- Email: [email protected]
Patch of seagrass is oldest organism on Earth
Doug Wechsler/naturepl.com/NaturePL
IN BRIEF Oldest organism on Earth is seagrass
You may not hear this little one’s call... A TARSIER could be screaming its head off and you would never know it. Uniquely among primates, some of the diminutive mammal’s calls are made up of pure ultrasound. Marissa Ramsier of Humboldt State University in California and her colleagues were puzzled to sometimes hear no sound when Philippine tarsiers (Tarsius syrichta) opened their mouths as if to call. Placing 35 wild animals in front of an ultrasound detector revealed that what they assumed to be yawns were high-pitched screams beyond the range of human hearing (Biology
Letters, DOI: 10.1098/rsbl.2011.1149). While some primates can emit and respond to calls with ultrasonic components, none are known to use only ultrasonic frequencies in a call. The dominant frequency of the Philippine tarsier’s ultrasonic call was 70 kilohertz, amongst the highest recorded for any terrestrial mammal. They can hear up to 91 kHz, well beyond the 20 kHz limit of human hearing. Whales, dolphins, domestic cats and some bats and rodents are the only other mammals known to communicate in this way. Having the equivalent of a private communication channel could help tarsiers warn others of predators such as lizards, snakes and birds which can’t detect such frequencies, says Ramsier. Eavesdropping on insects could also help them locate their prey.
…but katydid can be heard from Jurassic MOST sounds vanish forever after a few seconds, but not the calls of a Jurassic katydid. After examining the sound-making structures on its exceptionally preserved fossil wings, biologists have recreated its musical calls. Katydids, or bush crickets, make sounds by rubbing the edge of one wing against a series of teeth on the other. The shape of the teeth determine whether the calls are 18 | NewScientist | 11 February 2012
complex sounds containing many frequencies, or pure tones. The newly discovered fossil katydid (Archabollus musicus) has wing structures that show it “sang” a pure tone at 6.4 kilohertz, within the human audible range, says Fernando Montealegre-Zapata at the University of Bristol, UK (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1118372109).
Sounds at that frequency can travel long distances – useful for night-time communications. Nocturnal mammals cannot easily work out the source of pure tones, which would have helped the katydids escape these predators, says Montealegre-Zapata. Jurassic forests were probably noisy places at night – there is evolutionary evidence that frogs were croaking by this time, and fossils suggest some Jurassic dinosaurs were nocturnal.
IT’S green and very, very old. A swathe of seagrass in the Mediterranean could be the oldest known living thing on Earth. Carlos Duarte of the University of Western Australia in Perth sequenced the DNA of Posidonia oceanica at 40 sites spanning 3500 kilometres of seafloor, from Spain to Cyprus. One patch off the island of Formentera was identical over 15 kilometres of coastline (PLoS One, DOI: 10.1371/journal. pone.0030454). Like all seagrasses, Posidonia oceanica reproduces by cloning, so meadows spanning many kilometres are genetically identical and considered one organism. Given the plant’s annual growth rate the team calculated that the Formentera meadow must be between 80,000 and 200,000 years old, making it the oldest living organism on Earth. It trumps a Tasmanian seagrass believed to be 43,600 years old.
Dad’s got the brains of the family Fatherhood is such a drain on three-spined sticklebacks that males seem to have evolved bigger brains to cope. Male and female brains are different sizes in many species, but never to the extreme that Alexander Kotrschal of Uppsala University, Sweden, has just reported in an Icelandic population of these fish (Gasterosteus aculeatus). He found that male brains weigh 24.2 milligrams on average, compared with the females’ 19.7 mg – although the sexes are typically the same size (PLoS One, DOI: 10.1371/journal. pone.0030055). Males may need bigger brains because they have sole charge of nest building and caring for fertilised eggs, Kotrschal says.
IN BRIEF Oldest organism on Earth is seagrass
You may not hear this little one’s call... A TARSIER could be screaming its head off and you would never know it. Uniquely among primates, some of the diminutive mammal’s calls are made up of pure ultrasound. Marissa Ramsier of Humboldt State University in California and her colleagues were puzzled to sometimes hear no sound when Philippine tarsiers (Tarsius syrichta) opened their mouths as if to call. Placing 35 wild animals in front of an ultrasound detector revealed that what they assumed to be yawns were high-pitched screams beyond the range of human hearing (Biology
Letters, DOI: 10.1098/rsbl.2011.1149). While some primates can emit and respond to calls with ultrasonic components, none are known to use only ultrasonic frequencies in a call. The dominant frequency of the Philippine tarsier’s ultrasonic call was 70 kilohertz, amongst the highest recorded for any terrestrial mammal. They can hear up to 91 kHz, well beyond the 20 kHz limit of human hearing. Whales, dolphins, domestic cats and some bats and rodents are the only other mammals known to communicate in this way. Having the equivalent of a private communication channel could help tarsiers warn others of predators such as lizards, snakes and birds which can’t detect such frequencies, says Ramsier. Eavesdropping on insects could also help them locate their prey.
…but katydid can be heard from Jurassic MOST sounds vanish forever after a few seconds, but not the calls of a Jurassic katydid. After examining the sound-making structures on its exceptionally preserved fossil wings, biologists have recreated its musical calls. Katydids, or bush crickets, make sounds by rubbing the edge of one wing against a series of teeth on the other. The shape of the teeth determine whether the calls are 18 | NewScientist | 11 February 2012
complex sounds containing many frequencies, or pure tones. The newly discovered fossil katydid (Archabollus musicus) has wing structures that show it “sang” a pure tone at 6.4 kilohertz, within the human audible range, says Fernando Montealegre-Zapata at the University of Bristol, UK (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1118372109).
Sounds at that frequency can travel long distances – useful for night-time communications. Nocturnal mammals cannot easily work out the source of pure tones, which would have helped the katydids escape these predators, says Montealegre-Zapata. Jurassic forests were probably noisy places at night – there is evolutionary evidence that frogs were croaking by this time, and fossils suggest some Jurassic dinosaurs were nocturnal.
IT’S green and very, very old. A swathe of seagrass in the Mediterranean could be the oldest known living thing on Earth. Carlos Duarte of the University of Western Australia in Perth sequenced the DNA of Posidonia oceanica at 40 sites spanning 3500 kilometres of seafloor, from Spain to Cyprus. One patch off the island of Formentera was identical over 15 kilometres of coastline (PLoS One, DOI: 10.1371/journal. pone.0030454). Like all seagrasses, Posidonia oceanica reproduces by cloning, so meadows spanning many kilometres are genetically identical and considered one organism. Given the plant’s annual growth rate the team calculated that the Formentera meadow must be between 80,000 and 200,000 years old, making it the oldest living organism on Earth. It trumps a Tasmanian seagrass believed to be 43,600 years old.
Dad’s got the brains of the family Fatherhood is such a drain on three-spined sticklebacks that males seem to have evolved bigger brains to cope. Male and female brains are different sizes in many species, but never to the extreme that Alexander Kotrschal of Uppsala University, Sweden, has just reported in an Icelandic population of these fish (Gasterosteus aculeatus). He found that male brains weigh 24.2 milligrams on average, compared with the females’ 19.7 mg – although the sexes are typically the same size (PLoS One, DOI: 10.1371/journal. pone.0030055). Males may need bigger brains because they have sole charge of nest building and caring for fertilised eggs, Kotrschal says.