Characteristics and Classification of Protists

1. Chapter 25 Protists Table of Contents Section 1 Characteristics of Protists Section 2 Animal-like Protists Section 3 Plantlike and Funguslike Protists Section 4 Protists and Humans

2. Section 1 Characteristics of Protists Chapter 25 Objectives • Define protist. • Describe a hypothesis for the origin of eukaryotic cells. • Explain how protists are classified. • Describe the two major ways by which protists obtain energy. • List three structures protists use for movement. • Describe how protists reproduce.

3. Section 1 Characteristics of Protists Chapter 25 A Diverse Group of Eukaryotes • Protists are unicellular or simple multicellular eukaryotic organisms that are not plants, fungi, or animals.

4. Section 1 Characteristics of Protists Chapter 25 Characteristics of Protists Click below to watch the Visual Concept. Visual Concept

5. Section 1 Characteristics of Protists Chapter 25 A Diverse Group of Eukaryotes, continued • The First Eukaryotes • Evidence suggests that the first protists arose from endosymbiotic prokaryotes.

6. Section 1 Characteristics of Protists Chapter 25 Origin of Eukaryotic Cells Click below to watch the Visual Concept. Visual Concept

7. Section 1 Characteristics of Protists Chapter 25 Classification • Protists are classified by the characteristics that make them fungus-like, plant-like, or animal-like.

8. Section 1 Characteristics of Protists Chapter 25 Characteristics • Unicellular and Multicellular • Most protists are unicellular, but some form large, multicellular bodies.

9. Section 1 Characteristics of Protists Chapter 25 Comparing Organisms that are Unicellular and Multicellular Click below to watch the Visual Concept. Visual Concept

10. Section 1 Characteristics of Protists Chapter 25 Characteristics, continued • Nutrition • Many protists are autotrophs, organisms that make their own food. • Other protists are heterotrophs, organisms that must get their food by eating other organisms or their byproducts.

11. Section 1 Characteristics of Protists Chapter 25 Characteristics,continued • Motility • Protists use flagella, cilia, or pseudopodia for locomotion.

12. Section 1 Characteristics of Protists Chapter 25 Reproduction • Protists reproduce either asexually, sexually, or both. • They reproduce asexually by binary fission or multiple fission. • They often reproduce sexually by conjugation.

13. Section 2 Animal-like Protists Chapter 25 Objectives • Discussthe key characteristics of Protozoa, Ciliophora, Sarcomastigophora, and Apicomplexa. • Describehow protozoa use pseudopodia to move and to capture food. • Explainhow ciliates move and reproduce. • Describehow mastigophorans move and capture food. • Describethe role of apicomplexans in disease.

14. Section 2 Animal-like Protists Chapter 25 Phylum Protozoa • Animal-like protists can be found in the phylum Protozoa. • Protozoa use large, rounded, cytoplasmic extensions called pseudopodia forboth movement and feeding.

15. Section 2 Animal-like Protists Chapter 25 Phylum Protozoa, continued • Protozoan Diversity • Protozoans include organisms that inhabit the oceans, lakes, soil and even the human intestines.

16. Section 2 Animal-like Protists Chapter 25 Phylum Ciliophora • Animal-like protists include the phylumCiliophora. • Ciliates move using cilia, which are short, hairlike, cytoplasmic projections that line the cell membrane.

17. Section 2 Animal-like Protists Chapter 25 Phylum Ciliophora, continued • Characteristics • Ciliates have the most elaborate organelles, including two types of nuclei.

18. Section 2 Animal-like Protists Chapter 25 Feeding Habits of a Ciliate Click below to watch the Visual Concept. Visual Concept

19. Section 2 Animal-like Protists Chapter 25 Phylum Ciliophora, continued • Reproduction • Ciliates reproduce asexually by binary fission and sexually by conjugation.

20. Section 2 Animal-like Protists Chapter 25 Phylum Sarcomastigophora • Animal-like protists include the phyla Protozoa,Sarcomastigophora. • For locomotion, sarcomastigophorans use flagella.

21. Section 2 Animal-like Protists Chapter 25 Phylum Apicomplexa • Animal-like protists include the phylaApicomplexa. • These protists are animal parasites.

22. Section 2 Animal-like Protists Chapter 25 Types of Animal-like Protists Click below to watch the Visual Concept. Visual Concept

23. Section 3 Plantlike and Funguslike Protists Chapter 25 Objectives • Describefour main body forms of algae. • List the common name for each of the seven phyla of plantlike protists. • Explainhow green algae and plants are similar. • Describefour phyla of funguslike protists. • Compareplasmodial slime molds, cellular slime molds, and water molds.

24. Section 3 Plantlike and Funguslike Protists Chapter 25 Characteristics of Algae • Algae can be unicellular, colonial, filamentous, or multicellular. • Seven phyla of plantlike protists are Chlorophyta, Phaeophyta, Rhodophyta, Bacillariophyta, Dinoflagellata, Chrysophyta, and Euglenophyta.

25. Section 3 Plantlike and Funguslike Protists Chapter 25 Plantlike Protists • Phylum Chlorophyta (Green Algae) • The phylum Chlorophyta contains more than 17,000 identified species of protists called green algae. • Both green algae and plants have chlorophylls and accessory pigments, store food as starch, and have cell walls made up of cellulose.

26. Section 3 Plantlike and Funguslike Protists Chapter 25 Plantlike Protists, continued • Phylum Phaeophyta (Brown Algae) • The phylum Phaeophyta includes approximately 1,500 species of multicellular organisms called brown algae. • Brown algae are mostly marine organisms, and they include plantlike seaweeds and kelps.

27. Section 3 Plantlike and Funguslike Protists Chapter 25 Plantlike Protists, continued • Phylum Rhodophyta (Red Algae) • The 4,000 species in the phylum Rhodophyta are known as red algae. • A few species of red algae live in fresh water or on land, but most red algae are marine seaweeds.

28. Section 3 Plantlike and Funguslike Protists Chapter 25 Plantlike Protists, continued • Phylum Bacillariophyta (Diatoms) • The phylum Bacillariophyta contains as many as 100,000 species of unicellular protists called diatoms.

29. Section 3 Plantlike and Funguslike Protists Chapter 25 Plantlike Protists, continued • Phylum Dinoflagellata (Dinoflagellates) • More than 2,000 species of organisms called dinoflagellates make up the phylum Dinoflagellata. • Some species of dinoflagellates, such as those in genus Noctiluca, can produce bioluminescence, a display of sparkling light often seen in ocean water at night.

30. Section 3 Plantlike and Funguslike Protists Chapter 25 Plantlike Protists, continued • Phylum Chrysophyta (Golden Algae) • The phylum Chrysophyta contains about 1,000 species of golden algae. Most golden algae live in fresh water, but a few species are found in marine environments.

31. Section 3 Plantlike and Funguslike Protists Chapter 25 Plantlike Protists, continued • Phylum Euglenophyta (Euglenoids) • The phylum Euglenophyta contains about 1,000 species of flagellated unicellular algae called euglenoids. • Euglenoids are both plantlike and animal-like. Many are autotrophic, like plants, but they lack a cell wall and are highly motile, like animals.

32. Section 3 Plantlike and Funguslike Protists Chapter 25 Structure of Euglena

33. Section 3 Plantlike and Funguslike Protists Chapter 25 Funguslike Protists • Biologists recognize two groups of funguslike protists: slime molds and water molds.

34. Section 3 Plantlike and Funguslike Protists Chapter 25 Funguslike Protists, continued • Phylum Myxomycota (Plasmodial Slime Molds) • Plasmodial slime moldsare multinucleate. • As the plasmodium creeps along the forest floor by cytoplasmic streaming, it consumes decaying leaves and other debris by phagocytosis.

35. Section 3 Plantlike and Funguslike Protists Chapter 25 Funguslike Protists, continued • Phylum Dictyostelida (Cellular Slime Mold) • Cellular slime moldslive as individual haploid cells that move about like amoebas. • Each cell moves as an independent organism, creeping over the ground or swimming in fresh water and ingesting food.

36. Section 3 Plantlike and Funguslike Protists Chapter 25 Funguslike Protists, continued • Phylum Oomycota (Water Molds) • Water molds are composed of branching filaments and many of this phylum are parasitic.

37. Section 3 Plantlike and Funguslike Protists Chapter 25 Funguslike Protists, continued • Phylum Chytridiomycota (Water Molds) • Members of phylum Chytridiomycota, or the chytrids, are primarily aquatic protists characterized by gametes and zoospores with a single, posterior flagellum.

38. Section 4 Protists and Humans Chapter 25 Objectives • Statefour environmental roles of protists. • Describealgal blooms and red tides and their impact. • Statean important role for protists in research. • Lista use of protists as food and three uses of protist byproducts. • Describefour protist-caused diseases.

39. Section 4 Protists and Humans Chapter 25 Protists in the Environment • Protists produce large amounts of oxygen, form the foundation of food webs, recycle materials, and play a role in several symbiotic relationships.

40. Section 4 Protists and Humans Chapter 25 Protists in the Environment, continued • Ecology of Protists • Algal bloomscan lead to the depletion of oxygen in water. • Red tides produce harmful toxins.

41. Section 4 Protists and Humans Chapter 25 Protists in Research • Research on protists has helped biologists understand a number of fundamental cellular functions, such as leukocyte movement.

42. Section 4 Protists and Humans Chapter 25 Protists in Industry • Protists as Food • For thousands of years, humans have been collecting seaweeds for food.

43. Section 4 Protists and Humans Chapter 25 Protists in Industry, continued • Protist Byproducts • Protists provide important byproducts, such as alginate, carrageenan, and agar.

44. Section 4 Protists and Humans Chapter 25 Protists and Health • Parasitic protists cause malaria, giardiasis, cryptosporidiosis, and trichomoniasis in humans.

45. Section 4 Protists and Humans Chapter 25 Protists and Health • Malaria • Parasitic protists in the genus Plasmodium cause malaria, which is characterized by severe chills, headache, fever, and fatigue. • Each year, nearly 3 million people die from malaria.

46. Section 4 Protists and Humans Chapter 25 Life Cycle of Plasmodium

47. Section 4 Protists and Humans Chapter 25 Malaria Life Cycle Click below to watch the Visual Concept. Visual Concept