Classification and Protista

1. Classification and Protista

2. Why do Scientists Classify? Imagine a grocery store… How are they organized? What would happen if they were not organized? How is your life organized?

3. Why do Scientists Classify? Almost 13 billion known species of organisms Need to keep organized! (Easier to study!) • Classification the grouping of information or objects based on similarities.

4. Why do Scientists Classify? • Taxonomy is the science of grouping and naming organisms. Useful because: once classified, scientists will know a lot about an organism

5. Early Classification Systems Aristotle (4th century B.C.) -observed animals -watched appearance, behavior, movement -fly, swim, and walk/crawl/run -observed similarities and differences -used differences to divide into smaller subgroups

6. Linnaeus Carolus Linnaeus (1750s) -used observations as basis of his system -placed organisms based on observable features Devised naming system for organisms: Binomial Nomenclature

7. Linnaeus Binomial Nomenclature- 2 part naming system -uses Latin words First name (genus); second name (species) Genus speciesFelis concolor Genus is capitalized; species is NOT. If you can’t italicize, underline the genus and species!

8. Classification Today Species with similar evolutionary histories are classified more closely together. -when organisms share a common ancestor, they share an evolutionary history

9. Levels of Classification -based on contributions of both Aristotle and Linnaeus There are 7 levels of classification. Remember the first letter of this sentence: King Philip Came Over For Good Spaghetti.

10. 7 Levels of Classification Kingdom broadest level Phylum Class Order Family Genus Species most specific

11. Levels of Classification

12. Taxonomic Categories • Taxon- a named group of organisms • Taxa range from having broad diagnostic characteristic to having specific characteristics • Genus- is defined as a group of species that are closely related and share a common ancestor

13. Taxonomic Categories • Family- is the next higher taxon, consisting of similar, related genera. • Ursidae family contains 9 species of bears

14. Higher Taxa • Order- contains related families • Class- contains related orders • Bears belong to order carnivora and class mammalia

15. Higher Taxa • Phylum or division- contains related classes • Kingdom- contains related phlya or divisions • Domain is the broadest of all taxa and contains one or more kingdoms • Bears are classified in phylum chordata, Kingom Animalia, and Domain Eukarya

17. Using the Classification System Field guides help identify organisms. -they highlight differences between similar organisms (like trees) Taxonomic Key (AKA Dichotomous Key) -paired statements that describe the physical characteristics of different organisms

18. Taxonomic Key • 1. Fruits occur singly ....................................................... Go to 3 • 1' Fruits occur in clusters of two or more ......................... Go to 2 • 2. Fruits are round ....................................................... Grapes • 2' Fruits are elongate ................................................... Bananas • 3. Thick skin that separates easily from flesh .............Oranges • 3' Thin skin that adheres to flesh .............................. Go to 4 • 4. More than one seed per fruit ............................ Apples • 4' One seed per fruit ............................................ Go to 5 • 5. Skin covered with velvety hairs .................... Peaches • 5' Skin smooth, without hairs ........................... Plums

19. Domains • Broadest, most inclusive taxon • Three domains • Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles) • Eukarya are more complex and have a nucleus and membrane-bound organelles

20. Archaea live in harsh environments and may represent the first cells to have evolved. Sewage treatment plants, thermal vents, etc.

21. Eubacteria, some of which cause human diseases, are present in almost all habitats on earth. Live in the intestines of animals Many bacteria are important environmentally and commercially.

22. Domain Eukarya is Divided into Kingdoms • Protista (protozoans, algae…) • Fungi (mushrooms, yeasts …) • Plantae (multicellular plants) • Animalia (multicellular animals)

23. Most are unicellular Some are multicellular Some are autotrophic, while others are heterotrophic Protista

24. Fungi • Multicellular, except yeast • Absorptiveheterotrophs (digest food outside their body & then absorb it) • Cell walls made of chitin

25. Multicellular Autotrophic Absorb sunlight to make glucose – Photosynthesis Cell walls made of cellulose Plantae

26. Animalia • Multicellular • Ingestiveheterotrophs(consume food & digest it inside their bodies) • Feed on plants or animals

29. Similarities and Differences in the Protist Kingdom • All are eukaryotes (cells with nuclei). • Live in moist surroundings. • Unicellular or multicellular. • Autotrophs, heterotrophs, or both. • Some can move - others cannot.

30. 3 categories of Protists: • Animal-like • Fungus-like • Plant-like

31. Animal-like Protists (Protozoans) *Unicellular Heterotrophs *Four groups based on movement: those with flagella, cilia, pseudopods, and the ‘others’.

32. Protozoans with Pseudopods • Pseudopods also called ‘false feet’ • Cell membrane pushes in one direction & the cytoplasm flows into the bulge. • This allows the protozoan to move, dragging the rest of the cell behind it.

33. Pseudopod Movement EXAMPLE OF HOW PSEUDOPODS MOVE FLOW PUSH DRAG

34. Pseudopods & Feeding They can form pseudopods to surround & trap food. Then form a food vacuole to break down food in the cytoplasm.

35. Pseudopods • Reproduce by mitosis • Contractile vacuole - it collects extra H2O & expels it from cell • Thin cell membrane • No definite shape. • Example - Amoeba

36. Protozoans with cilia • Cilia - hairlike structures - help organisms move, get food and sense environment. • Multicellular with 2 nuclei. • 1 nuclei controls everyday functions • 1 nuclei is for reproduction. • Reproduce by mitosis or conjugation.

37. Ciliates • Oral groove lined with cilia - moves H20 containing food into food vacuole at end of oral groove. • Food vacuole breaks down food and sends through cell. • Anal pore sends out waste. • Example of protozoan w/ cilia: paramecium.

38. CONTRACTILE VACUOLE CILIA FOOD VACUOLE ORAL GROOVE FOOD VACUOLE ANAL PORE

39. Protozoans with flagella • Organisms called zooflagellates • Use long whiplike part called flagella to move. • These usually live inside other organisms.

40. Other Protozoans • Called sporozoans - parasites • Feed on cells & body fluids of hosts Sporozoans like Plasmodium (causes malaria) have more than 1 host: mosquitoes and then humans

41. Examples of Animal-like Protista • Cilates- move by cilia • Sarcodines- pseudopods • Sporozoans- spores • Zooflagellate- Flagella

42. Plantlike Protists • Better known as algae • Autotrophs • Size: unicellular to very large • Contain different pigments so they come in different colors. • Euglena: special type of algae -when there is no sunlight they become heterotrophic.

43. Plant-like protists arealgae. • Algae are eukaryotic autotrophs. • They, along with other eukaryotic autotrophs, form the foundation of Earth’s food chains. • They produce much of Earth’s oxygen.

44. There are three unicellular phyla of algae: • Phylum Euglenophyta • Phylum Bacillariophyta • Phylum Dinoflagellata

45. Members of first phylum of algae, Euglenophyta, are both plant-like and animal-like. • Euglena are autotrophs since they make food from sunlight and • Heterotrophs since they ingest food from surrounding water.

47. The second unicellular algae, Bacillariophyta, are photosynthetic autotrophs. • They have shells of silica. • They make up a large portion of the world’s phytoplankton which is Earth’s largest provider of oxygen.

48. DIATOMS

49. The third unicellular algae, Dinoflagellata, are a major component of marine phytoplankton. • These algae have at least two flagella set at right angles to each other and thick cell walls made of cellulose plates. • Blooms of dinoflagellates cause “Red Tide.”