NATURALISTS' FIELD CLUB

Evening Star, Issue 25169, 8 May 1944, Page 5

NATURALISTS' FIELD CLUB

The lecturer at the indoor' meeting of the Dunedin Naturalists* Field Cltib #&s Sir William Benham, F.K.S,, one of the founders of the club. A most interesting address under the title of ' Busy Little People,' dealing with the' start of life on the earth, and especially- the most minute forms of plant and arihnat life, Was given. Taking as a standard of measurement the Wood corpuscle with its four to five million units to the millimetre, the lecturer pointed out that an ordinary gnat measured 7.5 millimetres, so that we' have life far smaller than the gnat—the red blood corpuscles, also the chlorophyll grains and bacteria. The work of the chlorophyll grain is to release oxygen into the air, and until plant life- was established on the globe the air was not fit for animal life. Early in the world's history plant life carrie into being, ami it was at a later period that animal life was evolved. The early plants first appeared in the Devonian period. They were 1 sparsely branched and almost leafless (as instanced in the " fairsetail " plants). As pictured in the geological records that time has left in the rocks of the earth, after this earliest period there followed other periods, ftn-d" vegetation showed a gradu&llv increasing of branch and leaf as the more complicated plants wrt evolved. Earliest forms of animal life were sluggish creatures fflftifily newt-like in form. With increase of leftfproducing vegetation the" atmosphere became enriched with oivgen, and so favourable for the development of many forms of animal lite. . .■ . . A relic of one- of* these early forms' of animal life exists in New Zealand to-d»v in the trtatara, which is directly -descended from the primitive reptiles, _ The oxygen released by trees is vastly greater than is generally realised. It has been estimated that att ordinary-sized ela? tree carries about seven million leaves,

whose surface when added together may amount to five acres. A single birch treo With 200,000 leaves will give to the atmosphere gallons of water" in an ordinary day, ftnd an enormous amdtthi 6r oxygen. The use of coriipost. heaps is -being strongly encouraged at the present time. This Is no new idea, as it has always been necessary ' for Nature to Utilise similar methods to reduce the abundant vegetable material down to a form in which" it can be again Of Use. This decay cf vegetable matter is due to ; the action of these "busy little beings," the bacteria. They are the smallest recognisable living beings, measuring 8/10th of a micron, which equals O,QQOBmiB, It is an astonishing deduction that human beings are absolutely dependent for th'eir very existence on these minute ' busy little beings." The lecture was very interesting to the fairly large field club audience, and was illustrated by screen pictures and diagrams. At the conclusion the speaker was heartily thanked. '■■,,, Mrs Moore" gave a report on the club's excursion to the Ross Creek track, and a note of the fungi collected.