最近一些同学在备考 SAT 阅读时提到，有些科学类文章中出现了陌生的术语，比如 ecological niche（生态位），考场上不太容易理解。而十月的 SAT 真题中，这一概念不仅出现了，还成了理解文章核心逻辑的关键！
什么是 Ecological niche
生态位指的是一个物种在生态系统中的功能角色。每种生物都有独特的“位置”或“作用”，用来获取资源、繁衍后代并维持种群生存。这就像大自然中的一间间“公寓”，每个物种都占据自己的房间，避免直接“撞房”引发竞争。
为了讲清这个可能有点抽象的生态位概念，我特意准备了一段 1 分半钟易懂小视频。
SAT 十月真题题目解析
树木与生态位的平衡之道
Rare species advantage (RSA) describes the situation in which there are few conspecifics (other members of the same species) in an organism's immediate surroundings, enabling the organism to avoid competition with conspecifics for the same resources; RSA is widely believed to play a crucial role in maintaining ecological stability. Among tree species in the Barro Colorado Island plot (latitude 9.15° N) and other tropical forest sites, there is little correlation between conspecific aggregation and the abundance of a given species in the wider local area, so RSA is expected, but in the Fenglin Nature Reserve (latitude 48.08° N) and other temperate forest sites, the aggregation-abundance correlation for tree species is strongly negative. Mathematical modeling suggests, however, that ecological niche distinction may mitigate the apparent risk to temperate ecological stability engendered by this pattern: ______
Which choice most logically completes the text?
A: as a tree species in temperate forests becomes more abundant, individuals of that species are more likely to be found near conspecifics, enabling abundant species to exploit localized resources to a greater extent than rare species can.
B: even though rare tree species in temperate forests tend to cluster with conspecifics more than rare tree species in tropical forests do, they are sufficiently rare locally that they benefit from RSA more than rare tropical species do.
C: although rare tree species in temperate forests encounter relatively high local competition from conspecifics, they can thrive by exploiting resources that are underexploited by other local species.
D: while an increase in abundance in one tree species often leads to a reduction in abundance of nearby species, temperate tree species tend to play different roles in the same ecosystem, reducing the expected effect of abundance on aggregation.
【解析】
热带森林与 RSA 高度相关，物种较少扎堆，保持了生态系统的稳定。而在温带森林，稀有树种即使和同类竞争激烈，但因生态位不同，它们可以利用其他树种未充分开发的资源，最终“另辟生路”。答案是 C。
✍️ 本期话题互动：生态位的概念，你还在哪些 SAT 真题里看到过？
