13.1 – Kingdom Protista

Kingdom Protista Characteristics: Eukaryotes Unicellular and multicellular organisms Considered “left-overs” of organisms: Consist of eukaryotic organisms that do not fit into Kingdom Fungi, Animalia or Plantae Protists are not animals, plants or fungi

Classification Kingdom Protista consists of diverse species that share similarities with other 3 kingdoms but do not meet all the requirements to fit into those kingdoms Classifying protists is extremely difficult as there is more than 1 accepted way of separating them General method is classifying protists by their nutritional patterns: Animal-like protists Plant-like protists Fungi-like protists

Animal-like Protists Referred to as protozoans Protozoans are Unicellular organisms Heterotrophs - they eat or ingest materials from their surroundings Protozoans are not categorized into a taxonomic group. This is a term used to describe animal-like protists that may be distantly related but share a set of characteristics.

Types of Protozoans Protozoans are described and grouped according to their method of movement. Heterotrophs – ingest small food particles and digest it inside food vacuoles containing digestive enzymes Do not have a cell wall 4 ways to describe a protozoan: Zooflagellate Amoeba Ciliate Sporozoan

Zooflagellates Possess 1 or more whip-like structures called flagella Flagella help with movement of the protist in water

Ciliates Ciliates are aquatic protists covered with cilia Cilia – hair-like projections that assist protists with movement in water and with gathering food Watch video: http://www.youtube.com/watch?v=Paed6uTdpQA

Amoeba No particular body shape Create pseudopods – temporary projections of cytoplasm Pseudopods help protist to move and feed on other organisms Intake food through process of endocytosis – engulf organism and form food vacuole Watch Amoeba Video: http://www.youtube.com/watch?v=W6rnhiMxtKU&feature=related

Sporozoans Non-motile protists Produce spores during reproduction

Plant-like Protists Plant-like protists are those that resemble plants because they are photoautotrophs. They contain chlorophyll and carry out photosynthesis Unicellular or multicellular protists Some plant-like protists have cell walls made up of polysaccharides and others do not have cell walls Types: Euglenoids Algae

Euglenoid Unicellular Contains flagella for movement Photoautotroph during the day – undergoes photosynthesis Heterotroph at night – feeds on dead organisms Question: Why can euglenoids not be classified in Kingdom Plantae?

Algae Unicellular or multicellular Photoautotrophs – have chloroplast and carry out photosynthesis 6 different groups of algae Question: Since most algae are aquatic, provide a reason why algae are “plant-like” and not plants?

Reproduction Asexual Reproduction Sexual Reproduction Animal-like and plant-like protists can reproduce sexually and asexually. Asexual Reproduction Protists reproduce by binary fission. 1 parent cell divides to produce 2 identical daughter cells Sexual Reproduction Other protists can reproduce by conjugation. Mates exhange DNA.

Reproduction Binary Fission Conjugation

Conjugation Question: As a eukaryotic cell, how would conjugation be more challenging vs prokaryotic cells undergoing conjugation?

Protists in our Everyday Lives Parasitic protists can cause diseases when it they come into contact with the human body Example: malaria, sleeping sickness, dysentery Algae Food indusry Seaweed can be eaten. Example: sushi Used as food additives in the manufacturing of food products. Example: beta-carotene Medicine Used for curing arthritis, influenza, tuberculosis