Most people have some knowledge of our fauna and flora. They recognize grizzly bears, zebras, condors, cobras, swallowtail butterflies, redwoods, etc. they might be able to talk about vertebrates, insects, conifers and fungi. However many organisms are totally unknown to the average person, and even to some biologists. This is a great pity as some of these organisms could be envisioned as aliens from outer space, so much do they differ from our “ordinary” life forms.
Have you ever heard of Slime Nets? Not many people have, and yet they form a component of many beaches. They are often parasites on algae or detritivores. See: en.wikipedia.org/.... How about Sipunculids? Yet we found them easily inside intertidal rocks on the Gulf of California Sonora coast along with rock boring clams. We also captured Amphioxus by rapidly digging them out of the sand. These ‘primitive” chordates were very difficult to catch as they burrowed into the sand, when they were exposed, so fast as to almost vanish instantly.
Priapulids (their name is indicative of their shape) are also little known inhabitants of the world oceans, as are Sea Spiders. Chytrids, and Archean Bacteria are actually common, but very little known to most people.. I only managed to find one Sea Spider and I must have gone through twenty pounds of seaweed to do it. There was a huge Sea Spider in a jar at the Invertebrate Museum at the University of Arizona, which had a leg span larger than the largest tarantula. The public has been made aware of Chytrids more recently because one species attacks amphibians and may share some blame for their decline. Archean Bacteria have been separated from Eubacteria relatively recently. As far as I know none of them are pathogens but instead inhabit the extreme habitats of the earth and are thus called extremophiles. They form pink rims around salt lakes, they live in near boiling water at the surface (as in Yellowstone) and they show up in many other places which cannot be easily inhabited by the living things of which the general public is aware.
Diatoms, a group which I’ve published on before, have some weird relatives in their grouping in the Stramenophiles, which includes the Slime Nets, Water Molds or Oomycota (including the causal agent for Potato Blight), the Xanthophytes, the Golden Algae, or Chrysophytes, the Brown Seaweeds (including the huge Kelps) and of course the Diatoms!
The Platyhelminthes are perhaps better known. These include the common Planarian, but also Tapeworms and Flukes. However there are other groups like Catanulid Flatworms that live in freshwater. Most of the freshwater planarian group are scavengers.
Many of these are considered as kingdoms these days, as our genetic understanding of the biota becomes a bit clearer. For one thing the so-called “Protista” is broken up into several quite distinct groups, including the unique etiological agent for giardiasis, the “flagellate” Giardia. See: Tudge, Colin, 2000. The Variety of Life. Oxford University Press.
In essence most of us are unaware of the true variety of life on our home planet and the strange creatures that live with us, including the fact (in the most recent studies — see www.ncbi.nlm.nih.gov/...) that without the bacteria and other microbes that live on and in our bodies, we would be by volume very little changed, but in number of cells we have roughly equal numbers of human cells to microbe cells. In other words, the small size of microbes in our bodies relative to the size of human cells allows them to have a very small mass than the rest of the human body, but equal numbers of cells. Earlier estimates gave much higher figures for microbes, but still the fact that the number of cells equal human cells should give us some pause for thought.
We live in a marvelous planet and since we share dominance with the bacteria and possibly ants, we should be careful what we do. So far we have not been especially good stewards.