Here at Nothing in Biology Makes Sense, we’re fascinated by all the weird, baroque ways that living things influence and coevolve with each other—so Ed Yong’s new TED talk about mind-controlling parasites is right up our alley. Just like his writing—currently on display at National Geographic‘s Phenomena, among many other venues—it’s a compendium of nifty natural history punctuated with highly educational gross-outs and the occasional black-belt level pun.
This post is a guest contribution by Michael Harvey, graduate student in Robb Brumfield‘s lab at the Museum of Natural Science at Louisiana State University. Mike studies avian evolution, phylogenomics, and Neotropical ornithology.
Blackwater river…approximate Bayesian computation…dawn song…genomic islands…wing chord…target DNA enrichment…
My life as an evolutionary biologist straddles two worlds. I study the comparative phylogeography of Amazonian birds, and on the one hand my research involves laboratory and computational methods that push the limits of new technologies and analytical techniques, and on the other, expeditions to the tropics that are nearly indistinguishable from the natural history work conducted by Victorian era biologists. I am a PhD student at Louisiana State University, and for most of the year my work is in the lab and at my desk. For several months of the year, however, my work is general ornithological collecting expeditions to the Amazon Basin.
Every Friday at Nothing in Biology Makes Sense! our contributors pass around links to new scientific results, or science-y news, or videos of adorable wildlife, that they’re most likely to bring up while waiting in line for a latte.
First of all, my deepest apologies for the lateness of this post. As you may know I am a 4th year medical student and today was Match Day and I was deep in the throws of celebrating the completion of 4 years of medical education as well as learning where I will be training for the next three years in Family Medicine. So, without further adieu, your links for this week.
CJ decided to that there were too many good links and had to share several. First, as a skater herself she found an article relating to transmission of skin flora between close team mates and those competing in roller derby. Next she decided to share how the sequester is going to affect science jobs and the next few years could be difficult. But finally, a cool post on five animals that could possibly take over the world, which makes me look at spiders a little closer now.
Next, Jeremy likes the fact that new evidence from the Mars rover is favorable to the possibility of conditions that could have sustained life on the red planet.
From Noah, a video documenting several scientists as they inventory one of the worlds most biodiverse locations, the Yasuni Biosphere Reserve.
Finally, in the spirit of March Madness, from Devin comes a battle of the Mammals. “Mammal March Madness from the Mammal’s Suck blog. Although the tournament is purely fictional, the facts and natural history information given out during the extended live tweet rounds are amazing. The first rounds are already complete, but tune in for the exciting finals. Live action via twitter: @Mammals_Suck and general info via the website:”
Evolutionary biologists are fascinated by islands. There are a number of reasons for this. Islands systems can act as natural evolutionary experiments. They are small, less biodiverse, and isolated, so their biota can often be treated as simplified models of more complex mainland ecosystems (e.g. Darwin’s finches on the island Daphne Major). Ecologically similar islands can also act as replicates, with related taxa playing out the same evolutionary scenarios over and over again in isolation (e.g. Caribbean Anolis). Or they can act as life preservers, providing isolated strongholds for ancient evolutionary lineages that have long been extinct in the rest of the world (e.g. the Tuatara of New Zealand).
The Socotra archipelago is a particularly interesting, but poorly studied island system. Socotra consists of four islands in the Indian Ocean. It is extremely isolated (150 miles from the horn of Africa, 240 miles from the Arabian Peninsula) yet it has a continental origin. That means it was once part of the supercontinent Gondwana and suggests that some species may have lived there since it first became an island (~17.6 million years ago). Socotra has a very high level of endemism, with 37% of its plant species and 90% of its reptiles occurring nowhere else. As the islands are very remote and in a politically unstable part of the world, most of this unique biodiversity has not been studied using modern techniques. The islands are rugged and mountainous, reaching 1500m elevation, and primarily classified as tropical desert, making for a fairly fantastical landscape. A recent paper by Goméz-Diaz et al. (2012) takes a broad-brush approach to characterizing a chunk of Socotra’s obscure diversity: the Hemidactylus geckos.
This post is a guest contribution by Kathryn Turner, a PhD student at the University of British Columbia, who studies the evolution of invasive thistles. Kathryn writes about her scientific interests at the slyly named site Alien Plantation and tweets under the handle @KTInvasion.
Invasive species are a big problem. A real big problem. In the US alone, invasive species cost nearly $120 billion in damages per year (Pimentel 2005). 42% of species on the Threatened and Endangered list are there primarily because of invasive species.
Which leaves us with two questions. First, most obviously, how is it that a species is able to come into a new environment that it is not adapted to, surrounded by new environmental conditions and foreign biological interactions, and thrive? Thrive so exaggeratedly, that it can out-compete and displace species which have been there for millennia, adapting precisely to those environmental conditions and biological interactions? How can an individual survive to propagate a population? How can any species accomplish this? Second, less obviously: why can’t more species do it? Humans transport animals and seeds (and spores and larvae, etc, etc) around all the time, but only 10% establish self-sustaining populations, and only 1% spread to new habitats, becoming potentially invasive; this is known as the ‘tens rule’ (Williamson 1993) – a funny ‘rule of thumb’ for which I could never quite figure out the math.
Actually, that’s not really true. Biologists generally agree that predators, prey, parasites, and competitors can exert natural selection on the other species they encounter, but we’re still not sure how much those interactions matter over millions of years of evolutionary history.
On the one hand, groups of species that are engaged in tight coevolutionary relationships are also very diverse, which could mean that coevolution causes diversity. But it could be that the other way around: diversity could create coevolutionary specificity, if larger groups of closely-related species are forced into narower interactions to avoid competing with each other.
Part of the problem is that it’s hard to study a species evolving over time without interacting with any other species—how can we identify the effect of coevolution if we can’t see what happens in its absence? If only we could force some critters to evolve with and without other critters, and compare the results after many generations …
Oh, wait. That is totally possible. And the results have just been published.
Explaining global patterns of biodiversity is a fundamental goal in biology. Understanding how the tens of millions of species on earth have arranged themselves into populations, communities, and ecosystems, is critical for conserving them in the face of a rapidly growing human population and global climate change.
The latitudinal gradient in species diversity is perhaps the most famous such pattern, and it has confounded biologists for decades. Almost invariably across taxonomic groups, hemispheres and continents, as one moves from polar regions towards the equator, species diversity increases (see the figure for a depiction of global bird diversity). The concept of diversity here can be broken down into three parts: “alpha diversity” or the diversity of species in a single location; “beta diversity”, or the turnover of species observed when moving among locations; and “gamma diversity” or the diversity of species found in an entire region. The latitudinal diversity gradient holds true for all three elements.