The book treats the New York Stock Exchange as an ecosystem. Stocks at the stock market are considered as species competing for investors' money in the same way rabbits compete for grass. An investor who chooses what stock to buy participates in a process of natural selection where the "fittest" stock wins.
Investors are preoccupied with prices, which are neither indicators of value, nor constitute competitive variables. To study the competitive struggle, one needs to look at the TRUE competition variables for each stock, namely the share volume and dollar value daily exchanged.