Animal Classification,
Phylogeny, and
Organization
Chapter 7
(Systematics)
There are between 1.5 and 2 million species
or “kinds” of animals
And between 4 and 30 million more species
to be discovered & classified
Classification: The ordering of organisms into
groups on the basis of their relationships
Taxonomy: The science of naming organisms
Systematics: Determining evolutionary
relationships of organisms
Karl von Linné
(Carolus Linnaeus)
(1707-1778)



Swedish Botanist that recognized that different
species could be grouped into broader
categories based on shared characteristics
Created binomial naming system
Modern classification system used today
Persian Cat



Shares characteristics with other domesticated
cats (tabby, hairless)
Domesticated cats share characteristics with
other types of cats (bobcat, puma)
Which share characteristics with dogs, bears,
pigs
Mammals!
Hierarchical system of classification: Arranged
organisms into an ascending series of groups
based on relatedness. These major groups are
called taxa.
Taxonomic Hierarchy
DOMAIN
KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES
Taxonomic Groups
Hierarchy of Relatedness
Each group contains animals having more in common with each
other than with the members of any other equivalent category
DOMAIN
KINGDO
M
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES
Domains
Eukaryota
ALL eukaryotic organisms
“True nucleus”
Domains
Eubacteria
Prokaryotic microorganisms
“true” bacteria
Domains
Archaea
Prokaryotic microbes that live
in extreme environments.
(anaerobic)
Most primative life-forms
known
Robert H. Whittaker – Distinguished kingdoms
based on cellular organization and mode of
nutrition.
DOMAIN
KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES
There are five……
Kingdoms of Life
Monera
Protist
Plant
Fungi
Animal
Kingdoms
Monera
All prokaryotes!
Single celled
-peptidoglycan
Make or absorb food
Bacteria and cyanobacteria (blue-green algae)
Kingdoms
Protista
Eukaryotic
single cells or colony
of cells
Protozoa, amoeba, paramecium
Kingdoms
Fungi
Eukaryotic
multicellular
cell wall
-chitin
non-motile
absorb food
Mold, yeast, fungi
Kingdoms
Plantae
Eukaryotic
multicellular
cell wall
-cellulose
non-motile
produce food
-photosynthetic
Higher plants, multicellular algae
Kingdoms
Animalia
Eukaryotic
multicellular
lacks cell wall
motile
ingest food
Vertebrates, Invertebrates
Animal Kingdom






Subdivided into more than 30 phyla (pl)
Each phylum divided into classes
Each class into orders
Each order into families
Each family into genera (pl)
Each genus into species
A common pond crayfish is classified as:
Kingdom Animalia
Phylum Arthropoda
Class Crustacea
Order Decapoda
Family Cambaridae
Genus Procambarus
Species P. acutus
Every phylum must have at least one class, order, etc..
More specialized levels of taxonomy deal with
further subdivisions such as superfamily or
subfamily, suborder, or subspecies
Linnaeus’ system for naming species known as binomial
nomenclature (two names) or “scientific name”
Universally accepted
No two animals have the same name
Homo sapiens
1st word: Name of genus (capitalized)
2nd word: Name of species (lower case)
Entire word italicized or underlined (Latin origin)
Homo sapiens Homo sapiens H. sapiens
The scientific name for a crayfish is Procambrus
acutus
Animal Systematics


Goal: To arrange animals into groups that reflect
evolutionary relationships.
There are 3 types of groups.
Monophyletic group:
Groups with single
ancestral species and its
decendents.
Polyphyletic group:
Members can be traced to
separate ancestors.
Paraphyletic group:
Some but not all members
of a lineage.
Cladogram
Cladograms
Taxa
Depicts a sequence in the origin
of derived characters.
Characters
Patterns of Animal Organization
Animal Symmetry
How parts of an animal arrange around a point or axis
Asymmetry: Absence of a central
point or axis around which body parts
are equally distributed (protists,
sponges)
Animal Symmetry
How parts of an animal arrange around a point or axis
Radial: Divides into similar halves by
more than two planes (sea anemone,
jellyfish)
Animal Symmetry
How parts of an animal arrange around a point or axis
Bilateral: Arrangement of body parts so
that a single plane divides the animal into left
& right mirror images
(vertebrates)
Cephalization: Formation of a distinct head
Bilateral Symmetry
Bilateral Symmetry
Anterior
Posterior
Head end
Tail end
Bilateral Symmetry
Dorsal
Ventral
Back of an animal
Belly of an animal
Bilateral Symmetry
Medial
Lateral
Midline of the body
Sides of the body
Bilateral Symmetry
Superior
Inferior
Above a point of reference
Below a point of reference
Bilateral Symmetry
Distal
Proximal
Far from the middle or point of
attachment
Close to the middle or point of
attachment
Radial Symmetry
Aboral
Oral
End opposite the mouth
End containing mouth
Diploblastic Organization
•Simplest tissue level organization
•2 layers:
•Ectoderm-outer layer, gives rise to
epidermis.
•Endoderm-gives rise to the tissue
that lines the gut.
Triploblastic Organization
•3 layers
•Ectoderm-outer layer of body
wall
•Endoderm-lines the gut
•Mesoderm-gives rises to
supportive, contractile and
blood cells.