TAXONOMY
SBI3U  
A Good Classification     1. It groups together all things that are
similar. 2. It excludes all things that are
dissimilar. 3. It serves a function.
TAXONOMY IS… the science of
discovering naming describing classifying
organisms
DISCOVERING
Danionella dracula Discovered in Burma Documented 2009 © Ralf Britz | Natural History Museum, London
The discovery of new organisms is the first step of taxonomy. Every year, new discoveries are made throughout the world, as taxonomists explore new areas, or new tools become avail- able for analyzing specimens.
TA X
O N
O M
Y IS
Electrolux addisoni (Compagno & Heemstra, 2007)
Not your average vacuum cleaner!
What’s in a name? A scientific name is the passport by which all organisms are known.
NAMING TA
X O
N O
M Y
Photo: Phil Heemstra | Wikimedia Commons
DESCRIBING Part of this process involves the comparison to related organisms to confirm if the species is new.
TA X
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Y IS
CLASSIFYING
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N O
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IS
LINNAEUS
"If you do not know the names of things, the knowledge of them is useless"
Critica Botanica 1737
Carl von Linné (or Linnaeus), the “father of taxonomy”, laid the foundations for the modern scheme of nomenclature - the discipline of naming species.
N A
M ES
M A
TT ER
Linnaeus gave classification the consistency and precision we need when we describe bio- diversity, trade commodities, buy seeds for farming, manage pests, or deal with any other of the many areas in which humans need taxonomic knowledge.
Carl von Linné, 1707-1778 Drawing: AMNH Library
Carolus  Linnaeus  
• Described  organisms  with  two  word  names   • Developed  binomial  nomenclature   • First  word  =  genus  name   • Second  word  =  species  name  
Modern classification is based on the 18th century work of Carolus Linneaus
• Organisms are assigned to groups called “taxa” (sing. “taxon”)
• Taxa are hierarchically arranged
• Each subsequent taxon contains fewer species than the preceding taxon
• Only members of “species”, the smallest taxon, are able to produce fertile offspring
Why  binomial  nomenclature?  
• Much  easier  than  a  10+  word  name  under  old   “polynomial  system”  
• Same  name  no  maFer  where  you  go   • Less  confusion   • Binomial  =  SCIENTIFIC  NAME  
What  is  a  species  anyway?  
• Biological  species  concept   –A  group  of  actually  or  potenLally  breeding  natural   groups  that  are  reproducLvely  isolated  from  other   groups.  
» Ernst  Mayr,  1924  
ScienLfic  Names  You  May  be  familiar   with  
• Homo  sapiens   • Canis  lupus   • Felis  domes0cus  
All  organisms  classified  in  a  hierarchy  
• Kingdom  (broadest)   • Phylum   • Class   • Order   • Family   • Genus   • Species  (most  specific)  
↓KINGDOM ↓
PHYLUM ↓
CLASS ↓
ORDER ↓
FAMILY ↓
GENUS ↓
SPECIES
↓ ANIMALIA ↓
CHORDATA ↓
MAMMALIA ↓
CARNIVORA ↓
ODOBENIDAE ↓
ODOBENUS ↓
Dichotomous Key…
ØBiological key ØA series of branching two-part statements used to
identify organisms (or objects) ØEach step offers two mutually exclusive options
designed to divide one group of organisms into two smaller groups
ØCan be used to identify organisms using visual
information alone
Characteristics – organized either: A)Spider Key à similar to a tree diagram
List Structure