=COUNTIF(A2:A5,A2)+COUNTIF(A2:A5,A3) Counts the number of apples (the value in A2), and oranges (the value in A3) in cells A2 through A5. The result is 3. This formula uses COUNTIF twice to specify multiple criteria, one criteria per expression. You could also use the COUNTIFS function.
Punctuated equilibrium. Definition. noun. A theory that describes an evolutionary change happening rapidly and in brief geological events in between the long periods of stasis (or equilibrium). The theory is based on the stasis in fossil records, and when phenotypic evolution occurs, it is localized in rare, rapid events of branching speciation.
Development of the theory of punctuated equilibrium was initiated by Niles Eldredge in a study titled âThe allopatric model and phylogeny in Paleozoic invertebrates,â which appeared in Evolution in 1971.