SCV Outdoor Report: Signal-To-Noise Ratio
By Wendy Langhans
Sometimes an idea is too good not to borrow. Take, for example, the concept of signal-to-noise ratio. Audiophiles are only too familiar with a low S/N ratio - the annoying hiss, crackle, and static that disrupts their favorite piece of music. But others, included graphic designers, have “borrowed” this mathematical equation from electrical engineering and turned it into a metaphor for describing mis-communication. “All communication is a chain of creation, transmission, and reception of information. At each step along the way, the useful information—the signal—is degraded by extraneous or irrelevant information: the noise.”
Biologists have also borrowed this mis-communications metaphor: what happens when a creature CHOOSES to degrade or manipulate their visual signal? In other words, when a plant or animal wants to hide?
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Visually, there are three ways of doing this.
Crypsis. Coloration and patterns match the surroundings or break up the visual outline of the organism. Minimize the signal-to-noise ratio. In other words, hide in plain sight. Notice how the color, patterns and edges help this Western fence lizard blend into the rocky background.
Disruptive coloration. A combination of cryptic and conspicuous colors and patterns that distract or misdirect the predator. Keep the signal-to-noise ratio high - but only in in selected areas. In other words, “pay no attention to the man behind the curtain”. Look at the mottled light/shadow patterns on this Anise Swallowtail. Then notice the blue patch and tails. Could they be misdirecting a predator away from the butterfly’s head?
Masquerade. A high signal-to-noise reation allows the organism to be detected by the predator. However, the signal is misleading and results in the organism being mis-identified as inedible or dangerous. For example, this Broadwinged katydid can be easily spotted. But it resembles a leaf and is not very appealing to a meat-eating predator.
Manipulating the signal-to-noise ratio allows animals to hide in plain sight, or misdirect or even mis-lead each other. I can think of all sorts of ways that humans do the same thing, can’t you?
Upcoming Outdoor Events:
Saturday, March 12, 6 -8 PM, Star Stories at Towsley Canyon. We’ll be taking a journey on the celestial sidewalk of fame. It features mythological heroes, fierce animals, navigating guides and some pretty outstanding star-light from a few million years ago. Bring a blanket or tarp to lay on and bundle up warm. Meet at the front parking lot. For directions and trail maps, click here.
Trail Maintenance Schedule. Come join our volunteers as they help maintain our trails. Contact Steve at firstname.lastname@example.org for time and place.
Wednesday mornings, February 2, 9, 16, 23 & March 2, 9, 16, 23, 30.
Saturday mornings, February 12, 26 & March 12, 26.
For a glimpse of our local flowering plants, check out the Facebook page, “90 Days of Santa Clarita Valley Wildflowers”.
You can listen to stories like this every Friday morning at 7:10 a.m. on "The SCV Outdoor Report", brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.
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