Kingdom protista (Dianoflagellates )

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Dianoflagellates




  • They are protists  with two flagella that's why they are called dianoflagellates 
  • They are neither plant nor animal-like protist 
  • They contain chlorophyll/ carotene/ several groups of Xanthophylls 
  • complex cell covering, cortex is present 
  • Light sensitive organelle, eye spot is found in some of them
  • Erythropsidium :-smallest known eye
  • Habitat :-aquatic (can be fresh water / marine )
  • Nutrition - photosynthetic, ingestion of prey through Oodinium, Notiluca
  • Reproduction :-fission (asexual )
  • Sexual mode is seen only in some of them 

Red tide


  • They are also known as algal bloom 
  • The coloration of the sea into red is due to rapid multiplication of the red dianoflagellates, gonyaulux, is termed red tide

  • Chemicals released during this processs is extremely harmful for the survival of other aquatic life

Euglenoids


  • They share characteristics of both plants and animals 
  • They have a shape changing motion  - metaboly
  • Cell wall is not present 
  • Flexible body due to protein rich layer Pellicle
  • 2 flagella are  present
  • Chlorophyll is present 
  • Aquatic habitat
  • Mostly in stagnant fresh water
  • Photosynthetic in presence of light
  • Heterotrophic in absence of light 
  • Mostly asexual 

Slime moulds




  • They are saprophytic protists
  • Fungus like protists
  • Made up of individuals cells that form an aggregate
  • Habitat - soils, lawns, forest floors
  • Prefer moist decaying habits
  • Extremely resistant, can survive under adverse conditions
  • Heterotrophic, feed on bacteria, yeast, fungi, amoeba-like food ingestion




Protozoans


  •  Animal like protists
  • No cell walls
  • Aquatic/ moist habitats
  • Heterotrophic
  • Can be parasitic or predators
  • Holozoic animal like nutrition
  • Asexual and sexual both

Protozoans group

  1. Amoeboid protozoans
  2. Flagellated  protozoans
  3. Ciliated protozoans
  4. Sporozoans protozoans

Amoeboid protozoans

  • Resemble amoeba in presence of  Pseudopodia (false feet )
  • Some are predators with amoeba-like injestion of prey
  • pseudopodia- false feet 
  • Temporary extension of cytoplasm 
  • Helps in locomotion as well as feeding 
  • Some are parasites 
  • Entamoeba hystolytica  causes Amoebiasis

Flagellated protozoans

  • Protozoans with flagella
  • Can be free living or parasitic
  • Trypanosoma gambiense : sleeping sickness

Ciliated protozoans 

  • Protozoans with hair like structure arising from the surface of a cell called cilia
  • Cilia are capable of rhythmic motion
  • Multiple short cilia exist 
  • E,g Paramecium

Sporozoans

  • Non-motile protozoan 
  • Mostly parasitic
  • Reproduction by spore formation
  • E,x  plasmodium causing malaria

Importance of protists

  • Source of food for many life forms 
  • Medical research 
  • Valuable in industry 

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