Tuesday, July 29, 2008
So far, the previews have been pretty hyped up; the evolution of the eye is the fight for survival and of course, the eye is the weapon.
Intro about eye diversity. There's a really interesting description of eagle's eyes compared to human eyes focusing on the anatomy and how the anatomy of the eye changes vision. Not too bad. Then there's some talk of evolution as something that another thing does, specifically, "the eagle evolved" its eyes. Ouchie.
There's a segway with an animation timeline that displays evolution as linear.
We move on to the origin of eyes and use Polyorchis, the Bell Jelly, which has eye spots lining its base to talk about simple light receptors. The narrator describes an experiment where jellies are exposed to different light waves. The experiment is used to demonstrate how the eye aids in survival. In green light the jellyfish drift to bottom of tank, relaxed (the green light is the same wavelength as the ocean floor). In purple light the jellies become very active, pulsating (short wave light is higher energy - damaging to transparent organisms).
Narrator takes us back 500 million years ago (using that darn linear evolution animation). He describes the Cambrian explosion as an evolutionary arms race , the weapons being jaws, claws, body armor and eyes. In the Cambrian, we see the first evidence of compound eyes. There's some musing as to whether or not eyes were the reason for the explosion of life.
Little bit about insect eyes. Complex, compound eye. 29,000 lenses in Dragonfly eye. Poor focusing power, but rapid processing. Leave us with the idea that insect eyes and vertebrate eyes evolve from different ancestors.
Now we're talking about the vertebrate eye. It's a single lens camera of soft tissue. Someone talks about the vertebrate eye and it's history of being used to demonstrate the idea of an intelligent designer. There's a great animation showing Darwin's refutation of intelligent design of the eye, showing possible intermediate steps. I'm pretty impressed with this...it's not described in too much depth, but the average person could see it and get a pretty good idea of what's going on.
Okay...some dinosaurs and some really bad dino CGI. The narrator introduces Kent Stevens, who researches dinosaur vision. He made scale models and used lasers to plot the line of sight of both eyes. He then calculated degree of overlap (binocular field of vision). There's some talk about the advantages of binocular vision - mainly that it allows for judging depth and 3D vision. T. rex has 55 degrees overlap and therefore, like modern predators with similar overlap, probably hunted actively. Allosaurus had only 20 degrees of overlap and was therefore probably an ambush predators, like modern animals with lateral-facing eyes.
The narrator moves on to prey animals and how their eyes moved further and further apart over time, laterally. Rabbit eyes have 360 degree vision which allows them to see predators approaching from all angles, but see in 2 dimensions.
We begin with the evolution of night vision and how it may have aided in mammal survival during the Mesozoic. The narrator touches on the difference between eyes of nocturnals vs non-nocturnals; the cornea size. Larger corneas allow in more light. A really cool demonstration of Tarsier eyes and how they compare to human eyes.
Eyeshine. What is it? It seems that we won't ever know, but then tapetum lucidum, a layer of tissue behind the retina, is mentioned. Light bounces off the tapetum lucidum, giving a greater chance of absorption and causing some of the light to shine back out of the eye.
Color vision! Dinos out, mammals in. One group, the primates, settle into tree living. Somewhere along the line, there is an advantage to seeing more than just blue and green hues and the ability to see reds as well prevails. Why reds? Nate Dominy's research, which involves gathering the food of primates and using a spectrometer to analyze the colors of leaves that primates were eating, shows that red leaves composed most of the diets of tree-dwelling primates. Turns out red leaves are younger and more nutritious.
The narrator explains that binocular vision in primates, though they are not predators, comes in handy because the increased depth perception is compatible with arboreal living. Primates have 60 degrees binocular vision but that makes them vulnerable, so they live in groups to be safer, and therefore need larger brains?
So...I really liked the show. It was quite good. It had some fluff and there was a lot of hype, but I really feel that they did a good job of explaining why and how the eye evolved. To a layman, this show was neither too dumbed-down nor too technical.
What did you think?
Sunday, July 27, 2008
Friday, July 25, 2008
A breeze leads the gauzy curtains in a dance and the star mobile hanging from the ceiling turns slowly in circles.
The sheets are cool against my skin and soft on my bare feet; they feel like spring air on a perfect day - the kind where the air is elusive and so well matched to the temperature of my skin that I just don't notice it's there until the wind reminds me.
The cats hop onto the bed and settle into their favorite places.
Emily curls up at my feet, facing the door like a little guardian gargoyle. Her face is so flat that from the side, all I can see of her face is the glassy orb of her right eye. She turns to me and lazily winks at me. I hear this is a sign of trust and love. I blink back.
Echo leaps gracefully over my body to the narrow space between me and J. She lowers her body slowly to the bed and begins her usual grooming routine, starting with her little bulgy tummy. The pink pads of her feet match her tiny pink nose. I interrupt her grooming by stroking the back of her head. She leans back and pushes into my hand, purring loudly. I curl up around her, putting my head on J's belly. The television lulls me to sleep and I sleep soundly; a solid, warm human body next to me and two tiny goddesses at my side.
Thursday, July 24, 2008
And did I mention I miss school? I miss having a goal in mind, a challenge. I miss leaving class and nearly skipping back to my office with excitement over the stuff I just learned. I miss getting back tests and plugging the numbers into my calculator and finding out that all my hard work paid off. I miss almost all of it.
It's been really hard for me to keep up this blog this summer. I think it's because I'm not taking classes and I'm falling into a bit of a thinking rut. I don't feel like writing anything I have to research at the moment.
Anyway, here's what's been going on:
- I took a leave from Aikido. I just won't have the time come fall and I can't afford to pay 80$ a month to only take one or two classes.
- My cat's ACL seems to be mending just fine. But now she won't eat. I think it's just because she's been getting into Zeus's wet food and she's being snotty. I hope. Otherwise, it's back to the vet.
- I have a bazillion plans coming up: J's mom is visiting this weekend, my aunt turns 70 after that and then I have two weddings to go to (and I'm in one of them as a bridesmaid). Then school starts and the annual meeting follows!
- I've been reading Stephen Jay Gould's Wonderful Life and I'm loving it. It's really quite fascinating and it's also making me want to go to Alberta to visit the Burgess Shale.
- I've been going to the gym. Like, pumping iron. I love it! My goal is to be able to do a single pull-up and ten push-ups (the kind where your arms are under your shoulders and your elbows are tight against your side). So far, I can do almost 3/5 of a pull-up and 1 push-up.
And here are a few paleo pics, just to stay on topic:
The original head from the Brontosaurus mount at the Peabody Museum. Ick.
Some Ceratopsian skulls at the Peabody Museum
Thursday, July 17, 2008
Jerry Harris, you'll be interested to know that I met you in my dream. You were very nice. In my dream, you were the guardian of the common cabin refrigerators.
Really, the dream was kinda horrible...I mean, J was flirting with another girl and I wasn't registered for the conference and nobody would talk to me.
In reality, I'm just superpsyched about the conference. I can't wait. I'm pretty much wishing for October, which is something you just don't do in Vermont, given that there's only three months of warm weather.
Oh, and Echo tore her ACL. Poor thing was dragging her leg around and howling yesterday morning. I took her to the vet and they gave her some medicine, which, judging by my cat's look of euphoria, I can only imagine was something close to heroin.
She sat in that position for like, 4 full hours without moving. She's doing better today and I'm hoping surgery isn't in the future, or I can kiss the annual meeting goodbye...
Friday, July 11, 2008
This is Brontotherium (I'm not entirely sure which species...) at the Peabody Museum in New Haven, Connecticut. Doesn't the mount just ooze raw power? There's so much movement conveyed with such a fixed, inanimate object.
I wish I had mad Photoshop skillz so I could take out the glare and all that. Really, I wish I had Photoshop, period.
For some reason, I remember the display saying that the animal was in fact Brontops, though I could be wrong. I'm not 100% sure it's Brontotherium, but if EvoWiki is correct, the "slingshot-shaped" horns strongly suggest that it is.
Tuesday, July 8, 2008
If you want one of these:
you'll have to go to South Korea.
Monday, July 7, 2008
I got really excited when I saw the skeleton because I thought it was another organism bearing my last name, like Quetzecoatlus northropi. I just realized, though, as I was posting this, that "Nothrotherium" is one "r" off. Oh well. Anyone know the etymology of the name "Nothrotherium"?