Kingdom Protozoa2
Protists
Defining Characteristics– All are unicellular eukaryotes– What is a prokaryote?– Many species are both heterotrophic and
autotrophic simultaneously or at different stages of the lifecycle
Kingdom Protozoa5
Adaptability
Protozoans are ecologically important primary producers, consumers and as vital links in the food chain
Humans are greatly effected by parasitic protozoans either directly or indirectly – Effects range from irritating - fatal
Malaria (Plasmodium spp.) worldwide epidemic
Kingdom Protozoa6
Reproduction
Asexual reproduction – Replication of chromosomes and the splitting of the parent into
two or more parts – Binary fission – Multiple fission – Budding
Protozoans are problematic in their associations as colonial forms
– Through asexual reproduction protozoans are identical and could be considered multicellular
Kingdom Protozoa8
Classification
Alveolate Protozoans
Phylum Ciliophora
Phylum Dinozoa
Phylum Apicomplexa
Amoeboid Protozoans
The Rhizaria
Phylum Foraminifera
Phylum Radiozoa
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Phylum Ciliophora
Defining characteristics– Body externally ciliated in at
least some lifecycle stages
Have the highest degree of subcellular specialization and are considered advanced protozoans
Paramecium feces
Kingdom Protozoa10
Cilia
Cilia – Hair-like structures by which the organism moves,
collects food and senses their surroundings
Fastest of all the protozoans
Kingdom Protozoa14
Ciliate Lifestyles
65% of all ciliate species are free-living and mobile
Some ciliates form colonial aggregations and have sessile habits
Other ciliates have symbiotic relationships in invertebrates and vertebrates
Vorticella
Kingdom Protozoa15
Dinoflagellates (Phylum Dinozoa)
Know for bioluminescence and highly toxic red tides – Dense aggregations produce saxitoxin killing fish and
crustaceans Also contaminates shellfish causing diarrheic
shellfish poisoning Some benthic dinoflagellates produce a
neurotoxin that accumulates in tropical fish called Ciguatera
Kingdom Protozoa16
Phylum Apicomplexa (Sporozoa)
All members of this phylum are endoparasites– Includes Malaria (Plasmodium)– Toxoplasma gondii– Perkinsus spp.– Pneumocystis carinii
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Amoeboid Protozoans
Contains 56,000 described species 44,000 are only known as fossils
Most reproduce asexually through binary fission
Characterized by pseudopodia
Food is usually captured by phagocytosis
Body types range from free flowing to rigid with skeletal supports
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Class Foraminifera (Rhizaria)
Defining characteristics– Individuals secrete
multi-chambered tests, generally made of calcium carbonate (CaCo3)
Foram. tests
Kingdom Protozoa22
Foraminiferans
Extremely abundant, most are benthic and marine
Feed on diatoms and algae, very slow movers Organisms are extremely common and form
ooze– White cliffs of Dover are foraminiferan tests
Kingdom Protozoa24
Phylum Radiozoa (Rhizaria)
Defining characteristics– Body is divided into distinct
zones separated by a perforated membrane or capsule
Have pseudopodia supported with thin microtubules that give a spiny rayed appearance
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Radiolarians
Have shells made of silicon dioxide that can be very intricate
Feed on diatoms and other phytoplankton – Most species are planktonic
Benthic individuals move by use of pseudopodia – Can occur in large concentrations that form
ooze as well
Kingdom Protozoa27
Phytoflagellated Protozoans
Have chlorophyll and obtain energy directly from the sunlight
Some are strictly autotrophic or heterotrophic– Some are a combination of both
Both the Euglena and the dinoflagellates are examples of phytoflagellated protozoans