The first hammerhead shark was likely the result of a genetic deformity. A biologist explains how shark DNA reveals hammerheads’ history.
A great hammerhead shark's two eyes can be 3 feet apart on opposite sides of its skull. Ken Kiefer 2/Image Source via Getty Images
To make up for that trade-off, hammerhead sharks have special sense organs, called ampullae of Lorenzini, scattered on the underside of their hammer. These porelike organs can detect electricity. The hammerhead family treeIt would be nice if scientists like me could look at fossils and trace the development of hammerhead sharks over time. Unfortunately, fossils of hammerhead sharks are almost entirely of their teeth. That’s because the bodies of sharks do not have bones. Instead they’re made of cartilage, which is what your ears and nose are made of. Cartilage breaks down much more quickly than teeth or bones do, so it rarely gets fossilized.
Scientists long assumed the first hammerhead sharks did not have much of a hammer but, over time, some slowly evolved bigger hammers. We thought the different hammerhead sharks living today were snapshots from different periods in the evolutionary process — with the small hammerheads being the oldest species on the family tree and the huge hammerheads being the newest ones on the scene.
On the left is the expected evolution of hammerheads, assuming a gradual change of head shape. On the right is the observed pattern of evolutionary change based on DNA sequence data. Gavin Naylor, CC BY-ND
Österreich Neuesten Nachrichten, Österreich Schlagzeilen
Similar News:Sie können auch ähnliche Nachrichten wie diese lesen, die wir aus anderen Nachrichtenquellen gesammelt haben.
This bizarre DNA event recording system can track cellular activity from birth to deathThis recording system employs encoded DNA tapes to memorize the changes taking place in a cell during different stages of life.
Weiterlesen »
NJ police used baby DNA to investigate crimes, lawsuit claimsA man was identified as a suspect after his child’s blood was analyzed.
Weiterlesen »
Joe Manganiello’s Surprising Family Roots Revealed by DNAAs it turns out, the ‘Magic Mike’ actor’s paternal grandfather isn’t who he believed it to be, but rather was a Black and mixed-race man.
Weiterlesen »
Tamara McLoyd DNA on handgun marked as evidence in police officer killingDNA linked Tamara McLoyd to a gun found during her arrest, but a forensic expert couldn't say when or how her DNA got on the weapon.
Weiterlesen »
2 Ways to Overcome the Awkwardness of Offering CondolencesStop worrying about the 'right' way to support someone who's dealing with loss and grief and just be there. It means more than you realize.
Weiterlesen »
Other Sharks in Your AreaA nurse shark, a shark named Josh who will correct your pronunciation of “Kyiv” and “Saoirse Ronan,” and other sharks in your area.
Weiterlesen »