Biology 112
Outcome:

 Students should be able to:
 Understand the concept of binomial nomenclature as
developed by Linneaus and understand its advantages
for the scientific community
Principles of Taxonomy

 Classification systems are used to name organisms
and group them in a logical manner
 Taxonomy is the study of classification of living
things
 Organisms are living things that can be assigned a
classification based on their physical characteristics
Assigning Scientific
Names

 Referring to organisms by their common name can
be confusing
 Scientists have agreed to use a single name for each
species
 A species is a group of similar organisms that can
breed and produce fertile offspring
 Latin and Greek are used when assigning scientific
names
Binomial Nomenclature

 Carolus Linneaus (1707-1778) developed a two word
naming system called binomial nomenclature for all
species
 It is always written in italics, the first word is always
capitalized and the second word in lower case
 The first word indicates the genus (closely related
organisms) to which the species belongs
 The second word indicates the species, which may give
indication about a particular trait of the organisms
 Sometimes, there is a third word to indicate a subspecies
(which is called trinomial nomenclature)
Example of Binomial
Nomenclature

 Canis lupus is the gray
wolf with over 37
subspecies - binomial
 One of those subspecies
is the domestic dog,
which is named Canis
lupus familiaris
- trinomial
Check for Understanding

Do the organisms Ursus arctos and Ursus maritimus
belong to the same genus? Same species?
What characteristic do you feel as though the word
‘arctos’ conveys? ‘maritimus’?
Linnaeus’s Classification
System

 There are 7 levels that are considered to be hierachical –
from largest to smallest
 Each of these levels is called a taxon or taxonomic
category
 Kingdom
 Phylum
 Class
 Order
 Family
 Genus
 Species
Kingdom – plants and
animals

Phylum

 Organisms share
certain characteristics
 One such phylum
include mammals,
whom belong to
Phylum Chordata
Class

 Class Mammalia
 Narrows the
characteristics further
 In this case, all the
characteristics of the
phylum chordata with
the addition of warmblooded, have body
hair and produce milk
for their young
Order

 Similar families are
grouped into an order
 Order carnivora
 All the characteristics of
class mammalia with
the addition of meat
eaters
Family

 A group of genera that
share many common
characteristics
Genus and species

 Homo sapien
For the remainder of class…

 Textbook – read pages 447-450 and complete the
gudied reading for Section 18.1
 Complete question 6 on page 450
 Complete the question in the envelope...
 Section 18-1 Review – due the end of class