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| | However, the definition of "species" has changed over time and is sometimes problematic. | | However, the definition of "species" has changed over time and is sometimes problematic. |
| − | For example, there are cases where two species are not capable of interbreeding, but each is capable of interbreeding with a third species.<ref name="spark">[http://www.sparknotes.com/biology/evolution/speciation/section1.html Speciation] (SparkNotes)</ref>
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| − | Additionally, a "species" is sometimes defined in such a way that groups of creatures that do not ''naturally'' interbreed (perhaps because of geological isolation) are classified as separate species despite the fact that they ''can'' interbreed.<ref name="spark"/>
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| − | Furthermore, many extinct species known only from fossils have been given species names, despite the impossibility of determining their capability of interbreeding.
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| − | ==Origin of the term== | + | == Origin of the term == |
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| | [[Linnaeus]], who introduced the classification system in the 18th century, originally intended "species" to refer to the biblical creation "[[baramin|kinds]]", but the modern definitions of species do not match the biblical kinds. | | [[Linnaeus]], who introduced the classification system in the 18th century, originally intended "species" to refer to the biblical creation "[[baramin|kinds]]", but the modern definitions of species do not match the biblical kinds. |
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| | [[Charles Darwin]] wrote ''The Origin of Species'' {{years ago | 1859}} years ago, hoping to account for the diversity of plant and animal life with an entirely [[naturalistic]] explanation (see [[Theory of evolution]]). | | [[Charles Darwin]] wrote ''The Origin of Species'' {{years ago | 1859}} years ago, hoping to account for the diversity of plant and animal life with an entirely [[naturalistic]] explanation (see [[Theory of evolution]]). |
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| | + | == Defining species == |
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| | + | For example, there are cases where two species are not capable of interbreeding, but each is capable of interbreeding with a third species.<ref name="spark">[http://www.sparknotes.com/biology/evolution/speciation/section1.html Speciation] (SparkNotes)</ref> |
| | + | Additionally, a "species" is sometimes defined in such a way that groups of creatures that do not ''naturally'' interbreed (perhaps because of geological isolation) are classified as separate species despite the fact that they ''can'' interbreed.<ref name="spark"/> |
| | + | Furthermore, many extinct species known only from fossils have been given species names, despite the impossibility of determining their capability of interbreeding. |
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| | ==Ring Species== | | ==Ring Species== |