A new study suggests scientists have underestimated how many vertebrate species live on Earth. The researchers report that, on average, morphologically defined vertebrate species hide roughly two unrecognized, or “cryptic,” species. John Wiens, a professor at the University of Arizona, says this could mean twice as many species as previously thought and that many hidden species might already be at risk.
The study notes that cryptic species look almost the same but their DNA reveals separate genetic lineages. Advances in molecular sequencing have made DNA comparisons easier and less costly, and researchers used these tools to find hidden diversity. The team synthesized results from more than 300 published studies and compared methods for estimating cryptic species.
The paper highlights conservation problems: when a widespread species is split, each new species has a smaller geographic range and is more likely to face extinction. Few cryptic species have formal names or legal protection, and managers can breed different species unintentionally.
Difficult words
- vertebrate — animal with a backbone or spinal column
- morphologically — in the way an organism looks or forms
- cryptic — difficult to see or recognize as different
- lineage — sequence of ancestors or genetic family linelineages
- sequencing — process of reading the order of DNA
- synthesize — to combine information or results into onesynthesized
- extinction — complete disappearance of a species from Earth
- protection — legal or practical measures that keep species safe
- underestimate — to think a number is smaller than actualunderestimated
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Discussion questions
- How might finding more cryptic species change conservation priorities where you live?
- What problems could happen if managers accidentally breed different hidden species?
- Do you think researchers should use more DNA sequencing even if it costs money? Why or why not?
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