AHABS... Issue Seven

We Are So Limited!

The Physiological Basis For Proper Temperature And Salinity In The Maintenance Of Coral Reef Aquarium Animals.

By

Ronald L. Shimek, Ph. D.

“The First Rule For Maintaining Animals In Captivity:

Be Smarter Than The Animals You Are Trying To Maintain.”

Introduction:

There are a few basic “rules of thumb” that have to be learned when trying keep living things in the best of health. Probably the first and the foremost of these rules is that these organisms need to be provided with a mimic or analogue of the natural physical environment where the organisms do best. Sometimes this is easy to do, sometimes it isn't. However, in all cases, any captive living thing has the best chance of thriving when kept under conditions that are most like those in the natural world where individuals of that species do the best. For aquarists discussing marine animals, this raises the question, “Where does the animal do the best?”

This, in turn, devolves into another question, that being, “What do we mean by “ best,” and what...


Squirting Out The Answer To Who's On First

By

Ronald L. Shimek, Ph. D.

Phylogenetics – Answers To The Basic Questions Of Biology

In the last decade possibly the most exciting, and active, area of invertebrate zoological research has been the study of phylogeny, or the science of animal groups' evolutionary relationships. Biologists have always postulated about which animal groups were related to which other ones. Until recently, such postulation was generally accompanied by enough arm waving and jaw wagging to create significant if insubstantial breezes. There was no feasible way to actually pin down relationships and such relationships as were proposed were, in effect, exercises in logic. As with all such endeavors, they were limited by the assumptions, both stated and unstated used in drawing up the conjectured relationships, and they were limited by the actual physical evidence of those relationships, the comparative morphology of the animals involved.

However, now it has become possible to actually determine those relationships. Within some groups such as the vertebrates (animals with backbones), this study has always been made a good deal easier by an excellent fossil record which often can reveal useful intermediate groups. One of the best examples, the first fossil of Archaeopteryx , a classical un-missing “missing-link,” was found in the mid-nineteenth century. This small animal was a bit bigger than a pigeon and, depending upon the interpretation of the moment, was either a small dinosaur with feathers, or a small bird with teeth, a long tail, and fingers.

Dozens of other exquisite fossils in the vertebrate lineages, many of them recently discovered and described from several sites in China , have shown that many dinosaur lineages had feathers. Some of these lineages obviously lead to birds, while others had different descendents; some of the earlier...


Testudinaceous Amoebozoans

By:

Ronald L. Shimek, Ph. D.

The Little Things Mean A Lot

I thought I would take this opportunity to babble on a bit about some of the most unusual organisms that make their ways into coral reef aquaria, the shelled amoebae called the Foraminifera. A discussion of such creatures fits nicely with the theme of the main article. Amoeboid organisms, such as forams, really are THE “Canaries In The Coal Mine” of reef aquarium physical conditions. Their only protection from the “Great-Out-Of-Doors” is their cell membrane. Their shell is actually internal and covered by a thin layer of protoplasm; so, even more than corals, these organisms need the aquarist to provide them with “The Right Stuff.”

Forams, as they are commonly called, are almost wholly marine creatures, but they are found in a wide variety of habitats. They are not animals; they lack a number of animal characteristics, but they also lack the photosynthetic capabilities of organisms such as plants or algae. So, biologists consider they are neither plants nor animals, and they are taxonomically placed in a separate taxonomic “Kingdom,” with a number of other groups of bizarre creatures. This kingdom is called the Protista. Even though they are not animals, some protists, such as forams act somewhat like animals.

While many protists are not clearly visible to the unaided eye, forams are often evident and common in many marine environments, and those found in aquaria are often large enough to be observed easily with a hand lens or magnifying glass. Even so, though, they tend not to show too much detail. This due to two reasons, first there is often not much detail to see, and second, what detail is there is often very tiny; below the range of normal visual acuity. The lack of detail is in part due to the type of body these organisms have. They simply don't have a body divided into separate parts or...

 

Ron Shimek