![]() ![]() ![]() This phenomenon is termed as encystation. (a) Encystation : In response to unfavourable living condition, an Amoeba withdraws its pseudopodia and secretes a three-layered hard covering or cyst around itself. This kind of fission is called multiple fission. In course of time, each of these daughter cells starts a free life and transforms into an adult individuals. Later, each nucleus gathers a small amount of cytoplasm around it and the mother individual splits into many tiny daughter cells. Mode of multiple fission : Sometimes, the nucleus divides several times by amitosis to produce many nuclei, is not followed immediately by cytokinesis. Examples – Multiple fission occurs in many protozoans such as Plasmodium, Amoeba and Monocystis, Foraminifera. (ii) Multiple fission : Multiple fission is the division of the parent into many small daughter individuals simultaneously. Example Euglena and vorticella.īinary fission involves mitosis only and consequently, the resultant offspring's are genetically identical to the parent and each other. This kind of fission is designated as longitudinal binary fission. (c) Longitudinal binary fission : If the plane of cytoplasmic division concides with the longitudinal axis of the individual. (b) Transverse binary fission : If the plane of cytoplasmic division coincides with the transverse axis of the individual, the fission is termed transverse binary division. (a) Simple binary fission : If the plane of cytoplasmic division passes through any direction, the fission is called simple fission. Subsequently, the mother cell splits into two equal sized daughter halves or cells. Modes of binary fission : In Binary fission, the nucleus divides first and the cytoplasm next. Examples - Protozoans ( Amoeba, Euglena etc.) Bacteria and Planarians. During binary fission nuclear divisions or karyokinesis, always followed by division of cytoplasm or cytokinesis. (i) Binary fission : Binary fission is the division of the parent into two small, nearly equalized daughter individuals. Types : Asexual reproduction takes place in five principal ways : It is absent among the higher non-vertibrates and all vertibrates. Occurrence : Asexual reproduction occurs in protozoans and some lower animals such as sponges, coelentrates, certain worms and tunicates. Today, the scientists have been able to produce clones of multicellular animals ( e.g., boar calf names as Frosty, and Finn Dorset lamb named as the famous Dolly) artificially in the laboratory. Asexual reproduction produces identical offspring commonly referred to as a clone. It involves only mitotic cell divisions, and also termed somatogenic reproduction. The young one receives all its genes from one parent.Īsexual reproduction is also known as agamogenesis or agamogeny. (1) Asexual (Non-gametic) (2) Sexual (gametic)ĭefinition : Production of offspring by a single parent without the formation and fusion of gametes is called asexual reproduction. Types of reproduction : These are of two main types (4) Development of reproductive bodies into offspring. ![]() (3) Formation of reproductive bodies or units. This is cytological basis of reproduction. (2) Cell division, only mitotic, or both mitotic and meiotic. This is the molecular basis of reproduction. However, all modes have certain common basic features. Modes of reproduction vary in different organisms. Reproduction : Reproduction is the ability of living organism to produce a new generation of living individuals similar to themselves.īasic features of reproduction : All organisms reproduce. ![]()
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