Milkweed Seed

August 20, 2010


Photographer: Martin Richard
Summary Author: Martin Richard

The photo above shows off the exquisite yet rigid framework of a milkweed (asclepias) seed. The delicacy of the structure tells us that this is a realm in which gravity places a negligible role since it would impose an up/down gradient which would break the radial symmetry. If told that these are seeds, then we can guess that these structures are a means of dispersal, and that implies a great deal. First, there’s no obvious source of nutrition for the seeds -- no surrounding pulp. And there are a lot of seeds. The point is that theses seeds aren’t going to be "cared for," rather they’re going to be dispersed, and each seed will rely on the luck of its landing to germinate and grow. Next, the dispersal itself tells us that the seeds rely on a fluid medium, air or water, an atmosphere or an ocean, which implies unfrozen dispersal conditions. Many seeds -- variation. The luck of the landing -- selection. There we have it -- an unfolding lesson on the principles of evolution. Photo taken on July 27, 2010 from my front lawn in Helena, Montana. 

Photo details: Camera Maker: NIKON CORPORATION; Camera Model: NIKON D300S; Lens: 60 mm Micro Nikkor; Focal Length: 60.0mm (35mm equivalent: 90mm); Aperture: f/20.0; Exposure Time: 0.050 s (1/20); ISO equiv: 800; Exposure Bias: -0.67 EV; Metering Mode: Center Weight; Exposure: aperture priority (semi-auto); White Balance: Auto; Light Source: Unknown; Flash Fired: No; Color Space: Nikon Adobe RGB To eliminate any shaking, the camera was on a tripod and I used the timer to release the shutter. I took the shot against blackout curtains, with the weed illuminated at 5,500 degrees. In Photoshop, I inverted the image (flipping the colors to their opposites on the color wheel), then tweaked it in the channel mixer until I got what I liked.