A team of researchers built the most complete time‑calibrated evolutionary tree yet for the fish family Scombridae, which includes tunas and mackerels and represents about half of living warm‑blooded, ray‑finned fish species. They combined genetic data with fossil specimens and samples from multiple institutions to place when the family originated.
The results placed the origin of Scombridae near the asteroid strike 66 million years ago, but they showed that the traits of interest evolved later. Large body size and endothermy evolved independently in different Scombridae lineages rather than as a single, rapid response to the K‑Pg extinction. Endothermy arose three times, and at least two of those occurrences happened 10 to 15 million years after the asteroid.
The study’s authors note conservation implications. They point to dramatic declines in Atlantic bluefin tuna from overfishing and say that better evolutionary knowledge can help conservation efforts. The paper appears in Proceedings of the Royal Society B.
Difficult words
- evolutionary — relating to how species change over time
- endothermy — ability of an animal to make its own heat
- lineage — a group of related species over timelineages
- fossil — preserved remains or traces of ancient life
- conservation — protection of nature and wild species
- overfishing — catching too many fish, harming populations
- origin — the time or place where something begins
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How can knowledge about evolution help conservation of fish like bluefin tuna?
- Would you support stricter fishing limits to protect declining species? Why or why not?
- Why do you think traits such as large body size and endothermy might evolve at different times in related species?
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