October Update

Bought a standard poodle puppy.  Bringing him home October 5, so October will be full of housebreaking, and FUN.



Entries in Bryozoa (2)


How Can Infinitesimal Animals Be Geological Historians?

In my last post, I described the Bryozoans, animals that are so small, you can’t really see them without a microscope.  Yet these tiny creatures contain complete animal systems and exist in myriad, fascinating shapes.

         The Bryozoans have been subjects of early microscopic studies hundreds of years ago.  As such, they were mistaken for plants.  They have been subjects of more recent, advanced microscopy, when improved scopes, dissection, and slide preparation showed them to be animals.  They have been subjects of very recent molecular examination, when it became possible to study their relationships to one another with DNA data.

         And now, in a neat reversal, they have switched from being the subject of study, to providing data for a different scientific quest.  Some Bryozoans offer geological data about Antarctica. 

         Groups of similar species of Bryozoans have been found on the shores of both the Weddell and Ross Seas, which are now separated by 1500 miles of ice sheet in Antarctica that is 2 kilometers thick.  The similarity of the Bryozoan species suggests that at some point, perhaps 125,000 years ago, the ice sheet had melted, and there was a connecting seaway between the two Antarctic seas.

         So here are these Bryozoans, once again keeping up wonderfully with modern, scientific research.  What a wonderful phenomenon.



How Can Actual Animals Be So Tiny?

          Bryozoans are animals so tiny you almost can’t see them at all.  They were first discovered In the 1500’s, when microscopes became a popular novelty for people who could afford them. 

         Those early microscope hobbyists gathered samples of fluids and tissues and examined them out of pure curiosity.  In drops of sea water, or on stones or seaweed gathered from sea water, they found infinitesimal, delicate, plant-like organisms.  The early microscopists thought these were plants.  But as the centuries passed, and microscopes and microscope techniques improved, investigators found that these organisms were animals, with nervous systems, muscles, and digestive systems.

         The Bryozoans are similar in size and habitat to corals, but they are quite different.  Corals are more primitive: they have nerve nets instead of nervous systems, and contain only a simple digestive cavity with a single opening to take in food and give off waste.

         Now researcher Judith Fuchs, at the University of Gothenburg, has been able to study a large group of Bryozoans using DNA data.  She has discovered that these animals come from a common ancestor, even though some species live in salt water and some in fresh water.

         To me, the Bryozoans are just mind-boggling: Imagine packing all those animal systems into a creature too small to really see with the naked eye.  Imagine their tremendous variety of shapes, all of which evolved to enhance feeding, reproduction, survival.  Imagine the discovery and clarification of this whole animal group paralleling the development of biological technology, from early through advanced microscopy, from early to advanced genetics.

         And there’s more.  Stay tuned…