IB BIOLOGY TOPIC 5.5 CLASSIFICATION
TOPICS:
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5.5.1 Outline the binomial system of nomenclature
5.5.2 List seven levels in the hierarchy of taxa using
an example from two different kingdoms for each
level.
5.5.3 Distinguish between the following phyla of
plants, using simple external recognition features:
bryophyta, filicinophyta, coniferophyta and
angiospermophyta.
5.5.4 Distinguish between the following phyla of
animals, using simple external recognition features:
porifera, cnidaria, platyhelminthes, annelida,
mollusca and arthropoda.
5.5.5 Apply and design a key for a group of up to
eight organisms.
5.5.1 OUTLINE THE BINOMIAL SYSTEM OF
NOMENCLATURE
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Species are a group of organisms with similar
characteristics which can interbreed and produce
fertile offspring whereas a genus is a group of
similar species.
Species need an international name and so
biologists name them using the binomial system
of nomenclature.
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Each species is given two names. The first is the
genus name and is given an upper case first
letter.
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I.E. Homo
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The second is the species name and is given a lower
case first letter.
I.E. sapiens
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Homo sapien is the correct binomial nomenclature for
humans.
5.5.2 LIST SEVEN LEVELS IN THE HIERARCHY
OF TAXA USING AN EXAMPLE FROM TWO
DIFFERENT KINGDOMS FOR EACH LEVEL.
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Red Kangaroo:
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Diprotodontia
Family: Macropodidae
Genus: Macropus
Species: rufus
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White Oak tree:
Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Fagales
Family: Fagaceae
Genus: Quercus
Species: alba
5.5.3
5.5.4
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Porifera:
no clear symmetry
attached to a surface
pores through body
no mouth or anus
example: sponges
Cnidaria:
radially symmetric
tentacles
stinging cells
mouth but no anus
example: jellyfish
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Platyhelminths:
bilaterally symmetrical
flat bodies
unsegmented
mouth but no anus
example: tapeworm
Annelida:
bilaterally symmetrical
bristles often present
segmented
mouth and anus
example: earthworm
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Mollusca:
muscular foot and mantle
shell may be present
segmentation not visible
mouth and anus
example: slugs and snails
Arthropoda:
bilaterally symmetric
exoskeleton
segmented
jointed appendages
example: spiders and insects