Long before bacteria had to contend with antibiotic drugs, they had to survive extreme temperatures as Earth warmed and cooled over millennia. Could the adaptations they evolved to temperature—especially heat—help explain why certain strains are resistant to certain drugs? A new study by a research team at the University of California-Los Angeles that includes Santa Fe Institute External Professor Pamela Yeh suggests that defenses against extreme temperatures, do, indeed, give E. coli bacteria an advantage in fending off certain drugs.