Download 5.5 Classification

5.5
Classification
5.5.1
Outline the binomial system of nomenclature.
• Physician Carolus Linnaeus (1708-1778)
• Each species has two names, to give a precise reference to this
species
• Genus is given first and is always written with an upper case
letter.
– Homo
• Species follows the genus and is written in lower case
– sapiens
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Therefore the species name for humans is Homo sapiens
If written by hand underlined
If typed italics but this convention is often ignored
Often the name will be followed by another name in brackets
e.g. (Dickson) which refers to the first person to scientifically
identify the species.
5.5.2
List seven levels in the hierarchy of taxa—kingdom, phylum,
class, order, family, genus and species—using an example from
two different kingdoms for each level.
Taxonomic
Nomenclature
Human
Potato
Kingdom
Phylum
Class
Order
Family
Genus
Species
Animalia
Cordata
Mammilia
Primates
Hominids
Homo
Sapien
Plantae
Angiosperms
Eudicots
Solanales
Solanaceae
Solanum
Tuberosum
5.5.3
Distinguish between the following phyla of plants, using simple
external recognition features: bryophyta, filicinophyta,
coniferophyta and angiospermophyta.
• Bryophyta:
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stems radial symmetry (mosses)
stems bilateral symmetry (liverworts)
no true leaves or roots
no cuticle
reproductive structure are called sporangium
which are on long stalks with capsules on end. In
this image the spore is released from the
sporangium to develop into another plant.
• Filicinphyta:
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leaves
roots non woody stems
divided leaves
height up to 20m
reproduction: sporangia (sori) contain reproductive
spores
• Coniferophyta:
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Conifer and pines
trees (100m), shrubs,
woody (lignin) stems,
waxy narrow needle like leaves.
vascular system (tracheids)
reproduction:monoecious, microsporophylls (male) non motile
gametes often with air bladders for water/ air dispersal.
macrosporophylls (female) ovule on cone
• Angiospermophyta:
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Flowering plants and grasses
roots
stems
leaves.
vascular bundles (xylem/ phloem )
waxy cuticle,
annual or perennial up to 100m
reproduction:
ovules in an enclosed structure.
pollen grains produced from anthers
variety of pollen transfers vectors
5.5.4
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 number of layers in the
body plant, the opening for mouth and anus
and the method of support.
• Phylogenic studies (evolutionary relationship)
relies on more genetic studies to support the
modern classification of these groups.
• Phylum: Porifera (sponges)
– No body layers 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.
– Body plan is built around water canals that
circulate nutrient through the sponge for ingestion
by specialized cells.
– There is no mouth or anus
• Phylum: Cnidaria (Jelly fish, Sea anemones,
Corals)
– These have 2 layers in the body plan.
– There is a radial symmetry.
– Jelly fish are mobile organisms. Sea anemones are
sessile organisms.
– Single entrance that serves the cavity that
functions of the circulation of respiratory gases
and nutrient. 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.
– One entrance to 'gut'
which can have many
folds to increase surface
area.
– largely parasitic includes
flukes
• Phylum: Annelida (segment worms)
– 3 layers to the body plan / bilateral
symmetry
– body divided into ringed segments
with some specialization of segments
– Mouth connected via gut to a
separate anus.
– Skin surface used for gas exchange.
– Many marine forms but also
terrestrial species usually soil
burrowing
• Phylum: Mollusca (Snails, slugs and octopus)
– Bilateral symmetry with significant modification.
– An extraordinarily varied group.
– Phylogenic studies place them closer to annelids
than other groups.
– Body plan has three major features:
• Foot, a muscular structure used for movement and
burrowing.
• Central visceral mass containing all the organ structures
(separate mouth and anus)
• May have tissues that create a cavity containing a gill.
• The mantle frequently secretes a shell
• Phylum: Arthropoda ( Insects, Crustaceans,
Spiders, Scorpions, Millipedes)
– 3 layer body plant with bilateral symmetry.
– Hard exoskeleton composed of chitin.
• Chitin now used for surgical thread because of strength
– Jointed body segments.
– Jointed appendages.
– Some flying organisms in the class Insecta.
– Separate mouth and anus.