Some groups contain more species than others Species are not evenly distributed among taxonomic groups Insects predominate over all other life-forms 40% of all insects are beetles Groups accumulate species by Adaptive radiation Allopatric speciation Low rates of extinction

Insects outnumber all other species

Measuring biodiversity is not easy Out of the estimated 3 - 100 million species on Earth, only 1.7 - 2 million species have been successfully catalogued Very difficult to identify species Many remote spots on Earth remain unexplored Small organisms are easily overlooked Many species look identical until thoroughly examined Entomologist Terry Erwin found 163 beetle species specialized on one tree species

Species Richness Based solely on the number of species found in a given area species richness (# species within the community) R = s where s = the number of species

Shannon-Weiner Diversity Index Combines two quantifiable measures: species richness (# species within the community) species equitability (how even are the numbers of individual species) Calculated using the equation H = - Pi(lnPi) where Pi is the proportion of each species in the sample and is equal to ni/N where ni = the number of individuals in a given species i N = the total number of individuals collected