Sequential hermaphrodites
Sequential hermaphrodites (dichogamy) are organisms born as one sex which later change into the other sex, and can only function as one sex at one time. A few species in this group can sex change multiple times, but they can only function as one sex at a time. Unlike humans, these animal's DNA does not determine their sex, allowing full functional sex change without modifying the DNA.
* Protandry: When the organism starts as a male, and changes sex to a female later in life.
o Example: The Clownfish (Genus Amphiprion) are colorful reef fish found living in symbiosis with anemones. Generally one anemone contains a 'harem', consisting of a large female, a smaller reproductive male, and even smaller non-reproductive males. If the female is removed, the reproductive male will sex change into a female, and the largest of the non-reproductive males will mature and become reproductive. It has been shown that fishing pressure actually is causing a change in when the switch from male to female occurs, since fishermen naturally prefer to catch the larger fish. The populations are generally changing sex at a smaller size, due to artificial selection.
* Protogyny: When the organism starts as a female, and changes sex to a male later in life.
o Example: Wrasses (Family Labridae) are reef fish that are all Protogynous, but have two different life strategies:
1. For some species, they all start out as females, and when they get large enough they will sex change to males.
2. Other species start out as females or males (initial phase), and either may shift to become a supermale (terminal phase male). The females and the initial phase males have similar colorations. The supermale is larger and usually brightly colored, and there is only one in a given area of the reef. This supermale dominates the other wrasses of the species, and pair spawns (one male, one female) repeatedly. The initial phase males will group spawn, with many males and females participating. When the supermale dies, the largest wrasse in the area, male or female, changes into the new supermale.