Effect of Variable Surrounding on Species Creation
  We construct a model of speciation from evolution in an ecosystem consisting of a limited amount of energy recources. The species posses genetic information, which is inherited according to the rules of the Penna model of genetic evolution. The increase in number of the individuals of each species depends on the quality of their genotypes and the available energy resources. The decrease in number of the individuals results from the genetic death or reaching the maximum age by the individual. The amount of energy resources is represented by a solution of the differential logistic equation, where the growth rate of the amount of the energy resources has been modified to include the number of individuals from all species in the ecosystem under consideration. We observe that small evolutionary changes of the inherited genetic information lead to spontaneous bursts of the evolutionary activity when many new species may appear in a short period. 
Aleksandra Nowicka, Artur Duda, and Miroslaw R. Dudek