The “Wow! Junk DNA is not junk after all” news hook is a tempting one, but it needs to be resisted. At the very least, science writers need to recall some history.

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Stasia from Germany writes,

I made this tattoo when I was second year student in physics. Then I had just started my first scientific project and this simple but beautiful shape impressed me. Now I am a Ph.D student in chemical physics and this picture of hybridisation perfectly fits in the area of my scientific interests.

 

Carl: This is a diagram of pi orbitals (or p orbitals), a particular kind of room in which electrons live. For more, see here. And if you don’t like your pi orbitals tattooed, how about a towering sculpture?

This post is actually safe for work. The Penduline Tit is not a body part but an ordinary-looking bird. Penduline refers to the pendulous nest that the birds build for their eggs. What makes the bird interesting to me is not its Beavis-and-Butthead caliber name, but how it raises its young. If you think that nature is never destructive, or that natural selection automatically finds beautiful solutions to life’s problems, this bird has a lesson for you.

The Penduline Tit–do you mind if I just call it Remiz pendulinus?–is a common sight in Europe and parts of Asia. If these birds build nests in your backyard, you may get the impression that they’re the very picture of parental harmony. After a male attracts a female (in part thanks to a handsome black eye-mask), they mate. He then gets to work building a large nest hanging from a bough, with a narrow-mouthed opening in which the mother can hop in order to lay the eggs. Either the mother or the father will take on the job of incubating the eggs and then feeding the chicks once they hatch.

Sounds lovely, right? But there’s one disturbing little fact to consider: a third of the egg clutches laid by Penduline Tits are abandoned by both parents. The chicks are perfectly healthy, but they’re left to die.

As natural selection makes different genes more common in a species, some of those genes can come into direct conflict. Genes for male and female behaviors are particularly prone to clash, because a strategy that works best for genes in fathers may not be so good for the mothers, and vice versa. These clashing interests create what evolutionary biologists call sexual conflict.

To understand the source of the conflict in these birds, you have to bear in mind that natural selection favors genes that boost the reproductive success of individual animals–but that success has to be measured over an entire lifetime, not just a single clutch of eggs. If a female stays behind to take care of her clutch of eggs, those chicks will typically grow up and carry on her genes. But if she can desert the nest, leaving the father behind to take care of the chicks, she can find another male bird to mate with and have two clutches in a seson rather than just one. Researchers have found that females that have two clutches in a season end up with about one extra chick for the season compared to a female that stays in her original nest.

This strategy backfires if the father abandons the nest first. Natural selection apparently favors fathers that bolt, because they can find another female to mate with, too. But the female has an advantage over the male: she controls the information about the eggs. A father must time his desertion carefully if he will produce the most chicks. If a male abandons a female before she lays her eggs, she may not be able to successfully do so. Leaving early also creates the danger that another male will mate with the female and fertilize the last eggs in the clutch. If a male deserts too late, however, the breeding season may be so far gone that he loses the opportunity to mate with other females, since they’re already paired with other males. It’s crucial for the males to track the egg-laying process.

Females have evolved to make it hard for males to figure out what’s going on. As they prepare to lay eggs in the nest, they become very aggressive with their mate. In some cases they’ll even kill him as they keep him from seeing how far things have progressed. And once mothers have laid their eggs, they hide some of them at the bottom of the nest. Even if the male should manage to get in, he will be deceived. Experiments confirm that females hide their eggs as part of the sexual conflict over the chicks. If scientists uncover the eggs, for example, a female become far more aggressive in keeping the male away; nevertheless, the male usually deserts her that very day.

It’s very tempting to see human virtues in animals–imagining, say, that penguins love traditional (American) norms. I wouldn’t suggest look to the Penduline Tit for a role model for being a good parent. But that’s not because the birds play too many video games or are otherwise degenerate. They are simply stuck in the box sexual conflict put them in.

[Image via Wikipedia]

I’ve downloaded the first two episodes, which I don’t think I’ve seen since they first aired 28 years ago. I remember watching every episode intently as a 14-year old at the end of the Carter administration. The passage of time has revealed some hokiness around the edges.  The music, much of it by Vangelis, sometimes makes me think I’ve walked into a crystal shop. Sagan is fitted in corduroy blazers and what seems to be the precursor of the Members Only jacket. Some of the images still look good–like Sagan’s calendar of the cosmos–but there are also painfully long pans across a cardboard diorama of ancient amphibians, reptiles, and mammals. We are so spoiled today by Jurassic Park.

For some reason, what struck me as hokiest about Cosmos was the spaceship Sagan uses to coast around space to show off galaxies and pulsars. It is meant as a deeply profound experience–a voyage of the imagination across billions of light years (say it slowly, in proper Sagan style). But Sagan sits in a plastic bucket chair that survives today only in aging bus stations and flea markets.

The picture of science Sagan presents is also a bit too simple for my taste now (at least in the first two episodes I’ve watched again). He offers a black-and-white picture of science versus the forces of superstition, war, and other bad things. Greeks love knowledge, Dark Ages fall, Kepler rises! Only science will save us from the evils of nuclear war! Of course, Kepler’s discoveries were motivated by his mystical reading of the Bible. And, of course, science and war (hot or cold) have been intimately intertwined for the past century. The people who sacked the library of Alexandria did not build the atomic bomb. The generation of physicists who taught Sagan did.

But as I was tallying up the shortcomings of the show, something funny happened. My daughters, 7 and 4, are pretty well-trained now to stay out of the office. But as I was watching Cosmos on my computer, they snuck in and ended up sitting on my lap, captivated by the stately unwinding of DNA and the majestic trip through the cell. I could see they were starting to understand things that I’ve been trying to explain without much luck. In an age of hyper-fast editing cuts and soundtracks always turned to eleven, Cosmos can still mesmerize a child and give her an introduction to the natural world. Sagan’s accounts are sometimes a bit dated now, but nobody has done a better job of conveying a sense of the scale of nature, from that calendar to that bus-station spaceship to the dive into the cell–and it’s thanks largely to Sagan’s exceptional ability to talk about science in clear, even poetic terms. It is, I’m realizing, a show that shaped the way I look at the world, even now that I’m getting close to Sagan’s age when he filmed it. And for that, I can forgive any fashion faux pas.

But first, some background:

In April, a reader named Abigail sent in this tattoo, with the following description:

My first year of college, I wanted to be an English major, and I took Intro Chemistry to fill the science requirement. The brief unit on thermodynamics made me fall totally in love. Entropy made sense to me - scientifically, philosophically. I became a Chemistry major and love every second of it. I got the tattoo to mark my rite of passage - Entropy going both ways, with its symble delta-S in the middle, all supported in the roots of Yggdrasil, the world-tree of Norse mythology (harking back to my English-lit days).

Today, Abigail’s mother sent in this sad note:

Abigail is my daughter. I was with her when she got this tattoo last March, several months after she turned 18, while she was attending Reed College in Portland. It was an adventure for both of us. She came home for the summer in May, and four days later was in a fatal car accident.

I will be getting this same tattoo next week - Abigail’s personal design - from the same artist. It will memorialize both my daughter and her intellect and passion for science and philosophy.
The world has lost an incredible mind. Thank you Mr. Zimmer for displaying this artwork and sharing it with visitors to this site.

All great human passions have the same thing in common: a possibility to live on, in the minds of others after their original mind has passed. A tattoo is an outward sign of that inward connection. We will remember Abigail, and we will give her mother our deepest condolences. May Yggdrasil’s branches continue to grow within us all.

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