• Sea-side Splat!
Key Words:
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Classification
Taxonomy
Taxon
Phylogeny
Binomial system
Dichotomous key
• Classification is the grouping of
organisms based on similarities of features.
• Taxonomy is the science of studying
classification. It looks at features and tries to
arrange them in a logical order.
A ‘TAXON’ is a unit of
hierarchical classification:
• ‘hierarchical’ means in ascending
sequence.
• A ‘species’ is the fundamental taxon
• Groups of similar species form the next
largest taxon called a ‘genus’.
• Groups of similar genera form the next
largest taxon called a ‘family’
• …and so on, up to the largest taxon =
Kingdom.
What do you notice about how the
names are written?
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Fucus vesiculosus
Fucus serratus
Enteromorpha intestinalis
Patella vulgata
Balanus balanoides
Actinia equina
Littorina littorea
‘Binomial’ = 2 names
species – all in
lower case
Fucus vesiculosus
Genus – has
a capital letter
Italics (or underlined)
-to show the words are
different to ordinary text.
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Panthera leo
Panthera tigris
Panthera pardus
Canis lupus ( and Canis domestica)
Pan troglodytes
Ovis aries
Rattus norvegicus ; Rattus rattus
Perca fluviatalis
Carcharodon carcharias
…and some easier ones!
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Boa constrictor
Gorilla
Giraffus
Hippopotamus amphibius
Bison bison
Equus zebra
Tyrannosaurus rex
Elephas maximus
Classification is hierarchical!
Each unit is called a TAXON –
there are 7 of them.
Kingdom
Phylum
Class
Order
Family
Genus
species
Cat
Taxon
Man
KINGDOM
Animalia
Animalia
PHYLUM
Chordata
Chordata
CLASS
Mammalia
Mammalia
ORDER
Carnivora
Primates
FAMILY
Felidae - cats
Anthropoids - apes
Genus
Felis
Homo
species
cattus
sapiens
You need to remember the
sequence for the exam… so
here’s how!
‘Kinky Priests Come Over For
Great Sex’
Phylogeny
• A phylogenetic tree is a family tree that
shows a hypothesis about the evolutionary
relationships thought to exist among groups
of organisms. It does not show the actual
evolutionary history of organisms.
• Why a hypothesis?
Phylogenetic trees are usually
based on a combination of
these lines of evidence:
Fossil record
Morphology
Embryological patterns of
development
Chromosomes and DNA
Fossils
Similar
morphology
Embryology
DNA similarities
A phylogenetic tree
The Dichotomous key
• A key is a device for easily and quickly identifying
an unknown organism.
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The dichotomous key is the most widely used type in
biological sciences.
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The user is presented with a sequence of choices between
TWO statements, couplets, based on characteristics of the
organism. By always making the correct choice, the name of
the organism will be revealed.
A. one pair of wings ( goto 2)
1.
B. Two pairs of wings (goto 3)
Make a dichotomous key
Phylogenetic example:
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2
3
4
5
a) Endotherm (constant body temperature)
Goto 2
b) Ectotherm ( cold-blooded)
Goto 5
a) Fur
Goto 3
b) Feathers
Parrot
a) Fins
Whale
b) At least two legs
Goto 4
a) wings
Bat
b) 4 legs
Cat
a) fins
Fish
b) No fins or limbs
Snake