Reproduction in protozoa

This powerpoint covers all the different types of reproduction which take place in protozoans.

1. Presented By: Hemant Kumar REPRODUCTION IN PROTOZOA

2. PROTOZOA protos means ‘ first ’ zoion means ‘ animal ’ INTRODUCTION Term Protozoa was firstly introduced in 1818. Protozoa are eukaryotic, unicellular microorganisms, which lack cell wall. Includes more than 65,000 species.

3. REPRODUCTION IN PROTOZOA

4. A biological process by which new individual organisms i.e. offsprings are produced from their parent. Reproduction Protozoans reproduce by both asexual and sexual methods. Asexual Sexual

5. Binary Fission Plasmotomy Multiple Fission Budding Plasmogamy ASEXUAL REPRODUCTION

6. It is the division of one individual into two approximately equal parts. It is the primary method of reprodution . This involves mitotic division of nucleus i.e. karyokinesis which is immediately followed by cytokinesis . In ciliates (e.g. Paramecium), during fission, meganucleus divides amitotically and micronucleus usually by mitotic division. BINARY FISSION

7. Longitudinal Binary Fission : Cytokinesis occurs along longitudinal axis. e.g. Euglena Irregular Binary Fission : Cytokinesis may occurs along any plane. e.g. Amoeba Transverse Binary Fission : Cytokinesis occurs along transverse axis . e.g. Paramecium Oblique Binary Fission : Cytokinesis occurs along oblique plane. e.g. Ceratium TYPES OF BINARY FISSION

8. A special type of fission in which a multinucleate protozoan divides into two or more multinucleate daughter individuals. e.g. Pelomyxa , Opalinids etc . PLASMOTOMY

9. MULTIPLE FISSION In this, karyokinesis is not followed immediately by cytokinesis . In this, firstly the nucleus undergoes a series of divisions, results into a number of daughter nucleus, which usually arrange themselves at the periphery . Later the body cytoplasm divides into as many parts as there are daughter nuclei, resulting into formation of several daughter individuals. Example : Plasmodium, Aggregata

10. Schizogony : Formation of numerous daughter nuclei is followed by the formation of cytoplasmic buds, each contains a nucleus. e.g. Plasmodium MULTIPLE FISSION

11. In this, new organisms develop from an outgrowth or bud. It is a modified form of fission. When a parental body produce only one bud, it is known as monotomic . e.g. Vorticella When a parental body produce several buds simultaneously, called as multiple budding. e.g. Ephelota BUDDING

12. A type of reproduction in which the cytoplasm of two or more parent cells fuse together without the fusion of nuclei. After separation they remain unchanged. It usually serves for the purpose of digestion of large prey. PLASMOGAMY

13. Syngamy Conjugation SEXUAL REPRODUCTION

14. Fusion of two gametes resulting in the formation of zygote. Fused nucleus of zygote is called as synkaryon . SYNGAMY Types : Hologamy : Type of syngamy in which the two premature protozaon individuals do not form gametes, but themselves behave as gametes and fuse together to form a zygote . e.g. Copromonas (b) Isogamy : When two fusing gametes are morphologically similar but differ in behaviour , they are called as isogametes and their union is called as isogamy . Isogametes are generally produced by multiple fission. e.g . Chlamydomonas , Monocystis

15. (c) Anisogamy : When two fusing gametes are differ in morphology as well as in behaviour , they are called as anisogamy and their union is anisogamy . Usually small or motile gametes are male or microgametes and large non-motile ones are the female or macrogametes . e.g. Plasmodium, Volvox (d) Autogamy : It involves the fusion of gametes derived from the same parent cell. e.g. Actinophrys & Actinosphaerium

16. Also called amphimixis . Firstly discovered by Joshua Laderberg and Edward Tatum in 1946. It is the temporary union of two individuals where exchange of genetic materials take place by direct cell-to-cell contact. Conjugation takes place only between same groups of individuals. Organisms which take part in conjugation is called as conjugants . CONJUGATION

17. CONJUGATION

18. A mode of asexual reproduction in which offsprings are produced from an unfertilized egg. e.g. Chlamydomonas , Actinophrys PARTHENOGENESIS REGENERATION A process by which some organisms can restore the lost or amputated parts of their body. Most of the protozoans can regenerate their lost body parts .

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