Lab 14 Taxonomy and Phylogenetics - Classification and...

Classification and Phylogenetics
- Lab 14
Modified from “Classification & Evolution” By Robert P. Gendron
14-1
Key Concepts
• Classification
• Phylogenetics
• Cladistics
• Phenetics
• Classical Evolutionary Systematics
Purpose:
• review classification of organisms
• compare three schools of classification in biology
• construct and map the evolutionary relationships of
Caminalcules, fictitious creatures invented by the
evolutionary biologist Joseph Camin
Notes:
• You must complete the lab exercises &
assignment questions before the end of the
class period.
I. Systematics
Systematics is the study and classification of
organisms with the goal of reconstructing their
evolutionary history. Taxonomy is more general
than systematics and can be defined as the science
of identifying, naming and classifying organisms
into groups. Taxonomists may or may not use
evolutionary principles in developing
classification schemes. Most taxonomists use a
hierarchical system to classify species into
increasingly broad groups based on extent of
similarities in morphology and other
characteristics. Linnaeus, a Swedish physician/
botanist in the 1700s, helped develop the two part,
or binomial naming system that we use today to
classify organisms. The first word of the name is
the genus to which the species belongs. The
second name is the specific epithet. The
combination of genus and specific epithet gives us
a complete and unique scientific name for an
organism. For example, the scientific name for
the domestic dog is Canis familiaris (underlined
or italicized, genus name capitalized, species
name lower case). The dog belongs to a larger
group (taxon), the family Canidae. The
classification process continues hierarchically.
The next higher group is the order Carnivora,
which is followed by the class Mammalia,
subphylum Vertebrata, phylum Chordata, and
kingdom Animalia (Table. I).
Table I. Classification of the Domestic Dog. Note: For
plants, the term “Division” is sometimes used in place of
“Phylum”.
Whittaker, in 1969, developed a five kingdom
naming system that includes the kingdoms
Monera, Protista, Plantae, Fungi, and Animalia.
Other classifications schemes have been
proposed: a six kingdom system that divides
prokaryotes into two kingdoms (Eubacteria and
Archeabacteria); a three domain system that
separates organisms into the superkingdoms of
Eubacteria, Archaebacteria, and Eukarya; and an
eight kingdom system that divides prokaryotes
into two kingdoms (Eubacteria and
Archeabacteria) and divides protists into three
kingdoms (Archaezoa, Chromista, and Protista).
These different schemes of classification also
illustrate two extremes among taxonomists --
lumpers and splitters. Taxonomists who are
lumpers prefer to classify things in only a few,
broad groups while splitters favor naming many
groups, resulting in fewer taxa within each group.