Three scientists writing in the Biological Journal of the Linnean Society think they’ve come up with a proof against intelligent design. They report a form of adhesion used by the dwarf gecko species Gonatodes humeralis that is relatively simple, described here at Science Daily:
The setae of G. humeralis are short and simple compared to those of pad-bearing geckos, such as tokay geckos. The setae are located adjacent to friction-enhancing “spinules” — small projections, which play no role in adhesion, that are found underneath the feet of many lizards and geckos. The authors argue that the setae of G. humeralis result from a transformation of the spinules.
“Until now, we had not seen a gecko showing the beginnings of the adhesive system,” [U.C. Riverside biologist Timothy Higham] said. “In all the innovations seen in the animal kingdom, we rarely get to see their beginnings. Our findings serve as good evidence against intelligent design ideas.” [Emphasis added.]
What are setae? They are:
microscopic hairs… underneath its toes, which allow it to do something dramatically different than all other geckos in the Gonatodes genus: cling to smooth surfaces such as leaves. It does this without all of the complex structure of the toes that typify the geckos that we are more familiar with. In the lab, this gecko can climb smooth vertical surfaces using its incipient adhesive system.”
Higham explained that the setae interact with surfaces through attractive van der Waals forces.
Hmmm. Well, have they finally walloped ID — and a design icon at that like the gecko — by showing that a simpler form of an amazing natural biotechnology exists? Consider an analogy from human technology.
Yesterday my oldest son and daughter and I worked on a backyard construction project involving considerable driving of screws into two-by-fours. We had on hand a power drill and an ordinary screwdriver. I’m not especially handy around the house but even I recognize that there are times when a power tool is right, while at other times a simple manual version is sufficient or preferable. Here from a DIY website is a list of 13 occasions to use a regular screwdriver over an electric one.
It would never occur to anybody to say, on that basis, that either tool isn’t designed for its purpose. Obviously, they both are, with different considerations in mind, notably price, power, and durability. I’ve had a new electric drill go wobbly at a critical moment and need to be thrown out and hastily replaced. A hand screwdriver never fails. I would not want to dispose of my screwdrivers because now I’ve got a power tool. You can find yourself without a charged battery for the drill, but a hand screwdriver is always ready to use. Each has a role and an advantage.
Guess what? It turns out exactly the same is true of the simpler mechanism of adhesion found in G. humeralis:
The relatively simple expression of setae on the digits of G. humeralis thus provide an enormous advantage in sectors of the habitat typified by smooth, low-friction, inclined surfaces, such as leaves and slippery stems, allowing G. humeralis to avoid predators by occupying habitat that other members of the genus cannot. While it can securely attach to vertical bamboo shoots, for example, other species in the Gonatodes genus generally scale rough tree trunks, rocks, fallen palm trees and move on the ground — areas where their predators abound.
Is it possible that one mechanism arose first, followed by the other? Sure. Why not? It would be surprising if that were not the case. Life has a long and complex history. To imagine it all snapped into existence at one blow is not an idea associated with intelligent design.
Dr. Higham points out that the simpler design may be of use to researchers working on biomimetics:
Gecko-inspired robots tend to have fully developed adhesion systems. But is that necessary? Our work suggests that not much is needed to get a good adhesion system going, and may therefore help simplify how we approach biomimicry and how we recreate adhesion in the lab.
According to Wikipedia, screwdrivers were invented in Europe in the 15th century, while an electric drill like ours goes back about a century. When Black & Decker came up with that innovation, manufacturers didn’t stop making hand screwdrivers. Both are wonderfully useful designs, each with its purpose. In the context of nature, to imagine that history disproves design is as absurd as it is in human tool making.
Photo: G. humeralis, by Timothy Higham, U.C. Riverside.