Kingdom Protoctista

Kingdom Protoctista Includes Protozoa and Algae Some are microscopic, but some can be observed by the unaided eye Some are unicellular organisms, but some are multicellular (i.e. made up of many cells) with a simple body structure They DO have a nucleus and organelles They are very abundant, free living in water or damp environment, or as parasites in other organisms

Protozoa (Singular: Protozoan)

Protozoa “Animal-like” protoctist Found in wide range of habitats such as fresh water, sea water, soil and inside bodies of plants and animals, where moisture is available Usually unicellular Larger in size than bacteria Do not have cell wall

Protozoa Lack chlorophyll – why is this significant? Cannot carry out photosynthesis! Feed on smaller organisms and small food particles Motile – some of them possess flagella (singular: flagellum) or cilia (singular: cilium)

Flagella Cilia

Protozoa Examples of Protozoa: Amoeba Paramecium

Amoeba

Amoeba Acanthamoeba are free-living amoeba commonly found in tap water. It can cause damages to the cornea. Always use sterile solution to clean contact lenses!

Paramecium

Algae (Singular: Alga)

Algae “Plant-like” protoctist Found in sea water and fresh water Can be either unicellular or simple multicellular Each cell is surrounded by a cell wall Possess chloroplasts which contain chlorophyll and other photosynthetic pigments for making their own food by photosynthesis

Some different types of algae

Algae Examples of Algae: Spirogyra Seaweeds

Spirogyra

Seaweeds

Euglena Euglena is a protoctist that shows a mixture of features of protozoa and algae. It contains chlorophyll and carries out photosynthesis, but it also feeds on smaller organisms. It has a flagellum and is able to move about in water.

What is the main difference between prokaryotes and protoctists? Challenge What is the main difference between prokaryotes and protoctists? The presence of a distinct nucleus in protoctists!!!