1. The document discusses speciation and biological classification. It defines what a biological species is and describes pre-zygotic and post-zygotic barriers that lead to reproductive isolation and the evolution of new species. 2. Three types of speciation are discussed: allopatric, parapatric, and sympatric speciation which depend on spatial patterns of populations. 3. Taxonomic classification systems are based on common descent and use a hierarchy from domain to species, while phylogenetics studies evolutionary relationships through cladograms.

1. Speciation
and
Classification
BIOL 1407
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2. 2

3. Learning Objectives (Part I):
• Describe the forces that lead to the evolution of new
species
• Define a biological species
• Compare and contrast several forms of pre-zygotic
and post-zygotic barriers to reproduction
• Compare and contrast allopatric, sympatric, and
parapatric speciation
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4. What is a species?
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5. Western Meadowlark Eastern Meadowlark
https://www.youtube.com/watch?v=lv
AUgFb1cLY
https://www.youtube.com/watch?v
=vDpydv6VbtU
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6. 6

7. 7

8. https://www.youtube.com/watch?v=-XVMfNIJ53I 8

9. 9

10. 10

11. 11

12. Biological Species Concept
•1.
•2.
•3.
Ernst Mayr
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13. 13

14. Reproductive Isolation
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15. Reproductive Barriers Cause Speciation
Section 14.2 Figure 14.4
Prezygotic reproductive barriers =
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16. Practice!
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17. Reproductive Barriers Cause Speciation
Section 14.2
Postzygotic reproductive barriers =
Figure 14.4
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18. Reproductive Barriers Cause Speciation
Section 14.2 Figure 14.24
Stilts: ©Tim Fitzharris/Minden Pictures; Sperm: ©Francis Leroy, Biocosmos/Science Source; Chick: ©S.
Alden/PhotoLink/Getty Images RF; Stilt: USDA Natural Resources Conservation Service
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19. Spatial Patterns Define Three
Types of Speciation
Section 14.3 Figure 14.5
Reproductive barriers arise in three ways, depending
on spatial patterns:
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20. Spatial Patterns Define Three
Types of Speciation
Section 14.3 Figure 14.5
In allopatric speciation,
a barrier physically
separates a population
into two groups that
cannot interbreed.
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21. Spatial Patterns Define Three
Types of Speciation
Section 14.3 Figure 14.7
For example, Galápagos tortoises diverged into several subspecies
on different islands.
Left & right tortoise: ©Tui De Roy/Minden Pictures
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22. Spatial Patterns Define Three
Types of Speciation
Section 14.3 Figure 14.5
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23. Spatial Patterns Define Three
Types of Speciation
Section 14.3 Figure 14.8
Parapatric speciation may
be occurring in little
greenbuls.
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24. Spatial Patterns Define Three
Types of Speciation
Section 14.3 Figure 14.5
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25. Spatial Patterns Define Three
Types of Speciation
Section 14.3 Figure 14.9
Cichlid fish have
diversified into several
species in a small
African lake.
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26. Spatial Patterns Define Three
Types of Speciation
Section 14.3 Figure 14.10
Sympatric speciation also occurs
when gametes unite to form
polyploid offspring with more
chromosomes than either parent.
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27. Learning Objectives (Part II):
• Identify the proper way to name a biological species.
• Name the levels of the taxonomic hierarchy from
domain to species.
• 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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28. Naming species
Carl von Linné
AKA Carolus Linnaeus
1707-1778
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29. Binomial nomenclature
• 2-part name, Latinized
Genus + specific epithet
= Species name (scientific name)
• Typed in Italics
• Underlined when handwritten
• Examples:
Homo sapiens Homo neanderthalensis
Canis lupus Canis latrans
Crotalus atrox Crotalus horridus
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30. Taxonomic Hierarchy
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31. Figure 14.15
Biological Classification Systems Are
Based on Common Descent
Section 14.6
The taxonomic hierarchy
organizes species
into progressively
larger groups.
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32. The lingo of the organization of life.
Classification=
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33. The lingo of the organization of life.
Systematics=
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34. The lingo of the organization of life.
Taxonomy=
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35. The lingo of the organization of life.
Phylogeny=
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36. 14-36
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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37. The lingo of the organization of life.
Cladistics=
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38. 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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40. 40

41. 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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42. Identifying Groups in Cladograms
Section 14.6 Figure 14.21
A clade is also called a
monophyletic group.
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44. 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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45. 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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46. 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.

47. 14-47
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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49. 49

50. Homologous structures
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51. Analogous structures
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52. Vestigial structures
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53. Table 14.1
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