REPRODUCTION IN UNICELLULAR ORGANISMS

SSS 1

Biology

Third Term

Week 6

REPRODUCTION IN UNICELLULAR ORGANISMS

CONTENT

1. Reproduction in Amoeba by Asexual Reproduction by

1. Binary Fission
2. Multiple Fission

1. Reproduction in Paramecium by

1. Asexual Reproduction
2. Sexual Reproduction

1. Reproduction in Spirogyra by

1. Asexual or Vegetative Reproduction or Conjugation

1. Reproduction in the Earthworm by

1. Sexual Reproduction

Reproduction in Amoeba by Asexual Reproduction

Amoeba is a unicellular protozoa. Its mode of reproduction is asexual by fission and a number of fission.
Amoeba reproduces asexually by the process called binary fission. Binary fission occurs in single- celled organisms belonging to Kingdom Monera, and Protista (Amoeba and paramecium). In this process, the parent organism divides into two halves, each half forming an independent daughter organism.

Binary Fission

It happens below regular situation in water when the organism grows to a selected measurement, the nucleus divides into two equal daughter nuclei and every of the daughter nuclei develop into enclosed by half of the protoplast resulting in the manufacturing of two daughter cells. The cell division is solely mitotic.

Binary Fission in Amoeba

A number of Fission

In some unicellular organisms corresponding to amoeba, the cells rounds as much as a cyst-like construction. The protoplasm bear fission as the nucleus of the parent divides into a number of daughter nuclei by amitosis (repeated divisions). That is adopted by the enclosing one nucleus. Several cells are launched from the cyst. The kind of asexual copy happens below adversarial situation.

Binary and a number of fission in amoeba

EVALUATION

1. Define asexual reproduction.
2. Name two forms of asexual reproduction in amoeba;
3. State two difference between binary fission and a number of fission.

Reproduction in Paramecium

Paramecium is a protozoa that’s more developed than Amoeba. It reproduces each sexually and asexually. Asexual copy is by binary fission and sexual copy is by conjugation.

(a) Binary Fission in Paramecium

Binary Fission in Paramecium

Sexual Copy in Paramecium

Sexual copy by conjugation takes in Paramecium within the following steps:

1. Two individuals called conjugant come together and lie aspect by aspect.
2. The meganucleus of every conjugants disintegrate.
3. The micronucleus of every conjugants divides into two components twice, forming 4 micronuclei. Three of the 4 micro – nuclei in every conjugant disintegrate. The remaining micronucleus again divides into two.
4. One micronucleus from every conjugal migrates into the other conjugant. In different words, the conjugants trade nuclear material.
5. The migratory nucleus of 1 conjugant and the stationary nucleus of the opposite conjugant fuse in every individual to kind a fusion nucleus in each ex-conjugal divides into 4 new people, every with a brand new
6. The fusion nucleus in every ex-conjugant divides into 4 people every, with a brand new meganucleus and micronucleus.

Paramecium in Conjugation

Levels of conjugation in paramecium

EVALUATION

1. Explain sexual reproduction in paramecium
2. Describe asexual reproduction in paramecium with the help of an appropriate diagram.