Rare ‘primitive bugs’ neither primitive nor rare

First published:
TJ 9(1):4
April 1995

by Carl Wieland

The very name ‘Archaebacteria’ (‘ancient germs’) betrays the evolutionary belief once attached to these micro-organisms. The first ones discovered a few years back had very unusual metabolisms. Some could produce methane, other lived in very hot, salty environments, for example. Speculation assumed factual proportions, and they were touted as rare, ‘extremely primitive’ types which had somehow survived from a time when life had first evolved. Popular science shows fuelled this belief; hot chemical springs generating the forerunners of the archaebacteria replaced the idea of a soupy primitive ocean in many imaginations.

Because they are prokaryotes (lack of nuclei) they were originally regarded as being closer to other prokaryotes (bacteria and blue-green algae) in evolutionary terms than to the eukaryotes (creatures with nucleated cells—that is, all other plants and animals). However, genetic studies showed that they had more similarities with the eukaryotes, so the ‘primitive ancestor’ idea could not be sustained.

It now turns out that they are anything but rare. Archaebacteria have been found in significant numbers in the ocean—including cold waters quite different from the hot springs with which they are associated. For instance, it appears that they ‘provide up to 30 per cent of the single-celled marine biomass’ in some Antarctic waters.¹

Reference

1. Hecht, J., ‘Rare’ bug dominates the oceans, New Scientist 144(1952):21, 1994. Return to text.

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