sábado, 18 de febrero de 2012

Cómo cantaba un grillo del Jurásico

  Fernando Montealegre, expert in physiology, biomecánica and acoustics, which works as investigator associated with the University of Bristol, in England, and in collaboration with the Swiss Daniel Robert, they talk that since there was issuing a grasshopper that lived in the Earth it does 165 million years. His studies have been based on a fossil in mint condition found in China by paleontologists of the University of Beijing, examining the anatomical structure of the wings of the fossil - which are used by crickets and grasshopper to issue sounds - and they compared it with those of 59 current species. Across models and with ' curves of calibration ', they could calculate the frequency that was issuing the insect, a sound of low frequency and with a duration of 16 thousandth ones of second. The current grasshoppers issue sounds rubbing the wings. The insect sings to attract females. The grasshopper of the Jurassic one had a perfectly audible frequency for us. These insects, at present, come to 150 MHz of frequency. The evolution has perfected his singings, strictly to achieve his sexual fitting and to evade the predators that could listen to his sounds. That have developed ultrasonic sounds superior to 150 MHz, it might have had as aim not be detected easily by the bats, which move usually in lower frequencies. The bats appeared it does 65 million years.