Download Classification Systems

LEARNING GOALS:
By the end of class, I will be able to:
 Explain how organisms are classified
 Explain traditional and modern methods of classifying
organism
 Use and create a dichotomous key to identify and
classify organisms
WARM UP – TAXONOMY
How are all the items in a grocery store organized?
What are common ways of organizing things?
Why do we organize things?
INTRODUCTION TO CLASSIFICATION
Taxonomy
The science of naming, identifying and classifying organisms
Biological Classification
The organized grouping of organisms into categories based on:
 physical and structural features
 evolutionary relationships
CARL LINNAEUS
• 1707-1778
• Swedish scientist
• “father” of taxonomy
• classified organisms based on their
physical similarities
• established the current binary naming
system used to name species
Binomial nomenclature
Eg: Homo sapiens = humans
Panthera leo = African lion
BINOMIAL NOMENCLATURE
•
Each organism is assigned a 2 part scientific name using Latin words
(sometimes Greek)
•
Provides a common language for all scientists
Organisms are named using their genus name followed by their species name
 Homo sapiens
Genus name is capitalized
 Homo
Species name is not capitalized
 sapiens
Both genus and species names are italicized
 Homo sapiens
BINOMIAL NOMENCLATURE CONTINUED
Ursus horribilis – grizzly bear
Ursus americanus – North American black bear
Ursus arctos – Alaskan brown bear
Binomial Nomenclature can be used to determine how
closely related to organisms are. Pg 334 Q 5
Also complete Pg 334 Q 6
LEVELS OF CLASSIFICATION
7 main levels or taxa (singular taxon)
kingdom – group of phyla that share similar features
phylum – group of classes that share similar features
class – group of orders that share similar features
order – group of families that share similar features
Humans
Kingdom – Animalia
Phylum – Chordata
Class – Mammalia
Order – Primates
Family – Hominidae
Genus – Homo
Species – Homo sapiens
family – group of genera that share similar features
genus – group of species that share similar features
species – group of organisms that can successfully reproduce
Mnemonic: King Philip Came Over For Great Spaghetti
SIX-KINGDOM CLASSIFICATION SYSTEM
There are 6 kingdoms:
Eubacteria
 Prokaryotes; eg: bacteria
Archaebacteria
 Prokaryotes living in harsh habitats; eg: thermophiles
Protista
 Single or multicellular; some eukaryotes; eg. Algae
Fungi
 Multicellular, heterotrophs; eg: mushrooms, yeast
Plantae
Animalia
See Page 329
THREE DOMAINS
Today, many biologists call the broadest taxon a domain
There are 3 domains:
 Bacteria – prokaryotic cells
 Archaea – prokaryotic cells
 Eukarya – eukaryotic cells
Prokaryotes: no true nucleus, mitochondria or chloroplasts
Eukaryotes: more complex membrane-bound nucleus and
organelles
MODERN CLASSIFICATION
Linnaeus grouped species according to their morphology (structure and
function)
Biologists now use several types of evidence to help classify organisms
including evolutionary relationships
 Fossil records, historical geographical range, protein and DNA
similarities, etc.
 Based on the belief that organisms change over time
Phylogeny is the history of evolution of a species or group of organisms
 Phylogenetic trees (cladograms) are used to show these evolutionary
relationships
PHYLOGENETIC TREES
•
diagram representing evolutionary relationships between different species
•
created using fossil records and similarities in genetic codes
Clade is a group of
species that include a
single common ancestor.
Clades vary in size. A
large clade can include
smaller clades.
DICHOTOMOUS KEYS
• A series of paired statements that lead to the identification of an
organisms
• Used to help identify an unfamiliar organism
Try Activity 9.1.1 on pg 332 – Using a Classification Key
Homework: pg 334 Q’s 1 and 2
DICHOTOMOUS KEYS – MORE PRACTICE
Create a
dichotomous
key using
the
following
footprints.