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
Barbary falcon last ice age) from the Aswan area in Sudan, where "Falco peregrinus minor" occurs today, was identified to belong to the peregrine. The Barbary falcon is one of the rare cases that may arguably be considered a species under the biological species concept, but certainly not under the phylogenetic species concept rather than the other way around as usual. This case demonstrates that what makes a "species" is not only its descent, but also occurs to a population in the course of evolution, how it adapts, and how this affects its reproductive isolation (or lack thereof) from sister taxa. Barbary