Classification of
Living Things
Finding Order in
Diversity
Tacitus bellus
Populus tremuloides
Quaking Aspen
• *To study the diversity of life,
biologists use a classification system to
name organisms and group them in a
logical manner. All Scientist will be
using the same name
• Taxonomy is the branch of biology
that groups and names organisms
based on studies of their different
characteristics.
• Biologists who study taxonomy are
called taxonomists.
• Classification systems change with
expanding knowledge.
Carolus Linnaeus
Carolus von
Linnaeus
(1707-1778)
• Swedish botanist
• Developed Binomial Nomenclature
• ***All Scientist will be using the same
scientific name.
• Two-word naming system
– Genus
» Noun, Capitalized,
Underlined or Italicized
– Species
» Descriptive, Lower Case,
Underlined or Italicized
– Each species is assigned a two-part
scientific name
» Ex. Ursus arctos
System of
Classification
• Linnaeus’s hierarchical system of
classification includes eight levels (from
largest to smallest)
• Grizzly Bear (common name)
Ursus arctos
(scientific name)
–
–
–
–
–
–
–
–
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Eukarya
Animalia
Chordata
Mammalia
Carnivora
Ursidae
Ursus
arctos
Each of
the levels
is called a
TAXON
K
P
C
O
F
G
S
System of
Classification
• Taxonomic categories, an
acronym:
– Domain
– Kingdom
– Phylum
– Class
– Order
– Family
– Genus
– Species
Dear
King
Phillip
Came
Over
For
Good
Soup
Worksheet
Use the table to complete the worksheet
Evolutionary
Classification
• Phylogeny – evolutionary
relationships among organisms
• Evolutionary classification –
strategy of grouping organisms
together based on their
evolutionary history
– Fossil record
– Comparative homologies
– Comparative sequencing of
DNA/RNA among organisms
– Molecular clocks
Molecular Clock
Allows scientist to compare DNA
sequences from two species to
estimate how long it has been since
they diverged from a common
ancestor
Taxonomic
Diagrams
Phylogenetic Tree: Represent
hypothesized evolutionary
relationships
Mammals
Looks like a
Branch on a
tree
Turtles
Lizards and Snakes
Crocodiles
Birds
Taxonomic
Diagrams
Cladogram
Which
organism is
the
outgroup
Mammals
Which 2
organism
are more
closely
related
Crocodiles
and birds
Attempt to trace the
process of evolution by
focusing on shared features
Refer to page 496 to 497
Group
practice
Individual practice
(3)
(6)
(32)
(90)
(493)
The more
specific
you get,
the more
options
you have.
(5,404)
(94,240)
(953,434)
Dichotomous Keys
Identify Organisms
• Dichotomous keys contain pairs of
contrasting descriptions.
• After each description, the key directs
the user to another pair of descriptions
or identifies the organism.
Example:
1. a) Is the leaf simple? Go to 2
b) Is the leaf compound? Go to 3
2. a) Are margins of the leaf jagged? Go to 4
b) Are margins of the leaf smooth? Go to 5
Worksheet
Classification of Living Things
Domains
(Notice the domains on the
chart)
• Most inclusive category
• Larger than a kingdom
• There are 3
– Eukarya – includes the kingdoms
» Protists, Fungi, Plants & Animals
– Bacteria – corresponds to the
kingdom Eubacteria
– Archaea – corresponds to the
kingdom Archaebacteria
Slides 17-23
• Is more specific with the
classification
Kingdoms
• (Eubacteria and Archaebacteria)
Prokaryotes, with or without peptidoglycan
in cell walls
• Protista – Eukaryotes, diverse, not fungi,
plants, or animals
• Fungi – Eukaryotes, multicellular (except
yeasts), heterotrophic, chitin in cell walls
• Plantae – Eukaryotes, multicellular,
autotrophic, cell wall containing cellulose
• Animalia – Eukaryotes, multicellular,
heterotrophic, no cell wall
Kingdom Eubacteria
Streptococcus mutans
(can cause endocarditis
and dental caries)
Bacillus anthracis
(spores can live in soil
for years)
•
•
•
•
•
Common name: Bacteria
Unicellular prokaryotes
Peptidogylcan in cell wall
Ecologically diverse
Basic shapes are cocci, bacilli,
spirilla
• Reproduce both sexually and
asexually
Kingdom Archaebacteria
Archaea
first detected in
extreme
environments, such
as volcanic hot
springs.
• Cell wall does not contain
peptidogylcan
• Cell membrane contains unusual lipids
not found in other organisms
• Live in extreme environments (devoid
of oxygen):
– volcanic hot springs
– brine pools
– black organic mud
Kingdom Protista
• A classification problem – consists of
organisms that cannot be classified
as animals, plants, or fungi
• Most unicellular, some colonial and
some multicellular
• Autotrophic and heterotrophic
• Some move with flagella, pseudopods
or cilia
• Animal-like, plant-like and fungus-like
groups
• Reproduce by mitosis and meiosis
Entamoeba histolytica
Kingdom Fungi
Boletus zelleri
(Edible, but often
infected with fly
larvae)
Epidermophyton
floccosum
(one of the causes of
athlete's foot)
• Most feed on dead, decaying
organic matter by secreting
digestive enzymes into their food
source then absorbing it into their
bodies
• Cell walls of CHITIN
• Most multicellular; some
unicellular
• Heterotrophic
Kingdom Plantae
Sunflowers in
Fargo, North Dakota
Ginkgo biloba
Ginkgos are often very
long-lived. Some
specimens are thought
to be more than 3,500
years old.
• Multicellular
• Nonmotile – cannot move
from place to place
• Cell wall with cellulose
• Mostly photosynthetic
autotrophs
Kingdom Animalia
Hymenoptera
Dialictus zephrum
Txodes scapularis
Deer tick
•
•
•
•
Multicellular
Heterotrophic
No cell walls or chloroplasts
Incredibly diversity
• From
general
to
more
specific
Hierarchical System
of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
6
Kingdoms
How Many Kingdoms?
• Activity: What am I?
Ecotherms vs Endotherms
• Ectotherm, Any so-called
cold-blooded animal; that
is, any animal whose
regulation of body
temperature depends on
external sources, such as
sunlight or a heated rock
surface. The ectotherms
include the fishes,
amphibians, reptiles, and
invertebrates.
• Endotherm, so-called
warm-blooded animals;
that is, those that maintain
a constant body
temperature independent
of the environment. The
endotherms primarily
include the birds and
mammals.