Topic 1: PROTOZOA (Kingdom Protista) B.Sc. Part-I (ZOOLOGY) Paper 1 DIVERSITY AND EVOLUTION OF NON- CHORDATA
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