Some species are easy to identisr. The moose, for example, is obviously not going to interbreed with anything else. (Walking dinosaur costume)Other cases are much more diffrcult. Many bird species are almost identical to related species, but they do not interbreed. (Realistic dinosaur costume)There may be even more difference between the sexes of a given species than between two different species. For example, the skeleton of the big, robust male lion differs more from a female lion’s than the latter does from the skeleton of a female tiger. Or, there can be great geographic variation. The south Alaskan brown bear, a subspecies of Ursus crcfos, is enormous, heavy-set, and smallclawed.
The grizzly, the American subspecies of U. crctos that lives outside of southern Alaska, is a good deal smaller, scrawnier, and has long claws.
So the modern concept of a species is based on breeding dimamics, not on the morphology of animals-which means that species are real, natural systems.(Animatronic dinosaur) Moreover, many of the morphological features that biologrsts use to help identiff living species are contained in the soft tissues-for instance, color, feather, or fur patterns, the superficial display devices that animals often use to identi$r members of their own and other species. It is through these devices that they avoid sex with the wrong kind. Things are difficult, for paleontologists trylng to identi$r extinct species because they do not have access to such information. Higher level systematics differs from the species work in that it depends almost wholly on morphological divergence. This divergence is made up of two components, phylogenetic and gradistic.