|Travel Photography Isthmus
The biological diversity in this part of the world is astounding. Just this morning, I photographed a butterfly which, according to lepidopterists, is the first live photograph of this sub-species, ever. This luck suggests that taxonomy between the continents is still a bit of a wild west. But despite the apparent endlessness to it all, the world of diversity has limits, and I think, when talking about diversity, its important to know those limits.
The world contains about 44,000 arachnids, 82,000 molluscs and about 250,000 species of flowering plants. The total number of insect species? Over a million. Diversity can seem boundless, but the numbers seem more finite when you look exclusively at the advanced animals.
The world contains about 32,000 species of fish. 6,800 reptiles, 9,800 birds, 4,200 mammals, 6,500 amphibians. Of the 6,500 amphibians, about 4,800 are frogs. Since the 1950's, about 1,800 of these species have become threatened with extinction. Another 120 have actually gone extinct.
Rarely do articles that talk about extinction talk about totals, but it's been my experience that when you get out in the field, and get a sense of the distribution of, and populations of, different animal groups, you start to see the importance of these numbers, because the numbers start to have context.
Throughout the history of the world, most extinctions have been natural events. New organisms which can exploit an ecological niche are always evolving, and species become extinct when they can no longer compete with changing conditions, or face extinction when other organisms evolve more efficiently to compete in their niche.