Dive Dry with Dr. Bill

#263: Xenophobia

Xenophobia is not some new heavy metal band (thank goodness), it is the fear of those who are different. Although it can contribute to a species' survival ability, it can also cause some very ugly behaviors. Racial prejudice is one example. Now I'm not smart enough to know whether it is the Creator, evolution or a combination of the two that is responsible for the emergence of the various human races. As a biologist, what I do know is that all races are biologically compatible so we are all members of the same species. I wish we'd keep that in mind, accept the diversity that is in the human species, and live in peace not only this season but throughout the year.

Another negative manifestation of human xenophobia surfaces in the issue of immigration. Over the centuries, America has built its greatness on the waves of immigrants that have come to this country with a fresh work ethic and a desire to achieve the American dream. Yet with each wave, those already here have expressed concern over "those people" coming to our shores. Again, personally I welcome those who come here with the intent to work hard and better not only themselves but our country. However, I do take issue with illegal immigration since that is a case of law breaking, not xenophobia.

The animal and even the plant world are not immune to xenophobia. For example, certain plants on our island such as greasewood or chamise (Adenostema fasciculatum) release chemicals in the soil to prevent other plant species from growing too close to them. The survival value is that the greasewood gains less competition for water or nutrients. This can be very important, especially in years of drought.

For quite some time I've been curious about what I assumed was a case of "xenophobia" in a coralline marine alga. This red alga encrusts on rocks almost like a coat of thick pink to red paint. These algae can be quite common in our waters and, like a fresh coat of paint, they beautify the otherwise dull rocks. My apologies to any geologists, but I guess I just don't know enough about rocks to see the underlying beauty in them. The algae are referred to as coralline because they actually embed calcium carbonate into their cellular structure, the same mineral corals build their colonies of and we humans use to build strong bones. And they don't even have to drink milk or eat Wonder Bread to do so!

I'd noticed that ridges often developed at what I assumed were contact points or borders between different colonies even of the same alga. I sent the image below to Dr. Kathy Ann Miller at the University of California Herbarium, asking if the ridges might represent boundaries between algal colonies with different genetic makeup. She agreed with my hypothesis. I found it interesting that these simple red algae would exhibit a primitive form of xenophobia within their own species. It was certainly an example of the genotype's desire to perpetuate itself over other genotypes, even of the same species. One could equate it to a male human who, until DNA testing, could never be 100% certain of his fatherhood and therefore acted irrationally at times towards his mate if he simply suspected questionable paternity.

At least these algae merely build "walls" at their boundaries. Decades ago, while teaching marine biology and animal behavior at the former Toyon School, I learned of a similar phenomenon in our green aggregating sea anemones commonly seen in the local intertidal. These simple critters, relatives of jellyfish and coral, usually reproduce asexually by budding. This means that each member of a given colony is an exact genetic duplicate (yes, clone) of all the others. Not much biodiversity in those colonies!

When two aggregating anemone colonies grow towards one another and meet, the equivalent of World War III breaks out. These cnidarians possess stinging cells known as nematocysts, and some of you have probably experienced their impact if you brushed up against, or stepped on, a jellyfish. The nematocysts on the tentacles of anemones on the edge of each colony increase in number and form visible white masses that are far more potent than the nonexistent WMD's supposedly possessed by Iraq or Iran.

Equipped with such powerful deterrents, these anemones on the colony edges begin pummeling their nearest neighbors from the adjacent colony. I have seen footage of this combat and it is truly vicious, and deadly. All this to ensure that one's genotype is able to gain the resources to reproduce itself and outcompete other genotypes of the same species.

Many speak of the peace and harmony of nature, and how much better off humans would be if we modeled our behavior after that of other species. Sadly even "idyllic" Mother Nature is full of violence and death if you look at it through the eyes of an ecologist. However, humans are supposed to be more intelligent than other species, aren't we? Wouldn't it be nice if we could all learn to openly accept diversity within our species and live together in peace? After all, 'tis the season. Or do I have to contact my friends on the planet Xanadu to fake an invasion of Earth and bring us all together as human beings? My occasional dive buddy Scott Patterson used a similar plot in his latest novel, Lumina, which I read recently. It could happen, couldn't it? After all, that might not be the Star of David you see in the skies... but an approaching "UFO" with my friends. Peace on Earth... please! Beam me up, Scottie!

© 2007 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles," "Gentle Giants: Giant Sea Bass" or "Common Fish and Invertebrates of the Sea of Cortez" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!

Ridges forming "walls" at the edges of different colonies of the same coralline red alga species.

This document maintained by Dr. Bill Bushing.
Material and images © 2007 Star Thrower Educational Multimedia