Classification – Chapter 18

1. Classification – Chapter 18

2. Early Systems of Classification • Taxonomy – naming and grouping organisms according to their characteristics and evolutionary history. • Aristotle first classified organisms 2,000 years ago. “Classify This” • He classified living things as either plants or animals. • Grouped animals into: land dwellers, water dwellers, air dweller.

3. Early systems of Classification cont… • Grouped plants by: differences in their stems. • Biologists realized that Aristotle’s categories were not adequate. • They found that using common names for organisms caused a problem because they were named differently from place to place. Ex. Robin, called something different elsewhere • Common names may not describe species accurately. Ex. Jellyfish; it isn’t a fish at all, starfish, koala bear

4. Linnaeus’s System • Carolus Linnaeus (1707-1778) • Came up with a system of grouping organisms. • He used the organism’s morphology (form and structure) to categorize it.

5. Levels of Classification • Made up a hierarchy of seven different levels of organization to classify organisms. Keep Kingdom Plates Phylum Clean Class Or Order Family Family Gets Genus Sick Species

6. Kingdoms • Linneusseperated organisms into two kingdoms: plant and animal. • Phylum – subset in the animal kingdom. • Division – subset in the plant kingdom. • Within a phylum or division there are subsets called classes. • Subset within a class is an order. • Then family then genus and lastly species.

7. Examples: Bobcat Kingdom Animalia Phylum/division Chordata Class Mammalia Order Carnivora Family Felidae Genus Lynx Species Lynx rufus

8. Scientific Name Genus name + species name

9. Binomial Nomenclature • Bi-two • Two naming system Genus + species identifier Humans are known by our genus, homo and species name, sapiens meaning “wise” -scientific name is underlined or in italics. Linnaeus’s system is still used today.

10. Sometimes Botanists split species into subsets known as varieties. • Peaches and nectarines are fruits of two slightly different varieties of the peach tree, Prunuspersica.

11. Zoologists refer to variations of a species that occur in different geographic areas as subspecies. • Subspecies name follows the species identifier. • Ex. Terrapenecarolinatriunguisubspecies of the common eastern box turtle. Gets its name by having three, rather than four toes on its hind feet.

12. Phylogeny • Evolutionary history of organism. • Scientists consider the organism’s phylogeny when classifying it. • Linnaeus focused on features that are largely influenced by genes that are clues to common ancestry.

14. Review Game • Building a Cladogram

15. Homework • Pg. 339 • Questions: 1-6 • Wiki-space go to Chapter 18 page.

16. Imperium ("Empire") - the phenomenal world • Regnum ("Kingdom") - the three great divisions of nature at the time - animal, vegetable, and mineral • Classis ("Class") - subdivisions of the above, in the animal kingdom six were recognized (mammals, birds, amphibians, fish, insects, and worms) • Ordo ("Order") - further subdivision of the above - the class Mammalia has eight • Genus - further subdivisions of the order - in the mammalian order Primates there are four. e.g. Homo • Species - subdivisions of genus, e.g. Homo sapiens. • Varietas ("Variety") - species variant, e.g. Homo sapiens europaeus.

17. Section 3 Two Modern Systems of Classification 6-Kingdom Classification • Archaebacteriaautotroph/heterotroph • Eubacteriaautotroph/heterotroph • Protistaautotroph/heterotroph • Fungi heterotroph • Plantaeautotroph/heterotroph • Animaliaheterotroph

19. Archaebacteria • Unicellular • Live in extreme habitats • One of the first organisms to inhabit the Earth. Habitats: hot springs, salty lakes, swamps Anaerobic environments - without oxygen Thermophiles – heat lovers Methanogens – produce methane gas Halophiles – salt lovers

20. Halophiles • Thermophiles

21. Eubacteria • Common bacteria • Most use oxygen; few cannot live in the presence of oxygen. • Decomposers • Used in food making • Cause disease • Bioremediation – bacteria that eat oil spills

22. Shapes of Bacteria • Cocci – round • Bacilli – rod • Spirilla – spiral • Planes - staph • Chains – strepto ex. Streptococcus

25. Classifying Bacteria • Gram Staining • Procedure that stains bacteria. • Some bacteria stain pink other stain purple. • Gram stain positive – purple • Gram stain negative – pink • This tells scientists what kind of wall the bacteria has. More peptidoglycan more rigid wall --- gram positive

27. Gram positive

28. Gram negative

30. Classifying Bacteria • Agar – media that is used to grow bacteria. • Strict aerobe – grow only in the presence of oxygen. • Strict anaerobe – grow only in the presence of no oxygen. • Facultative anaerobe – prefer oxygen environments but can grow throughout a medium.

32. Classifying Bacteria • Some can metabolism certain substances. • Lactose – bacteria can metabolize lactose. • Ex. Lactobacillus Motile – some bacteria can move throughout a media.

33. Classifying Bacteria • Differential media: Some shows different reactions. • Selective media: Some can grow certain bacteria.

34. Viewing Microbes • Resolution(seeing detail) can be increased using immersion oil. • Allows the light ray to go directly through the objective lens.

35. Reproduction • Binary Fission

36. Conjugation • Bacteria gives its DNA to another bacteria.

37. Phylum Cyanobacteria • Photosynthetic – use the sun’s energy to make food. • Early atmosphere was filled with oxygen produced by cyanobacteria which allowed aerobic organisms to develop. • Lack a membrane-bound nucleus like all bacteria. • Enclosed with a jellylike case which help them cling together.

38. Cyanobacteria

39. Heterocysts • Some Cyanobacteria grow in chains. • Some of the cells specialize – these cells are called heterocysts. • Heterocysts contain enzymes for fixing atmospheric nitrogen. • Make nitrogen available to plants in a form that plants can use. • Nitrogen fixing bacteria

41. Eutrophication • Some cyanobacteria like Anabaena thrive on phosphates and nitrates that accumjulate in a body of water. • Sudden increase in the number of cyanobacteria due to a high availability of nutrients is called eutrophication or population bloom. • Then cyanobacteria die and heterotrophic bacteria eat them. • Their population increase which uses up a lot of oxygen in the water causing other organisms in the water like fish to die.

44. Phylum Spirochetes • Gram-negative, spiral-shaped heterotrophic bacteria. • Some are aerobic and some are anaerobic. • Move by means of a corkscrew-like rotation. • Some live freely, symbiotically, or parasitically. Ex. Treponemapallidum – causes the STD syphilis.

45. Phylum Gram-Positive Bacteria • Not all members are gram-positive • Some gram-negative bacteria are grouped in this phylum because they share molecular similarities with gram-positive bacteria. Ex. Streptococci – causes strep throat Lactobacilli – found on teeth, known to cause tooth decay.

46. Actinomycetes • Gram-positive bacteria • Form branching filaments • Grow in soil and produce many antibiotics. Antibiotics – chemicals that inhibit the growth of or kill other microscopic organisms.

47. Phylum Proteobacteria • Largest and most diverse phylum of bacteria. • Subdivisions: enteric bacteria, chemoautotrophic bacteria, and nitrogen-fixing bacteria

48. Enteric Bacteria • Gram-negative • Heterotrophic • Live in animal intestinal tracts. • Live in both aerobic and anaerobic environments. • Ex. E. coli • E. coli lives in the human intestine where it produces vitamin K and assists enzymes in the breakdown of foods. • Salmonella – food poisoning

50. Chemoautotrophs • Gram-negative • Extract energy from minerals by oxidizing the chemicals in these minerals. • Ex. Iron-oxidizing bacteria live in freshwater ponds that contain a high concentration of iron salts. Bacteria oxidize the iron in the salts to obtain energy. • Rhizobium nitrogen-fixing bacteria that live symbiotically with plants.