Thursday 22 November 2012

Looking at gulls – evidence of a God, or not?

                                                                                                                      [Image from]

Take a look at this picture of a gull. What comes to mind? Being “bombed” with faecal matter while walking along a promenade at the seaside, or putting up with loud and raucous calling when gulls squabble over discarded refuse? Or perhaps one is taken by its elegant colour scheme?

As I spent several years teaching animal locomotion, what I see in the picture is a near-perfect flying machine. The wings are aerofoils and, as long as air flows over them in gliding flight, they generate lift. This is because the wings have a convex upper surface and a slightly concave under side, so air has to travel faster over the upper surface causing a lower pressure. The gull is thus “sucked” upwards – just like aircraft wings operate, although birds were first in having this feature by quite a few years. Of course, the wings are also used in flapping flight, requiring powerful muscles, especially those used to depress the wing. When sufficient airspeed has been achieved, the gull propels itself using oscillations of the outer part of the wing, while holding the inner section relatively still, so that its aerofoil section is used efficiently. Explaining oscillation would require me to go into too much detail for this blog and, for that matter, so would explaining the mechanism of flapping flight.

Then there’s the shape of the body. The picture shows that the gull has a near-perfect streamlined shape thanks to its covering of feathers – but feathers of a different type to those of the outer part of the wing. The profile feathers allow the smooth flow of air over the body, so that turbulence behind the gull is very much reduced. This, in turn, reduces drag and thus conserves energy needed for propulsion. It means that the tail feathers can be used to deflect air and function as a rudder; and note the position of the feet – tucked up to ensure the smooth air flow is not badly disrupted. Profile feathers also create the shape of the wing and feathers of a third type down ensure that the gull’s high body temperature is maintained by acting as efficient insulators.

I could go on and on like this – and did during lectures but no-one can look at a gull without thinking that it is extraordinarily well adapted to moving through the air. For those who believe in Creation, all the features of the gull (and I’ve only mentioned a few here) are evidence of the power of God. For those who believe in evolution, there is the puzzle of how all the small stages that occurred in the transformation of a scaled reptile into the gull came about through mutations in genes. For atheists, it is a matter of chance; for theists, a result of something designed, just as for believers in Creation. Both theists and atheists are swept up in a sense of wonder at what they see. So, now comes a question. Is this sense of wonder identical in those that believe in a God and those that do not? If the answer is “yes” doesn’t that invalidate the argument of those, like Henry Gosse, who use such feelings as evidence of their God? Does anyone out there have any views on this?

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