'''Macroevolution''' is the theory that [[natural selection]] can, given enough time, lead to the creation of new [[clade]]s which are groups of organisms consisting of a single common ancestor and all the descendants of that ancestor. Macroevolution may require a large number of [[mutation]]s, though it may also come about as a result of a gross genetic change. For instance, there are two [[species]] of grey tree [[frog]]s in North America; one has two sets of [[chromosome]]s, and one has four. From an [[Theory of evolution|evolutionary]] perspective, this is the result of a random failure in [[meiosis]] in a generation of tree frogs which led to a new genetic makeup for one of the species. | '''Macroevolution''' is the theory that [[natural selection]] can, given enough time, lead to the creation of new [[clade]]s which are groups of organisms consisting of a single common ancestor and all the descendants of that ancestor. Macroevolution may require a large number of [[mutation]]s, though it may also come about as a result of a gross genetic change. For instance, there are two [[species]] of grey tree [[frog]]s in North America; one has two sets of [[chromosome]]s, and one has four. From an [[Theory of evolution|evolutionary]] perspective, this is the result of a random failure in [[meiosis]] in a generation of tree frogs which led to a new genetic makeup for one of the species. |