Phylum Zygomycota clusters more than 1100 different species, mostly
saprotrophic soil fungi, who exploits nutrients by decomposing waste products,
such as rotten fruit. Their name, refers to their reproductive sexual
mechanism, as it forms a structure called zygosporangium, arising from the
conjugation between two compatible hyphae, with each hyphae stemming from a separate
organism.  After conjugation, a cell wall
is formed behind the fusing hyphae, which at this point are called gametangia.
Next to this, the wall separating the two hyphae is broken down, leading to
fusion of both hyphae’s cell components into one organism, except their nuclei,
which are still separate entities. Following this, their nuclei fuse and the
walls around the zygosporangium grows even harder and thicker than before – this
converts the sporangium to a zygospore. After a long resting period, meiosis occurs,
and the fused nuclei are divided into two separate recombinant nuclei.  These are then later integrated and released
as meiospores. Most Zygomycota are harmless to humans, although a few are
pathological causing a disease called mucormycose,
which arises when spores are inhaled from dusty environments. 

Fungi in the third
phyla, phylum Ascomycota, are the
most abundant phylum as more than 65.000 species belong here. Their trademark
is their structural component, the ascus, which is a sac-like unit, harboring
eight ascospores, in which sexual and asexual reproduction occurs. The formation
of this component arises when a spore lands on a suitable substrate, after
which a haploid mycelium is formed. From this, asexual structures can be
produced, or sexual structures, gametangia, can be formed. The female sexual
structure is called ascogonium, while the male sexual structure is an
antheridium.  Fusing of sexual structures
leads to formation of one organism with two separate nuclei, this is called an
ascogonius hypha. At the tip of this hyphae, both nuclei fuse and forms a diploid
ascus, who undergoes meiosis and thus produces 4 recombinant haploid nuclei. These
4 haploid nuclei then divide asexually – which create 8 mature ascospores,
ready to be released.Due to the sheer amount of species, phylum Ascomycota, exert
both a positive and negative effect on the human condition. Beneficial species
such as Penicillium notatum and Saccharomyces cerevisiae contribute to
our health and or ability to produce beverages, while malign effects are seen
by species of the Aspergillus genus who can cause a respiratory disease, decay
food, synthetize carcinogenic toxins in nuts etc. The Aspergillus genus will be
investigated extensively later in this paper. 

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