Australia’s frogs are having trouble finding love. Traffic noise and other sounds of city life, such as air conditioners and construction noise, are drowning out the mating calls of male frogs in urban areas, 1eading to a sharp drop in frog populations. But, in the first study of its kind, Parris, a scientist at the University of Melbourne has found that some frogs have figured out a way to compensate for human interference in their love lives.
A male southern brown tree frog sends out a mating call when he’s looking for a date. It is music to the ears of a female southern brown tree frog. But, add the sounds of nearby traffic and the message just is not going out. Parris spent seven years studying frogs around Melbourne. She says some frogs have come up with an interesting strategy for making themselves heard.
“We found that it’s changing the pitch of its call, so going higher up, up the frequency spectrum, being higher and squeakier, further away from the traffic noise and this increases the distance over which it can be for heard,” Parris said.
The old call is lower in pitch. The new one is higher in pitch.
Now, that may sound like a pretty simple solution. But, changing their calls to cope with a noisy environment is actually quite extraordinary for frogs. And while the males have figured out how to make themselves heard above the noise, Parris says it may not be what the females are looking for.
“When females have a choice between two males calling, they tend to select the one that calls at a lower frequency because, in frogs, the frequency of a call is related to body size. So, the bigger frogs tend to call lower,” she explained. “And so they also tend to be the older frogs, the guys perhaps with more experience, they know what they’re doing and the women are attracted to those.”
Frog populations in Melbourne have dropped considerably since Parris began her research, but it is not just because of noise. Much of Australia has been locked in a 10-year drought, leaving frogs fewer and fewer ponds to go looking for that special someone.
Why do some frogs change the pitch of its calls?
由第三段“…further away from the traffic noise and this increases the distance over which it can be for heard,”得知青蛙改变音高是为了避免噪音干扰。
关于绒毛膜癌及侵蚀性葡萄胎的临床分期，II期是指（）
28岁已婚女性，2年前因输卵管妊娠切除右侧输卵管，继发不孕2年，现停经40天，阴道流血10天，尿HCG(+)，B超提示右侧输卵管妊娠3cm×2cm×2cm，盆腔无积液。选择哪种治疗为宜
40岁已婚育妇女，因停经50天，下腹剧烈疼痛2小时急诊。检查：血压70/50mmHg，腹部移动浊音(+)，剖腹探查见左输卵管妊娠破裂型，左输卵管包裹于血块中。选择哪种治疗为宜
40岁已婚育女性，因"先兆流产"做流产刮宫术，术中发现为宫颈妊娠，大量流血，经注射止血药，局部填塞等措施仍血流如注，血压80/60mmHg。此时宜选择哪种治疗
36岁已婚女性，停经45天，阴道流血7天，下腹剧烈疼痛2小时入院。检查：患者面色苍白，腹部移动浊音(+)。剖腹探查诊断为卵巢妊娠，选择哪种治疗方法为宜
最常见的异常胎位是
初产妇，规律宫缩8小时，阴道检查宫口开全，先露部位于坐骨棘水平以下2cm，矢状缝与骨盆横径一致，小囟门位于母体的右侧，胎位是
对母儿危害最大的异常胎位是
胎儿纵轴与母体纵轴平行，先露部宽大而软，胎位是
胎儿枕骨位于母体骨盆左后方，胎位是
