Sergio Carvalho via Flickr // CC BY-NC-ND 2.0
Sergio Carvalho via Flickr // CC BY-NC-ND 2.0

5 Strange Microbes (and 1 Bonus Organism)

Sergio Carvalho via Flickr // CC BY-NC-ND 2.0
Sergio Carvalho via Flickr // CC BY-NC-ND 2.0

The world is teeming with life, and we're always discovering new species—including some that stretch the limits of how we view and classify biological life forms. Here are a few that clearly don't play by the rules.


Diego Fontaneto via Wikimedia Commons // CC BY 2.5

Bdelloid rotifers are microscopic superstars inside a drop of water. These tiny transparent animals—which can be found all over the world (even Antarctica!)—are masters of survival and reproduction. When water becomes scarce, they dry up like brine shrimp, surviving for years completely desiccated. When water returns, they rehydrate themselves and continue on as good as new. Rotifers are all female and reproduce asexually, laying eggs that don't need to be fertilized and are essentially clones of themselves. While they're not the only animal that doesn't need a member of the opposite sex to reproduce, they're more successful than others: Bdelloid rotifers have evolved into 450 species. How can a creature evolve if it's only producing clones? Random mutations would produce changes, but cannot explain the rotifers' 80-million-year survival and successful speciation.

The secret to rotifers' evolution is that they steal genes from other living things. DNA analysis of bdelloid rotifers shows that about 10 percent of their genes come from bacteria, fungi, and plants. How does that happen? It turns out that bdelloid rotifers are also masters at surviving ionizing radiation, which damages DNA. The creatures are able to repair their own DNA, but can incorporate new genes (from the surrounding environment or something they ate) in the repair process. Over time, the new genes are used to adapt to the environment, leading to the evolution of new rotifer species as well as incorporating the necessary genetic material to protect against parasites.


Deuterostome via Wikimedia Commons // CC BY-SA 3.0

Euglena is a genus that contains hundreds of species of single-cell organisms that are not plant nor animal nor bacteria, but have features of all three. Most species of Euglena are mixotrophs that power themselves based on environmental conditions. When sunlight is present, for example, Euglena will use it to make food by photosynthesis using chloroplasts, the genes for which may have been taken from engulfed alga sometime in Euglena's evolutionary history. When there is no sunlight, Euglena ingests surrounding substances like an animal to get energy. But what's really amazing about Euglena is that its behavior can be useful to humans. A company in Japan is looking into using some species of Euglena for food and biofuel, and other species might be used to clean the environment as they eat pollutants.


Bernd Schierwater via Wikimedia Commons // CC BY 4.0

Among multicellular animals, the microscopic Trichoplax adhaerens is the master of minimalism. It's so simple, in fact, that for decades it was assumed that it was only a larval stage of another animal. T. adhaerens is comprised of just four types of cells, and is basically two sheets of cells with some more cells in between. It has no organs and no discernible front or back, though it does have a distinct upper and lower side—the organism uses that lower side both to eat and to adhere to surfaces. It can move either by changing shape or by using tiny cilia on its outer layers. It's perhaps not surprising T. adhaerens has an extremely simple genome, too, with 98 million base pairs, compared to over 3 billion for humans. They reproduce by splitting, by budding, or by sexual reproduction. Scientists don't know exactly how they manage the sexual reproduction; organisms have been observed degenerating into eggs, but fertilization is still a mystery.


Tardigrades, also called water bears or moss piglets, resemble eight-legged faceless bears, except they're generally a half-millimeter long. Hundreds of species of these tiny animals are found in every kind of environment on earth, but they prefer to be among moss, algae, and lichen. While ocean-based tardigrades are pretty normal, land and fresh water tardigrades are famously hard to kill. If the environment is dry, they dry up too, and go into a dormant state that they emerge from when wet conditions return, even years later. They can survive boiling or freezing temperatures. They can survive in the vacuum of space and in high pressure conditions. They can survive radiation that would kill lesser animals.

In case you want a tardigrade of your own, the International Society of Tardigrade Hunters has instructions for collecting them. A low-power microscope should suffice for observation.


A thermal vent. Image Credit: Sergio Carvalho via Flickr // CC BY-NC-ND 2.0

A microbe of the Archaea domain, Geogemma barossii is a microbe that likes it hot. This hyperthermophile, sometimes referred to as Strain 121, grows optimally at 220°F, but does just fine at 250°F (or 121°C, hence the name). It doesn't die until temperatures go over 266°F—one of the highest-known temperature tolerances of any living thing. The discovery of G. barossi's heat tolerance in 2003 gave pause to medical specialists when they realized that their sterilization procedures would not kill this microbe. However, Strain 121 cannot grow in the range of a human's body temperature, so it isn't considered infectious. Its normal home is thermal vents in the ocean floor.


The size of a grape, Gromia sphaerica is too big to be a microbe—but this single-celled organism is too cool not to include. This ancient relative of the amoeba lives at the bottom of the ocean, and was first discovered in the Arabian Sea in 2000. Adult specimens can grow to be 1.5 inches in diameter, or as small .019 inches. While a single cell that big is pretty strange, the most remarkable thing about G. sphaerica is the trails they leave behind on the sea floor. They weren't created by the organisms rolling downhill (they can actually move uphill), and they weren't created by ocean currents. Somehow, these big cells moved on their own and are heavy enough to leave a trail behind them. That raises questions about fossil trails from the Precambrian that scientists assumed were left by multicellular animals, but may have been left before multicellular life arose.

11 Facts About Fingernails

Whether there's dirt beneath them or polish atop them, your fingernails serve more than just decorative purposes: They help keep your fingertips safe and have a multitude of special functions that even your doctor might not be aware of. “The nails occupy a unique space within dermatology and medicine in general, particularly because they are such a niche area about which few people have expertise,” Evan Rieder, assistant professor in the Ronald O. Perelman Department of Dermatology at NYU Langone Health, tells Mental Floss.


Along with skin and hair, nails are part of the body's integumentary system, whose main function is to protect your body from damage and infection. Fingernails have four basic structures: the matrix, the nail plate, the nail bed, and the skin around the nail (including the cuticle).

Fingernail cells grow continuously from a little pocket at the root of the nail bed called the matrix. The pale, crescent-shaped lunula—derived from Latin for "little moon"—on the nail itself is the visible portion of the matrix. If the lunula is injured, the  nail won't grow normally (a scarred lunula can result in a split nail), and changes in the lunula's appearance can also be signs of a systemic disease.

Fingernail cells are made of a protein called keratin (same as your hair). As the keratin cells push out of the matrix, they become hard, flat and compact, eventually forming the hard surface of the nail known as the nail plate. Beneath that is the nail bed, which almost never sees the light of day except when there's an injury or disease.

Surrounding the matrix is the cuticle, the semi-circle of skin that has a tendency to peel away from the nail. The skin just underneath the distal end of the fingernail is called the hyponychium, and if you've ever trimmed your nails too short, you know this skin can be slightly more sensitive than the rest of the fingertip.


That's about 3 to 4 millimeters per month. But they don't always grow at the same speed: Fingernails grow more quickly during the day and in summer (this may be related to exposure to sunlight, which produces more nail-nourishing vitamin D). Nails on your bigger fingers also grow faster, and men's grow faster than women's. The pinky fingernail grows the slowest of all the fingernails. According to the American Academy of Dermatology, if you lose a fingernail due to injury, it can take up to six months to grow back (while a toenail could take as much as a year and a half).


You've probably heard that your fingernails keep growing after death. The truth is, they don't, according to the medical journal BMJ. What's actually happening is that the skin around the base of the fingernails retracts because the body is no longer pumping fluids into the tissues, and that creates a kind of optical illusion that makes the nails appear longer.


Scientists say it's still unclear why, but they suspect nail-biters do it because they're bored, frustrated, concentrating, or because it just feels comforting (and anxiety doesn't seem to play a big role). Perfectionists who don't like to be idle are very likely to have the habit. Biters expose themselves to the dangerous crud that collects underneath the nail: The hyponychium attracts bacteria, including E. coli, and ingesting that through nail-biting can lead to gastrointestinal problems down the line. Biting can also damage teeth and jaws.


Our primate ancestors had claws—which, like nails, are made of keratin. As human ancestors began using tools some 2.5 million years ago (or even earlier), evolutionary researchers believe that curved claws became a nuisance. To clutch and strike stone tools, our fingertips may have broadened, causing the claws to evolve into fingernails.


While the fingernail may be tough enough to protect tender flesh, it also has the paradoxical effect of increasing the sensitivity of the finger. It acts as a counterforce when the fingertip touches an object. "The finger is a particularly sensitive area because of very high density of nerve fibers," Rieder says.


"One of the most interesting facts about fingernails is that they are often a marker for disease within the body," Rieder says. Nail clubbing—an overcurvature of the nail plate and thickening of the skin around the nails—is a particularly significant sign of underlying illness, such as lung or heart disease, liver disease, or inflammatory bowel disease. Two-toned nails—whitish from the cuticle to the nail's midpoint and pink, brown, or reddish in the distal half—can be a sign of kidney and liver disease. Nails that are two-thirds whitish to one-third normal can also be a sign of liver disease. However, little white marks on your nails, known as milk spots (or punctate leukonychia) are just the remnants of any kind of trauma to the nail, from slamming it in a door to chewing on it too fervently.


Psoriasis is "typically thought of as a skin disease, but is actually a skin, joint, and nail disease, and when severe, a marker of cardiovascular risk," Rieder says. Psoriatic fingernails may have orange patches called oil spots, red lines known as splinter hemorrhages, lifting of the edges of the nails, and pits, "which look like a thumb tack was repeatedly and haphazardly pushed into the nails," he says.

Doctors often prescribe topical or injected corticosteroids to treat psoriatic nails, but using lasers is an emerging and potentially more cost-effective technique. Rieder relies on a pulsed dye laser, which uses an organic dye mixed with a solvent as the medium to treat nail psoriasis, "which can be both medically and aesthetically bothersome," he says. This laser is able to penetrate through the hard nail plate with minimal discomfort and "to treat targets of interest, in the case of psoriasis, blood vessels, and hyperactive skin," Rieder says.


Painting and other forms of decorating nails have a history of offering social and aesthetic cues through variations in nail color, shape, and length, Rieder says. In fact, he adds, in some cultures ornate and well-decorated fingernails "serve as a proxy for social status."

Five thousand years ago in China, men and women of the Ming Dynasty aristocracy grew their nails long and covered them with golden nail guards or bright home-made polishes. The long nails allegedly announced to the world their social rank and their freedom from performing menial labor.


Lee Redmond of Utah started growing her nails in 1979 and kept at it until she held the world record for "longest fingernails on a pair of hands ever (female)" in 2008. Her right thumbnail was 2 feet, 11 inches and the collective length of all her nails was 28 feet, 4 inches. She also applied nail hardener daily and painted them a reflective gold. Unfortunately, she broke her nails in a 2009 car accident and has no plans to regrow them.

More recently, the man who holds the Guinness record for the "longest fingernails on a single hand—ever" chose to chop them off at Ripley's Believe It Or Not! in New York City in July 2018. Shridhar Chillal of Pune, India started growing the nails of his left hand in 1952, when he was 14 years old. At last count, the total length measured 29 feet, 10.1 inches.


Today, biters don't have to use their teeth to trim their nails. While the earliest tools for cutting nails were most likely sharp rocks, sand, and knives, the purpose-built nail clipper—though it might be more accurately called a circular nail file—was designed by a Boston, Massachusetts inventor named Valentine Fogerty and patented in 1875. The nail clippers we know today were the design of inventors Eugene Heim and Oelestin Matz, who were granted their patent for a clamp-style fingernail clipper in 1881.

Billion-Year-Old Rocks Reveal the First Color Ever Produced by a Living Thing

Billions of years ago, before there were plants and animals on Earth, there were rocks, tiny organisms, water, and not much else. It’s hard to envision what our barren planet looked like back then, but scientists now have some idea of what colors dominated the landscape.

As Vice reports, a team of researchers from Australian National University (ANU) were able to pinpoint the oldest colors ever produced by a living creature: purple-red hues dating back more than 1.1 billion years. The pigments, which appear pink when diluted, were found in molecular fossils of chlorophyll that had been preserved in rocks beneath the Sahara desert. A billion years ago, though, this area was “an ancient ocean that has long since vanished,” Nur Gueneli of ANU said in a statement.

Chlorophyll may very well be green, but these pinkish pigments are a result of "fossilized porphyrins, a type of organic compound that forms an atomic ring around a magnesium ion to form a chlorophyll molecule," Vice explains.

While this provides an interesting visual, the color itself is less important than what it reveals about some of the earliest life forms on Earth. Scientists determined that the chlorophyll was produced by ancient organisms called cyanobacteria, which derived energy via photosynthesis and ruled the oceans at that time, researchers wrote in a paper published in the Proceedings of the National Academy of Sciences. Larger planktonic algae—a potential food source for bigger life forms— were scarce, which may explain why large organisms didn’t roam the Earth a billion years ago. That kind of algae was about a thousand times larger than the cyanobacteria.

“The cyanobacterial oceans started to vanish about 650 million years ago, when algae began to rapidly spread to provide the burst of energy needed for the evolution of complex ecosystems, where large animals, including humans, could thrive on Earth," ANU associate professor Jochen Brocks said.

So the next time you encounter algae, you can thank it for helping you secure a spot on this planet.

[h/t Vice]


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