ABSTRACT
In the previous chapters we described features of the multifaceted evolution on earth. We now wish to develop a model to use in understanding aspects of the relations between those features. For this let us establish some background by analyzing a simple case of growth. In particular, consider the common case where the change of a number or property is proportional to the number itself. If the likelihood of something happening to a member of the population (such as dying or procreating) is the same for all members then the total change (loss or gain of number) will be proportional to the total number of members that can change. Of interest to us here are cases where the change is an increase. These include the growth of capital under the compounding of interest, the growth of an embryo by cell multiplication, and the increase of a population under favorable conditions, such as tissue growth in a laboratory culture dish. Examples where the change is a decrease include radioactive decay of the population of unstable nuclei, discussed in Chapter 1, electrical discharge of stored energy, and the relaxation of active muscle tissue. Specifically, we can take the novel appearance and growth of a population with a heritable trait or cluster of traits, or else of a species in a new environment.
