sexual reproduction in protozoa

1. Md college
NAME:- Iraki Fiza Md Shakil
ROLLNO:- 1016
MSC Part 1/ Paper 1

2. TOPIC:- SEXUAL REPRODUCTION In PROTOZOA

3. PROTOZOA:-
 Protozoa is small,microscopic; single-celled or unicellular organisms.
 Free living protozoa mostly aquatic, fresh and marine water.
 Parasitic protozoa live inside the bodies of animals and plants.
 It is having one or more nuclie,but no nucleus ever in charge of specialized
part of cytoplasm.
 They exist either single or in colonies.

4. REPRODUCTION:-
 Protozoa carried out their reproduction by asexual and sexual mode of
reproduction.
 The higher group of protozoa follow mainly sexual reproduction.
 Some protozoa carried out both asexual and sexual reproduction based on the
types of the host cells.

5. SEXUAL REPRODUCTION:-
 Sexual reproduction means the liberation of special reproductive cells from
the body; and the fertilization of ovum by spermatozoon.
 As the protozoa do not have the so called ‘body,’ they cannot be said to
exhibit sexual reproduction in this sense.
 Certain protozoa perform sexual reproduction is of regular occurrence.
 For example,Plasmodium in mosquito cannot be completed without
gametogenesis and syngamy.
 Gametogenesis is termed as gametic meiosis.

6. Two types of life cycles in protozoa:-

7.  Sexual reproduction has two processes :-
syngamy conjugation

8. 1) Syngamy :-
 Syngamy is the complete and permanent fusion of the union of two gametes
for the generation of zygote.
 The nuclei of the gametes fuse to form a zygote nucleus or synkaryon.
 The zygote develops into the adult directly or fission of various types in
different forms.
 Syngamy may be of many types depending upon the degree of differentiation
displayed bye the fusing gametes.
 (a) Autogamy.
 (b) Exogamy.
 (c) paedogamy.
 (d) Hologamy.
 (e) Isogamy.
 (f) Anisogamy.
 (g) macrogamy.

9.  Autogamy :- The production of gametes by the division of single parent cells.
 Exogamy :- Syngamy taking places between the offspring of different
parents.
 Paedogamy :- Fusing individuals are young.
 Hologamy :- Fusion of two mature individuals of normal size behaving
themselves as gametes.
 Merogamy :- The uniting individual called merogametes or gametes and are
formed by special fission.

10.  Isogamy :- Fusion of two gametes having similar shape and size is called
isogametes and they union called isogamy.
 Anisogamy :- Fusion of teo gametes having differ in size, shape and
behaviour, they termed as anisogametes or heterogametes. Their fusion is
known asanisogamy and heterogamy.
 Macrogamy:- It is a syngamy between macrogametes of the species.
 Macrogametes means small gametes (male gametes in protozoa)
 Microgametes means large gametes (female gametes in protozoa)

11. CONJUGATION:-
 Random contact brings individuals of opposite mating types together (called
conjugation)
 Meiosis results in four haploid pronuclei
 Three pronuclei and the macronucleus degenerate.Mitosis and mutual
exchange of pronuclei is followed by fusion of the pronuclei.
 Conjugants separate.Nuclear divisions that restore nuclear characteristics of
species follow.Cytoplasmic divisions may accompany these events.

12. CONJUGATION:-

13. THANKYOU