快⬆️⬆️点击上方蓝字关注并星标这个公众号，一起涨姿势～
词数：615 words
难度：★★★☆☆
小贴士：
获取本文及2024年外刊合集，可以在公众号后台对话框中回复“合集”或者“PDF”，或点击文末左下角蓝色的“阅读原文”跳转获取。
——大橙子留
✦ +
+
上期划线句答案
To calculate how changes in activity levels can influence mortality risk, researchers referenced the NHANES results against a life-table model (where mortality rates are tracked at specific age points) and previous research into exercise and lifespan.
为了计算活动水平变化对死亡风险的影响，研究人员将美国国家健康与营养调查的结果与生命表模型（在特定年龄点追踪死亡率）以及先前关于运动与寿命的研究进行了对照分析。
✦ +
+
本期内容
◆
双语阅读
Para.1
What makes humans different from other animals? Ask any ten people and you’re likely to get ten different answers, ranging from our relatively large brains, to our incredible use of language and symbols, to our ability to dramatically modify the world around us. But if you asked me, I’d say that it’s our butts.Take a look around the animal kingdom. Even our closest living relatives among the great apes (chimpanzees, bonobos, and gorillas), don’t have proportionally as big butts as humans do. The main reason for this probably comes down to our unique style of locomotion. We’re the only mammals alive today whose primary way of getting around is walking on two legs. And becoming upright bipeds has had some important consequences for our derrières.
Para.2
The anatomical structure that we generally think of as a “butt” is made up of adipose tissue (fat) sitting on top of our gluteal muscles, which are attached to the bony pelvis. Ultimately, it’s the shape of our pelvis that dictates the shape of our butts, and that set of bones has undergone some major changes over the last six-or-so million years.
Para.3
The pelvis is made up of three parts: two innominates (or “hip bones”) and the sacrum. Each innominate is also made up of three bones (the ilium, ischium, and pubis) that fuse together during growth and development. And it’s the ilium that’s the real difference-maker between us and our ape relatives. A chimpanzee’s ilium is relatively tall and flat, with the flat sides facing forwards and backwards. Our ilia, on the other hand, are short and curved around more to the sides, making our pelvis bowl-shaped. These size and shape differences are linked to the evolution of bipedalism and the reorganization of our gluteal muscles that make upright walking possible.
Para.4
The three gluteal muscles are gluteus maximus, gluteus medius, and gluteus minimus (“gluteus” derives from the Latin for “butt”, so that’s “biggest butt,” “medium butt,” and “smallest butt”). Our gluteus maximus (especially the upper part) is very large compared to that of other primates. It extends the thigh and moves it backwards, and gives us power when we run or climb stairs. And it’s what gives our behind most of its shape. In other apes, though, the so-called “lesser gluteals” (gluteus medius and minimus) do a lot of this work, so the gluteus maximus doesn’t have to be a major player. Hence, no booty. What our lesser gluteals are doing instead is helping our hips not drop to the side when we stand on one leg (as we do every time we take a step forward). It’s the curved shape of our ilia that allows them to do that, by changing where those muscles are and, thus, their function. Our lesser gluteals provide stability rather than power.
Para.5
The last thing that helps make human butts unique is the fat — which might also have something to do with us becoming bipeds. Humans have relatively large brains that use a lot of energy. Our bodies store energy as fat, and we have a relatively high percentage of it for a non-aquatic mammal. This has led anthropologists to suggest that our body fat helps buffer our metabolically-expensive brains against lean times. This seems to be something that we are able to do because walking on the ground is both an energetically efficient way to get around. It also avoids the downsides of spending our lives in trees — having to support all of our weight on tree branches and exist at the mercy of gravity requires a lot of energy.
本文节选自：massivesci.com
发布时间：2020.8.31
作者：Darcy Shapiro
原文标题：How did human butts evolve to look that way?
◆
写作句总结
原句：The anatomical structure that we generally think of as a “butt” is made up of adipose tissue (fat) sitting on top of our gluteal muscles, which are attached to the bony pelvis.
结构：The sth that we generally think of as X is made up of Y sitting on top of Z, which are attached to A.
例句：The challenges that we generally think of as obstacles are made up of experiences sitting on top of our mindset, which are attached to our personal growth.
◆
阅读理解题
Which of the following statements best describes the relationship between human bipedalism and the evolution of gluteal muscles?
A. Human bipedalism led to a smaller gluteus maximus, while the lesser gluteals became the primary muscles for movement.
B. The development of bipedalism had no significant impact on the shape or function of human gluteal muscles.
C. Human bipedalism resulted in a larger gluteus maximus for power and lesser gluteals that provide stability.
D. The shift to walking on two legs caused a decrease in human body fat percentage, impacting the gluteal region.
◆
全文概括
The text explores the unique characteristics of the human buttocks, arguing that their size and shape are a crucial adaptation to bipedalism. The author posits that the evolution of the human pelvis, particularly the ilium, resulted in a larger gluteus maximus muscle, providing power for locomotion. This contrasts with apes, where smaller gluteals maintain balance. Furthermore, human body fat, stored in the buttocks, may have evolved to support the energy demands of our large brains, an adaptation facilitated by bipedal locomotion's energy efficiency. The text thus links human anatomy, specifically the buttocks, to evolutionary changes in posture and energy expenditure.
◆
打卡作业
翻译文章中的划线句，文末留言打卡，下期推送会在文章开头处公布参考翻译答案，大家一起来学习英语吧~
翻译 | 大橙子
校对 | 李柚子
词汇词组 | 西西弗
划线句讲解 | 流木
写作句总结 | 沅沅
免责声明：本文来自网络公开资料，仅供学习交流，其观点和倾向不代表本公众号立场。
