Slide Deck Summer I 2020

1. Biological
Classification
Systems
BIOL 1307
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3. Learning Objectives:
• Define: Taxonomy, systematics, phylogeny,
cladistics.
• Identify the levels of the taxonomic hierarchy
from domain to species.
• Define: Ingroup and outgroup.
• Use a cladogram to identify monophyletic,
paraphyletic, and polyphyletic groups.
• Use biological information to create a cladogram
• Interpret a phylogenetic tree or cladogram to
determine relationships between species
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4. Classify, Organize, Name
Carl von Linné
AKA Carolus Linnaeus
1707-1778
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Biological
Classification Systems
Are Based on Shared
Characteristics

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The taxonomic hierarchy organizes
species into progressively larger groups.

7. The lingo of the organization of life.
Classification=
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8. The lingo of the organization of life.
Systematics=
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9. The lingo of the organization of life.
Taxonomy=
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10. The lingo of the organization of life.
Phylogeny=
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11. 14-11
Phylogenetics is the study of evolutionary
relationships among species
Section 14.6
A phylogeny is an
evolutionary tree.
The most useful way to
construct the phylogeny
is to use the cladistic
approach.
Figure 14.17
Ancestral characters
(for placental mammals):
Features present in the ancestors
of placental mammals; these
features may also be present in
monotremes and/or marsupials.
Derived characters
(for placental mammals):
Features of placental mammals
that are different from those in
other mammals; arose after the
placental/marsupial split.
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12. The lingo of the organization of life.
Cladistics=
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13. Biological Classification Systems Are
Based on Common Descent
Section 14.6 Figure 14.17
A clade is a group of
organisms consisting of a
common ancestor and all of
its descendants.
Clades
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14. More Vocabulary
• Clade
• Monophyletic
• Polyphyletic
• Paraphyletic
• Ancestral (primitive) characteristic
• Derived characteristic
• Ingroup
• Outgroup
Helpful to know, but not on the test:
• Symplesiomorphy
• Synapomorphy
• Parsimony 14

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A Cladogram Can Be Drawn in
Several Ways

17. A Cladogram Can Be Drawn in
Several Ways
Section 14.6 Figure 14.18
These cladograms all show the same evolutionary relationships.
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18. Identifying Groups in Cladograms
Section 14.6 Figure 14.21
A clade is also called a
monophyletic group.
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20. Identifying Groups in Cladograms
Section 14.6 Figure 14.21
A paraphyletic group
excludes some of the
descendants of an
ancestor. See how
birds are excluded
from Class Reptilia?
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21. Identifying Groups in Cladograms
Section 14.6 Figure 14.21
A polyphyletic group
excludes the most recent
common ancestor of its
members. Birds and
mammals are
endotherms, but their
common ancestor was
not endothermic.
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22. Using Character Variation to Reconstruct Phylogeny
• Reconstructing phylogeny requires
determining ancestors and descendants.
• The form that was present in the
common ancestor is ancestral.
• Characters that arose later are derived
character states.
• An outgroup shows if a character
occurred both within and outside the
common ancestor.
• A series of species that share derived
characters form a subset called a clade.

23. Compare shared
primitive traits and
shared derived
character traits.

24. 14-24
Cladograms can be based on molecular
sequences
Section 14.6
This cladogram compares
variations in DNA sequence.
DNA can be obtained from
living and extinct species,
vastly increasing the amount
of information that can be
used.
Figure 14.21
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27. Homologous structures
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28. Analogous structures
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29. Vestigial structures
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30. Table 14.1
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31. Apply the Scientific Method
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How do scientists obtain
the data to construct a
phylogenetic tree?
What does the data look
like?

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