This is an excellent documentary that illustrates how biological ecosystems find an equilibrium that is a suitable adaptive response to the environment. This means all the organisms that express nourishing and defense behaviors in a given ecosystem become specifically suited to the environment and each other. Islands are one of the places this biological balance is illustrated clearly; where the particulars of the environment along with the baseline biological ecosystem that inherited the island come to express a behavioral economy that is adaptive in that specific context. Islands with no large land predators may bring about flightless birds for instance because of the lack of need to fly away.
Christmas Island is an excellent illustration of how that biological equilibrium can be dramatically disrupted by a newcomer to the biological social economy. This disruption can expose weaknesses that are present because there was no need to build defenses against the strategies of the imported invader prior to its arrival. This is what drives biology’s own evolutionary expression of a “Game of Thrones” and may also be a good insight into the way the various human cultures evolved throughout the world – a reflection of populations finding equilibrium with the environment, reflecting its nature, coupled with the periodic need to adapt to “invaders” as we began to cross pollinate as a result of things like trade, climate shifts and so on, leading to the human version of “Game of Thrones”.