Kingdom Protista

Introduction to the Kingdom Protista. Main characteristics, classification and different types of protists. Translation revision by Steven T. Gosch.

1. Pablo León Cruz www.biogeosfera.es KINGDOM PROTISTA

2. Protists Main characteristics of protists Eukaryotic organisms. Can be unicellular or multicellular. Very small, usually microscopic. Very simple structure: they have no organs or tissues. This kingdom includes eukaryotic living beings that, due to their characteristics, cannot be included in the other kingdoms, since they are not fungi, plants, or animals. There are two large groups: algae and protozoa.

3. Classification of the protists Algae Eukaryotic organisms. Can be unicellular or multicellular. Unicellular algae are microscopic in size, whereas multicellular can be several meters long. All algae live in aquatic environments. The vast majority float on water and are part of the plankton. Nutrition : Autotrophic. Interaction : Free-living, sometimes form colonies. Reproduction : Can be asexual by bipartition in unicellular organisms or by fragmentation in multicellular organisms but can also be sexual. They are classified into green algae, brown algae and red algae.

4. Classification of the protists Algae classification Unicellular algae: Can live freely, like Euglena , or form colonies, like Volvox. Multicellular algae: Classified by the pigments they use for photosynthesis . Green algae or chlorophytes : Pigment is chlorophyll. Almost all are found in freshwater areas, although there are some marine algae. Brown algae or pheophytes : Pigment is fucoxanthin. Form marine forests in the oceans of temperate and arctic areas. Red algae or rhodophytes : Main pigment is phycoerythrin. Inhabit marine ecosystems located in tropical regions.

5. Classification of the protists Green algae

6. Classification of the protists Brown algae

7. Classification of the protists Red algae

8. Classification of the protists Protozoa Eukaryotic organisms. All are unicellular. All are microscopic. All protozoa live in aquatic environments. Move using cilia, flagella or pseudopods. Some are sessile. Nutrition : Heterotrophic organisms. Interaction : Most are free-living, though some are parasitic. Reproduction : Usually asexual by bipartition. Classified as flagellated, ciliated, rhizopods or sporozoans.

9. Classification of the protists Classification of protozoa Flagellated : Have one or more flagella for movement and can be parasitic or free-living. An example is Trypanosoma . Ciliated : Have cilia with which they can move and can be parasitic or free-living. An example is Paramecium . Rhizopods : Move through pseudopods and can be parasitic or free-living. An example is Amoeba . Sporozoans : No structures for movement and are parasitic. An example is Plasmodium .

10. Classification of the protists Different types of protozoa

11. Importance of protists Protists are important for the following reasons Algae are part of the phytoplankton, which is the set of producer organisms in aquatic ecosystems . Certain species of algae have high culinary value and are used in human food, especially oriental cuisine . Agar, a substance used in microbiology, the preparation of medicines, perfumes and certain foods such as soup and ice cream, comes from the cell wall of some algae. Protozoa are part of the zooplankton, a set of microscopic organisms that feed many small fish . Many protozoa have an important role in the decomposition of organic matter in very humid soils or stagnant water . Parasitic protozoa can seriously damage the health of humans. This is the case for dysentery, malaria and sleeping sickness .