2013年6月29日 星期六

高機率聽力考題:Osedax食骨蠕蟲


原文網址:
http://www.nhm.ac.uk/nature-online/species-of-the-day/collections/collecting/osedax-mucofloris/
 (可以先看影片練習聽力喔!! )
http://eol.org/pages/49241/overview
http://www.osedax.com/


重點提示:



1. Osedax食骨蠕蟲顧名思義就是以骨頭為主食,主要的habitat在鯨魚的骨頭上,科學家也是第一次在鯨魚骨頭找到此種特殊的蟲。

Osedax mucofloris is also known as the bone-eating snot-flower worm. This bizarre animal was discovered and described in 2005, by Museum scientists working together with marine biologists in Sweden.

The animal lives on whale bones on the sea floor and it is thought that this species, and others closely related to it, have evolved unique adaptations to this unusual habitat.

2. 說它更像植物,因 為沒有眼睛沒有腿。 worm 有三個部分:red structure,green structure

The worms have no eyes, legs, mouths, or stomachs, but they do have colorful feathery plumes and green "roots."

worm 和 green structure 的細菌的共生
They use the roots to infiltrate the bones of dead whales, digesting the fats and oils inside with the help of symbiotic bacteria



它頭上有個紅的是吸氧的,綠的東西裏面很多細菌,好像消化海底石油,還有一個生殖的
The plumes connect to a muscular trunk, which can be withdrawn into a transparent tube when the worms are disturbed. At the other end of the trunk, hidden inside the whale bone, the body widens to form a large egg sac. The greenish roots, branching off from the egg sac, are filled with bacteria that break down oil in the whale bones.




3. Reproduction: 公的食骨蠕蟲非常小,會附著在母食骨蠕蟲上。性別由環境決定,一開始是無性的,長大才會漸漸改變。

It is important to understand Osedax mucofloris reproduction, as scientists want to know how these animals are able to disperse between isolated whale-fall habitats.

When the first species of Osedax was described, it was noted that the species seemed to exhibit very strong sexual dimorphism.(公母差異很大的) The males did not develop into mature adults. Instead, they appeared to remain as larval-sized individuals attached to the side of females,
fertilising eggs as they were released into the water column.

Sex in these worms is believed to be environmentally determined, with undifferentiated larvae that settle on bones developing as females and subsequent larvae that settle on females transforming into dwarf males.










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