Natural fiber exoskeletons of insects and arthropods. In shells and exoskeletons, the chitin fibers contribute to their hierarchical structure. In nature, pure chitin (100% acetylation) does not exist. It instead exists as a copolymer with chitin's deacetylated derivative, chitosan. When the acetylized composition of the copolymer is over 50% acetylated it is chitin. This copolymer of chitin and chitosan is a random or block copolymer. Chitosan is a deacetylated derivative of chitin. When the acetylized composition of the copolymer is below 50% it is chitosan. Chitosan is a semicrystalline “polymer of β-(1-4)-2-amino-2-deoxy-D-glucose”. One difference between chitin and chitosan is that chitosan is
Sexual selection in fungi by producing pheromones. In the isogamous budding yeast, Saccharomyces cerevisiae, pheromones are used to distinguish between different mating types and show a preference for higher concentrations of pheromones along with a rejection of lower concentrations. However, all of the pheromone studies within fungi have been performed in a laboratory. In order to further support this hypothesis, more research is necessary on the effects of natural gamete density, motility, and pheromone production in nature., Mushroom-forming fungi within Basidiomycetes produce sexually by the reciprocal migration of nuclei and have a male-biased OSR which aids in supporting that sexual selection is present within