The Protist Kingdom - A Diverse Classification of Organisms

4. Protista Kingdom • The Protist Kingdom is known as the "catch all" Kingdom; they are the organisms that don’t really fit in with any other Kingdom. Since there are such a wide variety of protists they are arranged into three groups. The three groups are arranged depending on whether they have animal-like characteristics, fungus-like characteristics, or plant-like characteristics. Therefore the three groups of protists are: Animal-like protists, Fungus-like protists, and Plant-like protists.

5. Protista Kingdom • At least a billion years before there were plants, animals or fungi, there were protists. Protists can be found almost anywhere there is water. The communities of organisms, mostly microscopic, that swims passively and weakly in the surface of oceans, ponds, and lakes. Many can also be found in damp soil, leaf litter, and other moist habitats.

6. Majorcharacteristics of Protists • Single celled protozoan & Multicellular algae. • Some are predators and resemble animals. • Some are autotrophic / heterotrophic & both • All protists are eukaryotic -have membrane bound organelles – have a nucleus. • Protists are classified by the way they obtain energy &move. • Biologists identified about 65,000 different types of protozoa,

7. Major Characteristics • Many species are free living while others are parasites. • Wide variety of sizes and shapes • Deceiving in their simplicity • Contractile vacuoles – specialized organelles that allow protists to pump out excess water and extract waste

8. Importance of Protists • Protists are extremely important in ecological and medical research. In medicine, certain protists are used to study the relationship between chromosomal structure and aging. Multicellular protists (made up of lots of cells) such as slime molds provide valuable insight about the chemical signals used in more complex organisms to coordinate cellular activity.

10. Amoeba Euglena Paramecium

11. Animal - Like • Animal-like protists are called protozoans ("first animals") because it is thought that they are the evolutionary history of animals. They share many common traits with animals. All of the animal-like protistsare heterotrophs; they are unable to make their own food. But unlike animals, they are unicellular. Since they can’t make their own food they must be able to move through their environment and catch their food. •     The animal-like protists are divided into four groupsbased upon their means of mobility and manners for catching their food. They are divided into: protists with pseudopods, protists with cilia, protists with flagella, and parasitic protists.

12. General Movement • Ciliate – paramecium – cilia (short hair like fibers) • Sarcodine – ameoba – pseudopodia (false feet) • Flagellates – Euglena – flagella (long whip like fiber) • Sporozoans – no method on their own – pathogens –

13. Pseudopodia – extention’s of protozaoa’s plasma membrane, which function in getting food and in locomotion

14. Animal – like Ameoba Paramecium

15. Sporozoansanimal - like • All are pathogenic • No method of movement on their own • Carry out both sexual or asexual reproduction • A reproductive cell that can produce new organsims w/o fertilization is a spore

17. Plant-Like Protists Plant-like protists are autotrophic; they can make their own foods. They live in soil, on the barks of trees, in fresh water, and in salt water. Plant-like protists are very important to the earth because they produce an abundant amount of oxygen. They are the basis for the aquatic food chain.     These protists are similar to plants. Most are photosynthetic. Some have stem-like structures called stipes and anchoring structures called holdfasts, while plants have actual stems and roots. Plant-like can be multicellular or unicellular and some unicellular will form colonies (a group of cells that live together in close association)

18. Plant-Like Protists Many of these protists release their eggs into the environment where the sperm will fertilize the egg. Plants on the other hand will retain the egg in the "parent" plant where it will fertilize. Fragmentation may occur – a kind of reproduction that occurs when an individual breaks up into pieces, each of which grows by mitosis into a new individual Some examples of plant-like protists are: Euglenoids, Dinoflagellates, Chrysophytes, Green Algae, Red Algae, and Brown Algae.

19. Plant-Like ProtistsAlternation of GenerationsAlgae • Life cycle of organisms that have a haploid stage followed by a diploid stage • Haploid stage forms gametes (sperm/egg) • Diploid form of alga developed from the zygote • Zygote to Sporophyte stage is diploid • Meiosis – occurs when the spores form • Mitosis –occurs when there is cellular growth • Book pg 516

20. Plant-Like Protists Brown Algae Euglena Green Algae

21. Dinoflagellates • Dinoflagellates are plant-like protists found in salt water. They are unicellular and have flagella to help them move through the water. The Dinoflagellates are capable of glowing in the dark. They are the cause of Red Tide, when there is an outburst in population and in turn water becomes red/brown in color. •     The Dinoflagellates can produce toxins. If a human eats seafood contaminated with the toxins he/she will have memory loss and other impaired brain functions. •     One dinoflagellate that has gotten out of control is Pfiesteria.  Pfiesteria grows in fertilizer and raw sewage. It has killed a billion fish along the costs of North Carolina, Maryland, and Virginia since 1991.

22. Dinoflagellates(red tide)

23. Fungus-like Protists • Fungus-like protists are heterotrophic, they cannot make their own food, and thus they must be able to move at some point in their lives. These protists contain long hyphae-like strands thus they contain the physical appearance of fungi. The difference lies in that the hyphae of fungi are white while the hyphae of protists are usually bright in color. •     The fungus-like protists can act as decomposers. They break down dead organisms by releasing digestive enzymes into the dead organism. In the end materials useful to other living organisms are released into the surrounding environment.

24. Fungus-like Protists • A fungus-like protist decomposes organic matters and may resemble many types of real fungi. They are broken down into groups of water molds and slime molds. • Two examples of the fungus-like protists are water molds and slime molds. • In slime molds, the plasmodium is a mass of cytoplasm that contains many diploid nuclei but no cell walls or membranes

25. Water Mold Slime mold Slime Mold Slime Mold