Another hot day. If I were a lizard, I’d probably be settled beneath these ferns.
Instead, I am settled indoors, sheltered from the sun. And the heat. And the humidity. Sheltered from any insects, too.
Gawd’s creation is kinda nice. But it ain’t as human-friendly as it’s cracked up to be. At least not without man-made shelters and more.
I suspected it was happening. Many a times I’ve stood in my backyard and thought to myself, “I smell evolution.” Is it really the case? According to recent research, it’s happening here in my own lower, somewhat flaccid member-state of the Bible Belt.
What’s happening? Native U.S. Lizards Are Adapting To Escape Attacks By Fire Ants. In particular -
Penn State Assistant Professor of Biology Tracy Langkilde has shown that native fence lizards in the southeastern United States are adapting to potentially fatal invasive fire-ant attacks by developing behaviors that enable them to escape from the ants, as well as by developing longer hind legs, which can increase the effectiveness of this behavior.
Holy crap. We have fence-lizards in our very yard. I should get a camera and document this alleged EVOLUTION in action. But wait – the lizard legs in my piece of turf don’t look longer, they just look as they are. Hmm. Seems I can’t see evolution. How do I really know it’s happening? Learn me some science? Do I have to?
Okay, I’ll try a little learnin’. Here goes –
Langkilde conducted an experiment in which she compared the responses to fire ant attacks of lizards that were collected from four different sites: one that had not yet been invaded by fire ants and ones that were invaded by fire ants 23, 54, and 68 years ago. Her goal was to determine whether the amount of time since invasion influences the ways in which lizards respond to attacks.
What did Tracy Langkilde find when she wasn’t in the kitchen (where the Bible god would have preferred her to be)?
“The lizards can survive this attack by twitching to flick off the ants and then by running away from the mound,” said Langkilde. “We found that the lizards from sites that have been invaded the longest were more likely than the lizards from sites that have not yet been invaded to perform this survival behavior. Many of the lizards from the uninvaded site and the most recently invaded site just sat there with their eyes closed while the ants attacked,” said Langkilde, who stopped the experiment after 60 seconds to prevent any of the lizards from dying.
And . . .
She also discovered that lizard leg length appears to be inherited from an individual’s parents. Langkilde concluded that the lizards living near fire ants are developing behaviors to increase their survival and are evolving longer hind legs in response to attacks by fire ants.
But wait a minute. How the hell do you get from lizards wagging their tails to the conclusion that Darwin was right and my grandpa was a monkey? What? I have more learning to do?
Screw that. I’ve got a cold Bud waiting. Where’s my wife to fetch one?
[recycled post: first appeared 1/28/09 here]
Oak leaf in a sago palm. What are the chances that a single leaf would fall from a tree and get blown by the wind to lodge in a palm frond like that? I bet if you performed an experiment consisting of a pile of oak leaves on a roof and a leaf-blower (to simulate wind), you’d go through quite a few leaves before you could get one to do that. To cause one leaf to exactly match the above outcome, down to finer than millimeter accuracy? Perhaps one in millions. You couldn’t do it.
That, in a nutshell, is why I don’t trust hindsight probability arguments. Because it was so unusual — very improbable — it was meant to happen.
Really? Maybe improbable is just improbable.
Science has struck another blow to my self-concept. I must be a bit of a masochist, cause I like it.
Reading Human Microbiome Project: Diversity of Human Microbes Greater Than Previously Predicted, I encountered this:
The human microbiome consists of all the microorganisms that reside in or on the human body. Outnumbering cells in the human body by 10 to 1….
Um, so does that mean that what I considered “me” is only 10% of the biological stuff I walk around as? If my body were teased apart into elemental units, only 10% would be the building blocks of Andrew, the other 90% free-riders?
Well, not quite. First there is this addition info:
…some of the microorganisms cause illnesses, but many are necessary for good health.
Switching metaphors here, so my body is not a train, it’s cars clung-to and filled with free-riding hobo microbes. Many of the passengers actually contribute to my health and well being. Are even essential.
The 10 to 1 ratio can be a bit misleading in this regard too: as with the train, ridden by 9 passengers for every one of its cars, if we were to form a ratio by weight, vs. by elemental units, the genetically-me-stuff would again dominate. Relative to bacteria, a human cell can be super-massive. A Gulliver to Lilliputians.
(Bad Andrew! Switching metaphors mid-stream again. Sit, stay.)
Still. Biological information such as above teaches us just how complex life is.
As a freethought endnote I invite creationists to ponder which “theory” better explains the 9 to 1 ratio: so-called Intelligent Design or evolution. Be honest now.
This morning the following image of a creationist came to mind: He/she stands atop a massive pile of sand, shovel in hand. At their feet, at the head of the shovel, is a divot just removed. The creationist claims, See, it’s not a pile, it’s a hole!
More sand has just been dumped atop the ever-growing pile of evidence for evolution.
In Evolution More Rapid Than Darwin Thought I encountered this finding:
Magnus Karlsson discovered that the distribution between the color variants of pygmy grasshoppers differs across different environments. In recently burnt over areas, a very high proportion of the grasshoppers are black. In unburnt areas, on the other hand, the black variant is unusual. What’s more, the proportion of black grasshoppers changes very rapidly between generations in the burnt areas, whereas the proportion in unburnt areas remains the same over the same period of time.
Magnus Karlsson presents data that show that the pygmy grasshoppers’ color changes by natural selection. He believes that the primary cause of these changes is birds and other animals that hunt using their vision. The black grasshoppers are simply less visible against the burnt background, so they survive more often. But as the environment changes and becomes more complex, the advantage of being dark diminishes, and other color variants can once again increase in number. [bold mine]
One of my first thoughts was, “but can we be sure this isn’t an epigenetic, phenomenon–that something in the environment isn’t triggering genetic expression in the grasshopper?” Fortunately, the research looked into that and ruled it out. This finding is all about the speed of natural selection. And it can be quite fast indeed.
News flash: Not only are you part of an ecosystem that sustains you, but you are also a unique ecosystem yourself, a host to other species.
Months ago at my prior Evolving Mind blog, I began a post, titled, An Oral Ecosystem, with these words:
That big, moist hole in your face — it’s an ecosystem thriving with life. Every time you swallow: death. Each time you brush and/or gargle: a mass slaughter.
Yes, your mouth is home to bacteria. You could say your mouth is a self-sustaining zoo with inhabitants different than the person sitting next to you. New research has revealed the same is true for . . . the skin of your hands! And the information could be used to convict you of a crime. How so?
The CU-Boulder study showed that “personal” bacterial communities living on the fingers and palms of individual computer users that were deposited on keyboards and mice matched the bacterial DNA signatures of users much more closely than those of random people. [source]
Cool. Watch for this finding to be incorporated into a future episode of CSI: Hoboken. Or Las Vegas. Or something. If it hasn’t already.
I wonder. Did the great god of bacteria grant them dominion over us, their ecosystem, providers of their shelter and nourishment?
