Hi, all! Monsters in My Backyard is taking a break this week while we go hunting for more monsters (in other words, while I do research for Wes’s next drawing). Back next week with a new post! Thanks for your patience!
Well, at their most basic, the eyes of animals have three jobs, according to biologists:
- the detection of light
- the detection of shadows
- the transmission of this information about light and dark to motor structures (because it’s one thing to be able to tell where a shadow’s coming from, quite another to be able to move away from it if you think it’s the shadow of a big, bad beast)
In the simplest kind of eye in the animal kingdom, found most often on the various tiny marine creatures we collectively call plankton, the motor structures that act on visual information aren’t muscle cells, like what you’d find in humans and other vertebrates, but cells lined with tiny hairs called cilia, which move the itty bitty organisms through their watery environments like the oars on a ship. The eye that provides these ciliated cells with info is similarly simple (alliteration away!); it’s made up of only two cells, one that receives the light, and another that processes shadows with the help of pigment.
Animal eyes range wildly in complexity, from the basic cup-shaped light and shadow detectors on the top sides of flatworms to the camera-like instruments of focus that we humans tend to roll every time we hear our bosses announce another brilliant idea for efficiency in the workplace.
There are sorts of stops in between, too. Squids and octopuses, for example, possess eyes that have lenses, as human eyes do, but lack the cells called cones that provide the human eye with the ability to perceive color. They can adjust their lenses to focus on objects near or far away but can only visualize those objects in terms of light and dark (though research suggests that octopuses have ways of reacting to color in their environments that have no parallels in human anatomy, which makes them really, really neat).
When it comes to human eyes, it’s been proposed that eyes have other functions besides the three listed above. Humans eyes not only receive information; they apparently also communicate it.
Unlike our relatives the great apes, humans have eyes that are partially white. This white part of our eyes is a structure called the sclera. The primate eye has a sclera, too, but it’s dark in color, frequently brown.
In 2006, anthropologists at the Max Planck Institute for Evolutionary Anthropology ran an experiment in which they had both great apes and human babies watch while researchers looked in one direction, then another, either by moving their heads or moving their eyes. The anthropologists found that the apes were more likely to follow the researchers’ gaze when the researchers moved their heads, while the human tots were more likely to follow when the researchers moved their eyes.
What this suggested is that our eyes evolved as a way of helping us cooperate on certain tasks. With our irises more visible against a white background, the researchers proposed, it would be easier to see where we were looking, so that others could see what caught our attention, too.
And let’s face it: as all the selfies on the Internet demonstrate, we spend a lot of time looking at human faces. In fact, it’s been suggested that eye contact is essential for creating a bond between a human infant and a caregiver, and that human babies spend twice as long staring into their caretakers’ eyes as primate newborns do. Is this behavior influenced by the evolution of the human eye? As always in science, research continues, but there’s a strong possibility that the eyes in this case really do have it.
Green is good! At least, that’s what we’re taught in our science classes when it comes to plants. Plants with healthy green leaves are busy getting down, doing photosynthesis (which, being a biochemical process, is actually the antithesis of getting down). They’re growing and becoming the mature leafy plant life that eventually animals like cows—or, you know, us—will eat for sustenance.
So why would a plant develop a pattern on its leaves that’s white? Why would a plant include code in its genes for a part of the leaf that doesn’t perform photosynthesis as well?
White clover, known scientifically as Trifolium repens, exists throughout Europe, North America, and parts of the Pacific. A lot of people reading this blog have seen it, I bet. Chances are that a few of us as kids plucked it and shouted something like, “I found a lucky clover!” while holding a bunch of it in a small bouquet. Presenting our white clovers in a cluster, we reasoned, made it that much harder to tell that the plants we found growing everywhere really had three leaves instead of the fabled four. How clever we were! (Or, how clever I was, if I’m the only dork here who was sure that that would work.)
Okay, so we/I sucked at getting the adults around us to see what we wanted them to see. Trifolium repens, however, is actually very good at getting the creatures that eat it to notice exactly what’s important.
One widespread form of white clover (which has white flowers, if you were wondering) has leaves that are solidly green, just as you‘d expect from a plant. In contrast, another variety has a pale v-shaped stripe in the center of each leaflet.
That stripe doesn’t exist just for pretties. The variety of white clover with the v-stripe, sometimes known unsurprisingly as “white-striped clover,” produces cyanide inside its cells. It makes just enough of that lethal compound to cause problems for small creatures like snails and slugs that otherwise would eat whatever clover they could find in low-lying areas.
It should come as no shock that the striped white clover is the more common form of clover along low-altitude coastlines like that of Long Island, New York, of the shores of North Carolina, where plant-eating molluscs like to slither. Survival of the fittest, baby! The molluscs in such places have learned that that stripe means danger and so the striped clover lives on. If you want to see the plain form of white clover in abundance, Minnesota is cool. Not as many shell-toting animals in those plains thereas there are by the ocean.
Even if striped white clover is toxic to small animals (and even if any kind of white clover’s ability to grow quickly across a large area of land has led most people label it a weed), it is a green plant, and green is still good:
- Its flowers attract bees, those wonderful pollinators.
- It’s able to deliver the nitrogen that other plants need to grow into the soil, making it good for crop rotation (provided it doesn’t take over the land).
- It’s bovine approved—white clover often gets added to livestock feed to improve its quality.
In other words, one animal’s poison is another one’s lunch. I think that’s how the quote goes, anyway.
“Box jellyfish” is a name given to the biological class of jellyfish that attack using some of the strongest venom known to man. Part of the reason we know that these jellyfish are the source of this excruciatingly painful venom is because, once upon a time, a doctor willingly had one sting him.
A little background: When most people discuss box jellyfish, usually they’re discussing one particular jellyfish species, Chironex fleckeri. Like other jellyfish, C. fleckeri has tentacles. Along its tentacles are cells that contained specialized structures called nematocysts. Nematocysts are a pain, literally. When the jellyfish is touched, the nematocysts shoot out tiny darts, each loaded with venom. It’s said that a single member of the C. fleckeri gang packs enough venom in its tentacles to kill 60 humans.
Additionally, C. fleckeri has impressively developed eyes for a jellyfish, along with a tendency to swim vigorously with a direction in mind, as opposed to drifting on ocean currents the way most jellyfish do. Just in case you thought were sleeping tonight.
C. fleckeri largely inhabits the waters of the Pacific Ocean from northern Australia up to Japan, an area that, when I think strictly about box jellyfish and not about the general beauty found there, I’m relieved to say is not in my backyard. It also can grow up to 30 centimeters long, with tentacles up to two terrifying meters in length trailing behind it.
However, even when nets were placed in the ocean near Australia’s north shore to establish safe swimming areas free of these substantial box jellies, some people got stung anyway. It turned out that that saying “big surprises coming in small packages” was true.
Chironex fleckeri is one member of a biological group of several types of jellyfish, class Cubozoa. The most obvious feature that sets Cubozoans apart from other amorphous jellyfish is that they have a box-shaped body, or bell. So even though we commonly refer to C. fleckeri as the box jellyfish, technically there are several others that fit the bill.
And not all of them are so big.
Carukia barnesi, another Cubozoan, is a jellyfish that not only is nearly transparent; it’s also only about 6 to 8 millimeters in size. Like the venom that C. fleckeri produces, C. barnesi‘s venom can kill a person. It takes about a half-hour after the sting to make its awful symptoms felt, however, so it’s very easy to get stung by this little jelly and not know it. Isn’t that something?
In fact, the source of those symptoms was such a mystery that for a long time the illness was known by another name, Irukandji syndrome, after an Australian tribe whose members often suffered from it. Only in 1961 did a medical professional determine the cause in what could have been a very stupid way.
Dr. Jack Barnes, a physician in Australia, had treated patients with Irukandji Syndrome who also had jellyfish stings but said that had never seen the creature that got them. He was certain that a jellyfish was at the heart of the pain. So one day in December, he went swimming in an area where jellies also were known to hang.
While swimming in those waters, Dr. Barnes found an incredibly tiny jellyfish floating in front of his diving mask. He captured it, conferred with a lifeguard who also caught one, and then did perhaps what only a man fueled by curiosity would do: he decided to let the little specimens sting not only him, but his nine-year-old son and the lifeguard, too.
Carukia barnesi is named after Dr. Barnes because of his efforts. I don’t know if that made the pain he endured after the stings worth it. Fortunately, all three of those people survived. Oh, and the tribe members who suffered attacks over the years also get honored, in a weird way—today, C. barnesi continues to be known commonly as Irukandji.
It’s interesting, how science and common lore sometimes come together on a topic and other times diverge wildly. Like when it comes to treating a jellyfish sting, for example. It actually has been demonstrated that vinegar can stop the cells along the jellyfish’s body from firing their venomous little barbs. In the case of a run-in with Irukandji, this can reduce the pain.
And if we’re talking about C. fleckeri, the big-gun box jellyfish, there is not only an anti-venom that’s been in use since the 1970s but also a treatment that would use zinc compounds to fight the conditions that cause cardiac arrest in C. fleckeri‘s victims.
You’ll notice that none of these responses involve urinating on a sting. Professionals have come out against the idea, saying that, in some cases, it could make the pain worse. In short, no need to add insult to injury; there are better ways to help jellyfish victims than peeing on them, even if some methods, like dousing with vinegar, require some thinking outside the box.
At least, that’s how it appears. Bacteria inhabit just about every untreated, unsterilized surface and environment on the planet. And our bodies happen to provide some of the best habitats for colonization.
Propionibacterium acnes is a bacterium that lives on human skin, deep in the pores, specifically. It hangs out near the sebaceous glands, which are the tiny glands near each that produce the oil, or sebum, each of us has lightly coating our skin and hair. P. acnes‘ strategy for life is pretty similar to the one I employ at county fairs and carnivals, which is, simply, to eat as much grease as possible. By taking up residency near the sebaceous glands, this itty bitty bacterium gets a nearly endless supply of the sebum it prefers to eat.
Unfortunately for the human host, whenever too much sebum and too many bacteria clog a pore (and whenever the body starts reacting to what it perceives as a big bacterial infection), acne can develop. A bunch of tiny bacteria can be all it takes to produce a huge, honking zit.
Our bacterial bumps aren’t nearly as bad as some of the ones plants develop, however.
Agrobacterium tumefaciens is another bacterial species with a long, lovely name. It infects plants, not humans, though the list of plants it can infect is substantial: roses, willows, maples, raspberry bushes, apple trees, cherry trees, almond trees—you get the idea. It’s a wide-reaching bacterial agent, and it’s pretty sneaky to boot.
A. tumefaciens enters a plant’s system through a fresh wound, one created through pruning and other forms of mechanical damage. Once inside, it does more than divide and conquer: it makes the plant’s own cells divide and conquer. Like a mad scientist minus the hysterical laughter, A. tumefaciens actually splices its own DNA into the DNA of a plant cell. The new DNA sequence tells the plant to produce growth-stimulating hormones. Under the hormones’ influence, the plant cells multiply so much that a cyst-like lump called a gall develops. Lo, A. tumefaciens gets a spacious new home inside the plant tissues!
Meanwhile, circulation of water and essential nutrients within the plant gets cut off.
Although galls can develop along the stem or on the roots, A. tumefaciens is mentioned in conjunction with what’s called crown gall, which is a lump that develops at the plant’s base, right around the soil line (the area known as the crown). The recommended treatment for crown gall? In the case of young trees, it’s sometimes believed to be more economical and better for general plant health to remove the plant. Older, larger trees can have the gall removed surgically or left with the plant for the rest of its woody days if the plant is otherwise healthy.
So if ever you or someone you know ends up lamenting a sudden, uncontrolled outbreak of acne growth, just remember, it could always be worse. At least your DNA is still your own, you know?