Kingdom Protista “ The Catch-All Kingdom”

Characteristics From the Wordle Most are unicellular, unless they form colonies Almost all protists are microscopic Some have the ability to move independently Protists are named for their mechanism of movement. Cilia, flagella and pseudopods are structures used for movement. 65,000 different species Most heterotrophic, others are autotrophic. Free-living or parasitic All capable of asexual reproduction through binary or multiple fission Some reproduce sexually through conjugation

Asexual vs. Sexual Reproduction

Asexual reproduction Most protists produce asexually. Binary Fission- a single celled protist divides into two cells. The parents DNA is simply copied and the cell divides in half. Each new offspring is identical to the parent.

Sexual reproduction Some protists have the ability to reproduce sexually. Conjugation- two parent cells unite, DNA (micronucleus) is transferred between the two cells. The genetic makeup of the offspring contains DNA from both parent cells. Offspring are genetically diverse.

Paramecium Conjugation http://www.youtube.com/watch?v=Kgey6Qx_-SI&feature=related

How are protists classified? Classification How are protists classified? Two ways Mechanisms of movement Acquisition of food/energy

Mechanisms of Movement Cilia Flagella Pseudopod

Cilia Cilia are tiny hair-like projections. Protists use these for movement Paramecium- cilia line the outside of their plasma membranes.

YouTube Clip of paramecium in action http://www.youtube.com/watch?v=QBcaOYui03s http://www.youtube.com/watch?v=AglfOAwFRhI&feature=related

Flagella or Flagellum Flagella are tail-like projections that are used for locomotion. The euglenoid uses a flagella for movement. Some bacteria also have flagella. The human male gamete has a flagella.

YouTube Clip of Euglena in action http://www.youtube.com/watch?v=0rNI8Bos_BQ

Pseudopods Pseudo= False, Pod= foot  “False-Foot” The amoeba is a protist that uses a pseudopod for locomotion and to engulf its “prey” or food. The pseudopod projects outward in a given direction and the rest of the “body” follow. Cytoplasmic Streaming- the constant movement of the cytoplasm within the cell.

Pseudopods Endo- = in Endocytosis is the process in which a cell brings in material from outside the cell. The cell engulfs the food particle. Exo- = out Exocyctosis is the process in which a cell sends material out of the cell. Eliminating waste products.

YouTube Clip of an Amoeba in action http://www.youtube.com/watch?v=7pR7TNzJ_pA http://www.youtube.com/watch?v=W6rnhiMxtKU

Acquisition of Energy All organisms must obtain energy in order to carryout life’s processes. ATP (Adenosine Triphosphate) is the molecule of energy that all cells need to survive. Heterotrophic Heterotrophs must consume other organisms in order to obtain food to convert to energy Autotrophic Autotrophs are organisms that have the ability to make their own food and then convert it to energy.

4 Phyla of Protozoans Sarcodina Ciliophora Zoomastigina Sporozoa

Sarcodina Include mostly Amoebas The largest phylum of protists Characterized by pseudopods. The largest phylum of protists 11,500 living species 33,000 fossilized species Eat other protists Ecological roles: Most are free-lving Some are parasitic Pathogen- some can cause disease Dysentery Infects the intestinal tract of humans. Symptoms include severe stomach ache, vomiting and diarrhea. Contracted by drinking contaminated water.

Ciliophora Characterized by the presence of cilia. Include the common protists Paramecium Stentor Voticella Ecological roles: Most are free-lving Some are parasitic Most feed on bacteria Pathogen- some can cause disease Bumper Car Disease attacks the blood cells of lobsters. Mostly affects lobsters that are held in captivity for commercial purposes.

Zoomastigina Characterized by their flagella 2,500 species Most free-living Ecological Role Mostly free living Pathogen- disease causing. African trypanosomiasis- species of protist that causes sleeping sickness. The protist is transmitted by the Tsetse Fly. The disease is endemic to the sub-Saharan region of Africa Sypmtoms include high fever, headaches and periods of insomnia. Usually goes undiagnosed until it is too late. Eventually, the victims central nervous system is affected and will lead to coma or deathl. Cause disease – zooflagellates African trypanosomiasis – sleeping sickness – tsetse fly Chagas Disease – kissing bug Leishmaniasis – sand fly giardiasis

Sporozoa Lack locomotor structures Instead they are spore producers. Examples of spores: Lack locomotor structures (NO cilia, flagella, or pseudopod) Instead they are spore producers. Spores are tiny seed-like structures that can remain dormant for years. Then when conditions are optimal they will begin to develop into an adult. 6,000 species Ecological Role Entirely parasitic and are passed on from host to host. Plasmodium malariae- species of sporozoa that cause the disease malaria.

Malaria Symptoms are similar to the flu. Victims suffer from anemia. Characterized by the mass loss of red blood cells. Caused by the protist Plasmodium malariae P, malariae is transmitted to humans by mosquitoes.

Malaria http://www.youtube.com/watch?v=JwsoK8O0lXE

Evolution of Protista Prokaryotes – 3.5 billion years ago Archaebacteria and Eubacteria Eukaryotes – 1.5 billion years ago Protozoan thought to be descendants of the first eukaryotes. Endosymbiotic Theory Explains how eukaryotic cells evolved from prokaryotic cells.

Endosymbiotic Theory