Ch. 10
Classification and Phylogeny
of Animals
ORDER from DIVERSITY!
1.5 million species of
animals named,
thousands added
every year
 “Natural System” of
classification: Animals
grouped according to
evolutionary
relationships based on
shared features

Systematic Classification
Based on Comparative biology
 Studies variations among animal
populations
 3 goals of Systematic Zoologists:

– Discover all species of animals
– Reconstruct their evolutionary relationships
– Classify them accordingly
Linnaeus & Classification
Each level is called a taxon.
This is the taxonomy of a human.
Kingdom: Animalia
Phylum: Chordata
Class:
Mammalia
Order:
Primates
Family: Hominidae
Genus: Homo
Species: sapiens
These are the 7 mandatory taxons
To Remember…
Use a memory sentence to remember the
order of the taxa, like…
Kings
King
Play
Phillip
Chess
Came
On
Over
Fine
For
Green
Great
Silk
Spaghetti
Naming
Scientific names or Latin names
 2 names = BINOMIAL NOEMNCLATURE of
the last two taxa

– Genus species
– Ex. Thunnus albacares
Naming
TRINOMIAL NOMENCLATURE?
Subspecies
Examples:
 Animals: breeds, races, ethnicity
 Plants: breeds, varieties
Somateria mollissima dresseri
Somateria mollissima borealis
What is a species?
GENERAL DEFINITION
 An interbreeding population
 Smallest phylogenetic grouping
 Has a geographic range (where it is
found)
 Has a evolutionary duration (when it has
lived)
Species

COSMOPOLITAN –
large, even worldwide
distribution

ENDEMIC – small or
restricted range of
habitat
Wallaroos
Typological Species Concept
Species defined by fixed, immutable
morphological features
 Defined a species with a Type Specimen
 Pre-dates Darwin but many features of
this system still used.

Biological Species Concept
-Based on interbreeding populations of common
descent that occupies a specific niche and share
morphology.
-Sibling Species: morphologically identical
populations that do not interbreed (ecological
races)
Evolutionary Species Concept
- Addresses time dimension lacking in biological concept
- Can include fossils
- Single lineage of ancestor-descendant populations distinct
from other lineages
Phylogenetic Species Concept
Based on groupings that cannot be subdivided further with physical AND
evolutionary characteristics
 Emphasizes common descent
 Most useful in Modern Cladistics

Phylogeny

Study of the phyla, evolutionary “tree”
that relates extant and extinct species.
Accomplished by
studying characters,
features used for
comparison
Characters
Homology – similar characteristics that
come from a similar ancestry (divergent
evolution)
 Homeoplasy - similar characteristics that
come from a different ancestry
(convergent evolution)
 Ancestral (relictual) – trait shared with
ancestors
 Derived – “new” trait, different from
ancestors

Sources of Characters
(Phylogenetic Info)
Morphology/ anatomy/physiology
 Evolution
 Biochemistry (enzymes, DNA)
 Environmental aspects
 Comparative cytology

Organization/Diagrams
Clades – species that share derived
characteristics form groups called clades,
unit of evolutionary common descent
 Cladogram – a branching classification
diagram that shows NESTED hierarchies of
organisms; branch length arbitrary

Simple cladogram
Characteristics to the
right indicate what
groups branch out,
and when
 Branches to the left
show the groups that
do not have the
necessary
characteristics to
continue on the
“family tree”

http://dragon.seowon.ac.kr/~bioedu/bio/ohp/t-130.jpg
Cladogram based on characters
science.kennesaw.edu/.../LecIntro/CladVert.GIF
Characters are listed in the table to the left
 Cladogram shows how these characteristics
and groups branching off are sorted

Sphyraena
Pomatomus
Acanthocybium
Sarda
Auxis rochei
Scombridae
Auxis thazard
Scomber
Lepidocybium
Ruvettus
Neoepinnula
Gempylus
Thyrsites
Nesiarchus
Rexea
Gempylidae
Paradiplospinus
Diplospinus
Promethichthys
Nealotus
Assurger
Cladogram
made from
genetic
characteristics
Lepidopus altifrons
Trichiurus
Lepidopus caudatus
Aphanopus
Benthodesmus
Trichiuridae
Organization/Diagrams

Phylogenetic Tree – diagram representing
REAL evolutionary lineages; branch length
indicate ancestors, relative amount of
changes in characters
Phylogenetic Tree –
distances depict
changes
Phylogenetic
Trees
Kingdoms
Whittaker’s Five-Kingdom classification