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Binomial system of nomenclatureSystem 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 TaxaTaxonomy is the study of
classificationOrganisms 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
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
Phylum: Bryophyta (Mosses, Liverworts, Hornworts)
Small terrestrial plantsDo 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 cuticleReproductive structures are
called sporangium which is on long stalks with capsules on end.
Phylum: Filicinophyta (ferns)
Have true leaves in fronds
New leaves unrollDivided leavesThere is cuticle on
leavesHave an underground
creeping stem (rhizome)Height up to 20m but
not woodyReproduction: 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 woodyProduce naked seeds
found in conesVascular 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 cuticleVascular bundles (veins)
are made up of xylem & phloem
Animal phylaThe kingdom of
animals is classified according to these characteristics:
HeterotrophicNo cell wallsNo vacuolesNo chlorophyllStore glycogen
Distinguish between the following phyla of animals, using simple external recognition features: porifera, cnidaria, platyhelminthes, annelida, mollusca and arthropoda.
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
partsThe opening for mouth and
anusMethod 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 planJelly 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
planBilateral symmetryBody 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 anusBody plan has three major
featuresFoot, 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 segmentsJointed appendages to
each segmentAt least 3 pairs of jointed
legsSome flying organisms in
the class InsectaSeparate mouth and anusMany free-living but also
some parasitic
Dichotomous KeysEach 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 QuestionsOutline 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.
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