Complex sentence: The paradox of the pesticides is a paradox that states that by applying pesticide to a pest, one may in fact increase its abundance when the pesticide upsets natural predator-prey dynamics in the ecosystem.
Split into simpler sentences: The paradox of the pesticides is a paradox that states that by applying pesticide to a pest, one may in fact increase its abundance. This happens when the pesticide upsets natural predator-prey dynamics in the ecosystem.