Summary
Species with few close relatives, such as the tuatara, representing unique branches of evolutionary history.
In depth
EDGE of Existence programme targets species with few relatives and high extinction risk, such as the Chinese giant salamander and long-beaked echidna. Their loss would erase unique evolutionary history.
EDGE lists prioritise species representing deep branches. Loss is irreplaceable. Examples include the elephant shrew and pangolins.
Remember: losing a lone lineage erases millions of years.
Some species sit on long, isolated branches of the tree of life with few or no close living relatives, so they represent unique evolutionary history. Examples are the tuatara, aye-aye, pangolins, platypus, coelacanth, the Chinese giant salamander and the ginkgo.
The EDGE programme (Evolutionarily Distinct and Globally Endangered) of the Zoological Society of London combines evolutionary distinctiveness (ED) with extinction risk (GE) to rank species for conservation, so those with most to lose receive priority attention. Extinction of such a species removes a whole lineage and its unique traits and gene sets, as when the Yangtze river dolphin (baiji) was lost.
Example: the saola and the Cuban solenodon rank high on EDGE.
Key idea: protecting distinct species preserves the breadth of the tree.
Frequently asked questions
What is Evolutionarily Distinct Species?
Species with few close relatives, such as the tuatara, representing unique branches of evolutionary history.
Which area of biology covers Evolutionarily Distinct Species, and how advanced is it?
Evolutionarily Distinct Species 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 Living Fossils, Phylogenetic Diversity, Endemic Species.
Can you give an example of Evolutionarily Distinct Species?
The tuatara is the only living member of an order of reptiles.
What should I learn before Evolutionarily Distinct Species?
Work through the Beginner topics in Taxonomy & Biodiversity first, such as Taxonomy, Binomial Nomenclature, Taxonomic Hierarchy, then return to Evolutionarily Distinct Species. Advanced topics assume the Intermediate vocabulary.
What topics are related to Evolutionarily Distinct Species?
The closest topics to Evolutionarily Distinct Species are Living Fossils, Phylogenetic Diversity, Endemic Species, Linnaeus. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Evolutionarily Distinct Species?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Evolutionarily Distinct Species. To practise the whole of Taxonomy & Biodiversity, use the Taxonomy & Biodiversity quiz.
How is Evolutionarily Distinct Species different from Living Fossils?
Evolutionarily Distinct Species: Species with few close relatives, such as the tuatara, representing unique branches of evolutionary history. Living Fossils: Species like the coelacanth and ginkgo that resemble ancient lineages with few relatives. Read both side by side and note what each one explains.
How should I study Evolutionarily Distinct Species 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 Living Fossils and explain the difference aloud. Finally, take the Taxonomy & Biodiversity quiz and come back to this page for any question you miss.