地球上的热带地区物种繁多。那里千姿百态、各种各样的生物远比地球上其他温度较低地区的物种要多得多。一项新的研究宣称,热带地区生物多样性的秘密可并非是那必不可少的高温——一整年持续不变的稳定温度才是关键所在。
The earth's tropics teem with species. They're far more biologically diverse than the cooler parts of the planet. And scientists have credited higher temperatures and greater amounts of sunlight. But a new study claims that the secret to tropical biodiversity isn't necessarily high temperatures - it's the steadiness of those temperatures the whole year ‘round. When today's biodiversity was taking shape millions of years ago, seasons as we know them didn't really exist. So temperatures all over the planet were much more consistent than they are today, even in regions where the temps were low. Researchers looked at insect diversity today at the temperate Harvard Forest in Massachusetts, in tropical Costa Rica and in the 53-million-year-old McAbee fossil bed in British Columbia. Which back then was steadily temperate. And ancient Canadian insect diversity was much more similar to modern Costa Rica's than to the Harvard Forest's. The work appears in the journal Paleobiology. So we may have been thinking backwards - it's not that the tropics have greater biodiversity. Could be that the seasons of today's temperate zones have diminished the biodiversity that once flowered. And animaled. -Steve Mirsky
地球上的热带地区物种繁多。那里千姿百态、各种各样的生物远比地球上其他温度较低地区的物种要多得多。科学家们认为造成这一现状的原因是由于热带地区有着较高的温度和更多的日照。但是,一项新的研究宣称,热带地区生物多样性的秘密可并非是那必不可少的高温——一整年持续不变的稳定温度才是关键所在。 现今的生物多样性是在数百万年前就已开始形成了,我们所知的四季当时还并不存在。因此,地球这整个星球的温度都比现在更加始终如一,即使在低温地区也一样。 研究人员在多处地点考察了昆虫多样性的现状,包括温带的马萨诸塞州的哈佛森林、热带的哥斯达黎加、以及位于不列颠哥伦比亚省(加拿大西部省名)有着5千3百万年历史前的麦克比化石层等。麦克比化石层曾经也是温度恒定区域。相比较而言,同哈佛森林相比,古代加拿大的昆虫多样性跟现代的哥斯达黎加更为相似。研究报告发表在《古生物学》杂志上。 因此,我们得回过头来重新想想——并不是热带才有着更丰富的生物多样性。或许是现今温带的四季使得生物多样性减少,因此花儿一年只开放一次,而动物们的繁殖期也减少到一年一次。