Keystone species mussel population explodes uncontrollably, driving out most other species. These creatures need not be apex predators. Sea stars are prey for sharks, rays, and sea anemones. Sea otters are prey for orca. The jaguar, whose numbers in Central and South America have been classified as near threatened, acts as a keystone predator by its widely varied diet, helping to balance the mammalian jungle ecosystem with its consumption of 87 different species of prey. The lion is another keystone species. Keystone mutualists are organisms that participate in mutually beneficial interaction and the loss of which would have a profound impact upon
Apex (mollusc) usually called the apical aperture. In orthocone cephalopods, the pointed end of the shell is called the apex, and shell growth is away from the apex and toward the aperture. The first chamber of the apex is sometimes called the protoconch. The apex of a valve of a bivalve shell is the area around what is most commonly the umbo or beak. In some species the embryonic shell or prodissoconch may be present at the apex of each of the two valves. Apex (mollusc) In anatomy, an apex (adjectival form: apical) is part of the shell of a mollusk. The