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Organisms Sexual and Asexual

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Introduction

10 organisms for Asexual reproduction Jelly Fish After fertilization and initial growth, a larval form, called the planula, develops from the egg. The planula larva is small and covered with cilia. It settles onto a firm surface and develops into a polyp. The polyp is cup-shaped with tentacles surrounding a single orifice, perhaps resembling a tiny sea anemone. Once the polyp begins reproducing asexually by budding, it's called a segmenting polyp, or a scyphistoma. New scyphistomae may be produced by budding or new, immature jellies called ephyra may be formed. Many jellyfish can bud off new medusae directly from the medusan stage. Aphids Male and female aphids mate in autumn. Sexual females, but also asexual ones, have two sex chromosomes while sexual males only have one. The aphids may go on reproducing gamogenetically (asexually) ...read more.

Middle

Sea Sponge Asexual reproduction of sponges is through budding or fragmentation, when a small piece of sponge falls off of the main sponge and grows into a new one. Many freshwater sponges form small structures known as gemmules, which function as overwintering devices. Fungus The Ascomycota, commonly known as sac fungi or ascomycetes, form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. This division includes morels, some mushrooms and truffles, as well as single-celled yeasts and many species that have only been observed undergoing asexual reproduction. Because the products of meiosis are retained within the sac-like ascus, several ascomyctes have been used for elucidating principles of genetics and heredity (e.g. Neurospora crassa). Ascomycota The reproduction of the Ascomycota is very varied and can be either asexual or sexual. ...read more.

Conclusion

Lumbriculus and Aulophorus, for example, are known to reproduce by the body breaking into such fragments. Many other taxa (such as most earthworms) cannot reproduce this way, though they have varying abilities to regrow amputated segments. Sexual reproduction Sexual reproduction allows a species to better adapt to its environment. Some annelida species are hermaphroditic, while others have distinct sexes. Most polychaete worms have separate males and females and external fertilization. The earliest larval stage, which is lost in some groups, is a ciliated trochophore, similar to those found in other phyla. The animal then begins to develop its segments, one after another, until it reaches its adult size. Cnidaria Asexual reproduction via budding is common among cnidaria, particularly among the Hydrozoa class. Asexual larvae bud laterally from the adult polyps, which develop into polyps themselves. The budding is often incomplete, so that colonies of genetically identical polyps physically connected with each other can form. ...read more.

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