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  2. Heterospory - Wikipedia

    en.wikipedia.org/wiki/Heterospory

    Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. The smaller of these, the microspore , is male and the larger megaspore is female. Heterospory evolved during the Devonian period from isospory independently in several plant groups: the clubmosses , the ferns including the arborescent ...

  3. Alternation of generations - Wikipedia

    en.wikipedia.org/wiki/Alternation_of_generations

    Spores of two distinct sizes (heterospory or anisospory): larger megaspores and smaller microspores. When the two kinds of spore are produced in different kinds of sporangia, these are called megasporangia and microsporangia. A megaspore often (but not always) develops at the expense of the other three cells resulting from meiosis, which abort.

  4. Marsileaceae - Wikipedia

    en.wikipedia.org/wiki/Marsileaceae

    While heterospory is the norm among all plants with seeds, such as the flowering plants and conifers, it is very rare among other groups of plants. Also, most heterosporous plants produce their two kinds of sporangia in different places on the plant.

  5. Sporophyte - Wikipedia

    en.wikipedia.org/wiki/Sporophyte

    Diagram showing the alternation of generations between a diploid sporophyte (bottom) and a haploid gametophyte (top) A sporophyte (/ ˈ s p ɔːr. ə ˌ f aɪ t /) is the diploid multicellular stage in the life cycle of a plant or alga which produces asexual spores. This stage alternates with a multicellular haploid gametophyte phase.

  6. Spore - Wikipedia

    en.wikipedia.org/wiki/Spore

    The main difference between spores and seeds as dispersal units is that spores are unicellular, the first cell of a gametophyte, while seeds contain within them a developing embryo (the multicellular sporophyte of the next generation), produced by the fusion of the male gamete of the pollen tube with the female gamete formed by the ...

  7. Selaginella - Wikipedia

    en.wikipedia.org/wiki/Selaginella

    Curled up Selaginella tamariscina Wallace's Selaginella (Selaginella wallacei). Selaginella, also known as spikemosses or lesser clubmosses is a genus of lycophyte.It is usually treated as the only genus in the family Selaginellaceae, with over 750 known species.

  8. History Channel - Wikipedia

    en.wikipedia.org/wiki/History_Channel

    History (stylized in all caps), formerly and commonly known as the History Channel, is an American pay television network and flagship channel owned by A&E Networks, a joint venture between Hearst Communications and The Walt Disney Company's entertainment division. The network was originally focused on history-based, social/science ...

  9. Evolutionary biology - Wikipedia

    en.wikipedia.org/wiki/Evolutionary_biology

    These alternative ways of dividing up the subject have been combined with evolutionary biology to create subfields like evolutionary ecology and evolutionary developmental biology. More recently, the merge between biological science and applied sciences gave birth to new fields that are extensions of evolutionary biology, including evolutionary ...