Summary
Methods integrating morphology, genetics and ecology to decide where species boundaries lie.
In depth
Integrative taxonomy combines multiple lines of evidence: morphology, DNA, behaviour, ecology and geography. Coalescent-based methods test species hypotheses.
Integrative taxonomy reduces errors from relying on a single data type. Machine learning aids analysis.
Example: acoustic differences separate cryptic bat species.
Species delimitation is the practice of deciding the boundaries between species, an essential step in discovery and conservation. Modern integrative taxonomy combines several lines of evidence: morphology (measurements and shape), DNA sequences analysed with coalescent models, ecology and habitat, behaviour such as song or courtship, geography and crossing experiments.
Algorithms such as ABGD, GMYC and BPP use genetic data to propose species, and concordance across independent data types gives confidence. Disagreements arise because speciation is gradual, so some groups are recognised as species by one concept and subspecies by another. The decision has consequences for legal protection.
Example: giraffes were proposed to comprise four species on genetic grounds, which would change conservation priorities.
Key idea: species are hypotheses to be tested.
Frequently asked questions
What is Species Delimitation?
Methods integrating morphology, genetics and ecology to decide where species boundaries lie.
Which area of biology covers Species Delimitation, and how advanced is it?
Species Delimitation is one of the 52 topics in Taxonomy & Biodiversity. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Species, Cryptic Species, Conservation Biology.
Can you give an example of Species Delimitation?
African elephants were split into savanna and forest species based on genetics.
What should I learn before Species Delimitation?
Work through the Beginner topics in Taxonomy & Biodiversity first, such as Taxonomy, Binomial Nomenclature, Taxonomic Hierarchy, then return to Species Delimitation. Advanced topics assume the Intermediate vocabulary.
What topics are related to Species Delimitation?
The closest topics to Species Delimitation are Species, Cryptic Species, Conservation Biology, Biogeographic Regions. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Species Delimitation?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Species Delimitation. To practise the whole of Taxonomy & Biodiversity, use the Taxonomy & Biodiversity quiz.
How is Species Delimitation different from Species?
Species Delimitation: Methods integrating morphology, genetics and ecology to decide where species boundaries lie. Species: A basic unit of classification; organisms that can interbreed and produce fertile offspring. Read both side by side and note what each one explains.
How should I study Species Delimitation 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 Species and explain the difference aloud. Finally, take the Taxonomy & Biodiversity quiz and come back to this page for any question you miss.