Fungi
Fungi are a clade of multi-cellular heterotrophs, with the exception of single-cellular yeasts. All fungal cells have cell walls composed of chitin. Though they are usually classified by their distinct fruiting bodies, the majority of the fungus can not be seen with the naked eye. It is an extensive structure called the mycelium made up of microscopic filaments called hyphae. Hyphae are responsible for absorbing nutrients from the environment.
Almost all of the fungus life cycle is in the haploid stage. During asexual reproduction, a structure is formed that produces spores by mitosis and often releases them to wind. Single celled fungi such as yeasts reproduce asexually by simple budding.
During sexual reproduction, hyphae emit pheromones that will bind to other hyphae of the opposite mating type. The pheromones only attract the hyphae of other mycelium as to keep genetic variation. Plasmogamy is the fusion the cytoplasms of two mycelia. The time during which two non-identical nuclei are within the same cytoplasm is called the Heterokaryotic stage. Eventually the two nuclei will fuse in a stage called Karyogamy. This is the only time in the fungi life cycle that it is diploid. These diploid cells will go through meiosis, producing four haploid spores.
During sexual reproduction, hyphae emit pheromones that will bind to other hyphae of the opposite mating type. The pheromones only attract the hyphae of other mycelium as to keep genetic variation. Plasmogamy is the fusion the cytoplasms of two mycelia. The time during which two non-identical nuclei are within the same cytoplasm is called the Heterokaryotic stage. Eventually the two nuclei will fuse in a stage called Karyogamy. This is the only time in the fungi life cycle that it is diploid. These diploid cells will go through meiosis, producing four haploid spores.