Fear of Snakes May Have Driven Pre-Human Evolution

Krishna Dagli writes "An evolutionary arms race between early snakes and mammals triggered the development of improved vision and large brains in primates, a radical new theory suggests. The idea, proposed by Lynne Isbell, an anthropologist at the University of California, Davis, suggests that snakes and primates share a long and intimate history, one that forced both groups to evolve new strategies as each attempted to gain the upper hand. Early primates developed a better eye for color, detail and movement and the ability to see in three dimensions — traits that are important for detecting threats at close range. Humans are descended from those same primates. "

Comments

Re:Conventional wisdom

[dreamchaser]

Addressed somewhat in the article (yes I actually read it).

Scientists had previously thought that these traits evolved together as primates used their hands and eyes to grab insects, or pick fruit or to swing through trees, but recent discoveries from neuroscience are casting doubt on these theories.

Tetra and quinta? chromatic humans

[arete]

To my knowledge - which is admittedly a year or so old - basically there are three relevant points.

1. Most people have 3 color receptors that they actually use, while some are colorblind to varying degrees including a relatively high number are red-green colorblind having effectively one RG and one B receptor. HOWEVER, where (what wavelength) the "R" "G" and "B" receptors is is NOT exactly the same for each person. So it is very possible that a perfect match for one person is not a perfect match for another especially for colors that are a complex mixture of wavelengths (eg most real-life pigments in sunlight) Note that generally matching the amount of the same pigment should generally be very, very close - to demonstrate this effect you mostly need to be combining very different wavelengths that "should" be the same added together.

The take-home geek message is that you can use an RGB monitor to match every color you can see - IF the monitor's RGB match yours. Otherwise it's not perfect. (Also see point 3)

Have two receptors very close together eventually becomes indistinguishable from just having one as they approach being in the same spot.

2. Some people are known as "tetrachromats" All examples I've heard about have been the mothers of red-green colorblind men. Essentially they have an extra receptor between R & G. This means that they can determine that two colors don't match in situations where everyone with three receptors would think they matched.

3. Apparently we may also have a 4th (or 5th, depending on pt 2) receptor in the ultraviolet range. However, most of the light in this range is blocked by the alchohol in our eye fluids, so this receptor is mostly pretty useless. However, this doesn't mean we don't see SOME color with this receptor right at the edge where it's not blocked by the alchohol - it's just not a very large part of our sight.

These colors definitely don't exist in monitors, which I personally and nonscientifically think is why I love staring at the LED on a PS2.

Re:I knew that already...

[operagost]

I forgot to add something else to the thread.

But on the other hand if you could choose otherwise, there would be a price you might not be so happy to pay: without death children are not born, illness and suffering does not end.

In Genesis 2, God says that he will "greatly increase" woman's pain in childbearing. Clearly, children were being conceived and born in Eden. Also, Eden is the definition of Utopia, and no trace of illness or suffering are to be found. Perhaps you do not find eternal life to be palatable, but the entire Judeo-Christian theology revolves around it (save for the Sadducees, whose position Jesus soundly refuted).