AbstractsBiology & Animal Science

Growth is cyclic in nature, periods of activity alternating with periods of comparative rest (PEARL, 1925; WIGGLESWORTH, 1939). Many authors have attempted to construct mathematical expressions for this cyclic growth, in addition to ideal growth curves as an aid in the study of bionomics. Some of these will be dealt with later in this thesis where they prove relevant to the theme. The term “cyclic growth” may be broken down into its constituent parts: (a) it is well known that growth or increase in the bodily dimensions of an animal (or plant) can occur in two main ways, viz. (1) by increase in cell number (cell division); (2) by increase in the size of the cells already present. (Of course, production of cell products may also be considered growth.) The two modes of growth are not mutually exclusive. (b) The definition of “cycle” put forth by KLEITMAN (1949) will be used in this thesis, viz., “A cycle ..... is a repetitive series of events or successive changes of states, thus being either qualitative or quantitative in nature, and its own distinctive feature is one of order of occurrence, rather than duration. Cycles are intrinsic in origin; they may be influenced by inernal and/or external conditions, which affect them quantitatively, but seldom qualitatively.”[...]