Horseshoe Crabs - Andrew David Thaler
Horseshoe Crabs, Coelacanths, Seven-gilled sharks, hagfish. Throughout the oceans there are creatures whose primitive bodies hearken back to earlier days in our evolutionary history. They possess basal characteristics that are more akin to those of the ancestors of our contemporary phyla. Because we can look into these organisms and learn something about our own deep past, we think of them not as modern descendants, but as living fossils, relics of a primeval state.
This is, of course, a misnomer.
Continue reading Misunderstood Marine Life # 7 — The Living Fossils
Sexual dimorphism in fiddler crabs. Female (A) and male (B) Uca panacea. Scale bars indicate 1 cm. From Darnell and Munguia 2011
Imagine yourself a fiddler crab. For this exercise, imagine yourself a male fiddler crab. Are you with me? Great. Check out your right claw, it’s a sleek, slender machine, perfect for picking through the sand as you sift out bacteria and other microorganisms for food. It also makes a handy shovel for digging nice deep burrows to protect you from harsh conditions. Now check out your left claw. Wow! This thing is massive. If you possess a particularly vivid mind and have place your ego within the carapace of Uca panacea, your giant claw is more than a quarter of your body weight. This comically mis-proportioned appendage is why those pesky bipeds call you and your cousins “Fiddler Crabs”.
See that female fiddler crab at the perimeter of your territory? Yes, she is checking you out. That giant claw of yours is primarily used to attract mates, signalling to interested parties that your are fit and fecund. You even have a special dance, unique to each fiddler crab species, to announce your vitality. And if some other, lesser-clawed, male tries to move in to your territory, why, you’re equipped with a serious piece of hardware to drive off that interloper.
Continue reading In sexual selection and thermoregulation, bigger is better, at least for fiddler crabs
Little yummy beer yeasts, thanks www.diArk.org
As our ancestors transitioned from hunter-gatherer to agricultural society, they had to domesticate the plants and animals we know today as farm life. Corn kernels became larger and more full of starch, cows became more docile, and all farm organisms became accustomed to life in rows or pastures tended by humans. But some of what we eat depends on more than just these plants and animals – example, take beer. A new study in PNAS by Diego Libkind et al. describes the domestication of the microbes and yeast needed to make lagers of old and describes an unwitting process paralleling agricultural domestication. Continue reading Happy Hour Science — Domesticating Microbes for Beer
A diagrammatic tree depicting the organisation of most eukaryotes into six major groups. The relationships amongst most of the major groups and the position of the ‘root’ of the tree are shown as unresolved (note however, the grouping of Opisthokonta and Amoebozoa). The arrow shows a possible precise placement of the root, based on gene fusion data. (Simpson and Roger 2004)
Depending on your view of phylogenetics, a recent publication in Nature reporting the discovery of a new kingdom-level branch on the tree of life, basal to Kingdom Fungi, is either a major revision of our current view of taxonomy or completely unsurprising and expected. While we mostly refer to the four kingdoms within Domain Eukarya as Protista, Plantae, Fungi, and Animalia, it’s understood by the scientific community that Protista is essentially a catch-all category, not a true clade, for eukaryotes that don’t quite fit into the other three groups. While this is convenient for organization, it fails to adequately express the diversity of protists. Four kingdoms is a useful system, but there’s no reason why diversity at the kingdom level couldn’t be much higher. A strict cladist could create hundreds, if not thousands of kingdoms from Protista alone.
Continue reading The moldy kingdom gets a new neighbor
Question: If your elected officials fail basic taxonomy, promote anti-science curriculum, and consistently attempt to undermine the fundamental underpinning of all biology, what happens when they start trying to legislate from this flawed view of reality?
Continue reading Florida Senate fails basic biology, accidentally outlaws sex.
There I was, proudly ambivalent about events happening across the pond. Some royal something or other getting civil union-ed with some wealthy something something. Apparently this happening also involves some high-falutin’ muckity-muck. I had managed to avoid just about everything about this event, until my shields were ultimately breached by an unlikely saboteur. The scientific journal Cell bizarrely decided to dedicate this weeks issue to the royal wedding by publishing this bit of ad nauseum:
Continue reading A Brief Primer on Inbreeding Depression
In The Mass Extinction of Scientists Who Study Species, Dr. Craig McClain argues that we are loosing a fundamental unit of biological science – the Taxonomist. He’s right, of course. Taxonomy is a shrinking field. Entire phyla sit, unstudied, as the expertise necessary to understand them retires and expires. With few to train the next generation of taxonomists, the field could slowly vanish. Molecular tools are supplanting traditional taxonomy (once described to me as “the ability to identify hundreds of species of centimeter-long worms by counting ass-hairs under a microscope”) as the de rigueur method for identifying organisms.
I do not disagree with Craig. Losing skilled taxonomists is tragic for the biological sciences. Unlike many leading the charge in support of taxonomy, I did not benefit from a rigorous taxonomic study in my early career. I fall into the same camp as Dr. Holly Bik, relying primarily on molecules, not morphology, to draw the distinctions between my samples. I never identified species by counting the ass-hairs on a worm, and my education is poorer for it.
Continue reading Conservation and the Concept of Species in a Biodiversity Crisis (Part 1)
fish face a tradeoff of where to use their energy, much like the polluted fish in the Lorax by Dr. Suess
Overfishing is most often implicated as the cause of decreasing fish stocks and that makes a lot of logical sense if you’ve ever seen a large commercial trawler unload its catch. But there very well might be another force at work in the precipitous decline in fish stocks worldwide: pollution. The basic premise is that it takes resources to deal with pollutants that normally would be given to growth and reproduction. Through polluting the ocean, we have selected for the fish individuals that can most effectively divert those resources, inadvertently also selecting for smaller fish that reproduce less. That has huge implications for the fish’s population dynamics and potentially total fish stock. More details below the fold…
Continue reading A recipe for the evolution of smaller fish stocks?