5.5: Classification Pp 142 - 149

Binomial system of nomenclature System of assigning scientific/binomial names to organisms designed by Carolus Linneaus in 18th century Based on idea that 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: Binomial name for Humans is Homo sapiens

Hierarchy of Taxa Taxonomy is the study of classification Organisms are placed in groups based on similarities & differences Organisms that share characteristics are placed into similar groups The more similar their characteristics, the closer the grouping Taxon (plural: taxa)is a group/unit in a classification system There are seven taxonomic units: Kingdom Phylum Order Family Genus Species

Kingdom Plantae Phylum Filicinophyta Phylum Bryophyta Phylum Angiospermohyta Phylum Coniferohyta

Plant Phyla Kingdom: Plantae Characteristics: Photosynthetic Chlorophyll Cellulose cell wall Permanent vacuoles Stores starch Classification of the major plant phyla is based on external observables structures

Using external recognition features only, distinguish between the following phyla of kingdom plantae: bryophyta, fillicinophyata, coniferophyta & angiospermophyta

Need to know: -Bryophyta -angiospermophyta -Filicinophyta -Coniferophyta

Phylum: Bryophyta (Mosses, Liverworts, Hornworts) Small terrestrial plants Do not have true roots, stems or leaves but they must have structures resembling them Leaf-like structures are often arranged in a spiral Usually have live in clusters which act like sponges holding water No cuticle Reproductive structures are called sporangium which is on long stalks with capsules on end.

Phylum: Filicinophyta (ferns) Have true leaves in fronds New leaves unroll Divided leaves There is cuticle on leaves Have an underground creeping stem (rhizome) Height up to 20m but not woody Reproduction: sporangia (sori) contain reproductive spores

Phylum: Coniferophytes (conifers & pines) All conifers are woody plants, most are trees with a single wooden trunk with side branches Differentiated into; roots, stem & leaves Leaves are waxy, long thin needles, often arranged in spirals, often a dark green colour Stem & roots are woody Produce naked seeds found in cones Vascular system (tracheids)

Phylum: Angiospermophyta (flowering plants and grasses) Differentiated into roots, stem, leaves & flowers Have flowers, although they may be small in wind-pollinated angiospermophyta Seeds produced in ovaries which become the fruit Leaves usually as leaf blade and leaf stalk, with veins visible on the lower surface Leaves have waxy cuticle Vascular bundles (veins) are made up of xylem & phloem

Animal phyla Heterotrophic No cell walls No vacuoles No chlorophyll The kingdom of animals is classified according to these characteristics: Heterotrophic No cell walls No vacuoles No chlorophyll Store glycogen

Distinguish between the following phyla of animals, using simple external recognition features: porifera, cnidaria, platyhelminthes, annelida, mollusca and arthropoda.

The six phyla are classified according to features such as: The syllabus specifies 6 of the 30 or more phyla from the animal kingdom that you are responsible for knowing The ones selected are what might be called invertebrates (lack of a spinal cord) The six phyla are classified according to features such as: Number of layers in the body parts The opening for mouth and anus Method of support Phylogenic studies (evolutionary relationship) relies on more genetic studies to support the modern classification of these groups.

Phylum: Porifera (sponges) no clear symmetry No body layer, rather there is an aggregate of different cell types Support is from either silica or calcium based spicules which link together to provide some support i.e. they are attached to a surface Body plan is built around water canals that circulate nutrients through the sponge for ingestion by specialized cells There is no mouth or anus

Phylum: Cnidaria (Jelly fish, Sea anemones, Corals) Body has radial symmetry They have two layers in the body plan Jelly fish are mobile organisms. Sea anemones are sessile organisms Single entrance that serves the cavity & functions as circulation of respiratory gases and nutrients i.e. they have mouth but no anus Have tentacles & stinging cells These organisms are secondary consumers and posses stinging cells with toxins called nematocysts to disable prey Corals secrete a CaCO3 skeleton

Phylum: Platyhelminthes (flatworms) 3 layers in the body plan bilateral symmetry unsegmented, flat body One entrance to “gut” which can have many folds to increase surface area i.e. have mouth, but no anus Largely parasitic, includes flukes

Phylum: Annelida (segment worms) 3 layers to the body plan Bilateral symmetry Body is divided into ringed segments with some specialization of segments Mouth is connected via gut to a separate anus Skin surface is used for gas exchange Many marine forms but also terrestrial species, usually soil burrowing

Phylum: Mollusca (Snails, Slugs, Octopus) Bilateral symmetry with significant modification Have mouth and anus Body plan has three major features Foot, a muscular structure used for movement and burrowing Central visceral mass, contains all the organ structures (separate mouth & anus) Mantle, a folded membrane structure that can surround other tissues and create a cavity containing gill. The mantle frequently secretes a calcareous shell.

Phylum: Arthropoda (Insects, Crustaceans, Spiders, Scorpions, Millipedes) 3 layer body plant with bilateral symmetry Hard exoskeleton composed of chitin Jointed body segments Jointed appendages to each segment At least 3 pairs of jointed legs Some flying organisms in the class Insecta Separate mouth and anus Many free-living but also some parasitic

Dichotomous Keys Each questions divides the group of organisms into two smaller groups based on a pair of alternative characteristics Subsequent groups may focus on more minor details In most cases the characteristic will be readily observed or measurable It is better to choose characteristics that are uninfluenced by environmental variation Shape and number are often good characteristics on which to base alternative pairings A complete key will have each type of organisms being classified separated with a final identifying name

Revision Questions Outline the binomial system of nomenclature. List down the seven levels in the hierarchy of taxa. Using simple external recognition features, distinguish between the following phyla of kingdom plantae: bryophyta, filicinophyta, coniferophyta and angiospermophyta. Using simple external recognition features, distinguish between the following phyla of kingdom animalia: porifera, cnidaria, platyhelminthes, annelida, mollusca and arthropoda.

Using observable characteristics only, design a dichotomous key for identifying the following arthropods.