changes in temperature, humidity and nutrient availability seem to trumped the benefits of

　　increased carbon dioxide，” said researchers from the National University of Singapore.

　　45 percent of the species studied now reach smaller adult sizes than they did in the past. The

　　researchers pointed out that warmer temperatures and changing habitats, caused by climate

　　change, are possible reasons for shrinking creatures.

　　“We do not yet know the mechanisms involved, or why some organism are getting smaller while others are unaffected，” the researchers said. “Until we understand more, we could be risking negative consequences that we can't yet quantify.”

　　The change was big in coldblooded animals. Only two decades of warmer temperatures were enough to make reptiles smaller. An increase of 1 degree centigrade caused nearly a 10 percent increase in metabolism (新陈代谢). Greater use of energy resulted in tiny tortoises and little lizards. Fish are smaller now too. Though overfishing has played a part in reducing numbers, experiments show that warmer temperatures also stop fish growth. There is a recent report on warmer temperatures' negative effects on plankton, the base of the marine ecosystem.

　　Warmblooded animals weren't immune from the size change caused by climate change. Many birds are now smaller. Mammals have been miniaturized too. Soay sheep are thinner. Red deer are weaker. And polar bears are smaller, compared with historical records.

【黄石市2016高考英语一轮阅读理解和书面表达选练（4）及答案】相关文章：

★ 【课堂新坐标】2017届高考英语（通用版）二轮复习书面表达专题训练：Ⅱ卷强化增分练 训练2（含解析）

★ 河南省三门峡市2014高考英语一轮（暑假）基础训练（7）附答案

★ 2014高考英语（新人教版）一轮基础训练（11）A、B卷（附答案或解析）

★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (53)

★ 贵州省贵阳市2014高考英语（新人教版）一轮阅读训练（23）附答案

★ 2014高考英语（新人教版）一轮基础训练（9）A、B卷（附答案或解析）

★ 2017届高考英语二轮复习书面表达限时测验：5（含解析）

★ 浙江省湖州市2014高考英语阅读理解一轮（暑假）精炼（1）含答案

★ 湖南省岳阳市2014高考英语一轮单项选择训练题（1）及答案

★ 2017届高考英语二轮复习书面表达限时测验：1（含解析）