Evolution is the most creative force on the planet. Everywhere we look, we find species with novel and phenomenal adaptations that put their comic book brethren to shame. In no ecosystem is this more apparent than in the vast and unfathomable ocean. Marine species, especially those in the deep sea, have evolved to survive in a environment that is completely alien to us. Several months ago, I unveiled “Five organisms with real super powers that rival their comic book counterparts“, but that was just the beginning. Without further adieu, I give you 5 more marine organisms that put their superhero counterparts to shame (and one bonus critter).
The blind shrimp with super senses
Rimicaris exoculata – http://eol.org/data_objects/13231836
In the deep sea, eyes are not among the most useful sense organs. While many deep-sea species have extremely reduced eyes, some have abandoned these organs entirely. Rimicaris exoculata is a shrimp endemic to deep-sea hydrothermal vents in the mid-Atlantic that is completely eyeless. Its carapace is smooth, without even a hint of reduced, vestigial eyes. This, unfortunately, is a problem because Rimicaris exoculata is a farmer. The blind shrimp grows bacteria in its gill chamber, bacteria that can convert the chemical-rich hydrothermal vent fluid into food for the shrimp.
For lack of a more descriptive adjective, hydrothermal vents are hot. Some can exceed 400°C. Rimicaris exoculata needs to get close to this hot vent fluid to feed its crop of bacteria, but not so close as to become a hydrothermal hors d’oeuvre. And so, the blind shrimp evolved a completely new light-sensitive organ mounted on the top of its carapace–the rhodopsin-rich dorsal eyespot.
The dorsal eyespot of Rimicaris exoculata doesn’t “see” in the normal sense, there is still almost no light in the deep sea. Rather, this shrimp is adapted to detect the black body radiation emitted by the hydrothermal vent. For Rimicaris exoculata, the deep sea glows with the light of super-heated hydrothermal fluid, allowing it to both find food for its bacterial crop and avoid getting cooked itself.
It should be no surprise that Rimicaris exoculata is undoubtedly the favorite deep sea organism of another blind champion with super senses–Daredevil.
There is no force more creative than the painstakingly slow process of evolution. Ever wanted to walk through walls? Naked mole rats can physically bore through concrete. How about fly? There are a couple dozen different ways to accomplish that goal, even if you’re a squid. Incredible power of regeneration? Flatworms, roundworms, and echinoderms have us beat. Among the vertebrates, species like the axolotl can regrow limbs, organs, and parts of their brain. For practically every super power we can imagine, something on the tree of life has come up with a real-world analog.
Some real super power are more super than others:
1. The immortal rotifer that absorbs the abilities of anything it touches.
Bdelloid Rotifers. photo by Diego Fontaneto
Around 80 million years ago, a small, unassuming group of metazoa decided that sex just wasn’t for them. Instead of going through the effort of recombining their genetic material with a mate every generation to produce a viable offspring with a roughly 50% contribution from each parent, Bdelloid Rotifers started reproducing asexually. Males completely disappeared from class bdelloidea, leaving females to generate genetic duplicates through parthenogenesis. This is not their super power.
Bdelloid rotifers are incredibly tough. When environmental conditions are less than favorable, they can enter a dormant state. In this dormant state,they can survive the worst unscathed. Dehydrated, they can endure extreme temperatures, drought, even ionizing radiation. A bdelloid rotifer in its dormant state can even survive in space. If that isn’t enough, while dormant, these rotifers continue to produce offspring, which also remain dormant. This is not their super power.
Bdelloid rotifers’ super power appears when they recover from their dormant state. As they rehydrate and repair whatever damage their cells incurred, they incorporate DNA fragments from their environment. This includes partially digested food and any DNA in close proximity to them, even bacterial and archael DNA. It is this ability that allows bdelloid rotifers to overcome the limitations of asexual reproduction and survive for 80 million years without mates. They can literally absorb the attributes of those around them.
Their incredible toughness, celibate lifestyle, and ability to absorb the powers of anything they touch, put Bdelloid Rotifers firmly on par with X-Men perennial favorite: Rogue.
Continue reading Five organisms with real super powers that rival their comic book counterparts
Aquaman has an unpleasant lunch. From New 52 Aquaman #1 DC Comics.
Two weeks ago, I challenged the world to consider how the greatest hero in the DC Universe would fair if forced to survive in the real world. The result was a hypothermic, brain-dead lump of jerky with brittle bones forced to suffer through constant screams of agony even as he consumes sea life at a rate that would impress Galactus. In short, the ocean is a rough place, even for Aquaman.
Since that post made its way across the internet, several people have asked me to discuss what adaptations Aquaman would need to survive in this, science-based, ocean. So I went back to my comic books and my textbooks to assemble an Aquaman with a suite of evolutionary adaptations that would allow a largely humanoid organism to rule the waves, trident triumphantly raised.
Continue reading The importance of being Aquaman, or how to save the Atlantean from his briny fate
When Dr. Gavin Naylor and his team started a genetic survey of existing shark and ray species, they didn’t expect the results of their project to make international news. Their recent paper (which, at over 250 pages and complete with more than 100 figures, is nothing short of epic), however, is too striking to ignore. The results indicate that there may be as many as 79 previously unrecognized cryptic species of sharks and rays.
A cryptic species is defined as a group that looks almost exactly like another, and may even live in the same region, but is genetically distinct. We’ve known that cryptic species of sharks and rays exist for some time, such as manta rays and scalloped hammerhead sharks, but 79 is a lot; as of the paper’s publication, only 1,221 species of sharks and rays were recognized.
According to Dr. Naylor,
“Organisms become genetically differentiated over time through the cumulative effects of mutation and recombination mediated via drift and selection. When they differentiate in isolation they eventually become so different from the parental stock from which they were derived that they can no longer produce fertile offspring when crossed with them. Some biologists use the point of reproductive inviability as the point at which new species should be recognized….. For practical purposes we recognize “new species” as being genetically or morphologically distinctive from previously recognized forms.”
The study’s methods, though enormous in scope, were relatively basic. According to Dr. Naylor, the study utilized a technique very familiar to geneticists: “standard DNA extraction, PCR, Sanger sequencing, alignment and analysis of a protein coding mitochondrial gene”. To achieve the goals of understanding both evolutionary relationships of sharks and rays and parasite host specificity ( where certain parasites associated only with one species), Dr. Naylor and his team obtained and analyzed samples from as many species as they could. The numbers are impressive- 56 of 57 known families of elasmobranchs were represented among the 4,283 samples from 305 species of sharks and 269 species of batoids. In other words, this study included approximately half of all known elasmobranch species, including many that had never been analyzed genetically before. Since 1986, when the project began, samples have been obtained in more than 50 countries, mostly through the team’s own field work!
Continue reading Genetics study reveals 79 potentially new species of sharks and rays: what does it mean for science and conservation?
I’m a bit late to the party, but last week, several news outlets reported that the Diablo Canyon Nuclear Power Plant was taken offline by “jellyfish-like creatures” that clogged several cooling intakes. While most sources were careful to point out that these were “jellyfish-like” organisms, some secondary sources truncated the description and announced that “Nuclear Power Plant Knocked Offline By Tiny Jellyfish, The Invasion Has Begun”. Unfortunately, these organisms are salps, not jellyfish, and you’d be more correct to describe them as human-like rather than jellyfish-like.
Salps, photo by Lars Plougmann
Salps are free-swimming pelagic tunicates, one of the most basal members of the chordate phylum. While they superficially resemble jellies to the untrained eye, they are far more derived, possessing three tissue layers (compared to the jelly’s two), a primitive, larval notochord, a perforated pharynx, and the rudimentary beginnings of a centralized nervous system. They form large, clonal colonies that are able to take advantage of plankton blooms by rapidly producing more clones to capitalize on an unpredicatable food source. Although I don’t have first hand reports, this is likely what happened in Diablo Canyon, as warm water discharges from nuclear power plants can trigger massive plankton blooms. Far from a “jellyfish invasion”, this was probably the natural response of a predator to increased food availability.
Continue reading #TaxonomyFail: Salps, Jellyfish, and the Diablo Canyon Nuclear Power Plant
This ray-finned fish was my dinner last night. Photo by Andrew David Thaler
When Carl Sagan described our planet as a “pale blue dot” he was invoking the fact that, despite being called Earth, our world is mostly Ocean. The surface of the Earth is a little more than 70% water and the ocean accounts for 98-99% of our total biosphere–the volume of the planet that can support life. Most contemporary theories point to ocean ecosystems–like deep-sea hydrothermal vents–as the launching point for the emergence and evolution of life. Ocean processes dominate biological interactions, even among unwitting terrestrial actors. A new paper, published in the Proceedings of the Royal Society: Biological Sciences, revisits an old debate about the ocean biodiversity and challenges the notion the ray-finned fishes have a marine origin.
In Why are there so few fish in the sea? the authors begin with the seemingly innocuous question–why are there so many more species in terrestrial environments than in marine environments? From there, they look at species counts, phylogenetic relationships, and diversification rates to determine the ancestral state of the most recent common ancestor of one fish class, Actinopterygii, the ray-finned fish. What they found was that, despite the vastly smaller habitat available for freshwater fish, the number of actinopterygian species found those ecosystems was roughly equivalent to the number of species found in marine systems. In both systems, the dominant groups are relative newcomers on the evolutionary stage, with superorder-level radiations happening between 111 – 150 million years ago. Most surprising, the authors discovered that the most recent common ancestor of actinopterygians may have been a freshwater, not marine, fish. Ray-finned fishes may have invaded the ocean from lakes and rivers.
Continue reading If fish evolved on land, where did they all go? Evolution and Biodiversity in the Ocean
From hairy-chested yeti crabs to the deepest known fields, hydrothermal vents have been enjoying a bit of science celebrity in the last few weeks. Beneath the headlines, there has been an eruption of vent-related research published in the scientific literature and some exciting new expeditions just left port.
The Discovery of New Deep-Sea Hydrothermal Vent Communities in the Southern Ocean and Implications for Biogeography
'Hoff' crabs in paradise. Image from ChEss Southern Ocean Consortium
The exhaustive author list on this paper reads like a who’s who in hydrothermal vent biogeography. This is the paper that introduced “the Hoff” crab to the world, but the findings are far more significant. Hydrothermal vent systems are sorted into biogeographic provinces, with different regions supporting different communities. The iconic giant tube worms dominate the eastern Pacific, while the western Pacific (prominently featured in Deep Fried Sea) plays host to fist sized snails, and the Atlantic features shrimp as its dominant species. There are several missing gaps in our understanding of how these qualitatively different communities are connected – the Southern Ocean, the south Atlantic, the Indian Ocean, and the Cayman Trough, among others. Filling in these gaps in our knowledge can help us understand the history and evolution of hydrothermal vent ecosystems.
Continue reading Updates from the Deep: New and Noteworthy in Hydrothermal Vent Research
From here, it looks like such a lovely pond. Photo by Andrew David Thaler
The murky brown water was still, reflecting, perfectly, the drifting clouds above. Had I not known what it was, an acre-wide manmade pond almost a dozen feet deep filled to the brim with hog feces, I might be tempted to describe it as “beautiful”. Hog lagoons like this are a common sight in North Carolina, though their use is in decline. My lab group arrived at this particular lagoon to take microbial samples, fungi in this case, from the steaming cauldron of organic waste: an ideal culture medium. Carefully, we loaded a small skiff and rowed out into the stink. Near the center, we gingerly dipped our sampling vials, affixed to the end of an old fishing pole, into the dense fluid. It was then that we noticed the rising waterline, the slow trickle at the stern, the shift in balance. We locked the oars and rowed, frantically, towards shore. Our labmates on shore had, thankfully, tied a line to the bow before we departed. The skiff’s gunwales were creeping closer and closer to the water. We were sinking. We were sinking in a lake of pig shit.
Continue reading That sinking feeling: Hog lagoons, superbugs, and the proliferation of antibiotics in livestock
Poor Vindaloo never learned to crow. Photo by Andrew David Thaler.
I awoke one morning early last spring to a noise I has been dreading for weeks, the first crow of a chicken that was not supposed to be a rooster. It took me several minutes to fully register what I was hearing. Rather that the classic cock-a-doodle-do we often associate with the rooster’s crow, the sound emanating from my hen house was an awkward, unstable noise not unlike a turkey squawking through a vat of molasses while being vigorously shaken. Over the next several months, two more cocks arrived crowing, in my flock. All three roosters, different breeds from different parents, made noises resembling nothing like a rooster’s crow. There was no pattern; some mornings they would crow off-and-on for a few hours, other mornings they would, for lack of a better word, gargle for half-an-hour straight.
I raise my chickens from day-old hatchlings. Those three roosters, from my very first flock, had never met an adult chicken. They imprinted on Amy and me and looked to us for guidance. When we introduced them to new food, new water dispensers, even small changes to their habitat (like a particularly terrifying log), we had to teach them. Instinctively, they would scratch for food, and if left to their own devices, they would attempt to eat everything, but for the most part, we had to show them how to eat, how to drink, how to roost. But we could not teach them how to crow.
Which is why Casey B. Mulligan’s Economix article in the New York Times – Species Protection and Technology – which argues that cloning could be an effective tool to restore extinct species (a topic I’ve been thinking about quite a bit in terms of population dynamics), is fatally flawed.
Continue reading Better Conservation through Cloning: this cock doesn’t crow
Gobble? image from http://www.public-domain-image.com
The noble turkey, a centerpiece of the American Thanksgiving supper. It looms large from its prominent position on the dining room table. The master of ceremonies – or, in my case, the guy who keeps slicing himself open with various sharp objects yet is inexplicably the one people call on when there’s knife-work needs doing – draws a set of fine, honed knives, set aside for this particular task, and carves, delicately yet firmly, into the hefty white meat of the turkey’s breast. Sure, some favor the dark, rich meat around the legs, but this white meat, soaked in gravy and topped with cranberry sauce or stuffing, that is what we crave.
“We give thanks,” the benediction may begin, “to Charles Darwin, for determining the underlying mechanism by which a theropod may, over the course of 65 million years, through a process of gradual change by means of the retention of beneficial traits through successive generations, evolve into this delicious, delicious bird.” And then, perhaps, that surly teenager, the one determined to point out the social inequalities inherent in the holiday and the colonialist attitudes which led to the wholesale extermination of America’s native peoples – every family has at least one – will chime in to quip “you know, evolution didn’t shape the turkey. The modern Thanksgiving turkey is the product of an extensive selective breeding program that began in the 1940′s. Commercial turkeys can’t even reproduce naturally, they have to be artificially inseminated.” At which point the older members of your family may blush and/or faint at such an unseemly turn of phrase.
Continue reading America’s lust for gigantic breasts leads to impotence: the population genetics of captive-reared turkeys