Taxonomy Notes (PPT)
Define Taxonomy: The classifying of organisms and the assigning of a universally accepted name
Why Classify?
How do taxonomists group organisms when they classify them? They are grouped together based on similarities (now
we also use molecular similarities in addition to physical)
Assigning Scientific Names
Why aren’t common names good to use when identifying an organism? Many have more than one common name
What is used to clear up the confusion? Give them a universally accepted scientific name
Ex: Cougar Felis concolor
Who was Carolus Linnaeus? A Swedish botanist that created the binomial nomenclature system
What is the first part of the scientific name? The genus name
How is it written? It is Capitalized
How must it always appear? Either underlined or written in italics
What is the second part of the scientific name? The species name
How is it written? It is lower case
How must it always appear? Either underlined or written in italics
Example: Human: Genus: Homo Species: Sapiens Scientific name: Homo sapiens
Grizzly Bear: Genus: Ursus Species: Arctos Scientific name: Ursus arctos
Linnaeus’s System of Classification
How many taxa levels does Linnaeus’ classification system have? His system had 7 (there are now 8)
Which taxa level is the largest and most inclusive? Kingdom (modern system is the domain)
Which taxa level is the smallest and most specific? The species
Place the taxa of the classification system correctly into the pyramid.
Species
More specific
Genus
Family
Order
Class
Phylum
Kingdom
The more taxonomic levels two organisms share, the closer related they are
More general
Give the full classification for humans. What is the scientific name for humans?
KINGDOM
Animalia (Animal)
PHYLUM
Chordata (with backbones)
CLASS
Mammalia (fur and milk)
ORDER
Primate
FAMILY
Hominidae (walk upright)
GENUS
Homo
SPECIES
sapiens
Evolutionary Classification
Define Phylogeny: The study of evolutionary relationships based on lines of descent.
What determines evolutionary relationships?
a.
Anatomy and physiology (common structures imply common ancestor)
b. Breeding and behavior patterns
c. Geographic distribution (biogeography)
d. DNA and biochemistry (DNA analysis and molecular clocks)
Cladograms can be used to show these relationships.
Clade or
lineage
What is a clade? A group of
organisms whose members
share homologous features
derived from a common
ancestor.
Speciation
Using Venn diagrams:
 Four groups are represented by circular regions.
 Each region represents different taxonomic levels.
 Regions that overlap, share common members.
 Regions that do not overlap do not have common members.
A
B
C
Label the appropriate regions in the Venn diagram with: mammals, vertebrates, insects, all animals.
A = __all animals__ C = Mammals
B = Vertebrates D = Insects
D
Dichotomous Keys:
What is a dichotomous key?
•
A key that is used to identify different organisms based on physical characteristics.
•
It is made up of sets of two statements that deal with a single characteristic of an organism, such as leaf shape
(toothed or smooth edge) or hair (has hair or doesn’t have hair)
g
e
c
i
f
b
h
j
d
a