Classification of Organisms and the Kingdoms of Living Things

1. Classification of Organisms and the Kingdoms of Living Things Chapter 14 & 19

2. Categories of Classification • Taxonomy- the science of naming organisms • Aristotle- 1st ~2000 years ago- grouped plants and animals according to structural similarities • Genus- Latin for group -Species- kind • 1700’s descriptive names (polynomials) - name for a bee- Apis pubescens, thorace subgriseo, abdomine fusco, pedibus prosticis glabis,untrique margine ciliatus- these are large and awkward

3. A simpler system • Linnaeus- Swedish botanist that devised the binomial nomenclature system • Latin- 2 word system that used Genus and species identifier • Honey bee- Apis mellifera

4. A brief history of classification

5. Scientific Names • Genus- always capitalized-Quercus • Species- never capitalized- Quercus rubra • Genus may be used by itself when describing a group of species • Species never used alone • After use of full name the scientific name may be abbreviated Q. rubra • Names are italicized when typed underlined when handwritten

6. Scientific names • Common way of communicating regardless of language • Latin- dead language- never changes • No two organisms can have same scientific name • Common names change with location- robin and garter snake

7. Why Common names are confusing

8. Levels of classification -Domain contains kingdoms -Kingdoms contain phyla -Phyla contain classes -Classes contain orders -Orders contain families -Families contain genera -Genera contain species

9. Levels of classification

10. Classification of a honeybee

11. What is a species? • How do you tell two species apart from each other? • 1942- Ernst Mayr- proposed the biological species concept • A group of naturally interbreeding populations that are reproductively isolated from each other • Sometimes species can interbreed such as dogs and wolves- these are called hybrids

12. Hybrids Dog Wolf Dog-Wolf hybrid There are many different Kinds of hybrids to look up Zorse, mule,liger, etc…

13. Problems with Biological species concept • Fails to describe asexually reproducing organisms- bacteria, protists, fungi, plants, some animals • In practice, scientists still use an organism’s features

14. Number of Species • Actual number described is much smaller than total number • 1.5 million described ~ 1 million are arthropods • Estimated 10 million in world- rainforests, oceans • Our knowledge is very limited

15. Evolutionary history • Classification based on similarities should reflect an organism’s phylogeny- its evolutionary history- not all features are inherited from a common ancestor- wings in birds and insects • Convergent evolution- similarities evolve in non-related organisms • Analogous structures- wings, body shape in fish and dolphins

16. Cladistics • A method of analysis that reconstructs phylogenies by inferring relationships based on shared characters • Ancestral character- a trait that is common to both all groups under consideration- birds and mammals are both vertebrates • Derived character- a trait that evolved only in one group buth not any others- feathers evolved only in birds

17. Cladogram of vertebrates

18. Cladogram of Plants Flowers Seeds Vascular tissue Cuticle

19. Cladistics • Based on the principle that shared derived characters show that two groups are closely related, shared ancestral characters, however, do not • Strength of cladistics is objectivity- this does not take into account the “strength” of a trait • According to cladistics birds are grouped with reptiles

20. Evolutionary systematics • Taxonomists give varying degree of importance to charaters • Phylogenetic tree is created • This allows scientists to use full powers of observations along with biases they may have • Both cladograms and phylogenetic trees arrive at similar conclusions

21. Vertebrate phylogenetic tree

22. 6 Kingdoms of Life • Where do biologists begin when they classify an organism? • What makes something an animal? A plant? • Biologists focus on a few fundamental characteristics

23. Fundamental Characteristics • Cell type- prokaryotic or eukaryotic • Cell walls- presence or absence, proteins involved • Body type-unicellular or multicellular • Nutrition-autotrophs or heterotrophs

24. 3 Domains • 1977- Carl Woese proposed that some prokaryotes are so fundamentally different than others that they should be placed separate in their own division • All eukaryotes are placed together • Bacteria (Eubacteria), Archae (Archaebacteria), Eukarya (Protists, Fungi, Plants, Animals)

25. 3 Domains

26. 3 Domains

27. Domain Bacteria • Contains Kingdom Eubacteria • All range from 0.1 to 15 um • Found almost everywhere • Bacteria that we are used to • Cell wall made of peptidoglycan • Unique amino acid sequences in ribosomes and RNA polymerases • 3 shapes- round, rod, spiral • Obtain energy from organic compounds, inorganic compoounds, heterotrophic, autotrophic, anaerobic, aerobic, decomposers

28. Eubacteria

29. Domain Archae • Contains Kingdom Archaebacteria • More closely related to Eukaryotes • Cell wall that lacks peptidoglycan • Unique lipids in cell wall • Genes that are interupted by introns like eukaryotes • Methanogens- form methane gas found in swamps, sewage, mammal intestines • Thermophiles- found in very hot conditions • Halophiles- found in highly salty areas • Acidophiles- highly acidic areas • Nonextremes- found in same as eubacteria

30. Archaebacteria

31. Domain Eukarya • Contains Protists, Fungi, Plants, Animals • Highlyt organized cells- contain nucleus and other organelles • Multicellularity- cells are coordinated • Sexual reproduction- haploid gametes fuse to create variation

32. Kingdom Protista • Most diverse- more of what they “are not” than what they are • Pseudopods- protists that use cytoplasmic lobes to move- amoebas- Forams make a shell and project pseudopods through shell • Flagellates- use flagella to move- Euglena • Ciliates - use cilia- Paramecium

33. Kingdom Protista • Double shells- diatoms- photosynthetic- double shells made of silica- part of plankton • Photosynthetic algae- green algae that you see in lakes and ponds, brown algae, red algae- all the seaweeds • Fungus-like protists- slime molds and water molds- produce spores and act like a fungus • Spore-forming protists- nonmotile as adults- parasitic spores produced, complex life cycles- malaria and other diseases

34. Kingdom Protista

35. Kingdom Fungi • Almost all unicellular • Yeasts are unicellular group • Cell walls that contain chitin • Cells interconnected and share cytoplasm • Slender strands called hyphae • Lack chlorophyll, roots, movement, leaves • Heterotrophs- decomposers that secrete enzymes then absorb the nutrients • Saprophytes- live on dead organsisms- some are parasitic

36. Kingdom Fungi • 3 kinds based on reproductive structures • Zygomycetes- zygosporangia- common bread mold • Basidiomycetes- mushrooms- produce basidiomycetes • Ascomycetes- asci- sac-like structures

37. Kingdom Plantae • Multicellular autotrophs • Most have vascular tissue for transporting water and organic molecules • Cannot move from place to place • Most have roots, leaves, stems • All do photosynthesis • Cell walls made of cellulose • Seeds or spores

38. Kingdom Plantae • 4 basic kinds of plants • Nonvascular- lack vascular tissues- mosses- has cuticle • Seedless vascular- ferns- roots, stems, leaves, no seeds but spores • Nonflowering seed plants- vascular tissue, seeds, no flowers- pine trees • Flowering plants- vascular tissue, seeds, flowers- rose bush, apple tree

39. Kingdom Plantae

40. Kingdom Animalia • Complex, multicellular heterotrophs- all must eat something else • No cell wall • Mostly diploid cells • Only group tp have muscles for movement • Most are invertebrates- 99% • Most animals live in the oceans • Can be very large-blue whale 100 ft- or small 0.02 inches- microscopic mites

41. Kingdom Animalia

42. Sponges- Porifera Jellyfish- Cnidaria Flatworms- Platyhelminthes Roundworms- Nematoda Worms- Annelida Mollusks- Molluska Arthropods- Arthropoda Starfish- Echinodermata Invertebrate chordates Vertebrates Hagfish Sharks Fish Amphibians Reptiles Birds Mammals Major animal phyla

43. Multicellularity • Colonial organisms- unicellular organisms begin to cluster together- they cannot communicate and still exist by themselves • Aggregations- a temporary collection of organisms that come together temoprarily and then separate- slime molds • True Multicellularity- cells are permanently associated with each other- only found in eukaryotes- cells become specialized for specific functions- differentiation

44. Complex multicellularity • Specialized cells and structures mad of these cells • Tissue (group of cells performing the same function) --> Organ( groups of tissues performing the same function) --> Organ System (groups of organs performing together) --> Organism (multiple organ systems working together)

45. Viruses