Drawing by Eric Lindahl
What miracle of evolution gave humans the ability to see details just inches away?
Snakes, says an anthropologist who has spent years trying to answer that question.
Especially venomous snakes that forced our distant relatives to improve their vision or perish.
Isbell’s theory, published in a recent issue of the Journal of Human Evolution, flies in the face of conventional wisdom and will require much more research to be verified. The current thinking holds that primates developed near-vision capabilities to help them capture bugs, or at least reach out and grab a piece of fruit.
But Isbell points out that when snakes began to eat primates, it made sense for the monkeys and apes of Africa to develop better eyesight. A snake, after all, is pretty harmless unless it’s close by. It’s not likely to romp across the lawn to attack a human, or even a smaller mammal.
But if it’s close, you better be able to see it.
Isbell says primates in Africa, who have had to fuss with snakes the longest, have the best eyesight. And South American primates, which fall between those two extremes of exposure to predation, fall between them in terms of vision.
And lemurs in Madagascar have never suffered predation by venomous snakes. They have the worst vision of primates.
Isbell says, “Primates have the best vision of all mammals,” she says. “And we have the best vision of all primates.”
Because of snakes, you can read Dvorak Uncensored.
Snakes on a Savannah!
“miracle of evolution”?? OMG, you heathen savage!
Sag:
I think that you hit the nail right on the head. This sounds more like an attempt at publicity than any meaningful conclusion drawn.
So, saggy — you’ll be showing up, then, at the Journal of Human Evolution for peer review. Right?
Spiders and scorpions don’t eat primates (except maybe very very tiny primates.) Collection of food is generally done by smell and not much detail is required of sight. Ticks can be sensed by touch – a small lump that isn’t hair is easier to feel than it is to see.
Snakes, on the other hand, can be identified by color and certain other details. It makes sense that vision must be sharper for close up review of the potential predator in front of you. Not all snakes are dangerous but they probably don’t smell much, if at all, different from each other, so those primates with the best vision will know when to run and when to ignore the snake.
Isbell says, “Primates have the best vision of all mammals,” she says. “And we have the best vision of all primates.”
So why do so many of us require corrective lenses?
Ok, other than a few very large Anacondas, how many snakes can eat a primate?
Our “Great Eyesight” developed along with our great brains. As we developed the ability to process the information, we developed the ability to gather the more important senses.
You can argue about the other 4, but sight is the most important sense, so primates with good brains have good sight.
Don
Ok, but how did a light-sensitive, electric-generating, actually useful cell evolve in the first place?
What mutation changed a skin cell, for example, to something that changed with different frequencies of light? And then, what good was that cell to the organism so that it kept producing those cells long enough for the next mutation that would have the cell send electricity to the brain? And then, what made that so useful so that the brain knew what to do with the different impulses it got?
Seems to me the basic questions about how certain functions get started are pretty much ignored.
What mutation changed a skin cell, for example, to something that changed with different frequencies of light?
Mutation X42-33874b-23L, first occuring in Aug 2,355,432,333 BC.
Is that what you meant?
And then, what good was that cell to the organism so that it kept producing those cells long enough for the next mutation that would have the cell send electricity to the brain?
Aha. A common misconception. A mutation does not have to be beneficial to be passed along to an organism’s offspring. In fact, the only real advantage of this mutation for several billion years was that it enabled some slower-moving mollusks to avoid jehova’s witnesses.
And then, what made that so useful so that the brain knew what to do with the different impulses it got?
Well, aside from that Jehova’s Witnesses thing (unknown until revealed to Joseph Smith by a flaming white salamander in 1822… little known fact but true)
Well… ya got me there, pardner. I can’t really imagine WHAT advantage a light-sensing organ would have for any creature which had the misfortune to be alive before the first season of Jerry Springer.
xray, just a little note to your excellent dissertation.
Before Jerry Springer, there was the Ted Mack Amateur Hour. That was a must see, hence the great increase in photo sensing cells. Since Ted Mack was on radio, the photo sensing cells congregated to one spot, usually on the front of the face but occasionally to the back of the head (my aunt Beryl comes to mind). Because of the minimal movement with radio, this congregation allowed the cells to just sit there and stare straight ahead (or behind). Eye movement came later with the advent of Jerry Springer and the flying fist, chair, and bra.
Ted Mack’s following gave us the phrases, “Built like a Mack !”, “He’s got Mack eyes”, after a fight, you “Mack up”, and “for the love of Mack, will you look”.
I disagree completely. Humans have really good eyesight in order to find the nipple, to feed, when they are young, and to, well, feed, when they become older.