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His theory of peripatric speciation ( a more precise form of allopatric speciation which he advanced ) , based on his work on birds , is still considered a leading mode of speciation , and was the theoretical underpinning for the theory of punctuated equilibrium , proposed by Niles Eldredge and Stephen Jay Gould .
 person: Niles Eldredge; person: Stephen Jay Gould
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
 Entities: Niles Eldredge, Stephen Jay Gould 
Answer:
 person: Niles Eldredge; person: Stephen Jay Gould