Eyes on the Prize

[john smith]

Here is an interesting article challenging the Intelligent Design theorist's contention that ID is evident in the design of the human eye. That is, evolution cannot account for the beauty and facility and complexity of the eye, and, therefore, the hand of God must be involved.

http://www.pandasthumb.org/archives/2006/11/denton_vs_squid.html

Just to recap, vertebrates (like ourselves), and the invertebrates Squid and Octopi have “camera eyes“. They differ in how the photoreceptors in the retina, the part of the eye that receives the image, is wired up to the brain. The vertebrate wiring system is often cited as an example of “bad”, or at least quirky, design that is explainable by evolution.

Fascinating reading about the structure of our eyeballs.

John

[Wise Young]

Evolution tends to converge towards certain solutions, even though they may not be the "best solution". For a long time, I did not understand this until I started to pay attention to Steven J. Gould and what he was saying. Some years ago, I heard one of his lectures on how evolution doesn't retrace its steps, that it builds on what is available even when what is available is not the best. On the other hand, evolution has produced the most incredible organisms, that far exceed anything that we can possibly even imagine.

The hummingbird (see my post (http://sci.rutgers.edu/forum/showthread.php?t=72703)), for example, is a stunning example of evolution that pushed natural mechanisms to the ultimate limit. This tiny little bird evolved the ability to fly better, faster, and more flexibly than any other bird, pushing feather, muscle, and brain design to the limits of cellular mechanisms. Yet, the hummingbird is so intelligent that it can mimic sounds of other animals and can remember precisely not only the positions but timings of feedings from dozens of flowers to maximize the nectar that it collects from each. However, the limits of evolution are clearly indicated by the size of the brains of hummingbirds. At a gram (1 cubic cm), their brains of hummingbirds may take up as much as half of their body weight.

It is true that a computer chip would be smaller but organic cellular mechanisms simply cannot be shrunk much further. But, perhaps I should not say this since the dragonfly is much smaller and an even more incredible flier than the hummingbird. They not only mate in midair but are remarkable predators that capture and eat mosquitos and flies in the air. Flies and mosquitos themselves are no mean fliers. Imagine having to engage in a dogfight for every meal and then eating it on the fly in midair. The neural mechanisms are incredible and occurs in a brain that is probably no larger than 1 cubic mm, a thousand times smaller than that of a hummingbird.

Wise.

[rfbdorf]

Another very illuminating concept I got from hearing Gould was how chance affects evolution on the large scale as well on the small scale - e.g., the pond in which a "superfish" has evolved dries up, or a meteorite hits the earth.
- Richard