Summary
The biological species concept defines a species as a group of interbreeding natural populations reproductively isolated from others.
In depth
The biological species concept (Mayr) applies to sexual organisms; it fails for asexual organisms, fossils and hybridising species. Alternatives: morphological, phylogenetic and ecological concepts.
Species boundaries are often fuzzy, and the concept used affects counts of biodiversity.
No concept fits all life: the biological concept uses interbreeding and reproductive isolation; the phylogenetic concept uses the smallest diagnosable monophyletic group; the ecological concept uses niche; the morphological concept uses form. Ring species, such as Ensatina salamanders, show how gradual differences can accumulate. Bacteria, which swap genes, are particularly hard to classify.
Hybridisation is common, and the genomes of many species, including humans (with Neanderthal DNA at 1 to 2 percent in non-Africans), show gene exchange. Species are better regarded as lineages that diverge along a continuum.
Example: the wolf and the coyote hybridise in the wild, yet remain distinct in most of their range.
Frequently asked questions
What is Species Concept?
The biological species concept defines a species as a group of interbreeding natural populations reproductively isolated from others.
Which area of biology covers Species Concept, and how advanced is it?
Species Concept is one of the 53 topics in Evolution. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Speciation Genomics, Sympatric Speciation, Evolution of Sex.
Can you give an example of Species Concept?
Horses and donkeys breed but produce sterile mules, so they are separate species.
What should I learn before Species Concept?
Work through the Beginner topics in Evolution first, such as Evolution, Natural Selection, Charles Darwin, then return to Species Concept. Intermediate topics assume the Beginner vocabulary.
What topics are related to Species Concept?
The closest topics to Species Concept are Speciation Genomics, Sympatric Speciation, Evolution of Sex, Speciation. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Species Concept?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Species Concept. To practise the whole of Evolution, use the Evolution quiz.
How is Species Concept different from Speciation Genomics?
Species Concept: The biological species concept defines a species as a group of interbreeding natural populations reproductively isolated from others. Speciation Genomics: Genome-wide analysis that identifies the loci and islands of divergence responsible for reproductive isolation. Read both side by side and note what each one explains.
How should I study Species Concept step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Speciation Genomics and explain the difference aloud. Finally, take the Evolution quiz and come back to this page for any question you miss.