In their classical experiments, Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that streptococci in a specific growth phase take up exogenous DNA, resulting in a transformation of their phenotype (note that they never talked of "transforming DNA into the streptococci", as you find it regularly in the literature, which is embarrassing.) These experiments proved that DNA is the genetic material. But Avery et al. did not speculate why the streptococci would be interested to take up DNA in the first place. Can you think of a reason(s) why and how streptococci and many other bacteria − E. coli being a notable exception − evolved "natural competence" ?