KINGDOM PROTOCTISTA
Examples include;
- Algae such as spirogyra, Chlamydomonas, euglena, Sargassum
- And protozoa such as amoeba, paramecium and Trypanosoma.
General Characteristics
- They are said to be eukaryotic since their nucleus is bound by a membrane
- Most are mobile, and use flagella, cilia and pseudopodia.
- Some are sessile.
- They reproduce mainly asexually, by binary fission, fragmentation and sporulation.
- Some reproduce sexually by conjugation.
- Some are heterotrophic e.g. paramecium.
- Others are autotrophic e.g. spirogyra.
Economic importance of protoctista
- Algae are the primary producers in aquatic food chains.
- They release a lot of oxygen to the atmosphere.
- Some cause human diseases like malaria and amoebic dysentry ,sleeping sickness
- Some are source of food for humans e.g. sargassum is a source of iodine
- Skeletons of diatoms used in paint making.
Spirogyra:
They have spiral chloroplast. They are green, thread-like filaments
Chlamydomonas:
- This is unicellular green algae and has a cup shaped chloroplast.
- They move towards light using the flagella
- Cilia assist the organism to move.
- The shape is due to the presence of a thin flexible pellicle.