Why is biodiversity important? Why should we preserve biodiversity? Why is it probably a good idea to keep all these species on the planet here? What do we get from other species? What do they do for us? Utilitarian Value Get stuff Get services/jobs done for us for free! Get enjoyment Intrinsic Value Note there is a HUGE debate about whether it is useful to put $ values on the utilitarian aspects. What are the ramifications on communities if a species goes extinct? Remember Gleason and Clements? Which curve shows every species matters equally? Which curve suggests many species can perform the same job in a community? Which curve shows species work ? (What do we mean synergistic?) Rate of Decom position Number of species in community Counting species! Linnaeus-1758-described about 12,000 species Number of described species today 2 million Much of the uncertainty revolves around number of insects in the tropics! We generally dont bother with microbes! Extrapolating Numbers (May) Assume all mammals have been identified. Found ratio of 1/3 Temperate to 2/3 Tropical mammals Assume all the Temperate insects have been identified (1 million) Then if this ratio is maintained we can extrapolate -----numbers of tropical insects should be..2 million Extrapolating Numbers (Erwin) Insecticidal fog Estimated number of species in a specific tree Then extrapolated given the number of tree species (a better known taxon) Argues for 30 million insects alone So id we have 2 million described + May said add 1 million more for tropical insects would=3 million total Erwin said add 30 million more for tropical insects=32 million total New Guinea estimates are 4-6 million Pimm a well respected ecologist said 100 million Ahhhh! Where are these species? Why would we like to know were species are? Is counting up the number of species in an area the best way to focus on what places to preserve? Only preserve One Strategy-Biodiversity Hotspots Minimum of 1,500 endemic species found nowhere else and lost 70% of their habitat (land plants and vertebrates) PROBLEMS? How has biodiversity changed over earths history? Figure Time (mya) Paleozoic Mesozoic Cenozoic EOSDCPTrJPCN Q ,000 1,100 Era Period Total extinction rate (families per million years): Number of families: The species alive today are only a tiny fraction of all those that have ever lived. The vast majority of all species in the history of the planet have gone extinct. So extinction is normal Average lifespan of a species from its origin to its extinction is between 1 and 5 million years What particular groups are at risk? Amphibians currently 40% (Nature article you red) Mammals now 26% Insects? Only about 5,000 have been looked at. 733/5,000=15% Are species renewable resources? Figure Time (mya) Paleozoic Mesozoic Cenozoic EOSDCPTrJPCN Q ,000 1,100 Era Period Total extinction rate (families per million years): Number of families: million years to recover Thus, on the times scale of the human species, environmental disruption is permanent. Under these circumstances the prospects for re-diversification are limited. Andy Knoll, Norm Myers (aibs.org) There is much recent concern about PRESERVING THE EVOLUTIONARY PROCESSES BY WHICH DIVERSITY IS GENERATED Death is one thing, an end to birth is something else. Michael Soule