In Evolution: The Origin of Species, players do the work of nature, putting animals into play and evolving them trait by trait to help them survive and thrive. Each player starts with a hand of six cards that feature an animal on the back and one or two traits on the front. Each round consists of four phases. During Development, players take turns playing one card from their hand either as an animal (face-down) or as a trait on one of their existing animals (face-up and tucked under the animal). Traits include Carnivorous, Camouflage, Sharp Vision, Swimming, Poisonous and Communication; if a card has two traits, the player chooses which trait the animal acquires, hiding the other trait under the animal. Once a player passes during this phase, he can no longer play cards.