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Pediastrum possesses a haplontic life cycle, and can be divided into three types. [12] The most commonly seen is the first kind of asexual life cycle (ALC1), which generates autocolonies. In ALC1 the zoospores aggregate into an orderly flat disk, with concentric rings (central cell, six cells, and then nine cells.)
diplontic life cycle — the diploid stage is multicellular and haploid gametes are formed, meiosis is "gametic". haplodiplontic life cycle (also referred to as diplohaplontic, diplobiontic, or dibiontic life cycle) — multicellular diploid and haploid stages occur, meiosis is "sporic". The cycles differ in when mitosis (growth) occurs.
Alternation of generations is defined as the alternation of multicellular diploid and haploid forms in the organism's life cycle, regardless of whether these forms are free-living. [6] In some species, such as the alga Ulva lactuca , the diploid and haploid forms are indeed both free-living independent organisms, essentially identical in ...
Dinoflagellates have a haplontic life cycle, with the possible exception of Noctiluca and its relatives. [5] The life cycle usually involves asexual reproduction by means of mitosis, either through desmoschisis or eleuteroschisis. More complex life cycles occur, more particularly with parasitic dinoflagellates.
Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic division of diploid gametocytes into various gametes, or by mitosis.
The haploid organism's gamete then combines with another haploid organism's gamete, creating the zygote. The zygote undergoes repeated mitosis and differentiation to produce a new diploid organism. The haplodiplontic life cycle can be considered a fusion of the diplontic and haplontic life cycles. [50] [citation needed]
The life cycle of Oedogonium is haplontic. The egg from the oogonia and the sperm from the antheridia fuse and form a zygote which is diploid (2n). The zygote then undergoes meiosis and reproduces asexually to form the filamentous green alga which is haploid (1n).
Coccidinium are haplontic, meaning that for the majority of their life cycle they are haploid. Reproduction can occur either asexually or sexually. Sexual reproduction has been clearly observed in 1934 when Chatton and Biecheler witnessed a two-by-two fusion of imperceptibly dissimilar spores from separate organisms of C. mesnilii , resulting ...