The Protozoans

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The Protozoans

• Ciliates
• Amoeboid Protozoans
• Flagellated Protozoans

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Kingdom Protozoa

• 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

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Eukaryote Cell
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Prokaryote Cell
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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

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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

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Asexual Reproduction
Amoeba
Ciliate
Flagellate
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Classification

• Kingdom Protozoa
• Phylum Ciliophora (Ciliates)
• The Sarcodinids (Amoeboid Protozoans)
• Phylum Foraminifera
• Phylum Radiozoa
• The Flagellated Protozoans
• Phytoflagellated protozoans
• Zooflagellated protozoans

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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

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Cilia

• Cilia
• Hair-like structures by which the organism moves,
  collects food and senses their surroundings
• Fastest of all the protozoans

Cilia structure
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Ciliate Biology

• Oral groove
• Cytostome
• Cytoproct
• Contractile vacuole

Paramecium
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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
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The Sarcodinids (Amoeboid Protozoans)

• Contains 4 phyla Foraminifera, Radiozoa,
  Amoebozoa, and Heliozoa
• 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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Phagocytosis
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Amebas and Humans
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Phylum Foraminifera

• Defining characteristics
• Individuals secrete multi-chambered tests,
  generally made of calcium carbonate (CaCo3)

Foram. tests
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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

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Phylum Radiozoa

• 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
• Benthic individuals move by use of pseudopodia
• Can occur in large concentrations that form ooze
  as well

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The Flagellated Protozoans

• Characterized by the possession of a definite
  body shape and the possession of one or more
  flagella
• Most species are free-living and mobile

Noctiluca
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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

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Dinoflagellates

• 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

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Phytoflagellated Protozoans
Euglena
Chlamydomonas
Noctiluca
Ceratium
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Zooflagellated Protozoans

• Free-living forms
• Most individuals are sessile and have a single
  flagellum that beats to obtain food and nutrients
  
• Parasitic forms
• 25 of zooflagellate spp. are parasitic in
  humans, invertebrates, and other vertebrates
• Usually have complex lifecycles with intermediate
  hosts
• Malaria is caused by the genus Plasmodium
  technically a member of the phylum Sporozoa

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Zooflagellated Protozoans
Choanoflagellates
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Malaria (Plasmodium)