19.1 Section Objectives – page 503

1. 19.1 Section Objectives – page 503 1. What life characteristic is each of the organisms exhibiting?2. How are these organisms alike and different? The Amoeba is surrounding its food. The Didinim is feeding on a Paramecium. The Euglena moves by whipping its flagellum. Beating cilia draw food into the mouth of this Stentor.

2. Unit Overview – pages 472-473 Viruses, Bacteria, Protists, and Fungi Protists • What is a protist? • Animal-like protists

3. Section 19.1 Summary – pages 503-509 What is a protist? • Kingdom Protista contains the most diverse organisms of all the kingdoms. • Members of Kingdom Protista have: • membrane-bound organelles (eukaryotes) • a wide variety of shapes & sizes • one or many cells

4. Section 19.1 Summary – pages 503-509 What is a protist? • The characteristic that all protistsshare is that, unlike bacteria, they are all eukaryotes, which means that most of their metabolic processes occur inside their membrane-bound organelles.

5. Section 19.1 Summary – pages 503-509 What is a protist? • Although there are no typical protists, some resemble animals in the way they get food. • Protozoa: animal-like protists that are heterotrophic • Unlike animals, though, all protozoans are unicellular. Protozoa

6. Section 19.1 Summary – pages 503-509 What is a protist? • Unlike animals, though, all protozoans are unicellular. Protozoa

7. Section 19.1 Summary – pages 503-509 What is a protist? • Other protists are plantlike autotrophs, using photosynthesis to make their food. • Plantlike autotrophic protists are called algae. Algae

8. Section 19.1 Summary – pages 503-509 What is a protist? • Unlike plants, algae do not have organs such as roots, stems, and leaves. Algae

9. Section 19.1 Summary – pages 503-509 What is a protist? • Still other protists are more like fungi because they decompose dead organisms. Slime mold • However, unlike fungi, funguslikeprotists are able to move at some point in their life and do not have chitin in their cell walls.

10. Section 19.1 Summary – pages 503-509 What is a protist? • Some protists cause diseases, such as malaria and sleeping sickness, that result in millions of human deaths throughout the world every year. • Unicellular algae produce much of the oxygen in Earth’s atmosphere and are the basis of aquatic food chains.

11. Section 19.1 Summary – pages 503-509 What is a protist? • Slime molds and water molds decompose a significant amount of organic material, making the nutrients available to living organisms.

12. Section 19.1 Summary – pages 503-509 What is a protozoan? • Although a diverse group, all protozoans are unicellular heterotrophs that feed on other organisms or dead organic matter. • They usually reproduce asexually, but some also reproduce sexually.

13. Section 19.1 Summary – pages 503-509 Diversity of Protozoans • There are four main groups of protozoans: the amoebas (uh MEE buz), the flagellates, the ciliates, and the sporozoans (spor uh ZOH unz).

14. Section 19.1 Summary – pages 503-509 Ciliates: Protozoans with cilia Anal pore Cilia • The roughly 8000 members of the protist phylum Ciliophora, known as ciliates. • Ciliates: use the cilia that cover their bodies to move. Oral groove Gullet • Ciliates live in every kind of aquatic habitat—from ponds and streams to oceans and sulfur springs. Contractile vacuole Micronucleus and macronucleus

15. Section 19.1 Summary – pages 503-509 A Paramecium Anal pore Cilia • Within a paramecium are many organelles and structures that are each adapted to carry out a distinct function. Oral groove Contractile vacuole

16. Section 19.1 Summary – pages 503-509 Amoebas: Shapeless protists • Amoebas have no cell wall and form pseudopodia to move and feed. • Pseudopodia: cytoplasm-containing extensions of plasma membranes. Pseudopodia Cytoplasm Nucleus Food vacuole Contractile vacuole

17. Section 19.1 Summary – pages 503-509 Amoebas: Shapeless protists • Although most amoebas live in saltwater, there are freshwater ones that live in the ooze of ponds, in wet patches of moss, and even in moist soil. • Because freshwater amoebas live in hyoptonic environments, they constantly take in water. • Contractile vacuoles: collect and pump out excess water

18. Section 19.1 Summary – pages 503-509 Flagellates: Protozoans with flagella • The phylum Zoomastigina consists of protists called flagellates. • Flagellates: have one or more flagella. Nucleus Chloroplast • Flagellated protists move by whipping their flagella from side to side. Mitochondrion Eyespot Flagellum Pellicle Contractile vacuole

19. Section 19.1 Summary – pages 503-509 Flagellates: Protozoans with flagella • Some flagellates are parasites that cause diseases in animals, such as African sleeping sickness in humans. • Other flagellates are helpful.

20. Section 19.1 Summary – pages 503-509 Protist Reproduction • A protist usually reproduces asexually by dividing crosswise and separating into two daughter cells. • Whenever their food supplies dwindle or their environmental conditions change, paramecia usually undergo a form of conjugation.

21. Section 19.1 Summary – pages 503-509 Sporozoans: Parasitic protozoans • Protists in the phylum Sporozoa are often called sporozoans • Sporozoans: produce spores. • Spore: a reproductive cell that forms without fertilization and produces a new organism. Sporozoans

22. Section 19.1 Summary – pages 503-509 Sporozoans: Parasitic protozoans • All sporozoans are parasites. • They live as internal parasites in one or more hosts and have complex life cycles. • Plasmodium, members of the sporozoan genus, are organisms that cause the disease malaria in humans and other mammals and in birds.

23. Unit Overview – pages 472-473 Viruses, Bacteria, Protists, and Fungi Protists • Algae: Plantlike protists • Funguslike protists

24. Section 19.1 Summary – pages 503-509 What is a protist? • Algae are plantlike autotrophs, using photosynthesis to make their food. • Algae: plantlike protists • Unlike plants, algae do not have organs such as roots, stems, and leaves. Algae

25. Section 19.2 Summary – pages 510-516 What are algae? • Algae include both unicellular and multicellular organisms. • Phytoplankton: photosynthesizing unicellular protists • The photosynthesizing unicellular protists, known as phytoplankton are so numerous that they are one of the major producers of nutrients and oxygen in aquatic ecosystems in the world.

26. Section 19.2 Summary – pages 510-516 What are algae? • Through photosynthesis, algae produce much of the oxygen used on Earth.

27. Section 19.2 Summary – pages 510-516 Euglenoids: Autotrophs and Heterotrophs • Eugelnoids are unicellular, aquatic protists that have both plant and animal characteristics. Nucleus Chloroplast Mitochondrion Eyespot Flagellum Pellicle • Unlike plant cells, they lack a cell wall made of cellulose. Contractile vacuole

28. Section 19.2 Summary – pages 510-516 Euglenoids: Autotrophs and Heterotrophs • Eugelnoids might also remind you of protozoans because they have one or more flagella to move. • They use their flagella to move toward light or food.

29. Diatoms: The golden algae • Diatomsare unicellular photosynthetic organisms with delicate shells that make up a large part of phytoplankton.

30. Section 19.2 Summary – pages 510-516 Diatoms: The golden algae • Diatoms contain chlorophyll as well as other pigments called carotenoids that usually give them a golden-yellow color. • The food that diatoms make is stored as oils rather than starch.

31. Section 19.2 Summary – pages 510-516 Diatoms: The golden algae • These oils give fishes that feed on diatoms an oily taste. • They also give diatoms buoyancy so that they float near the surface where light is available.

32. Dinoflagellates: The spinning algae • Dinoflagellates have cell walls that are composed of thick cellulose plates. • Dinoflagellates contain chlorophyll, carotenoids, and red pigments. • They have two flagella located in grooves at right angles to each other.

33. Section 19.2 Summary – pages 510-516 Dinoflagellates: The spinning algae • Several species of dinoflagellates produce toxins. • One toxin-producing dinoflagellate, Pfiesteria piscicida, that some North Carolina researchers discovered in 1988, has caused a number of fish kills in the coastal waters from Delaware to North Carolina.

34. Section 19.2 Summary – pages 510-516 Dinoflagellates: The spinning algae • Another toxic species, Gonyaulax catanella, produces an extremely strong nerve toxin that can be lethal. • In the summer, these organisms may become so numerous that the ocean takes on a reddish color. • This population explosion is called a red tide.

35. Section 19.2 Summary – pages 510-516 Dinoflagellates: The spinning algae • The toxins produced during a red tide may make humans ill. Red tide

36. Section 19.2 Summary – pages 510-516 Red algae • Red algae are mostly multicellular marine seaweeds.

37. Section 19.2 Summary – pages 510-516 Brown algae • Almost all of these species live in salt water along rocky coasts in cool areas of the world.

38. Section 19.2 Summary – pages 510-516 Brown algae • The largest and most complex of brown algae are kelp. • In kelp, the thallus is divided into the holdfast, stipe, and blade.

39. Section 19.2 Summary – pages 510-516 Green algae • The green algae are the most diverse algae, with more than 7000 species. • The major pigment in green algae is chlorophyll, but some species also have yellow pigments that give them a yellow-green color.

40. Section 19.2 Summary – pages 510-516 Green algae • Green algae can live singly or in colonies. • Colony: a group of cells that lives together in close association. Volvox

41. Section 19.2 Summary – pages 510-516 Green algae • Green algae can reproduce both asexually and sexually. • Algae can reproduce asexually through fragmentation. • Fragmentation: an individual breaks up into pieces and each piece grows into a new individual.

42. Section 19.1 Summary – pages 503-509 fungus-like protist Slime mold • Unlike fungi, funguslikeprotists are able to move at some point in their life and do not have chitin in their cell walls.

43. Section 19.3 Summary – pages 517-521 What are funguslike protists? • Certain groups of protists, the slime molds, the water molds, and the downy mildews, consist of organisms with some funguslike features. • Funguslikeprotists are more like fungi because they decompose dead organisms.

44. Section 19.3 Summary – pages 517-521 What are funguslike protists? • There are three phyla of funguslikeprotists. • Two of these phyla consist of slime molds. • Slime molds have characteristics of both protozoans and fungi and are classified by the way they reproduce.

45. Section 19.3 Summary – pages 517-521 What are funguslike protists? • Water molds and downy mildews make up the third phylum of funguslikeprotists. • Some disease-causing species damage vital crops.

46. Section 19.3 Summary – pages 517-521 Slime Molds • Many slime molds are beautifully colored, ranging from brilliant yellow or orange to rich blue, violet, and jet black.

47. Section 19.3 Summary – pages 517-521 Slime Molds • They live in cool, moist, shady places where they grow on damp, organic matter, such as rotting leaves or decaying tree stumps and logs. • There are two major types of slime molds—plasmodial slime molds and cellular slime molds.

48. Section 19.3 Summary – pages 517-521 Slime Molds • Slime molds are animal-like during much of their life cycle, moving about and engulfing food in a way similar to that of amoebas. • However, like fungi, slime molds make spores to reproduce.

49. Section 19.3 Summary – pages 517-521 Plasmodial slime molds • Plasmodial slime molds get their name from the fact that they form a plasmodium. • Plasmodium: a funguslike protist that produces a multinucleate glob of cytoplasm • This slimy, multinucleate mass, is the feeding stage of the organism.