The Progression of Life in the Sea

Abstract

DIFFERENT views are still held as to where life in the world had its origin, but no one questions that it began in close connexion with water. That it began in the sea, where the necessary elements were present in appropriate concentrations and in an ionised state, is an idea which appeals to many with increasing force the more closely it is examined. This view has been developed recently by Church² in his memoir on "The Building of an Autotrophic Flagellate,"in which he boldly attempts to trace the progression from the inorganic elements present in sea-water to the unicellular flagellate in the plankton phase, floating freely in the water. The autotrophic flagellate, manu-r facturing its own food, he regards as the starting-point from which all other organisms, both plants and animals, have sprung. To understand the first step in this progression, the passage from the dead inorganic to the living organic remains, is as it has always been, Qne of the great goals of science, not of biological science alone, but of all science. Recent research has, I thinkj thrown much light on the fundamental problems im volved. In a paper published last year, Baly, Heilbron, and Barker,3 extending and correcting previous work by Benjamin Moore and Webster,⁴ have shown that light of very short wave-length (λ = 200 µµ), obtained from a mercury-vapour lamp, acting upon water and carbon dioxide alone, is capable of producing formaldehyde, with liberation of free oxygen. Light of a some^ what longer wave-length (λ = 290 µµ) causes the mole* cules of formaldehyde to unite or polymerise to form simple sugars, six molecules of formaldehyde, for example, uniting to form hexose. The arresting fact brought out in these researches is that the reactions take place, under the influence of light of appropriate wave-lengths, without the help of any catalyst, either organic or inorganic. Where a source of light is used which furnishes rays of many wave-lengths, the simple reaction of the formation of formaldehyde is masked by the immediate condensation of the formaldehyde to sugar, but this can be prevented by adding to the solution a substance which absorbs the longer waye-lengths, so that only the short ones which produce formaldehyde are able to act.