Stress has been related to low fecundity (reproductive success) in all animal populations. Evolutionarily, the stress pathway that enables prey to escape predators and animals to evade danger can have harmful effects when activated over long periods of time. In populations of animals, limited resources and low nutrition trigger pathways of response to the long-term stressors associated with overcrowding that result in low reproductive success. Do a little research on infertility in the United States. How does the stress response relate to infertility in our modern population?