Reproduction in Amoeba

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Life Cycle of Amoeba

Amoeba

Amoeba always reproduce asexually. There are different ways of asexual reproduction in Amoeba and they are as follows:

1) Binary Fission:
Parent Amoeba divides into two daughter amoebae in favorable conditions. This is known as binary fission. Different phases of mitosis are accompanied with changes in the shape of body. In prophase, body becomes spherical with numerous pseudopodia and nucleus show intranuclear spindle. Chromatids appear as duplicated chromosomes in the nucleus. In metaphase chromosome arrange at the equator. In anaphase daughter chromosomes move towards opposite poles. In telophase. pseudopodia assume normal shape, constriction appear in the middle. One of the daughter retain contractile vacuole and the other acquires new vacuole. Now the parent after binary fission starts living as two individuals which later on grow in size.


 Binary Fission in Amoeba



2) Sporulation:
Some species of Amoeba reproduce by sporulation. Sporulation begins with breakdown of nuclear membrane and release of chromatin into the cytoplasm. Cytoplasm of parent body segregate around daughter nucleus. This cytoplasmic layer changes into tough, resistant spore membrane. Later on residual cytoplasm disintegrates and releases spores in water. These spores sink down at the bottom of the pond. On return of favorable season, these spore membrane rupture and release Amoeba.

Sporulation in Amoeba
(Image Source: https://learn.careers360.com/school/question-show-the-multiple-fusion-in-amoeba-24327/ )

3) Encystment and Multiple Fission:
Under unfavorable conditions like drought, extreme temperature etc Amoeba withdraws its pseudopodia and becomes spherical. It secretes three layered cyst around itself. Now its nucleus undergoes repeated mitosis and daughter nuclei gets surrounded by mass of cytoplasm called amoebulae/pseudopodiospores. This encysted Amoeba lives under suspended condition with extremely slow metabolism. On return of favorable season, Amoeba hatches out from cyst and resumes active life. Encystment is also a means of dispersal. 

Encystment in Amoeba 
(Image Source: https://www.toppr.com/ask/question/pseudopodiospores-are-formed-in/)

4) Regenration:
Amoeba has a great power of regeneration. Even a small piece containing a part of nucleus can rapidly regenerate to a complete Amoeba. 







 

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