The International Day for Biological Diversity (or World Biodiversity Day) takes place annually on May 22. It is a United Nations–sanctioned international day for the promotion of biodiversity issues. Created by the Second Committee of the UN General Assembly in 1993 until 2000, it was held on December 29 to celebrate the day the Convention on Biological Diversity went into effect.
Biodiversity, is a portmanteau of “biological diversity,” and generally refers to the variety and variability of life on Earth. According to the United Nations Environment Programme, biodiversity typically measures variation at the genetic, the species, and the ecosystem level. Terrestrial biodiversity tends to be greater near the equator, which seems to be the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, and is richest in the tropics. These tropical forest ecosystems cover less than 10 per cent of earth’s surface, and contain about 90 percent of the world’s species. Marine biodiversity tends to be highest along coasts in the Western Pacific, where sea surface temperature is highest and in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time,but may slow in the future.
Rapid environmental changes typically cause mass extinctions. More than 99.9 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth’s current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described.The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon). In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor (LUCA) of all organisms living on Earth.
The age of the Earth is about 4.54 billion years old. The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland. More recently, in 2015, “remains of biotic life” were found in 4.1 billion-year-old rocks in Western Australia. Many researchers postulate that, “If life arose relatively quickly on Earth .. then it could be common in the universe.”
Since life began on Earth, five major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic eon (the last 540 million years) marked a rapid growth in biodiversity via the Cambrian explosion—a period during which the majority of multicellular phyla first appeared. The next 400 million years included repeated, massive biodiversity losses classified as mass extinction events. In the Carboniferous, rainforest collapse led to a great loss of plant and animal life. The Permian–Triassic extinction event, 251 million years ago, was the worst; vertebrate recovery took 30 million years. The most recent, the Cretaceous–Paleogene extinction event, occurred 65 million years ago and has often attracted more attention than others because it resulted in the extinction of the dinosaurs.
The period since the emergence of humans has displayed an ongoing biodiversity reduction and an accompanying loss of genetic diversity. Named the Holocene extinction, the reduction is caused primarily by human impacts, particularly habitat destruction. Conversely, biodiversity impacts human health in a number of ways, both positively and negatively. The United Nations designated 2011–2020 as the United Nations Decade on Biodiversity.
The date of International Biodiversity Dat was shifted to commemorate the adoption of the Convention on May 22, 1992 at the Rio Earth Summit, partly to avoid the many other holidays that occur in late December. Areas of Biodiversity promoted so far include Water and Biodiversity, Marine Biodiversity, Forest Biodiversity, Development and Poverty Alleviation, Invasive Alien Species, Biodiversity and Agriculture, Biodiversity and Climate Change, ways to protect Biodiversity in Drylands, Biodiversity: Life Insurance for our Changing World, how Biodiversity affects Food, Water and Health for All, how biodiversity can help with poverty alleviation sustainable development and forest biodiversity