Animals that Swim

Chapter Six: Aquatic Animals on Shalimar

Shalimar's oceans provided a comfortable environment for the development of the Eaters (animal life forms). Stable temperatures and plenty of Cookers (plants) made life easy for organisms that could not make their own food.

The unicellular life forms that did not acquire chloroplasts needed to find sources of energy so that they could continue their life processes. Many of them would engulf protein molecules and other life forms if they could. Some, like the amoebae on earth, were able to change their shapes to surround and capture their food.

Exactly how these organisms learned to organize themselves as true multicellular animals is not known, but some small colonies of cooperating but undifferentiated cells exist in Shalimar's oceans today. We assume that these are intermediate forms. We have tentatively sorted the animals that we have found into three phyla, Trappers, who have hard outer shells and who actively capture their food, Worms, who have segmented bodies shaped like a piece of rope, and Acceptors, who are rooted and who capture food as it drifts down to them.

The reproductive process in Shalimar's animals seems chaotic to visitors from earth. During reproduction, cells sometimes duplicate the normal chromosomes and then do not divide, leading to cells with double the number of chromosomes. Sometimes these cells do not work and die, but sometimes they live. We believe that one characteristic of Shalimar's life forms, i.e., repeated modules of identical structures, is a result of this chromosomal duplication. Detailed information may be found by clicking on the headings below:

© Elizabeth Anne Viau, 1996. This material may be used freely for instructional purposes but not sold for a price beyond the cost of reproduction. Please e-mail me at if you use this material. I'd be interested to know how it works for you!