Lichen anatomy and physiology the Ascomycota, with about 40% of species forming such an association. Some of these lichenized fungi occur in orders with nonlichenized fungi that live as saprotrophs or plant parasites (for example, the Leotiales, Dothideales, and Pezizales). Other lichen fungi occur in only five orders in which all members are engaged in this habit (Orders Graphidales, Gyalectales, Peltigerales, Pertusariales, and Teloschistales). Lichenized and nonlichenized fungi can even be found in the same genus or species. Overall, about 98% of lichens have an ascomycetous mycobiont. Next to the Ascomycota, the largest number of lichenized fungi occur in the unassigned fungi imperfecti. Comparatively
Conservation biology of parasites only the loss of certain host species from the wild, but host population bottlenecks or the fragmentation of host populations would predictably lead to the extinction of host-specific parasites. The paper also noted that parasites exert selective pressures upon their host populations that increase host genetic diversity. At first, this view met with open scepticism. However, it became clear that the co-extinction of hosts and their specific parasites is likely to increase the current estimates of extinction rates significantly. A decade later, a study focusing on highly host-specific groups such as fig wasps, parasites, butterflies, and myrmecophil butterflies estimated the