英语课程计划-The International Day

The International Day for Biological Diversity, sometimes called World Biodiversity Day, is a United Nations holiday based on biodiversity issues. It started in 1993 and is held on May 22. This is the date of the Rio Earth Summit of 1992. This was a major meeting to discuss life on our planet. A total of 172 governments attended the Summit, with a total of 108 heads of state. The main topics were the environment and sustainable development. Governments discussed ways to halt the destruction of irreplaceable natural resources and to protect ecosystems¹. The day now focuses on the threats climate change has on biodiversity. Experts say that tackling both together will mean we have a better chance of keeping the Earth’s natural riches.

Biodiversity is the total variety of all forms of life on our Earth. It includes life at the genetic² and cell level, through to all plant, fish, insect and animal species. Biodiversity also includes the thousands, perhaps millions, of ecosystems that make up our natural world. The word "biodiversity" arrived in 1985. It is a contraction³ of the words "biological” and “diversity". The word has grown into a very important concept we all need to understand. A respect for biodiversity means an understanding that we must help save our environment. Today, biodiversity is one of the world’s most important issues. Many say that together with climate change, damage to biodiversity is the biggest threat to our survival.

1 ecosystems   

n.生态系统( ecosystem的名词复数 )

参考例句：

• There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
• Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样，从雨林到半荒漠等不一而足。 来自辞典例句

2 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

3 contraction   

n.缩略词，缩写式，害病

参考例句：

• The contraction of this muscle raises the lower arm.肌肉的收缩使前臂抬起。
• The forces of expansion are balanced by forces of contraction.扩张力和收缩力相互平衡。