Friday, November 25, 2011

a lucky bunch

Happy Thanksgiving. If you are participating in the Black Friday festivities, I hope you avoid being tased, pepper sprayed, punched, trampled, or any variety of associated violence. In keeping with the Thanksgiving spirit, I thought I would write a post about being thankful. This holiday season, let's all be thankful simply for our existence...

What was Charles Darwin’s primary contribution to science? If you answered “evolution,” slap yourself in the face.

Just kidding. Don’t. But truthfully, Charles Darwin did not come up with the idea of evolution. He explained it. He came up with natural selection. That was his major contribution to science.

People began to connect the fossil dots long before Darwin came along. In fact, there was sort of a natural history craze that was happening (especially in England. Gotta love those crazy Brits). They noticed that similar fossils seemed to gradually change over the strata. The evolution wheels had already started to turn in the years before Darwin. Naturalists unarguably recognized that species gradually changed over time, but had no foggy idea as to the mechanism that produced this gradual change.

Enter Charles Darwin. He proposed the idea that certain traits may give animals a survival and therefore reproductive advantage over others. These animals are statistically more likely to score and have babies. Those babies are then more likely to also carry the advantageous trait from their mom or dad (or both). And here is evolution on the smallest scale- a genetic change between generations. It carries on down the line until the changes become so drastic that a new species is born. This is speciation via natural selection.

Okay, to be honest, I just made it sound way simpler than it is. Not all traits that evolve are necessarily “selected for.” Sometimes they are random, sort of meaningless characteristics. Take human eye color, for instance. There are hazels, browns, blues, and greens. These colors evolved, certainly. But were they selected for? Did having blue eyes make somebody more likely to have fit offspring over brown eyed people? Probably not. Random, chance mutations caused these diverging eye colors. Not selective pressure.

There in lies a nuance of evolutionary theory that often goes overlooked. Evolution is not intelligent nor guided (sorry, pro-intelligent design homies). Nor is it a perfect process (queue dancing appendix here). Some things evolve purely by random chance, and natural selection acts upon only the traits that make a critter more likely to have fit offspring. All life is a result of the interaction between random chance and natural selection.

Eye color. Jellyfish. Strep throat. Poison ivy. You. These are all things that are here thanks in large part to chance. We earthlings are a lucky bunch, aren’t we?

Thursday, November 17, 2011

dna... or something like it

Hypothetical situation: you work as an official at NASA and the news comes in. Extraterrestrial life has been found and confirmed. What is the first thing that you want to know about it? Well, if it’s intelligent, it would be polite to ask if it is having a good day. Otherwise, I personally think the most interesting and important question would be “is it a DNA- based life form?”

DNA. What do you know about it? You probably know that it codes for our genes. It is unique to each species and each individual within that species. It’s a molecule that looks like a twisty staircase. You might even know what it stands for- deoxyribonucleic acid. And you would be right about all of this. These are the basics of DNA. But lets get our hands a little dirtier.

The “rails” of the twisty staircase are the structural foundation for DNA, but the steps of the staircase are what’s really important. There are four different kinds of “steps.” A step may be one of four molecular bases- adenine, guanine, cytocine, or thymine (commonly represented by A, G, C, T). A gene is made up of about 3000 bases, with A, G, C, and T appearing in different orders. The order in which the A, G, C, and T appear define the gene. Humans have about 30,000 genes. Do the math, and that’s a frickin ton of DNA. That’s not even counting the trash DNA that doesn’t code for genes- which is quite a lot.

And what makes it even more marvelous is that it is universal. All earthly life- from bacteria, to plants, to fungi, to sea sponges, to vertebrates- is DNA-based. Not only are they all DNA based, but the language in which the DNA is coded is the same across life. “ATTTGCCAGATTACAAT” codes for the same thing in a bacterium as it does in a rose bush, as it does in you. That’s why we can put the genes for human insulin into a bacterium and we get… well, human insulin.

Point is, DNA is a highly complex molecule whose processes are just as complex. The DNA system has been evolving since life began, making it one of the oldest and arguably most intricate biological coordinations of structure and function in existence. Earthly existence, that is…

Wouldn’t it be something to take a look at how an extraterrestrial life system works? Assuming that this extraterrestrial species reproduces and traits are inherited across generations, there must be some system by which these traits are inherited. It’s hard to think outside of the DNA box, but let’s try. Maybe they have genetic material that is arranged in something other than a double helix- like a sphere or something. Does it have a structural component and then the genetic message woven in like ours? Does it use similar molecules or ones that we’ve never even seen before? Is 100% of it functional, or are there portions that are trash and just left over from evolutionary past (let me refer you to the name of the blog here!)? The questions and possibilities are endless.

As remarkable as it would be to discover a completely new system of genetic inheritance, I can’t help but hope that it’s not all that different from our own. What a tribute it would be to our humble deoxyribonucleic acid to find that it is a product of the same evolutionary forces felt by lifesystems throughout the cosmos. It’s a romantic notion, really. I like the thought of being related to ET through a shared biomechanism that evolved multiple times, light years apart. It will truly make you feel “one with the universe.”

Unless these extraterrestrials are like the terrifying ones from Alien. Then I think I’ll keep my DNA queries to myself. But even then, it might still be worth being eaten to find out.

Wednesday, November 9, 2011

my humps, my humps, my lovely lady lumps

Although I usually post on Fridays, I will be on a research trip starting tomorrow and unable to write. And since I know you are all waiting breathlessly at your computers for a new post, I’m posting early so as not to cause anyone to plummet into depression.

Take a look at the cartoons below.


Above and to the left, we have a rendering of the original Arthur the Aardvark. Above and to the right, we have a rendering of the modern-day Arthur that we all know and love. What changed between the two? A sweater has been swapped for the dorky button down. No handkerchief. Glasses were added. Most noticeably, new Arthur is missing the elongated snout (which is pretty much the defining feature of a real aardvark’s head, might I add). But overall, if you had to sum it up, what is the big difference? Okay I’ll just tell you.

The new character is more round.  From the head, to the glasses, to his ears, to the lines of his shirt, his features are more rounded. And this is no happy coincidence. Why, you ask? Because old Arthur had really bad ratings until his creator figured out that the human mind is hard wired to respond positively to round shapes. Scheming cartoonists. And there’s another circular cartoon character that has been crafted to work his way into your heart by appealing to your basic animal affinity for curvature…

But when we’re talking about biologically relevant features as opposed to Mickey Mouse or Arthur the Aardvark, roundness plays a part in A.) parental care B.) male --> female attraction.

Babies are round. Ever notice that? From their button noses and big round eyes to their weirdly fat asses and limbs, the pudgy little creatures elicit feelings of protectiveness and affection from (most) adults. This is an evolved mechanism for increasing the level of care an offspring receives from its parents. This response is so primal that it even extends trans-species. I don’t know about you, but I get way more excited about little kittens and puppies than grown cats and dogs, respectively. Though you don’t consciously realize it, shape recognition is a basic feature of the animal brain and exists even in critters like insects and crustaceans.

Specifically, mammals’ shape recognition centers generally seem to activate at the site of roundness. When the optical shape recognition part of the brain senses curvature, a signal is sent to the amygdala (emotion center) and causes good feelings like affection, protectiveness, or attraction. This all happens subconsciously- we’re not even aware of it. It is hard wired in us. Especially males.

To see this in action, visit your local college bar. Girls have their boobs pushed up to their clavicles and are donning clothes that make their butts look maximally perky and round. Eyeliner and mascara help to create the illusion of big, round, bright eyes. Lip gloss helps to make lips look plump. Tight clothes accentuate the circular lines of the waist and hips. High heels help to flex the calf muscle and round out the lower leg. And these girls are spot on- they know (even if it is only subconsciously) what gets attention. It’s all beginning to make sense now…

One might even make the connection that this reaction is heightened in males to increase paternal fidelity. That is, the father feels a stronger connection to its round little babies and is more likely to help contribute parental care- making the offspring’s chance of survival better.

Do you feel like nothing more than a slave to your instincts? It’s okay. You can’t help it. They’re there for a reason.

Friday, November 4, 2011

baby mommas and baby daddys

This past summer, I lived by myself in a little house out in the middle of a cornfield in rural central Louisiana. A bunch of barn swallows decided it would be the perfect place to be the local hangout/nesting site. At first, I would sit on the porch and watch them, appreciating their pretty blue feathers, rusty bellies and elegant silhouettes against the sky. As the weeks went on, they would not shut the eff up and I took to throwing lit firecrackers at them. What? Don’t judge me.

One morning, as I was leaving for work, I seemed to piss them off more than usual. They began to dive-bomb me. Aggressively. I felt one’s tiny little feet graze my hair. They were not letting up. I looked back at the porch and saw what had set them off. A baby swallow had hopped out of the nest and onto the porch that morning and I had walked within a foot of it. My feelings of avecide faded and I understood. They were just doing what they were programmed to do- they look out for their babies just like we do.

Parental care is well-researched behavior, and, simply put, is the investment that a parent makes in its offspring. It is a behavior that varies greatly both between and within taxa. Some frogs lay their eggs and haul ass, never to see the shining faces of their froglets. Then you have frogs that carry their babies in pores on their very own backs to keep them safe. Even invertebrates (those soulless, unrelatable creatures like bugs) sometimes lay their eggs in another animal, so that when they hatch they’ll have something to eat. Even though mom doesn’t stick around, that is still a form of parental care.

If you go to Google Scholar and type in “parental care,” most of the papers that pop up will be studies about birds. Parental care is especially interesting in birds. Can you think of any reasons why? Contrast it with mammals. Mammal moms carry the fetus internally until birth and most times, dad hit it and quit it and he’s nowhere to be found. At the end of the day, it’s up to mom whether or not the offspring will be taken care of after birth. How is this process different in birds?

They lay eggs instead of getting knocked up. Fetal development happens outside of the female. Eggs and egg laying certainly take energy from the female, but it is drastically less of an investment than pregnancy. When human females experience a miscarriage, the loss is profound both emotionally, but also physically. This is just how it is for mammals. We (females) physically invest an enormous amount of energy and resources into our offspring. But how many times have you seen a bird abandon her nest for apparently no reason? It happens all the time. It’s nothing for a bird to find another willing mate and drop some more eggs.

So imagine you’re a male bird. A few days after sex, Tina (your current partner) lays some eggs and guess what. They’re 50% your problem. She can easily go find another guy bird who will mate with her and actually help rear the offspring. So you better get in gear and start helping out, or Tina will abandon your ass and your name will die with you.

With this system of external fetal development, there is more of an opportunity for males to contribute to their offspring’s chances of survival. The parental investment is more evenly balanced. Not a bad set-up, if you ask me.

Friday bonus:
In light of the recent exotic animal escape in Ohio, a friend of mine has posted his take on the situation. Great read. Check it out.