When the gametangia fuse, syngamy occurs and produces a zygote (2n). The sproangia produces mitospores which through mitosis developes into gametangia, or sex organs. After the zygote undergoes meiosis, germination occurs forming mycelia and sporangia with opposite mating strains, (+) and (-). Bread mold, Rhizopus stolonifer, most often reproduces asexually. Sexual reproduction involves contact between opposite mating strains of the fungus to form a zygospore. nigricans is a coenocytic, or tubular fungus ( zygomycota). Follow Us: Bread mold reproduces asexually, using mitosis to form spores, and sexually. Rhizopus nigricans, or black bread mold, also has a haploid life history. The 2n zygote then developes into the filamentous green algae.Īnother example is found in the fungi kingdom. Syngamy occurs when the sperm and egg fuse and forms the zygote (2n). The parent also contains antheridia which produce sperm(1n) and an oogonium which produces the egg(1n). In the first process, zoospores (mitospores) escape from the zoosporangium which is located in the parent algae and they develope into filaments. Oedogonium grows in two different ways, through zoospores, or through syngamy of sperm and egg.

Volvox, for example is a colonial green algae in which both male gametes and egg are produced in the 1n stage, which then fuse together to form a zygospore, an encysted zygote that is protected from the harsh conditions of the environment.Īnother green algae that exhibits 1n life cycle is the Oedogonium, which is filamentous, or a chain of cells formed in one plane. Haploid life cycle occurs in green algae. One important aspect about haploid life cycle is that only the gametophyte phase is present, the sporophyte does not exist in a haploid life cycle. The fused gametes either all come from one single individual or from more than one individuals.Īfter syngamy, the fused gametes become the zygote and become diploid again, the process repeats again. The gametes then fuse in a process called syngamy, or fertilization. Isogamy and anisogamy, and sometimes oogamy may occur. It can either start asexual reproduction or it can produce gametes through mitosis.

The organism has two options but not in all cases. The four cells would then go through mitosis and become the organism. Meiosis produces four cells from each zygote and these four cells can be spores or other structure, depending on the organism. Haploid life cycle is the most common in algae (without dikaryotic phase) and most fungi (with dikaryotic phase).Ĭolonial alga such as red alga, brown alga, and green alga and filamentous alga such as red, green, and brown alga all exhibit haploid life cycle.Ī general life history includes both a 1n stage and a 2n stage separated by meiosis and syngamy.īefore meiosis, the individual is diploidzygote.Īfter the zygote goes through meiosis, it develops into a haploid (1n) spore or some other 1n structure.

Bread mold and spore formation