Angela Haseltine Pozzi’s mixed media sculptures on exhibit at the Coos Art Museum look like intertidal invertebrates in tidepools. But you wouldn’t be able to key them out.

So, what is it about a shape that makes us think, “sea anemone” or “coral?” What is it about other patterns that make someplace look “marine?”

We humans have “bilateral symmetry,” meaning the left and right halves of our bodies are about the same. We also have a “ventral” surface (our fronts) and a “dorsal” surface (our backs). And we have “polarity.”

The vast majority of multi-cellular animals have polarity — a “head” end; most also have bilateral symmetry, but not all do. Seems to me one of the reasons we so enjoy looking in the sea is because many of the most noticeable sea creatures that stay put have “radial symmetry,” applied in a squat form or a long one. (You could cut up an animal with radial symmetry from the top rather like a pie and have each piece be like the others.)

While we have a one-way gut with an “in” end and an “out” end, some of our favorite marine invertebrates are essentially sacks — one opening for both “in” and “out.”  (Sea jellies and sea anemones, for examples.) Some marine invertebrates have in and out openings, though the two openings may be near one another. (Clams and tunicates, for examples.)

“Mouth ringed with appendages” is a common body plan detail, too. Stinging or grasping tentacles drift in the water until snagging food, then the snagging triggers the tentacle to pull the catch into the mouth. Sea anemones, sea cucumbers, some tube worms, and others follow this plan. A more active food-gathering apparatus is used by barnacles and some others: legs or other appendages sweep the water for dinner.

Some marine organisms are solitary (such as most sea anemones), some are communal (such as most corals); both patterns seem natural to us in an undersea environment. Many communal organisms start with one creature that splits or buds or otherwise reproduces to create another individual adjacent to the first. Over time, such reproduction can pack a random mass or cover space in a more ordered pattern, depending on the species.

The crowding of various shapes in Pozzi’s exhibit seems right, too. Such chock-a-block positioning is characteristic of rich marine habitats. Most marine invertebrates start out in life as free swimming/floating larvae. (Some looking quite different from their parents, as well as following a different lifestyle.) Where they end up when their development dictates settlement depends on the currents, and what ends up living on a particular area is determined, in part, by what’s living and breeding up-current from that area. Since there are generally more larvae seeking space than there is space available, life can get quite crowded.

Some organisms, such as barnacles, may select a particular spot before attaching, but on the whole, the water can bring in a mix of young to attach to a given area. Of course, organisms need to endure the conditions where they’ve attached to survive.   

There is certainly an up and down in the sea — with light coming from above and pressure increasing with depth, for starters. However, on land gravity pulls on precious water and air doesn’t hold much weight, so up and down seem to be more critical to life on land than life in the sea.  It seems right that a sea anemone grows on the side of a wall or down from a cave ceiling; such flexibility of position is less expected in land animals and plants.

Light and color are different underwater, too, and shocking colors seem quite appropriate in a marine scene.

We don’t have to memorize specific body plans and details of individual species to perceive a shape as “something alive” or a place as “marine.” We can sense a cohesiveness in the patterns of “undersea” that makes it recognizable.

Pozzi’s delightful artwork, “Low Tide on the Oregon Coast” and “Undetermined Species” will be showing at the Coos Art Museum through Sept. 20. See what you think!

For information on how to arrange an exploration of our fascinating natural history for your group or your visiting guests, contact Marty at (541) 267-4027 or mgiles@wavecrestdiscoveries.com. Questions and comments about local natural history are welcome.