5.5 CLASSIFICATION Ms. TRS ANIMALIA ( multicellular heterotrophs) FUNGI –eukaryotic, multicellular ( except yeast), saprotrophs PLANTAE (eukaryotic, multicellular autotrophs) PROKARYOTA ( bacteria – unicelluar prokaryotic ,auto- or heterotrophic forms) PROTOCTISTA – unicellular eukaryotic heterotrophs with a few exceptions 5.5.1: Binomial system of nomenclature • Designed by Carolus Linneaus in 18th century • Every species has a Latin name, made up of two parts • First part is the name of the Genus • Second part specifies the species • Name should be printed in italics (underlined if hand written) and first part capitalized • Example • Humans are Homo sapiens BINOMIAL SYSTEM OF NOMENCLATURE: Two named First name = capital letter; if typed always in italics; if handwritten always underlined Naming system Homo sapiens Developed by Carl Linnaeus – a Swedish Bottanist (1707 – 1778) Exam question: Outline the binomial system of nomenclature (4) GENUS SPECIES Answer: Called binomial because two names are used; First name is genus, with first name being a capital; Second name is species, with no capital; Italics are used when the name is printed; The name is underlined if it is handwritten; Discuss the value of classifying organisms  Species Classification - It is easier to find out which species an organism belongs to when you have other organisms to compare it to; You can make assumptions about characteristics of a species in general; Evolutionary links, you can make assumptions about traits of a common ancestor; You can also predict how they evolved. Which of these two reef sharks are most closely related and why? Carcharhinus Perezi Carcharhinus melanopterus Same genus, different species Triaenodon Obesus 5.5.2: Hierarchical system of classification • • • The Hierarchical system has seven levels called taxons (plural: taxa) Each taxon can contain one or more of the sub-group below it The seven level hierarchies of taxa are: 1. 2. 3. 4. 5. 6. 7. Kingdom Phylum Class Order Family Genus Species • To remember the taxa in the correct order: • King Philip Came Over For Good Spagetti Kingdom Animalia Plantae Phylum Chordata Angiospermae Class Mammalia Dicotyledoneae Order Primate Rosales Family Hominidae Papilionaceae Genus Homo Pisum species sapiens sativum 5.5.3: Distinguish between Plant Phyla • Kingdom: Plantae • Characteristics: • • • • • Photosynthetic Chlorophyll Cellulose cell wall Permanent vacuoles Stores starch • Classification of the major plant phyla is based on external observable structures • Main points: 1.roots, leaves and stems; • 2. vascular tissue; • 3. reproduction 4 Major plant phyla Bryophyta – Filicinophyta Coniferophyta Angiospermophyta – - PLANTAE Bryophyta (mosses) No roots or stem Small leaf like structures, rhizoids for roots No vascular tissue Reproduce using spores Spores are formed in capsules Filicinophyta (ferns) Roots, leaves and short stems Leaves divided into sections and curled Coniferophyta (conifers) Woody trees Have narrow needles for leaves with thick waxy cuticle Have vascular tissue Have vascular tissue Reproduce using seeds in Reproduce using cones, not enclosed in spores produced fruits under leaves Wind pollinated Angiospermophyta (flowering plants) Roots, leaves and stems, stem can be woody Have vascular tissue Produce flowers Seeds are enclosed in ovaries that form fruits Seeds dispersed through fruits Division Bryophyta •No true roots, stem or leaves •Have rhizoids instead of roots •No vascular tissue – must absorb water from surface instead of absorbing from roots •Reproduce by spores made in capsules •Moss are commonly found in damp, shady areas Filicinophyta (ferns) • Have true roots, stem and leaves. Stem not woody in most of the plants • First group of vascular plants: – Xylem and phloem transport resources between distant organs. Reproduce by spores made in sporangia under leave Seen in tropical and temperate forests Coniferophyta • Includes ~ 550 species of large trees with thick woody stem including pines, firs, spruces, and redwoods • Most conifers have needles or narrow leaves modified to prevent water loss and thick waxy cuticle • Have vascular tissue • All produce seeds in cones • Seeds are not enclosed in ovary or fruit. • Most use wind pollination for reproduction. • Almost all conifers are evergreens Angiospemophyta • True flowering plants • Angion means “container,” – seeds are enclosed in fruits. During development, the ovule becomes seed and the ovary becomes fruit. • Includes ~ 235,000 species of flowering plants • May rely on wind, birds, insects, and even mammals for pollination and reproduction. • Have vascular tissue IB exam questions Plants are a diverse group of eukaryotic organisms. Describe the different characteristics of the bryophyta, filicinophyta, coniferophyta and angiospermophyta. 9 marks Outline the structural differences that characterize bryophytes, filicinophytes, coniferophytes and angiospermophytes. 9 marks Bryophyta: No roots, have rhizoids, simple stem and leaves Non vascular Produce spores in capsule Filicinophyta: Have roots, stems and leaves, leaves are large and divided into sections Have primitive vascular tissue Reproduce by making spores in sporangia on the underside of leaves Coniferophyta: Have woody stem, narrow needle like leaves with thick waxy cuticle Have well developed vascular tissue Produce seeds in cones Seeds are not enclosed in fruits Angiospermophyta: Produce flowers Flowers have ovules in ovaries Seeds are enclosed in fruits.( ovules form seeds and ovary forms fruit) 5.5.4 Distinguish between the major invertebrate phyla using external features Features of invertebrate phyla Phylum Porifera Example: Cnidaria Example: Platyhelminthes Example Annelida Example: Mollusca Example: Arthropoda Example: Symmetry Digestive tract Segmentation Other features Porifera (sponges) ANIMALIA Invertebrates Cnidaria (jellyfish/coral polyps) Platyhelminths (flatworms) No symmetry No mouth or anus No segmentation Water flows in and out of body through pores Radial symmetry Tentacles/ One opening to gut No segmentation Stinging cells - nematocysts Bilateral symmetry One opening to gut No segmentation Gas exchange over large surface area Annelida (segmented worms) Mollusca Bilateral symmetry D.T:With Mouth and anus Very segmented Bristles on body/ (snails/clams/ Usually bilateral/ no segmentation octopuses) DT: with Mouth and anus Arthropoda (insects/spiders/cru staceans, millipedes) Most of them have a calcium shell covering soft body Bilateral symmetry D.T : with Mouth and anus segmented Jointed legs + exoskeleton of chitin Phylum Porifera • Includes sponges • Characteristics: no body symmetry, no tissues, no organs; hermaphrodites; filter feeders; water moves in and out of the body through pores; sessile 5.5.4 Phylum Cnidaria • Includes corals, jellyfish, and sea anemone • Characteristics: stinging cells for food and protection; one-way digestive tract; radial symmetry; no segmentation drifters or sessile 5.5.4 Phylum Platyhelminthes • Includes flatworms like planaria, flukes, and tapeworms. • Characteristics: distinct head region (cephalization); bilateral symmetry; most are parasites; one-way digestive tract; no heart or lungs; flat shape - why? 5.5.4 Phylum Annelida • Includes earthworms, marine worms, and leeches. • Characteristics: segmented; bilaterally symmetrical; well developed nervous, digestive, and circulatory systems; two-way digestive system. 5.5.4 Phylum Mollusca • Includes snails, clams, octopus and squids. • Characteristics: bilateral symmetry; two-way digestive tract; exoskeleton (shells) of calcium carbonate; soft bodies; most are aquatic 5.5.4 Phylum Arthropoda • Includes insects, arachnids (spiders), and crustaceans • Characteristics of all arthropods: exoskeleton made of chitin; jointed appendages; segmented body; bilateral symmetry, open circulatory system • Molting – process of shedding and exoskeleton and growing a new one to grow larger. Dichotomous Key • A dichotomous key is a method used to identify organisms according to their physical traits based on a system of answering yes or no questions about an organism. Through a process of elimination the organism is identified. • Visible features are used • Questions should be unambiguous • Each question should divide the organisms into two distinct groups • Identification game: http://www.scenicoregon.com/webanic/pages/animals.html IB exam questions • Which phylum does sponges belong to? • What is the important feature of flat worms?