species -- n. biology : a group of animals or plants that are similar and can produce young animals or plants : a group of related animals or plants that is smaller than a genus

captivity -- n. the state of being kept in a place (such as a prison or a cage) and not being able to leave or be free : the state or condition of being captive

artificial insemination – n. medical: a medical process in which semen is used to make a woman or female animal pregnant without sexual intercourse

on the verge of – expression at the point when (something) is about to happen or is very likely to happen

extinction -- n.the state or situation that results when something (such as a plant or animal species) has died out completely