生物多样性

理解生物多样性——即生态系统中不同物种的多样性——对健康的生态系统至关重要，并且关键种（如黄石公园的狼、海带森林中的海獭，或作为传粉者的蜜蜂）对生态系统有着超乎寻常的影响，因此失去一个关键物种可能引发连锁反应，影响许多其他物种。

Understand that biodiversity — the variety of different species in an ecosystem — is essential for healthy ecosystems, and that keystone species (like wolves in Yellowstone, sea otters in kelp forests, or bees as pollinators) have an outsized impact on their ecosystem, so that losing one key species can cause a cascade of changes affecting many others

学习证据 / Evidence

• 将生物多样性定义为生态系统中物种的多样性
• 解释生物多样性的重要性（稳定性、恢复力、生态系统服务）
• 定义关键种并给出至少两个例子
• 描述因移除或增加某个物种而引发的营养级联或连锁反应

• Defines biodiversity as the variety of species in an ecosystem
• Explains why biodiversity matters (stability, resilience, ecosystem services)
• Defines keystone species and gives at least 2 examples
• Describes a trophic cascade or chain reaction from removing/adding a species

评估问题 / Assessment

如果{{name}}了解到黄石公园重新引入狼群后整个生态系统发生了变化，他/她能解释什么是“关键种”，并说明为什么一个区域拥有多种不同的物种很重要吗？

If {{name}} learns about how wolves were brought back to Yellowstone and the whole ecosystem changed, can they explain what a 'keystone species' is and why having many different species in an area matters?