BIONOMICS. 71 



CHAPTER IX. 



BIONOMICS. 



THE term Bionomics is used to denote the study of 

 the relationship of an organism to its environment, 

 in the widest sense. We may here briefly notice (i) The 

 relationship of an organism to the inorganic world, and 

 (2) The relationship of an organism to other organisms. 



I. Physical Relations. — Many organisms live their 

 life and pass away, leaving very little, if any, direct material 

 impression on the world around them. Such may be illus- 

 trated by Amoeha or a jelly-fish. Others, again, have by 

 their resultant " energy done a great deal in determining 

 the present physical condition of the earth. Amongst the 

 Protozoa there are the Radiolaria and Foraminifera. ^ Their 

 countless numbers compensate for their microscopic size. 

 They secrete from the sea-water around them hard skele- 

 tons, some calcareous and others siliceous, which, on the 

 death of the animals, collect on the sea floor in great 

 quantities. In Chapter VII. (page 60), on deep-sea fauna, 

 the *' oozes " thus formed are alluded to. Whatever may be 

 the ultimate fate of these oozes, we know that large strata of 

 limestones, especially also chalk, are often made up almost 

 entirely of shells of Foraminifera. 



Other rock-building forms are the sponges, echinoderms, 

 certain worms, Crustacea^ and Mollusca, all having calcareous 

 skeletons which contribute to the formation of limestone 

 rocks, consolidated under water, and then upheaved and 

 exposed. But the most important rock-builders are the 

 corals. The ceaseless, united energy of these animals has 

 resulted in the production of enormous structures, such as 

 the Great Barrier Reef, extending for more than 1000 miles 

 along the N.E. coast of Australia. 



