University of Missouri researcher adds to timeline of human evolution by studying an island fox.
藉由研究海島狐狸，美國密蘇里大學的研究人員增添了，人類演化的年表。
圖1. 海島狐狸的骨骸 (圖援用自原文)
Nearly two decades ago, a small-bodied "human-like" fossil, Homo floresiensis, was discovered on an island in Indonesia. Some scientists have credited the find, now nicknamed "Hobbit," as representative of a human ancestor who developed dwarfed features after living on the island, while others suggest it represents a modern human suffering from some type of disease because of its distinct human-like face and small brain.
將近二十年前，在印尼的一個島嶼上，發現一種小身軀“類似人類”的化石(佛羅勒斯人，史前人屬的一種人類)。一些科學家一直認為，該目前被暱稱為"霍比特人"的發現是一種，在島嶼上生活後，發展出矮小特徵的人類祖先代表。不過，其他科學家委婉表示，其代表一種，罹患某種疾病的現代人。因為，其明顯類似人類的面孔及小腦袋。
Colleen B. Young, a graduate student in the Department of Anthropology at the University of Missouri, has always been naturally curious about the nature of the human "footprint," or how humans impact their environments and vice versa. She believes the Hobbit adjusted from a longer-legged version of itself to meet the demands of an isolated, island environment.
密蘇里大學人類學系研究生，Colleen B. Young天生對人類"足印"的特質，亦即人類如何影響環境及反過來，始終是好奇的。她認為，霍比特人從其本身較長腿版進行了調整，來迎合孤立島嶼環境的需求。
圖2. 分析中使用的狐狸骨頭。 從左到右：股骨、脛骨、橈骨和肱骨。 (圖援用自原文)
“Homo erectus, considered our recent ancestor, likely developed its long legs over time in order to increase its ability to walk long distances as its environment expanded,” Young said. “So, when humans arrived on that island in Indonesia and became isolated, their bodies — once built for efficiency over long distances — were probably no longer beneficial for their new environment. Instead, a smaller body size probably improved their lifestyle.”
Young宣稱：「被認為是咱們最近的祖先，直立人隨著時間推移，其活動的環境擴大時，為了提升走長距離的能耐，可能發展出長的腿。因此，當人類到達印尼的那個島嶼，而變得孤立時，他們一度為長距離之效率增高的身軀，就其新環境而言，可能不再是有利的。相反，較小的身材可能改善了他們的生活方式。」
Young, who is working on her doctorate in biological anthropology in the College of Arts and Science, tested several popular assumptions about the characteristics of Homo floresiensis by comparing an island fox from California’s Channel Islands with its mainland U.S. relative, the gray fox.
正在密蘇里大學理工學院，攻讀生物人類學博士學位的Young，藉由比較來自加州海峽群島，一種島嶼狐狸與其同類—美國本土的灰狐狸，驗證了幾種有關佛羅勒斯人，諸特徵的普遍假設。
Young said upon arrival, the island fox underwent a 30% reduction in body size and developed smaller body features that are different than the mainland gray fox. She believes this change in body size was likely due to adjustments the island fox made to survive in its new, isolated environment.
Young表示，到達島嶼後。在身材上，島嶼狐狸經歷了30％的減少。因此，發展出不同於大陸灰狐狸的較小身軀特徵。她認為，該在身材上的改變，可能是由於島嶼狐狸，為了存活於孤立之新環境，做出的調整。
“The gray fox is a migratory, omnivorous animal, similar to our recent ancestors,” Young said. “This study indicates that animals living on islands that become smaller in size may also have distinct limbs and body features just because of their new island environment. Therefore, the distinctive body features on the small-bodied Homo floresiensis are probably products of evolving in an island environment, and not resulting from suffering from diseases.”
Young宣稱：「類似咱們最近的祖先，灰狐狸是一種遷徙、雜食性的動物。這項研究顯示，生活在島嶼上，身材變小之動物，也可能具有獨特的四肢及身軀特徵，只因為其新的島嶼環境。因此，在佛羅勒斯人獨特的身軀特徵，可能是在一種島嶼環境中演化的產物，而不是起因於罹患疾病。」
Young said this animal model, which includes taking into account the surrounding ecosystem, can help scientists better understand the body size and limbs of Homo floresiensis, and how they relate to human ancestors. She thinks this model can also help open new doors in the field of anthropology.
Young表示，這種包括將周遭生態體系納入考量的動物模型，能有助於科學家們更深入瞭解，佛羅勒斯人的身材與四肢，及其與人類祖先的關係。她認為，在人類學的領域中，這種模型也能協助開啟新途徑。
“The popular idea that every little difference in a fossil means the discovery of a new species is probably not as accurate as we once thought,” Young said. “There was probably a lot more variation going on throughout human evolution than we first thought, and these findings exemplify that variation can occur just by migrating to and living on an island. We’re just starting to scratch the surface.”
Young宣稱：「這種於化石中，每一細小差異的普遍見解。意味著，一個新物種的發現，可能不像人們曾經想像的那樣準確。在整個人類演化過程中，可能發生比人們最初認為的更多變化。不過，此些研究發現是，因遷徙到並生存於島上，就會發生變化的例證。他們才剛開始搔到此種變化的表面。」
“Static allometry of a small-bodied omnivore: body size and limb scaling of an island fox and inferences for Homo floresiensis” was published in the Journal of Human Evolution..
“小身軀之雜食動物的靜態生長異率(是指與年齡無關之尺寸的形狀相關事物)研究：島嶼狐狸的身材與肢體測量及佛羅勒斯人的推斷”一文，發表於《人類演化雜誌》期刊。
原文網址：https://showme.missouri.edu/2020/a-new-evolutionary-clue/
翻譯：許東榮
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