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Topic 5.5

Topic 5.5. Classification. Why Classify?. How many ‘different sorts’ of living things are there on the planet?. How many species are there in the world?. Let’s start with some classification!. Take 5 minutes to write down ways in which we can classify the students in class today

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Topic 5.5

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  1. Topic 5.5 Classification

  2. Why Classify? • How many ‘different sorts’ of living things are there on the planet?

  3. How many species are there in the world?

  4. Let’s start with some classification! • Take 5 minutes to write down ways in which we can classify the students in class today • Key features of a classification key are that it must be clear, consistent, and easily implemented

  5. Why Classify? • In order to sort out and compare living things, we need to organise them into ‘manageable’ categories • A good classification system allows us to make generalisations AND organise our ideas about organisms • Classification involves giving every organism an AGREED NAME • Classification involves arranging organisms into apparently related organisms

  6. The American Robin (TurdusMigratorius) The European Robin (ErithracusRubecula)

  7. What is taxonomy?

  8. Taxonomy is the process of (scientific) classification Taxis: Greek for ‘Arrangement or Division’ ‘Nomos’: Greek for ‘Method or Law http://www.youtube.com/watch?v=F38BmgPcZ_I

  9. Systems used to classify living organisms • Linnaean Binomial Nomenclature system • Cladistics (Ancient Greek –Branch) • Phylogenetics

  10. The evolution of taxonomy… The Linnaean classification system was created long before scientists understood that organisms evolved. Because the Linnaean system is based on morphology (form and structure) rather than on evolutionary theory Most biologists are switching to a classification system that reflects the organisms' evolutionary history • Phylogenetic tree • Cladogram

  11. Cladistics • A taxonomic system based on common evolutionary ancestry • The Method of choice for classifying organisms, since it recognises and involves evolutionary theory • Developed since 1958 • Any group of organisms are related by descent from a common ancestor. • There is a bifurcating pattern of cladogenesis. • Change in characteristics occurs in lineages over time. • Cladistics introduction

  12. Phylogenetic tree • An ‘Evolutionary Tree’ • Shows inferred evolutionary relationship among species based on similarities/differences in their genetic material or physical appearance

  13. Linnaean Classification • Developed by Carl Linneaus • Swedish botanist & taxonomist • Is still used today, basis for classification and naming of all new species. • Based on physical traits, most of his classifications are still accurate. • http://www.youtube.com/watch?v=F38BmgPcZ_I

  14. Binomial Nomenclature • Each species is assigned a two part scientific name. • Written in italics • If handwritten, underline the name • First word is capitalized (Genus): NOUN • Second word is lowercase (Species): ADJECTIVE

  15. Binomial Nomenclature Homo sapiens Modern human Genus species Eretmochelysimbricata Hawksbill Turtle (imbricate: arrange so that they overlap like tiles) The genus name can be abbreviated if you have already used the full name in your text

  16. Linnaeus also defined four groups of humans, and the divisions were based on both physical and social traits. By 21st-century standards, his descriptions can be regarded as racist. • How does the social context of scientific work affect the methods and findings of research? • Is it necessary to consider the social context when evaluating ethical aspects of knowledge claims?

  17. There are seven (err, actually 8) levels of classification • Biological taxonomy is hierarchical • As we move from kingdom (domain) to phylum, all the way to species, organisms share more and more characteristics. • This system allows us to group organisms while also assigning unique species names.

  18. (Domain) King Philip Came Over For Good Spaghetti

  19. How is Life Classified? Pre-1969: Life is classified into 2 Kingdoms: Plantae and Animals 1969 – 1999: Life is classified into 5 Kingdoms: Monera, Protista, Plantae, Fungi, Animalia: using Linnaean Classification System – based on anatomy, morphology, embryology and cell structure BUT: The Traditional 5 kingdom System does not explain how kingdoms may be related through evolutionary relationships among the kingdoms

  20. The Three Domains • Karl Woese discovery of Archae

  21. The 3 domains were proposed by Dr Karl Woese Dogma The eukaryote-prokaryote dichotomy was the central dogma of biology. Woese was making a claim of extraordinary scope. He was saying that we had missed one-third of all living things. People did not like that (5). "I hadn't been trained as a microbiologist, so I didn't have this bias" [about impossibility of bacterial classification]. (Woese)

  22. Classification is a ‘messy’ branch of science… Just compare the University of Oxford and the University of Berkeley…

  23. Oxford University Museum of Natural History 5 Kingdoms: one prokaryotic, four eukaryotic

  24. University of California Berkeley

  25. Classification in the Animal Kingdom

  26. Kingdom Animalia Contains organisms as diverse as coral and mice….

  27. Classification in the Plant Kingdom

  28. Plant Classification (UMCB)

  29. From Kingdom… Linnaeus originally divided living things into 2 (then 3) kingdoms… • Animalia • Vegetalia (Plants) • Mineralia (Minerals, since abandoned) We now widely recognise FIVE kingdoms: • Kingdom Plantae(the plants) • Kingdom Animalia(the animals) • Kingdom Fungi (the fungi and moulds) • Kingdom Protocista(protozoa and alga) • Kingdom Prokaryote [Monera] (the euBacteria and archebacteria)

  30. Kingdom Animalia • Eukaryotic • Multicelluar • Heterotrophic • Terrestrial and aquatic • Sexual (a few are asexual) • Motile (a few are non-motile)

  31. Kingdom Plantae • Eukaryote • Multicellular • Autotrophic • Mostly terrestrial • Sexual and asexual • Nonmotile Mosses, Ferns, flowering plants, conifers

  32. Kingdom Fungi • Eukaryotic • Heterotrophic • Unicellular and multicellular • Mainly terrestrial • Asexual and sexual • Non-motile Mushrooms, puffballs, yeasts, rusts, water moulds

  33. Kingdom prokaryotae (Monera) • Prokaryotes • Heterotrophic and autotrophic • Anaesrobic and aerobic • Aquatic, terrestrial and aerosol • Mostly asexual • Mostly non-motile (one kind are motile)

  34. Kingdom Protoctistae (Protists) • Eukaryotes • Heterotrophic and autotrophic • Unicellular • Mostly aquatic • Mostly asexual • Motile and non-motile Protozoa, slime moulds, algae Brown Algae

  35. …To Species • A group of organisms which can interbreed and produce fertile offspring. • Species are named: Genus species • Heliconiuscharithonius • The smallest taxonomic group, though many subspecies are recognized. Might potentially interbreed if a barrier or other challenge was removed (ie: distance)

  36. Test yourself

  37. Classification of the malaria parasite, Plasmodium falciparum • Kingdom Protista • (Subkingdom) Protozoa • Phylum: Apicomplexa • Class: Sporozoasida • Order: Eucoccidiorida • Family: Plasmodiidae • Genus: Plasmodium • Species: falciparum, malariae, ovale, vivax

  38. Classification of the malaria vector: AedesAegyptae • Kingdom: Animalia • Phylum: Arthropoda • Class: Insecta • Order: Diptera • Family: Culicidae • Subfamily: Culicinae • Genus: Aedes • Species: Aegyptae

  39. Now your turn: IB Classification Requirements • 5.5.2: List seven different levels in the hierarchy of taxa: kingdom, phylum, class, order, family, genus and species, using an example from two different kingdoms for each level • Scenic Oregon Hierarchical Classification • Use the Scenic Oregon I-animal website to write information about an animal of your choice • Use the University of Berkeley Website to write information about a plant species of your choice

  40. 5.5.3 Distinguish between the following phyla of plants, using simple external recognition features Resources: • Clegg, P. 165 – 168 • Evolution Drop-down menu in the Blog has resources on all major plant phyla

  41. 5.5.4 Distinguish between the following phyla of animals, using simple external recognition features: porifera, cnidaria, platyhelminths, annelida, mollusca and arthropodaResources:Clegg, P. 165 – 168Evolution Drop-down menu in the Blog has resources on all major invertebrate phyla

  42. Classification of the Kingdoms: Synonyms One prokaryote kingdom Bacteria Monera • No nucleus • Divide by binary fission (asexual) Four eukaryote Kingdoms Protoctista Fungi Plantae Animalia

  43. Dichotomous Keys

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