模拟测试卷1-2019-8月新卷 What is the purpose of the lecture？

[00:00.00]Narrator:Listen to part of a lecture in an Archaeology class.[00:08.00]Lecturer:Last time, we discussed technologies like radio carbon dating and digital imaging that help us interpret archaeological evidence. [00:18.50]Now you remember, we looked at some of the challenges of drawing conclusions from the available evidence. [00:25.80]One example I want to mention has a strong impact on our ideas about the population size of ancient settlements.[00:34.00] In particular - in Western Europe, during the period known as the Early Middle Ages. [00:40.70]The Early Middle Ages, from roughly 500 C.E. to 1000 C.E., refers to the period in Western Europe following the fall of the Roman Empire.[00:52.20]Now you remember, the Roman Empire was the major world power about 2000 years ago. [00:58.80]At its height, it included all the land around the Mediterranean sea and extended as far north as, well, the island of Britain - and Roman sites have been easy for archaeologists to find. [01:11.80]There are ruins of huge buildings like the Colosseum in Rome or even entire cities like the ruins of Pompeii just south of Rome. [01:22.30]And when we look across the expanse of the empire, the evidence shows a landscape that was densely populated. [01:29.50]In addition to the obvious remains, the huge public buildings and monuments, we see countless remains found in private buildings like statues, decorative artifacts, shards of pottery.[01:42.10]But then, there's a sharp decline in the amount of archaeological evidence that dates from the Early Middle Ages. [01:49.20]Now from this picture, it would be tempting to conclude that there was an equally sharp decline in population but let's look again. [01:58.50]As we said, the Romans left behind countless long-lasting remains, items made of materials that were strong, durable. [02:07.90]Roman houses for example, were made of mortar and cement - with tile for the roofs. [02:13.70]But in the Early Middle Ages, homes were made of organic materials, mostly wood, and they had thatched roofs, simple structures of straw and mud.[02:24.00] Materials like these decay over time, so naturally that makes it difficult to find these sites.[02:31.20]Another reason Roman sites are so much easier to locate, is that even small artifacts are visible. [02:38.50]Roman pottery for example, it was typically glazed, so it's very shiny and easy to see against the soil. [02:46.80]The pottery of the Early Middle Ages were brown or gray, and it wasn't glazed, so you'd have trouble spotting it at an excavation.[02:55.90] It's - it’s kind of camouflaged against the soil, so it's easy to draw the wrong conclusions about population size based on the available evidence. [03:06.10]I mean let's compare two sites that were unearthed in Britain, one dating from the Roman Empire, the other from a few centuries later, during the Early Middle Ages.[03:16.60]The Roman site is called Bradley Hill. [03:19.40]Bradley Hill was a farmstead that would have been inhabited by a few families - so figure about 20 people living there. [03:27.30]From this one site, we have remains of a tiled roof and other sturdy materials and thousands, literally thousands of shards of shiny pottery. [03:36.80]Now compare that with the settlement in Britain from the Early Middle Ages called Yeavering. [03:43.40]We know from writings from that period that Yeavering was the estate of a regional king and that it was occupied by over a hundred people for more than 200 years. [03:54.50]But what's left of Yeavering? Virtually nothing. Nothing from the palace, most likely built of wood. [04:01.80]In fact the only evidence we have of that are the post holes, the holes dug in the earth where the timbers or wooden posts were placed to support the walls and roofs. [04:13.00]And we didn't even know about these until aerial photographs revealed markings that weren't evident from the ground. [04:20.30]And this is just one example of how a new perspective, in this case made possible through aerial photography, helped us realize that evidence, or the lack of it could lead to false conclusions. [04:33.50]Now look, I'm not saying, I mean, it's possible, even likely that there was some decline. [04:39.20]I'm just saying that evidence, especially when it's incomplete, or analyzed in isolation doesn't tell the whole story. [04:46.70]Now all this may not seem relevant to this week's reading about the ancient Mayan populations in Central America, which we'll get to in a minute, but you'll notice that your book includes population distribution maps that have been generated based on archaeological evidence. [05:05.00]So, a word to the wise, population distribution maps for Western Europe show lots of large empty spaces by the Early Middle Ages, even though evidence like those post holes and documents about Yeavering might paint quite a different picture.