5.5: 5.5: ClassificationClassification

Topic 5: Ecology & EvolutionTopic 5: Ecology & Evolution

Miss FriedmanMiss Friedman

5.5.1: Binomial system of 5.5.1: Binomial system of nomenclaturenomenclature

►Designed by Carolus Linneaus in 18Designed by Carolus Linneaus in 18thth centurycentury

►Based on idea that every species has a Latin Based on idea that every species has a Latin name, made up of two partsname, made up of two parts

►First part is the name of the First part is the name of the genusgenus►Second part specifies the Second part specifies the speciesspecies►Name should be printed in italics (underlined Name should be printed in italics (underlined

if hand written) and first part capitalizedif hand written) and first part capitalized

ExampleExample

Humans are Humans are Homo sapiensHomo sapiens

5.5.2: Hierarchical system of 5.5.2: Hierarchical system of classificationclassification

►Organisms that share characteristics are Organisms that share characteristics are placed into similar groupsplaced into similar groups

► The more similar their characteristics, the The more similar their characteristics, the closer the groupingcloser the grouping

► The purpose of classification is to:The purpose of classification is to: Clearly identify an organism with a name that is Clearly identify an organism with a name that is

unique to the species and avoids confusion with unique to the species and avoids confusion with local naminglocal naming

Show evolutionary linksShow evolutionary links Allow us to predict anatomical, physiological and Allow us to predict anatomical, physiological and

genetic characteristics it may share with other genetic characteristics it may share with other organismsorganisms

► The Hierarchical system has seven The Hierarchical system has seven levels called levels called taxons (plural: taxa)taxons (plural: taxa)

► Each taxon can contain one or more Each taxon can contain one or more of the sub-group below itof the sub-group below it

► The seven level hierarchies of taxa The seven level hierarchies of taxa are:are:

1.1. KingdomKingdom2.2. PhylumPhylum3.3. ClassClass4.4. OrderOrder5.5. FamilyFamily6.6. GenusGenus7.7. Species Species

5.5.3: Plant Phyla5.5.3: Plant Phyla

►Kingdom: PlantaeKingdom: Plantae►Characteristics:Characteristics:

►PhotosyntheticPhotosynthetic►ChlorophyllChlorophyll►Cellulose cell wallCellulose cell wall►Permanent vacuolesPermanent vacuoles►Stores starchStores starch

►Classification of the major plant phyla is Classification of the major plant phyla is based on external observables based on external observables structuresstructures

►Need to know:Need to know:

-Bryophyta-Bryophyta - -angiospermophytaangiospermophyta

-Filicinophyta -Coniferophyta-Filicinophyta -Coniferophyta

Phylum: Bryophyta Phylum: Bryophyta (Mosses, Liverworts, Hornworts)(Mosses, Liverworts, Hornworts)

► Small terrestrial plantsSmall terrestrial plants► Do not have true roots, stems or leaves but Do not have true roots, stems or leaves but

they must have structures resembling themthey must have structures resembling them► Leaf-like structures are often arranged in a Leaf-like structures are often arranged in a

spiralspiral► Usually have live in clusters which act like Usually have live in clusters which act like

sponges holding watersponges holding water► No cuticleNo cuticle► Reproductive structures are called sporangium Reproductive structures are called sporangium

which is on long stalks with capsules on end.which is on long stalks with capsules on end.

Phylum: Filicinophyta Phylum: Filicinophyta (ferns)(ferns)

►Have true leavesHave true leaves►New leaves unrollNew leaves unroll►Divided leavesDivided leaves►Have an underground creeping stem Have an underground creeping stem

(rhizome)(rhizome)►Height up to 20mHeight up to 20m►Reproduction: sporangia (sori) contain Reproduction: sporangia (sori) contain

reproductive sporesreproductive spores

Phylum: ConiferophytesPhylum: Coniferophytes (conifers & pines)(conifers & pines)

►All conifers are woody plants, most are All conifers are woody plants, most are trees with a single wooden trunk with trees with a single wooden trunk with side branchesside branches

►Leaves are waxy, long thin needles, Leaves are waxy, long thin needles, often arranged in spirals, often a dark often arranged in spirals, often a dark green colourgreen colour

►Produce seeds found in conesProduce seeds found in cones►Vascular system (tracheids)Vascular system (tracheids)

Phylum: AngiospermophytaPhylum: Angiospermophyta (flowering plants and grasses)(flowering plants and grasses)

►Have flowers, although they may be small Have flowers, although they may be small in wind-pollinated angiospermophytain wind-pollinated angiospermophyta

►Seeds are ovaries which become the fruitSeeds are ovaries which become the fruit►Leaves usually as leaf blade and leaf Leaves usually as leaf blade and leaf

stalk, with veins visible on the lower stalk, with veins visible on the lower surfacesurface

►Leaves have waxy cuticleLeaves have waxy cuticle►Vascular bundles (veins) are made Vascular bundles (veins) are made

up of xylem & phloemup of xylem & phloem

5.5.4: Animal phyla5.5.4: Animal phyla►The kingdom of animals is classified The kingdom of animals is classified

according to these characteristics:according to these characteristics:►HeterotrophicHeterotrophic►No cell wallsNo cell walls►No vacuolesNo vacuoles►No chlorophyllNo chlorophyll►Store glycogenStore glycogen

► The syllabus specifies 6 of the 30 or more The syllabus specifies 6 of the 30 or more phyla from the animal kingdom that you phyla from the animal kingdom that you are responsible for knowingare responsible for knowing

► The ones selected are what might be The ones selected are what might be called invertebrates (lack of a spinal cord)called invertebrates (lack of a spinal cord)

► The six phyla are classified according to The six phyla are classified according to features such as:features such as: Number of layers in the body plantNumber of layers in the body plant The opening for mouth and anusThe opening for mouth and anus Method of supportMethod of support

Phylogenic studies (evolutionary Phylogenic studies (evolutionary relationship) relies on more genetic relationship) relies on more genetic studies to support the modern studies to support the modern classification of these groups.classification of these groups.

Phylum: Porifera Phylum: Porifera (sponges)(sponges)

►No body layer, rather there is an aggregate No body layer, rather there is an aggregate of different cell typesof different cell types

► Support is from either silica or calcium Support is from either silica or calcium based spicules which link together to based spicules which link together to provide some supportprovide some support

► Body plan is built around water canals that Body plan is built around water canals that circulate nutrients through the sponge for circulate nutrients through the sponge for ingestion by specialized cellsingestion by specialized cells

► There is no mouth or anusThere is no mouth or anus

Phylum: Cnidaria Phylum: Cnidaria (Jelly fish, Sea anemones, Corals)(Jelly fish, Sea anemones, Corals)

► They have two layers in the body planThey have two layers in the body plan► There is radial symmetryThere is radial symmetry► Jelly fish are mobile organisms. Sea Jelly fish are mobile organisms. Sea

anemones are sessile organismsanemones are sessile organisms► Single entrance that serves the cavity that Single entrance that serves the cavity that

functions as circulation of respiratory gases functions as circulation of respiratory gases and nutrientsand nutrients

► These organisms are secondary consumers These organisms are secondary consumers and posses stinging cells with toxins called and posses stinging cells with toxins called nematocysts to disable preynematocysts to disable prey

► Corals secrete a CaCOCorals secrete a CaCO33 skeleton skeleton

Phylum: Platyhelminthes Phylum: Platyhelminthes (flatworms)(flatworms)

►3 layers in the body plan3 layers in the body plan►One entrance to “gut” which can have One entrance to “gut” which can have

many folds to increase surface area.many folds to increase surface area.►Largely parasitic, includes flukesLargely parasitic, includes flukes

Phylum: Annelida Phylum: Annelida (segment worms)(segment worms)

► 3 layers to the body plan3 layers to the body plan► Bilateral symmetryBilateral symmetry► Body is divided into ringed segments with Body is divided into ringed segments with

some specialization of segmentssome specialization of segments►Mouth is connected via gut to a separate Mouth is connected via gut to a separate

anusanus► Skin surface is used for gas exchangeSkin surface is used for gas exchange►Many marine forms but also terrestrial Many marine forms but also terrestrial

species, usually soil burrowingspecies, usually soil burrowing

Phylum: MolluscaPhylum: Mollusca (Snails, Slugs, Octopus)(Snails, Slugs, Octopus)

► Bilateral symmetry with significant modificationBilateral symmetry with significant modification► Body plan has three major featuresBody plan has three major features

Foot, a muscular structure used for movement and Foot, a muscular structure used for movement and burrowingburrowing

Central visceral mass, contains all the organ Central visceral mass, contains all the organ structures (separate mouth & anus)structures (separate mouth & anus)

Mantle, a folded membrane structure that can Mantle, a folded membrane structure that can surround other tissues and create a cavity containing surround other tissues and create a cavity containing ag ill. The mantle frequently secretes a calcareous ag ill. The mantle frequently secretes a calcareous shell.shell.

Phylum: ArthropodaPhylum: Arthropoda(Insects, Crustaceans, Spiders, (Insects, Crustaceans, Spiders,

Scorpions, Millipedes)Scorpions, Millipedes)

►3 layer body plant with bilateral 3 layer body plant with bilateral symmetrysymmetry

►Hard exoskeleton composed of chitinHard exoskeleton composed of chitin► Jointed body segmentsJointed body segments► Jointed appendages to each segmentJointed appendages to each segment►At least 3 pairs of jointed legsAt least 3 pairs of jointed legs►Some flying organisms in the class Some flying organisms in the class

InsectaInsecta►Separate mouth and anusSeparate mouth and anus►Many free-living but also some parasiticMany free-living but also some parasitic

5.5.5: Dichotomous Keys5.5.5: Dichotomous Keys

► Each questions divides the group of organisms into Each questions divides the group of organisms into two smaller groups based on a pair of alternative two smaller groups based on a pair of alternative characteristicscharacteristics

► Subsequent groups may focus on more minor detailsSubsequent groups may focus on more minor details► In most cases the characteristic will be readily In most cases the characteristic will be readily

observed or measurableobserved or measurable► It is better to choose characteristics that are It is better to choose characteristics that are

uninfluenced by environmental variationuninfluenced by environmental variation► Shape and number are often good characteristics on Shape and number are often good characteristics on

which to base alternative pairingswhich to base alternative pairings► A complete key will have each type of organisms A complete key will have each type of organisms

being classified separated with a final identifying being classified separated with a final identifying namename