雅思写作话题及范文:The diagrams below show the life cycle of a species o.

雅思写作话题及范文:The diagrams below show the life cycle of a species o.

范文

Salmon begin life as eggs on a pebbly riverbed, hidden among reeds in the slow-moving upper reaches of a river. After five to six months the eggs hatch into ‘fry’. For approximately the next four years, these baby salmon will live in the lower, faster-flowing waters of their river. During this time they measure between three and eight centimetres in length.

By the time salmon reach twelve to fifteen centimetres, they are termed ‘smolt’, and at this time they migrate further downriver into the open sea. After five years at sea, the salmon will have grown to adult size, which is between seventy and seventy-six centimetres. They then begin swimming back to their birthplace, where they will lay their eggs, and the cycle starts anew.

In summary, the salmon passes through three distinct physical stages as it grows to maturity.Each of these stages takes place in a very different aquatic location. It is noteworthy that the first two stages of this fish’s life occur in a fresh water environment, while the third stage is lived in saltwater.

鲑鱼的生命起源于卵石河床上的卵，隐藏在缓慢移动的河流上游的芦苇中。五到六个月后，鸡蛋孵化成“鱼苗”。大约在接下来的四年里，这些小鲑鱼将生活在河流中流速更快的较低水域。在此期间，它们的长度在3到8厘米之间。

当鲑鱼长到12到15厘米时，它们被称为“斯莫尔特”，此时它们会进一步向下游迁徙到公海中。在海上生活五年后，鲑鱼将长成成年鱼，大小在70到76厘米之间。然后，它们开始游回它们的出生地，在那里产卵，然后循环又开始了。

综上所述，鲑鱼在生长成熟的过程中会经历三个不同的生理阶段。每个阶段都发生在非常不同的水生位置。值得注意的是，这种鱼的前两个阶段生活在淡水环境中，而第三个阶段生活在盐水中。