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Paramecium (/ ˌ p ær ə ˈ m iː s (i) ə m / PARR-ə-MEE-s(ee-)əm, /-s i ə m /-see-əm, plural "paramecia" only when used as a vernacular name) [2] is a genus of eukaryotic, unicellular ciliates, widespread in freshwater, brackish, and marine environments. Paramecia are often abundant in stagnant basins and ponds.
Since autogamy in flowering plants and autogamy in unicellular species is fundamentally different, and plants and protists are not related, it is likely that both instances evolved separately. However, due to the little overall genetic variation that arises in progeny, it is not fully understood how autogamy has been maintained in the tree of life.
In biology, a biological life cycle (or just life cycle when the biological context is clear) is a series of stages of the life of an organism, that begins as a zygote, often in an egg, and concludes as an adult that reproduces, producing an offspring in the form of a new zygote which then itself goes through the same series of stages, the ...
Added a label for the buccal overture, a structure frequently mislabeled as the cytostome on diagrams of Paramecium. For an accurate representation of these structures, see: Ralph Wichterman, The Biology of Paramecium, 2nd Edition, 1986 (fig. 1.3A, on... 19:47, 5 June 2017: 1,142 × 1,007 (149 KB) Deuterostome: Lengthened buccal cavity, for ...
A few types of organisms, such as many fungi and the ciliate Paramecium aurelia, [11] have more than two "sexes", called mating types. Most animals (including humans) and plants reproduce sexually. Sexually reproducing organisms have different sets of genes for every trait (called alleles). Offspring inherit one allele for each trait from each ...
The eggs of fish and amphibians are jellylike. Cartilagenous fish (sharks, skates, rays, chimaeras) eggs are fertilized internally and exhibit a wide variety of both internal and external embryonic development. Most fish species spawn eggs that are fertilized externally, typically with the male inseminating the eggs after the female lays them.
Paramecium caudatum [1] is a species of unicellular protist in the phylum Ciliophora. [2] They can reach 0.33 mm in length and are covered with minute hair-like organelles called cilia. [3] The cilia are used in locomotion and feeding. [2] The species is very common, and widespread in marine, brackish and freshwater environments. [4] [5]
In plants both phases are multicellular: the haploid sexual phase – the gametophyte – alternates with a diploid asexual phase – the sporophyte. A mature sporophyte produces haploid spores by meiosis, a process which reduces the number of chromosomes to half, from two sets to one. The resulting haploid spores germinate and grow into ...