Protozoa Over all View.
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Transcript of Protozoa Over all View.
ProtozoaOver all View
By
–V.PARTHASARATHY–Lecturer in Zoology–Vivekananda College,–Tiruvedakam West
Characteristics of Protozoa
• Unicellular OrganizationUnicellular Organization – Since Protozoa are single celled they often rely on other
organisms for some necessities
• ReproductionReproduction::– Asexual:
1. binary fission: cytoplasmic division follows mitosis, producing two organisms
2. budding: 3. multiple fission or schizogeny: cell or organism is split into many
new cells or organisms
– Sexual
Reproduction
Symbiosis: an intimate association between two organisms
Three types of symbiosis:1. Parasitism: one organism lives in or on a
second organism, called the host. – the host is harmed, but usually survives
2. Commensalism: one organism benefits and the other neither benefits nor is harmed
3. Mutualism: both organisms benefit from the relationship
Protozoan Taxonomy
Phylum Sarcomastigophora Subphylum
Mastigophora Subphylum Sarcodina
Phylum Apicomplexa Phylum Ciliophora
SARCOMASTIGOPHORA
Phylum Sarcomastigophora: 18,000 species, largest protozoan phylum
Characteristics:1. Unicellular or Colonial2. Locomotion by flagella, pseudopodia, or
both3. Autotrophic, saprozoic, or heterotrophic4. Single type of Nucleus5. Sexual Reproduction (usually)
LOCOMOTION
Subphylum Mastigophora: locomotion by one or more flagella
Subphylum Sarcodina: locomotion and food gathered by pseudopodia (false foot)
- includes the Amoeba
Pseudopodia- temporary cell extension used for movement and
gathering foodTypes:1. Lobopodia: broad extensions used for locomotion
and engulfing food2. Filopodia: provide constant two-way streaming that
delivers food in a conveyor belt fashion 3. Reticulopodia: similar to filopodia, except they
extend out and form net-like series of extensions4. Axopodia: thin, filamentous and supported by a
central axis of microtubules
The AMOEBA
APICOMPLEXA
Phylum Apicomplexa:
Characterisitics:1. All are parasites2. Apical Complex for penetrating host cells3. Single type of Nucleus4. Usually No Cilia and Flagella5. Life cycles that typically include asexual
and sexual phases
Malaria caused by Plasmodium
Phylum Ciliophora: Characteristics:1. Cilia for locomotion and for the
generation of feeding currents of water.2. Relatively rigid pellicle and more or less
fixed shape3. Distinct cytostome (mouth) Structure4. Dimorphic nuclei, typically larger
macronuclei and one more smaller micronuclei
Ciliophora
Locomotion: cilia• Cilia are generally similar to flagella but are
much shorter, more numerous and widely distributed over the surface of the organism– cilia have evolved into more specialized structures
Trichocysts: used for protection, rodlike or oval structures that can be discharged and stuck to predators
Trichocysts
Body types
Nutrition: • some ciliates possess an oral groove
• cilia sweep food particles down this groove toward the cytopharynx where a food vacuole forms
• some ciliates even possess an anal pore which is used to remove waste from the organism
Genetic Control and Reproduction:
Ciliate have two kinds of Nuclei1. Macronuclei: large polyploid nucleus that
regulates daily metabolic activities2. Micronuclei: one or more small nucleus
which are genetic reserve of the cell
• Ciliates can reproduce asexually by transverse binary fission and occasionally by budding
• Ciliates can reproduce sexually by conjugation
Conjugation:1. Random contact brings individuals of opposite
mating types together (called conjugants)2. Meiosis results in four haploid pronuclei3. Three pronuclei and the macronucleus degenerate.
Mitosis and mutual exchange of pronuclei is followed by fusion of the pronuclei.
4. Conjugants separate. Nuclear divisions that restore nuclear characteristics of species follow. Cytoplasmic divisions may accompany these events
Conjugation