EXTRA4 What does the professor say about how the city of Caral came to an end?

[00:00.00]Narrator: Listen to part of a lecture in an archaeology class.
[00:07.34]Professor: If I asked you to name an ancient civilization from Peru, many of you might say the Incas. [00:14.74]But let’s consider instead the impact of a mysterious culture in north central Peru that thrived in a collection of valleys called the Norte Chico region. [00:26.88]Archaeologists have been finding evidence that suggests that Norte Chico is the region where the early inhabitants of South America first began a pivotal transition from being hunters and gatherers and formed a complex and substantially developed society. [00:45.89]This would be around 3,000 BCE, well before the Incas even existed. [00:52.56]These sites were so advanced that nothing like them could be seen anywhere else in the Americas at the time. [01:00.38]There’s no official name for the culture yet, but it seems that its architecture and development had a profound influence on subsequent culture in the Americas for thousands of years afterwards. [01:15.79]At each site, archaeologists have identified one or more enormous platform mounds, sort of like rectangular-terraced pyramids, throughout the whole region, people were organized enough to plan and produce these large terraced pyramids, something the Americas have never seen before. [01:38.30]And each of the sites apparently served as a residential center, so people lived and worked there. [01:45.98]It seems they were farmers. 
[01:48.34]Now, this collection of over twenty residential centers is very exciting for a number of other reasons as well. [01:56.83]For one thing, their existing has called into question a previous theory about how complex society emerged in the Americas. [02:07.30]You see, in the 1970s and 80s, archaeologists had examined a coastal site in Peru called Apsero. [02:15.98]Aspero was one of the first of these sites in Norte Chico to be discovered and studied extensively. [02:23.62]That was about 40 years ago. [02:26.06]It’s directly on the coast and has these same mounds dating from the same period, about 3000 BCE. [02:34.56]Apparently, Aspero was a fishing village and based on this fact, archaeologists concluded that the first complex society was based on and sustained by ocean and marine resources without agriculture. [02:50.69]They didn't know yet, though that Aspero was just one of many such sites in the region and most of these other sites were inland, quite a distance away from the coast. [03:02.98]But now we know that all these inland sites exist and that they were all built around the same time. 
[03:11.04]Another exciting thing about this recent research is that it calls into question some long-held assumptions about how complex societies developed. [03:21.98]You know, when we work with any ancient society and consider its classification, a standard traditional hallmark used to classify the culture as complex is the presence of ceramic pottery. [03:38.06]The other major birthplaces of complex civilizations around the world like Egypt or Mesopotamia, they all had pottery, but did this mysterious culture provide us with evidence of ceramic pottery? [03:54.91]No, this culture is unconventional in that respect.
[04:00.58]Researchers have also discovered mechanical remains of domesticated plants including cotton, squash, chili, beans, and avocados. [04:12.02]But interestingly, they found almost no evidence of preserved corn or other grains. [04:18.89]This means that this early culture developed not only without pottery, but also without a staple grain-based food, which is usually the first large-scale agricultural product of complex societies. [04:34.44]So here again, the ancient Peruvians took a different path to civilization.
[04:40.78]Additionally, in one specific archaeological site, Caral, they’ve uncovered artifacts called khipu. [04:50.18]Basically, a khipu is an intricate collection of hanging strings, cotton string of many colors. [04:58.06]Each khipu strings contains an elaborate combination of color and design that communicates meaning. [05:06.46]Each one has a wide variety of special intricately tied knots. [05:11.88]People transmitted information in this manner. [05:15.24]There was meaning associated with the color selected, the knot used, the fiber chosen. [05:22.20]There are even those that speculate it may have been a writing system. [05:27.62]Interestingly, the 3,000 inhabitants of this one particular city, Caral, appeared to left. [05:36.02]Why? [05:36.89]Well, here’s what we know. [05:39.14]There doesn’t appear to be any evidence of invasion from outside enemy forces. [05:45.48]There were no signs of rebellion from the people who lived there. [05:49.99]What we see instead is an orderly process whereby the occupants covered the buildings with substantial amounts of gravel and pebbles and then were gone.