Fungus commonly known as sac fungi or ascomycetes, constitute the largest taxonomic group within the Eumycota. These fungi form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. This phylum includes morels, a few mushrooms and truffles, unicellular yeasts (e.g., of the genera "Saccharomyces", "Kluyveromyces", "Pichia", and "Candida"), and many filamentous fungi living as saprotrophs, parasites, and mutualistic symbionts (e.g. lichens). Prominent and important genera of filamentous ascomycetes include "Aspergillus", "Penicillium", "Fusarium", and "Claviceps". Many ascomycete species have only been observed undergoing asexual reproduction (called anamorphic species), but analysis of molecular data has often been
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