VOA科学技术2023--Simple Logs May Be Oldest Human-built Wood Structure

Simple Logs May Be Oldest Human-built Wood Structure

Researchers have found a structure that may be the oldest evidence yet of early humans building with wood.

The structure is simple: two logs, fitted together with a notch¹.

It is half a million years old. It provides a rare look at how ancient human relatives were working with wood and changing their environments, researchers wrote in a study published recently in Nature.

Larry Barham of the University of Liverpool in Britain was one of the writers of the study. Barham said, "It took me a while before I appreciated what we were looking at." He added about the structure, "It didn't look very nice, to be honest. But it is much more complex than I thought."

Barham and his team dug up the log structure, and several wooden tools, from a riverbed area that sits above a waterfall in the African country of Zambia. They think the crossed logs could have been the base for a bigger structure like a walkway or a platform.

Barham explained that wood usually rots quickly due to the weather. As a result, little evidence remains² of how our ancient relatives used the material. But the log structure that researchers found had been below the river's surface, which helped save them.

So when Barham's team found the logs in 2019, they were still able to see signs that early humans had shaped them.

"Everything just looks so fresh, you think, ‘It cannot be this old,'" Barham said.

It was difficult for researchers to estimate the age of the wood structure. Traditional dating techniques could not get deep enough into the past. In this study, researchers used a new method called "luminescence dating."

Luminescence dating uses tiny minerals in the sand to estimate how long materials have been buried, explained study writer Geoff Duller.

Duller is an expert in dating methods at Aberystwyth University in Wales.

The log structure was made at least 476,000 years ago, while the wood tools are slightly younger, under 400,000 years old. That places the materials in a time before our species³, Homo sapiens.

The earliest-known Homo sapiens bones date from roughly 300,000 years ago in Morocco. The Kalambo Falls logs were determined⁴ to be from about 476,000 years ago.

The objects would have been made by another kind of early human relative — possibly Homo heidelbergensis, which was around in Africa at the time, the study's writers said.

Homo heidelbergensis had a bigger braincase and flatter⁵ face than earlier hominins - species on the human evolutionary⁶ lineage.

If these ancient humans were putting effort into building these structures, it suggests they may have stayed for a while or made repeated visits. In other words, they were not just groups of hunter-gatherers, said Dirk Leder of Germany's Lower Saxony State Office for Cultural Heritage⁷. Leder was not involved with the research.

Annemieke Milks of Britain's University of Reading was also not involved in the study. Milks said about the finding, "It's an important window into what these humans were capable of."

Words in This Story

notch – n. a small cut that is shaped like a V

appreciate – v. to understand the worth or importance of something

platform -- n. a flat surface that is raised higher than the floor or ground

rot – v. to slowly decay⁸

species -- n. a group of animals or plants that are similar and can produce young animals or plants

lineage – n. a chain of species each of which is considered to have evolved from one before

1 notch   

n.(V字形)槽口，缺口，等级

参考例句：

• The peanuts they grow are top-notch.他们种的花生是拔尖的。
• He cut a notch in the stick with a sharp knife.他用利刃在棒上刻了一个凹痕。

2 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

3 species   

n.物种，种群

参考例句：

• Are we the only thinking species in the whole of creation?我们是万物中惟一有思想的物种吗？
• This species of bird now exists only in Africa.这种鸟现在只存在于非洲。

4 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

5 flatter   

v.向...谄媚，奉承，使高兴，使感到荣幸

参考例句：

• We flatter ourselves that we provide the best service in town.我们相信我们提供的服务在本市最好。
• It turns my stomach to hear him flatter.听到他拍马屁，我实在感到讨厌。

6 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

7 heritage   

n.传统，遗产，继承物

参考例句：

• The ancient buildings are part of the national heritage.这些古建筑是民族遗产的一部分。
• We Chinese have a great cultural heritage.我们中国人有伟大的文化遗产。

8 decay   

vi.腐烂，衰落；n.腐烂，腐朽，衰败状态

参考例句：

• The vegetables have begun to decay.那些蔬菜已开始腐烂。
• Our powers decay in old age.我们的体力在老年时就衰退。