Sunday, October 10, 2010

Leave them alone. They’re trying to clone!

Although they are animals, sea anemones are as lovely as the flower they are named after. Their colors range from red through orange, white, and green, some are even marbled in two tones. Tentacles fringe the perimeter, in the center is the orifice, or mouth. Sea anemones belong to the phylum Cnidaria. Because this group of animals lack a two-ended digestive tract, the mouth also functions as their anus.

At Pacific Science Center's Puget Sound Salt Water Tide Pool, we encourage you to touch the tentacles, which are used to sense and manipulate food and to defend the animal. We ask you not to touch the orifice! And now that you know what it is for, you probably don’t want to.

Sea anemones are normally round. But recently we have had a large number of anemones become elongated in one direction and narrow in the other. They look for all the world like rubber bands being stretched out tight.

These are one type of anemone, Anthopleura elegantissima, the aggregating anemone. While anemones can reproduce sexually by releasing free-swimming gametes into the water, many types also reproduce asexually. In the case of the aggregating anemone, the animals clone themselves. The stretched out individuals are part way through the process. Their two ends will each become a fully functional animal. The area in the middle thins until it eventually disconnects, freeing two daughter organisms.

Clonal groups of these anemones will often populate a large rock or flat area on a beach. When two groups meet, they use special stinging cells to battle each other. Don’t worry! None of the anemones in our exhibit is known to have a sting that can be felt by humans.

So when you see an anemone in the midst of cloning, please show it a little extra care. Cloning is fascinating, but it is also risky and costly of the animal’s resources. Choose another anemone – a round one – to touch. Though in a different way than we are used to, it is reproducing, and needs an extra bit of privacy.

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