Topic 1: PROTOZOA (Kingdom Protista)

B.Sc. Part-I (ZOOLOGY) Paper 1

DIVERSITY AND EVOLUTION OF NON- CHORDATA

PROTOZOA

TERMINOLOGY

• Leeuwenhock, first gave preliminary accounts of some protozoan

forms.

• Goldfuss (1818) coined the term Protozoa but he included many

non protozoan forms.

• Von Siebold (1845) recognized the unicellular nature of protozoa

and established it in true sense

PROTOZOA • Unicellular or acellular, eukaryotic and commonly motile hetrotrophic

organisms are called protozoa.

• It is a loose assemblage of different groups.

Features

They exhibit all types of symmetry.

Most species occur singly but many are colonial.

Body is bounded by cell membrane or plasmalemma

Body may be naked or covered by a pellicle or test, made up of silica or

calcium carbonate

Protozoa- Features • The pellicle is a thin layer supporting the cell membrane in

various protozoa, such as cilliates, protecting them and allowing them to retain their shape, especially during locomotion.

• The pellicle varies from flexible and elastic to rigid.

Protozoa- Features • A filamentous network of cytoskeleton may form a

dense supportive structure, called epiplasm.

• Usually uninucleate but maybe more than single nucleus in some forms.

• Locomotor organelles may be flagella (Euglena), cilia (Paramecium), pseudopodium (Amoeba) or absent in parasitic forms ( contractile myonemes are present in the body).

Protozoa- Features

• Pseudopodia- lobopodia (Amoeba) , filopodia (radiolarians), Rhizopodia ( Elphidium) , Axopodia (Actinophrys)

• Nutrition may be holozoic (Amoeba), holophytic (Euglena) , saprophytic, mixotrophic or parasitic.

• Intracellular type of digestion occurs within the food vacuoles.

• Respiration is performed generally through the body surface, and water regulation of the body is accomplished by contractile vacuole.

• Asexual reproduction occurs by fission or budding. In certain forms sexual reproduction may occur either by conjugation or fusion by gametes.

• In Opalina and Pelomyxa , the peculiar binary fission called Plasmotomy occurs, in which, a multinucleate adult parent undergoes cytokinesis to form multinucleate daughter cells, followed by karyokinesis in each cell.

PROTOZOANS

PHYLUM SARCOMASTIGOPHORA

PHYLUM APICOMPLEXA

PHYLUM MICROSPORA

PHYLUM CILIOPHORA

Barnes, R.D. (1982). Invertebrate Zoology, V Edition

Protozoans

phylum sarcomastigophora

Sub phylum mastigophora

Class phytomastigophora

Class zoomastigophora

Superclass opalinata

Sub phylum sarcodina

Superclass rhizopoda

Class lobosa

Class filosa

Class granuloreticulosa

Superclass actinopoda

Class acantharia

Class polycystina

Class phaeodaria

Class heliozoa

phylum apicomplexa

Class sporozoa

Class piroplasmea

Phylum microspora

Phylum ciliophora

Class kinetofragminophora

Class oligohymenophora

Class polyhymenophora

Barnes, R.D. (1982). Invertebrate Zoology, V Edition

PHYLUM

SARCOMASTIGOPHORA • Largest phylum of Protozoa.

• Cell size between 10- 30 micrometers.

• Locomotory organs- Flagella ( subphylum-

Mastigophora) or pseudopodia (subphylum- sarcodina)

Phylum Sarcomastigophora

Subphylum Mastigophora

Subphylum Sarcodina

Subphylum Mastigophora

Class- Phytomastigophora

Class – Zoomastigophora

Super class- Opalinata

Class Phytomastigophora

• Usually possess chloroplasts.

• They can have one or two flagella.

• The nucleus is vesicular.

• Phytomastigophores are primarily

autotrophic.

• Contains orders like – Euglenida,

volvocida, dinoflagellida.

Ceratium Euglena

Class

Zoomastigophora • No chromoplasts or leucoplasts.

• One to many flagella.

• Often there is an undulating membrane.

• Parasitic, commensals, symbionts.

• contains orders like- kinetoplastida,

diplomonadida, trichomonadida.

Superclass- Opalinata • Body covered with oblique rows of cilia.

• Two or many monomorphic nuclei.

• Binary fission generally symmetrogenic.

• Sexual reproduction involves syngamy with

flagellated gametes.

Subphylum Sarcodina

Super class

Rhizopoda

Class Lobosa

Class Filosa

Class Granuloreticulosa

Super class Actinopoda

Class Acantharia

Class Polycystina

Class Phaeodaria

Class Heliozoa

Sub phylum - Sarcodina • Possess flowing extensions of the body called

pseudopodia.

• Either asymmetrical or spherical.

• Some have a hard shell.

• Presence of flagellated gametes in many

sarcodines.

Super class Rhizopoda Super class Actinopoda

•Lobopodia, filopodia, or reticulopodia are

used for locomotion or feeding.

•They are generally the creeping forms.

•Actinopodia radiating from spherical body

used for locomotion and feeding.

•Primarily floating or sessile sarcodines.

Class lobosa pseudopodia, usually lopopods.rarely filiform or

anstomosing.

There are two sublasses under it- gymnamoeba

and testacoelobosa.

Gymnamoebans like Amoeba, Entamoeba,

Pelomyxa. Lack shells.

Testacoelobosans like Arcella have shells over

body.

Arcella

Class filosa They have tapering and branching

filopodia, rarely anstomising.

This class also includes naked amoebas

(Vampyrella) and shelled amoebas

(Euglypha)

Vampyrella Euglypha

Class granuloreticulosa

they have fine granular reticulose rhizopodia

(reticulopodia).

This class includes and order foraminiferida, example-

Globigerina.

chiefly marine species, they have multichambered shells

and pseudopodia appears from aperture or wall

perforations or both.

Most foraminiferan shells are calcareous, but some are

siliceous, and others are built of sand grains.

Foraminiferans live near the water surface when young,

but gravitate downward with age. When the animals die,

the shells drop to the bottom, forming foraminiferan

ooze.

Limestone used in some Egyptian pyramids contains

skeletons of foraminiferans, especially of nummulites,

which have coin-shaped skeletons.

Super class Actinopoda • The three classes acantharia, polycystina and Phaeodaria

are called as radiolarians.

• Most beautiful protozoans, entirely marine and planktonic.

• Radiolarian skeleton is usually siliceious but acantharian

contain strontium sulphate.

• They sink to the bottom at time of death and form the

radiolarian ooze

CLASS ACANTHARIA Radiolarians with Radiating skeleton of strontium sulfate,

presence of axopodia.

Most without central capsule separating endoplasm and

ectoplasm.

Example- Acanthometra.

Class polycystina

• Radiolarians with silicious skeleton and

perforated capsular membrane.

• Example Collozoum (colonial form)

CLASS PHAEODARIA

• Radiolarians with a siliceous skeleton

but a capsular membrane containing

only three pores.

• Example- Aulocantha.

Aulocantha

CLASS HELIOZOA • Without central capsule. Naked, or if

skeleton present, of siliceous scales and spines.

• Rounded body with radiating axopodia

• Primarily fresh water forms.

• Example- Actinophrys.( sun animalcule)

Phylum apicomplexa

Class

sporozoa

Class

piroplasmea

Phylum apicomplexa • With apical complex at some stage.

• Apical complex is assemblage of cytoskeletal elements and secretory oraganelles.

• Spores usually present but lacking polar filaments.

• All species are parasitic.

Apical complex

Class sporozoa

• reproduction can be sexual and asexual.

• Includes two sub classes gregarina and coccidia.

• In gregarines mature trophozoites are large and occur in host’s gut and body cavities. Includes

parasites of annelids and arthropods. Example- Gregarina, Monocystis.

• Coccidians have mature trophozoites small and intracellular. Example- Eimeria, Plasmodium.

Class piroplasmea • Contains no spores.

• Parasites of vertebrate red blood cells

transmitted by ticks.

• Example- Babesia.

Babesia – life cycle

Phylum microspora

• Spores have presence of polar

filaments.

• All species are parasitic.

• Example- Nosema

Phylum ciliophora

class kinetofragminifora

Class oligohymenophora

Class polyhymenophora

Phylum ciliophora • All possess cilia or compound ciliary structures

as locomotor or food acquiring organelles at some time in the life cycle.

• Most possess a cell mouth, cytostome.

• Presence of two types of nuclei.

• Fission is transverse.

• Sexual reproduction never involves the formation of free gametes.

• Found in freshwater, marine waters and water films of soil.

Class kinetofragminofora

• Isolated kineties in oral region of body

bearing cilia but not compound ciliary

organelles.

• Has subclasses- gymnostomata,

vestibulifera, hypostomata, suctoria.

• Example- Didinium, Balantidium,

Microthorax, Ephelota

Class oligohymenophora • Oral apparatus usually well developed

and containing compound ciliary

organelles.

• Subclasses- hymenostomata and

peritrichia

• Example- Paramecium, Vorticella.

Class polyhymenophora

• Oral region with conspicuous adoral zone of

buccal membranelles.

• Some species with uniform body ciliation, others

with compound organelles, such a cirri.

• Example- Bursaria, Urostyla.

Urostyla