2. Learning Objectives
• Define a biological species.
• Describe the forces that lead to the evolution of new
species.
• Categorize the various reproductive isolating
mechanisms.
• Compare and contrast several forms of prezygotic and
postzygotic barriers to reproduction.
• Compare and contrast allopatric and sympatric
mechanisms of speciation.
• Identify the proper way to name a biological species.
• Describe different species concepts.
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21. Spatial Patterns of Speciation
Section 14.3 Figure 14.5
Reproductive barriers arise in three ways, depending
on spatial patterns:
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22. Spatial Patterns of Speciation -
Allopatric
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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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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31. 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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