Monday, March 28, 2016

merely a pigment of the imagination – part 1

European Starling
I recently was asked to design some birds for a mural here in Shreveport to be painted by the public. I got to pick which birds, and made my list of Passerines that are local, attractive, colorful, recognizable, and easily translatable to paint-by-numbers. I was zooming through the designs, recommending Pantones with excitement until I crashed into a little brick wall called the European Starling.

People are attracted to bright colors. Butterflies, beetles, amphibians, and of course birds bear colors that span from Roy to G. Biv. You and I are sadly not as colorful (though current trends on Pinterest are trying their hardest to change that – somebody stop the madness).  We're all pretty much shades of brown and blacks, and when lined up on a spectrum, really don't show that much variation from one person to the next.

So melanin-y. (Wikipedia)
We’re colored primarily via pigments called melanins. Our two primary types of melanins are eumelanin (blacks and browns) and pheomelanin (reddish browns). The infinite combinations of quantities of eumelanins and pheomaelanins comprise the spectrum of human coloration, spanning from skin to hair to eye color and characterize mammalian coloration. Birds also utilize melanins, as is finely exemplified by the Red-tailed Hawk to the right.

Reds, oranges, and yellows also are results of pigments. Carotenoids are the family of pigments that give animals these beautiful fire colors and, as a rule, cannot be manufactured by animals’ cells. Instead, they have to acquire them from the environment via diet. Cue back to the amazing story about Cedar Waxwing’s tail tips turning orange due to the consumption of both yellow and red honeysuckle berries, and flamingos being pink dependent on their consumption of crustaceans in their shallow wading pools.

Though not as common, another coloration mechanism exists in birds. Pigments called porphyrins are identifiable by their fluorescence when exposed to ultraviolet light. Unlike melanins or carotenoids, which are lipids (fats), porphyrins are modified amino acids and can reflect back greens, brilliant reds, pinks and even browns when exposed to white light. In fact, I noticed a few years back when working with a Barred Owl that it had a soft pink tinge to the underside of its wings. After some research, I discovered that that pink tinge was due to the presence of porphyrins in owl plumage. Had I shown a UV light on that owl, it would have lit up like a Christmas tree (read the paper here).

So what about blues? Where do they come from? And why couldn’t I draw that European Starling? These questions lead us into a whole different box of cookies called structural coloration – a mechanism of producing color without a pigment. Blue, and the colors of an iridescent surface like a European Starling, do not exist as physical entities within feathers. No molecule or "thing" exists within feathers that is actually blue-colored or iridescent-colored. In fact, one might say such colors are merely pigments of the imagination...

Hold your bated breath. Part two on structural coloration headed your way.

TEASER. (Wikipedia)

Wednesday, March 23, 2016

wham bam thank you ma'am

Summer of 2008 was one of my best yet. It was filled with early morning fishing trips, catching my first bass on a fly rod, southern home cooking and mowing the lawn using my dad’s 360 degree riding lawn mower. I can still smell that summer when I think about it – including a prominent olfactory memory of Calamine anti-itch lotion.

As the summer came to a close, my dad and I decided to plan a father-daughter hiking trip before I headed back to college. We started training by walking the neighborhood with our packs and slowly adding gallons of water each week to increase the weight. At the time, I thought he was trying to get in shape to keep up with me. Now, I see it was him who was worried about my then 95-lb little body trying to carry a whole pack for three days; and he was right to worry – it took me a few weeks to build up the stamina. Once August rolled around, we were ready and headed up to a wilderness area in Arkansas with only our packs in the bed of the truck.

We spent most of the first day hiking down, and took our first break at a stream. I sat on a log wearing a gray shirt tee shirt and my trusty khaki shorts. Once we rested up we began hiking up. And up. And up. We took another break and I sat down another log to chug some water. We repeated this several times until light started to get dim, we found an area to set up camp. I ate dinner, also sitting on a log in my khaki shorts, and then we turned in.

The bugs were deafening that night. I don’t think either one of us got any sleep. You’d think it would be silent in the middle of a wilderness area at night, but not in Arkansas and not in the middle of the summer. I remember asking myself, as I tossed in my tiny hot tent that night, if I should be worried about any of the bugs.

The next day was more of the same, until about halfway through the day I began to hurt… and itch. And burn. My under-butt region and the tops of my thighs began to itch past the limits of what I thought was humanly possible. A quick trip behind a tree and a peek at my behind revealed to me that my butt had turned red. So red that the individual bites were indiscernible until closer inspection. Chiggers – how had I not thought to beware the chiggers in my little khaki shorts?

Redbugs, or chiggers as we call them in the South, are not actually bugs. They’re arachnids, like spiders and scorpions and belong to the genus Trombicula. They’re a type of mite barely big enough to see with the naked eye when they’re adults and are cute little vegetarians that eat plants. But the babies, well, let me tell you about the babies.

Larval redbugs feed on skin. They like to find tight, protected spots like YOUR PANTIES or fat folds to burrow into your skin and secrete enzymes that start to digest it. And then they slurp it up. The slurping and chewing causes extreme irritation and itching to their hosts. They’ll stay attached for up to five days, and then drop off of your body like you never meant anything to them at all. They don’t even take you out for breakfast the next morning – wham bam thank you ma’am.

Upon returning home from our hiking trip, I counted 110 chigger bites on my butt and upper thighs, and an additional 70 or so elsewhere. I’m sure I was not my usual frickin delightful self for those few days as I lamented wearing my loose-fitting shorts and sitting on so many chigger-infested logs like a dope. I had to take Tylenol PM to sleep at night for a week.

Despite their panty fetishes, chiggers really are pretty non-invasive parasites. They don’t suck blood and don’t enter your body past your superficial layer of skin. Parasites can get so much worse than little baby redbugs munching on some skin cells. Still, if you're not a southerner and find yourself in our neck of the woods during the summer, take precautions. No one deserves to be used like that.

Monday, March 21, 2016

tiny lab monkeys but without the guilt

The husband of a dear friend (hi MK and Andy!) recently challenged me to incorporate a fruit fly into an illustration. Obviously, I made a hipster fruit fly logo because that’s what everyone has been missing in their lives. A few folks asked me what the G, T, C, and A meant in the illustration – so, here it is.

Drosophila melanogaster is a species of fruit fly that has been used as a model organism in labs for about a hundred years, like tiny lab monkeys but without the guilt. In 1909, an entomologist named Charles Woodworth suggested they be used to study genetics, kind of like Gregor Mendel used pea plants. Woodworth’s idea was brilliant.

Drosophila are sexually dimorphic, meaning it’s easy to tell males from females by appearance. This is useful when it comes time to mate them. Secondly, they have only four chromosomes, which are easily observed during times of genetic activity. They have several discreet physical traits that are genetically determined, like eye color, wing shape, bristles, and body color. They breed quickly and a lot- allowing people to observe multiple generations in a reasonable amount of time. Lastly, they’re easy and cheap to maintain. They’re frickin fruit flies.

For decades people have been studying these guys. They’ve given us insight into how basic genetics, beyond the white or red pea plant blooms, operate in a system founded on DNA. In 2000, we completed sequencing the entire genome of Drosophila melanogaster- that is, the sequence of 139,500,000 G’s, C’s, T’s, and A’s that make a fruit fly a fruit fly.

Not only can you look up every single nitrogenous base (G, C, T, or A) present in a red-eyed, black-bodied, curly-winged, bristleless fruit fly, you can look up where those genes reside, what sequences control them, and what bits of DNA don’t do anything.

One might ask what good it does to have such an intimate genetic knowledge of a fruit fly, and one might be totally justified in asking that question. The answer is this: 75% of known human genes that cause disease are present in the fruit fly’s genome. About 50% of their coding DNA also codes in us. By studying the fruit fly’s genome, we’re studying how things like diabetes and cancer work. And that’s important.

So if you haven’t hugged a fruit fly today… don’t. They smell weird. But do tell it thank you for its service to science.

Thursday, November 19, 2015

daily doses of tiny dinosaurs

Since I took a furry dependent into my care, I’ve made it a daily habit to come home at lunch. It’s not always easy to find the 45 minutes to an hour in my workday, and I usually feel stressed and rushed as I shovel food in my face while simultaneously running around with Rosy in the backyard. But today, I decided to just sit beneath the tree and “smell the roses,” as they say.

Today was clear and beautiful and cool: the kind of cool that is replaced by the warm sun rays in the most pleasant of ways. As I sat with eyes closed, I could hear Rosy’s little nose sniffing around, the faint sounds of Youree Drive traffic, and birds. I love listening for the birds.

One block over, I heard a large flock of Cedar Waxwings. Behind me, a handful of robins making fools of themselves. In my front yard, the usual suspect, Mr. Blue Jay, doing a pretty good impression of the Red-Tailed Hawk I heard perched not too far away. I’d be remiss if I didn’t mention the Barred Owl that lulled me to sleep last night from the pecan tree in my backyard. As visually inspiring as our avian cousins are, they deserve equal admiration for their vocalizations.

I think I love birds because they are just so ridiculous. Consider the metabolic energy that is required to produce their elaborate colors, patterns, and feather structures with the primary selective pressure being to look sexy. And then their elaborate songs! They have two voice boxes that are capable of producing sounds at the same time (thanks to a structure called a syrinx- not unlike your larynx). So basically they can sing twice… at once. And would you believe it, the primary selective pressure for this is to sound sexy. Not to mention their incredible visual capabilities that exceed our own in almost every way -- they see more of the world than we ever will. Migratory birds gaze at the night sky as little nestlings, learning the stars by which they navigate their migrations. Corvids like crows and jays can solve problems that baby humans can’t.

So here we have these furby-sized dinosaurs that are pimped out and more perceptive than many vertebrates their size. But they’re not these elusive, exotic creatures that must be sought out in the farthest reaches of the wilderness to be observed. They’re accessible; they live in the trees around our houses and serve as our personal alarm clocks each morning. They de-stress us as we sit beneath pecan trees on our lunch breaks and often raise their babies under the trusty shelters of our porches. They’ve adapted to urban settings like New York City yet still thrive in nature. These daily doses of tiny dinosaurs are part of our human experience and among the most relatable connections we have to nature in increasingly non-natural settings.

Show some love to some birds this weekend. Many are migrating right now and are weary. Be hospitable and provide them a meal. Give them a place to take a bath with fresh water. Put a cat indoors. It’s the least we can do for the tiny dinosaurs.

Bird doodles

Friday, October 23, 2015

you go, little burs

It’s a miracle I haven’t written a post about dogs yet- if you’re friends with me on Facebook, you’ve probably noticed I’ve developed a borderline obnoxious obsession with my newly adopted puppy. Don’t you worry; I’ve got some in the works. This one only features the cutest dog in the WHOLE WIDE WORLD.

Rosy (synonyms or nicknames: Rosalind, Roseballs, Lady Rose, Roseface, or Rosepot) has some of the sweetest paws you’ll ever squeeze. So when I see her suddenly limping on our walks, it always causes me momentary distress. As we’ve found out, my neighborhood is populated with those little burs that get stuck on your socks and shoes, or in this case, paws. They’re the seeds of Soliva sessilis, a leafy green weed that commonly invades people’s lawns. Though Rosy and I try to avoid them on our walks, she still manages to catch a few each time. To her credit, she’s a champ and patiently holds still as I locate them and pluck them from her feet.

Fig. A. Thanks Disney.
We take for granted our two legs and locomotive powers as human animals. They help significantly in our reproductive challenge of genetic diversity. Proven time and time again, diverse genes, when sexually combined, produce more fit offspring. Should genetic diversity be lacking in a reproductive pool, you get inbreeding and decreased fitness (Figure A).

This model is so important that almost any sexually reproductive species you consider has evolved adaptations to accommodate it. Be it the wings of male drone ants that carry them to unrelated queens in  different nests or the roaming behaviors observed in male primates (playas, I’m looking at you), Animalia likes lots of genes to choose from when it comes to swapping DNA.

Plants are no different, though they do have the immobility issue to overcome. When it’s likely that a plant’s nearest neighbors are its siblings, it needs a way to get its DNA package over to a plant that is not as closely related. Basically, plants must depend on their environment to do the traveling for them. That environment includes gravity, wind, water, precipitation, bugs, and animals like you and your adorable dog.

For them, it’s a matter of life vs. evolutionary death. They depend on us to get their DNA over to a plant other than their immediate family (who can blame them!?) I prefer they not involve Rosy’s paws in their sexy quests, but I also wish I didn’t have to pluck that weird hair from my forehead every few weeks. Nature deals the cards and we make the best of it.

Actually, the Soliva sessilis burs, though annoyances, are in a way a nice addition to our walks. In a neighborhood where people cut their lawns and trim their bushes so no animals can find refuge, plant non-native flowers, immediately reach for a shovel upon the discovery of a harmless snake and allow their outdoor cats to stalk and kill birds, I secretly root for the little weed. In a humanized, unnatural setting, the little guys are doing what it takes to further the fitness of their species.

You go, little burs.

Tuesday, September 29, 2015

mirabilis jalapa got moxy

I currently rent a little 2-bedroom house in Shreveport, Louisiana. Built in the forties, it features an old phone booth in the hallway, a foldout ironing board in the kitchen wall, and those pretty clear crystal-looking doorknobs. I really am fond of the place, but whenever people ask where I live, I always preface with “I don’t live in the greatest area…”

And I don’t. But my immediate neighbors are all good folks who keep tidy lawns and look out for each other. So when I moved in, I decided to make the place mine as much as I could and enjoy being a young working gal who comes own to a nice little home every day. I started with the backyard.

The backyard was overgrown, so I cut it to a luscious 3 inches and weed-eated the perimeter to rid it of the leggy weeds. It took a whole Saturday, but by the end of it, the yard was clean and manicured. And it’s stayed that way until about a month ago.

As life and work in general picked up in September, I let the yard fall behind (getting a new puppy might have had something to do with that…). I recently noticed that those weeds I spent so long cutting had grown back, but looked more like bushes. On closer examination, I realized that I had attempted to murder one of my all-time favorite plants. Luckily, it’s a determined plant with moxy and heart, God love it.

 4 o'clock at my mom's house
Four o’clocks (Mirabilis jalapa) are blooming bushes with pretty green heart-shaped leaves.  Their flowers open in the late afternoon (hence the name) and stay open all night. Come dawn, they close up again. Although this is pretty cool, it’s not the coolest thing about four o’clocks.

Their color, or rather, how they inherit their color, may be the neatest thing about this plant. They come in three different colors- yellow, pink, and white. But a single flower on a whole bush can show multiple colors- and in unique patterns.

Four o'clock color inheritance clearly does not follow the traditional dominant-recessive model that good ole’ Gregor laid out. For instance, the dominant recessive model would dictate that if a red cow (red being dominant) made babies with a blue cow, there would be a 75% chance of having red babies and 25% chance of having blue babies. But all the babies would be either red or blue. But what if some of the babies were purple? What if they were striped blue and red? That would be incomplete dominance.
Spunky 4 o'clock at my house

Four o’clocks exhibit incomplete dominance. A *completely yellow flower cross pollinated with a completely pink/red flower yields an orange-flowered plant. The more generations there are, the more complicated the genetics get – think Punnett squares that are 16 x 16. You start getting multi-colored flowers, and in different patterns. They are really very lovely.

The 4 o’clocks in my mom’s yard are both yellow and pink. The feisty ones in my current backyard are all pink. I’m thinking about going to my mom’s house and grabbing some of the multicolored ones and matchmaking them with the yellow ones at my house.

What do you think would happen?


Friday, June 26, 2015

like a fat kid at the doughnut case

The past two weeks have kicked my butt. I’ll just say that they have involved falling in love with and giving away the best kitten in the world, stressful challenges at work, being sick (twice), being hit in a very scary car accident, friends moving away, and numerous other challenges and confrontations that, when added together, will just get a gal down.

Yesterday, I had the good, unexpected laugh that I’ve needed. You see, two weeks ago, I bought basil and mint plants at the farmers market and placed them in my kitchen window. I haven’t been overly attentive to them, instead glancing at them quickly each morning as I grab some breakfast and rush out of my house. I’ve noticed that the mint plant seems to be growing in height, not so much sprouting leaves. But finding a sunnier spot for it hasn’t been at the top of my priority list.

So yesterday, I came home and sloughed into my kitchen for a glass of water to find my mint plant with all of its leaves plastered to the window like a fat kid looking in doughnut case at the grocery store. I can’t tell you exactly why I found this to be so hilarious, but I definitely stood in my kitchen laughing by myself like a maniac for a solid minute.

It occurred to me that Minty (that’s what I’m calling it now- I’m having kitten withdrawals don’t you judge me) was doing some pretty neat things in my window sill. First off, it’s not growing the big leaves I’d like to put in my iced tea. Instead, it’s become lanky and growing stem length. This is a behavior (that’s right, plants behave) it has evolved to find sunlight when it’s not getting enough. Also, it’s moving its leaves to maximize the sunlight that it can find. Minty is being very proactive for Minty’s well being. I’m proud.

This begs the question- how does a plant A.) “know” wtf is going on around it B.) “act” on those conditions? Where are the sensing organs to tell it it’s not getting enough sun? How does the info from those sensors translate into movements and actions? Do plants have plant nerves?

Answer: plants do stuff via plant hormones.

Giberellins are the class of hormones responsible for stem elongation. Right now, they’re coursing through the vascular system of Minty, only affecting cells and tissues that they’re supposed to activate. Giberellins are flowing through the puny leaves just like they are the stems, but only causing growth in stems. This is just how human hormones work too.
Giberellin organic structure.

Once I find a sunnier home for my plants, they’ll signal to lower the production of gibberellins and to up the production of cytokinins, which will cause leaf growth. Which means I will be enjoying some iced tea very soon.

So next time you walk past a plant, you may want to offer it some chocolates and tell it it’s pretty. You never know what kind of hormonal swings our plant cousins are enduring.