural history museums
A young pair of Meyer's Lories (Lorikeets), Trichoglossus flavoviridis meyeri.
Image: Iggino [larger view].
"Can you help us identify a mystery lory in our collection?"
I was pleasantly surprised to find this email request from Donna Dittmann, Collections Manager and Museum Preparator for the Section of Genetic Resources at Louisiana State University Museum of Natural Science in Baton Rouge, Louisiana.
"Sure," I wrote back. "Send it to me and I'll see what I can do."
I, and some of my lories,…
jwhitfield | February 6, 2009Back when I started this, I remarked that one of the reasons I hadn't read the Origin was that I couldn't imagine it being essential to a grasp of contemporary science. Regarding evolution, I think you could still make a case for this. But in other ways, that statement shows that you really shouldn't opine on topics you know nothing about.
Specifically, I'm talking about ecology (by which, just to be clear, I mean the study of the interactions of living things with each other and their environment, rather than 'nature' or 'environmentalism'). It's been said that all European philosophy is a…
jwhitfield | February 4, 2009When the Origin was published, the idea that species were not fixed entities had been in the air for some time, thanks to Lamarck, Robert Chambers, anonymous author of the best-selling Vestiges of the Natural History of Creation, and Darwin's own grandfather, Erasmus.
But unlike those men, Darwin put all the different pieces together into a coherent whole. How was that? Chapter 11 of the Origin, 'Geographical distribution', gives some hints.
First there's the nurture. In the age of long-haul flights and wildlife documentaries, it's easy to forget how difficult it was to see different…
gregladen | January 6, 2009It turns out that a recently discovered population of land iguanas on the Galapagos is probably a new species that represents the basal (original) form of Galapagos land iguana. Moreover, this iguana is found in an unexpected place, according to a paper just coming out in the Proceedings of the National Academy of Sciences (PNAS).
And it's pink.
In 1984, Hickmann and Lipps said the following about the various pieces of evidence giving age estimates for the Galapagos islands:
... all are less than about 2 million years old. This age, together with independently determined geologic ages,…
gregladen | December 13, 2008 What was Neanderthal-Modern Human interaction really like? Fifty four teeth (some of which are fragments) and nine other bones dating to about 40-43,000 years ago represent the "most recent, and largest, sample of southern Iberian late Neanderthals currently known."
These and some closely related remains may indicate that these Middle Paleolithic holdouts were kissing cousins of nearby anatomically modern humans. Or maybe not.
We know that Neanderthals occupied all of Europe for over 125 thousand years during a period known (from the artifacts) as the "Middle Paleolithic." During…
gregladen | December 5, 2008Allen's Rule. One of those things you learn in graduate school along with Bergmann's Rule and Cope's Rule. It is all about body size. Cope's Rule ... which is a rule of thumb and not an absolute ... says that over time the species in a given lineage tend to be larger and larger. Bergmann's Rule says that mammals get larger in colder environments. Allen's Rule has mammals getting rounder in colder climates, by decreasing length of appendages such as limbs, tails and ears.
All three rules seem to be exemplified in human evolution. Modern humans tend to be larger and rounder in cooler…
The Scientific, Political, Social, and Pedagogical Context for the claim that "Race does not exist."
gregladen | November 29, 2008These days, many people say that race is largely a social construct; while it may have a place in describing the population genetics of some species, is not particularly applicable to humans. I'm one of those people. The race concept is generally inapplicable or at best misleading when used as it often is with our species. This is why race should be abandoned in favor of other ways of describing human variation.
At the same time, there are political, social, and pedagogical reasons to put aside the race concept. Race is not that useful of a concept to begin with, and beyond that it has…
gregladen | October 22, 2008Homo floresiensis more widely known as the "Hobbit," may have had arms that were very different from those of modern humans.
A paper in the current issue of the Journal of Human Evolution explores the anatomy of H. floresiensis. To explore this we first have to understand the concept of "Humeral torsion." Humeral torsion is the orientation of the humeral head relative to the mediolateral axis of the distal articular surface. Don't bother reading that sentence again, I'll explain it.
The humerus is the upper arm bone, that runs between your shoulder and your elbow. The humeral head is…
gregladen | October 13, 2008 A very good day of grunting worms. Credit: Ken Catania So-called Gene-Culture Co-Evolution can be very obvious and direct or it can be very subtle and complex. In almost all cases, the details defy the usual presumptions people make about the utility of culture, the nature of human-managed knowledge, race, and technology. I would like to examine two cases of gene-culture interaction: One of the earliest post-Darwinian Synthesis examples addressing malaria and sickle-cell disease, and the most recently published example, the worm-grunters of Florida, which it turns out is best…
grrlscientist | September 18, 2008tags: ratite, tinamous, evolution, biogeography, phylogenomics, convergence, flightlessness, Paleognath, homoplasy, vicariance
White-throated Tinamou, Tinamus guttatus.
Image: Wikipedia.
New research suggests the ostriches, emus, rheas and other flightless birds known as ratites have lost the ability to fly many times, rather than just once, as long thought. Further, the ratites appear to form a group with the tinamous, a group of birds that can fly, while the ostriches are set apart as the "sister group" -- the closest relatives.
Birds are divided into two groups based on jawbone…
gregladen | July 29, 2008Did Past Climate Changes Promote Speciation in the Amazon?
Any time you've got a whopping big river like the Amazon (or a mountain chain like the Andes, or an ocean, or whatever), you've gotta figure that it will be a biogeographical barrier. Depending on the kind of organisms, big rivers, high mountains, oceans, forests, deserts, and so on can provide a habitat or a barrier, and when there is a barrier, populations may end up splitting across that barrier and diverging to become novel species.
The role of the big tropical rivers such as the Amazon and the Congo, and the role of rain…