The document discusses various types of interactions between species within ecosystems, including competition, predation, symbiosis, and coevolution. Competition occurs when different species or individuals attempt to use the same limited resources. Predator-prey relationships involve a predator that hunts for prey. Symbiosis describes close relationships between species, which may involve mutualism where both benefit, commensalism where one benefits and the other is unaffected, or parasitism where one benefits and the other is harmed. Through coevolution, species in close relationships can evolve adaptations over time that improve or reduce the impacts of these interactions.