Kingdom Protista Objectives: Describe the main characteristics of the Protista Kingdom How are Protists classified and want are the characteristics of each group. Explain how complex eukaryote cells are thought to have evolved from much simpler prokaryotic cells?

The Kingdom Protista composed of microscopic and macroscopic organisms of various types these organisms are classified together mostly because they do not fit into other kingdoms the phyla are not closely related protists are less diverse than bacteria or archaea, but are more diverse than the other eukaryotic kingdoms

Main Characteristics eukaryotic (like plants, animals and fungi) can be autotrophic or heterotrophic; most are aerobic most are single celled, but not all are

Classification Three main groups: Protozoa – animal-like Algae – plant-like Slime Moulds – fungus-like and Water Moulds

Protozoa Animalia Protozoa the protozoa should belong in the Animal Kingdom except for one reason: they are unicellular Animalia Eukaryotic Heterotrophic No cell wall Reproduce sexually/asexually Terrestrial and aquatic Multicellular Protozoa Eukaryotic Heterotrophic No cell wall Reproduce asexually/sexually Aquatic only – water, body fluids, moist areas Unicellular

Protozoa the protozoa obtain their food as scavengers, as predators (engulfing bacteria through endocytosis), or as parasites living in larger organisms most are motile – classification based on method of locomotion (except Sporozoans) there are 4 major phyla Sarcodines (use pseudopods) Ciliates (use cillia) Flagellates (use flagella) Sporozoans (parasites)

Protozoa Sarcodines (aka amoeba) – produce limb- like extensions of the cytoplasm called pseudopodia to move and engulf prey Ciliates – covered in cilia that have a coordinated beat to enable organism to move Flagellates – have one or more whip-like flagella that enable movement Sporozoans (parasites) – produce spores

Protozoa Many of the protozoans are parasitic, many of which prey on humans Malaria: Plasmodium sp. Amoebic Dysentry: Entamoeba hystolytica Beaver Fever: Giardia lamblia

Algae the algae should belong in the Plant Kingdom except for, lots of reasons: Plantae Eukaryotic Autotrophic Terrestrial (and aquatic) Cellulose cell wall Multicellular Reproduce sexually/asexually Algae Eukaryotic Autotrophic (wee bit of hetero) Exclusively aquatic Cellulose cell wall with gel-like substance thrown in Multicellular/Unicellular Reproduce asexually/ “sexually” – no embryo Some are motile

Algae Six phyla based partly on the types of chloroplasts and pigments Dinoflagellates – unicellular Euglenoids – unicellular Diatoms – unicellular Red Algae – multicellular Brown Algae - multicellular Green Algae – multicellular (mostly)

Algae Brown Algae Red Algae Euglenoids Dinoflagellates Bioluminescence Green Algae

Slime Moulds and Water Moulds Very difficult to classify: Produce spores like fungi Have cellulose cell walls like plants Some can move and ingest food like protozoans

Water Moulds must be wet (soil is wet) officially named Oomycota, but known as downy mildews and white rusts Phytophthora infestans caused the Great Potato Famine that killed nearly a million people in Ireland in 1846–1847 Plasmopara viticol almost wiped out the French wine industry in the 1870s it was brought to Europe from America to use as a natural insecticide for aphids this infestation led to the use of the first fungicide 

Slime Moulds Professor John Tyler Bonner: slime moulds are "no more than a bag of amoeba encased in a thin slime sheath, yet they manage to have various behaviours that are equal to those of animals who possess muscles and nerves with ganglia – that is, simple brains." basically, it is like a group of amoeba living together as opposed to the cellular structure of the true fungi

Slime Moulds Two groups: Cellular slime moulds (Ascrasiomycota) Plasmodial slime moulds (Myxomycota)

Slime Molds Dog Vomit SM SM growing on grass but not eating it Chocolate Tube SM

Evolution... it has been hypothesized that protists evolved from ancient prokaryotes more than 1 bya fungi, plants and animals then evolved from protists hundreds of millions of years ago however, even protists in the same phyla can be completely unrelated so… ?

Origin of Eukaryotes How did complex eukaryote cells evolve from much simpler prokaryotic cells? possible theory - Endosymbiosis