Section 1
Conversation l — Community Planning in the Colonies
Narrator
Listen to part of a conversation between a Student and her United States History Professor.
Professor
So, Amanda, you've asked a lot of questions about trade during the colonial period of the United States. Has our discussion clarified things for you?
Student
Well, yeah, but now, I think writing about trade for my paper isn't going to work.
Professor
Oh, so your questions about shipping routes were for your research paper?
Student
Yeah. But now, I see that I probably need to come up with a new paper topic. Actually, there was one other idea I had. I have been thinking about doing something about community planning in the early British settlements in Eastern North America.
Professor
Oh. OK. I am curious. Why are you interested in doing something on community planning in colonial times?
Student
Well, I am much more into architecture. It’s my major and I mean, planning out a town or city goes along with that. I mean, not that I don't like history...l am interested in history…really interested. But I think, you know, for a career, architecture is more for me.
Professor
That's great. I've gotten some very thought-provoking papers from Students whose interests go beyond history.
Student
OK. But for the paper you wanted us to try to include a comparison, right?
Professor
Yes. Actually, that was really the purpose of the assignment. The way the United States developed or perhaps I should say the colonies, since the land that would become the Eastern United States…uh...there were British colonies there four hundred years ago. But anyway…uh... development in the colonies differed greatly depending on geography. I am looking for papers that have ideas about something that happened one way in the Northern colonies happened a different way in the Southern colonies.
Student
Is that true in terms of urban planning?
Professor
Very true. Towns in the Northern colonies were centralized and compact. They provided a meeting point for exchanging goods, for participatory government, and for practicing religion. Houses would be built along the roads that led into town. And just outside the developed area, there would usually be an open area of some sort for grazing animals and also group activities. Actually, the model for planning a town in the Northern colonies was not unlike the model for the development of towns in medieval Europe. After all, the colonists had just come from Europe and the medieval period was just ended.
Student
Medieval Europe. But what about the South? If I remember correctly... In the South, at least initially, they didn't build towns so much as they built trading posts.
Professor
That's right. Most of the settlers in the North wanted to start a whole new life. But most of the people who came from Europe to the South just wanted to make some money and then go back. It is not surprising that some of most common buildings were storage facilities and port facilities.
Lecture l-Music — Ancient Greek Music & Plato
Narrator
Listen to part of a lecture in a music class.
Professor
Today we are going to do something a little different. In the past few classes, we've listened to traditional music from around the world and we've talked about the characteristics of these music, what makes these styles distinctive, what kinds of instruments are used. And you've talked about what sounds familiar to you and what sounds strange. And many of you found some of what we've listened to very strange indeed.
Well, today I want to start talking about western music and I am going to start in ancient Greece. But, now here's the part that's different. We're not going to talk very much about the actual music. Instead, we are going to talk about what the Greeks believed about music.
Now, there are some very good reasons to approach the material in this way. First, well, we don't have very much ancient Greek music studied. Only about 45 pieces survived…uh...these are mostly records of poems and songs. And we are not sure how well we can reproduce the melodies or rhythms, because they were apparently improvised in many cases. So we really don't know all that much about what the music sounded like.
What we do know about - and this really is the most important reason I am approaching today's lecture the way I am - is the Greek philosophy about music and its continuing influence on western attitudes toward music.
Now, if we're going to understand the philosophy, we have to first understand that music for the Greeks was about much more than entertainment. Yes, there was music at festivals and we have sculptures and paintings showing people listening to music for many of the same reasons that we do. But this isn't the whole story.
The important thing about music was that it was governed by rules, mathematical rules. And for those of you who are also studying music theory, you’ll see that it is in fact highly mathematical.
Um...and for the Greeks, the same mathematical principles that govern music also govern the universe as well as the human character, the essence of personality. People's characters were believed to be very sensitive to music.1f you started playing around with the rules, you know, messing up the mathematical order, you could do serious harm. That's why music was considered so powerful, if you knew the rules, it could do great good. But if you broke them, you could do great harm to the character of the listener.
So, we have this Greek idea that music is directly related to human character and behavior.
The philosopher, Plato, talks about this in the context of education. For Plato, music is an important element in education, but only the right kind of music. That means the kind of music that builds the kind of character a good citizen or a future leader would need. Yes. For Plato, there is a kind of music that instills the qualities of leadership, just as there is a kind of music that makes a person soft and weak.
Now, Plato has very specific, very conventional kinds of music in mind. He is not fond of innovation. There were musicians in Plato's day who were experimenting with different melodies and rhythms. A definite no-no for Plato. He thinks that breaking with tradition leads to all sorts of social problems, serious problems, even the breakdown of the fabric of society. I am thinking back now to when I first started listening to rock 'n' roll and I remember my father saying it was a bad influence on us. I think he would have gotten along well with Plato.
Anyway, I don't need to tell you what I think about Plato's ideas about innovation, do l? Though I have to say it's interesting that the same arguments against new music and art are still being made. Perhaps like the Greeks, we recognize, and maybe even fear the power of music.
Lecture 2-Geology — Movement of Tectonic Plates
Narrator
Listen to part of a lecture in a geology class.
Professor
As we've discussed, Earth's crust is made up of large plates that rest on a mantle of molten rock. These plates…uh...now these tectonic plates support the continents and oceans. Over time, the tectonic plates move and shift, which moves the continents and the ocean floors too. Once it was understood how these plates move, it was possible to determine past movements of Earth's continents and how these slow movements have reshaped Earth's features at different times.
OK. Well, (as) studying the movements of the plates can tell us about the location of the continents in the past, it can conceivably tell us about their location in the future too, right? So, in recent years, some geologists have used plate tectonic theory to make what they call geopredictions. Geopredictions are guesses about what Earth's surface might look like millions of years from now.
So, we know how certain continents are currently moving. For example, the continents of Africa has been creeping north toward Europe. And Australia has been making its way north too, toward Asia.
Does anyone know what's happening to the Americas? l...l think we've talked about that before. Lisa?
Student
They are moving westward, away from Europe and Africa. Right?
Professor
Right. And what makes us think that?
Student
The Atlantic Ocean floor is spreading and getting wider, so there is more ocean between the Americas and Europe and Africa.
Professor
OK. And why is it spreading?
Student
Well, the seafloor is spilt. There is a ridge, a mountain range that runs north and south there. And the rock material flows up from Earth's interior here, at the split, which forces the two sides of the ocean floor to spread apart, to make room for the new rock material.
Professor
Good. And that means, over the short term…uh…and by short term I mean 50 million years, that's a blink of the eye in geological time. Um…over the short term, we can predict that the Americas will continue to move westward, farther away from Europe, while Africa and Australia will continue to move northward.
But what about over the long term? Say 250 million years or more. Well, over that length of time, forecasts become more uncertain. But lots of geologists predict that eventually all the continents, including Antarctica, will merge and become one giant land mass, a super continent, one researchers calling Pangaea Ultima, which more or less means the last super continent.
Now, how that might happen is open to some debate. Some geologists believe that the Americas will continue to move westward and eventually merge with East Asia. This hypothesis is based on the direction the Americas are moving in now. But others hypothesize that a new super continent will form in a different way. They think that a new subduction zone will might occur at the western edge of the Atlantic Ocean.
Paul, can you remind us what a subduction zone is?
Student
Yeah. Um...basically, a subduction zone is where two tectonic plates collide. So if an ocean floor tectonic plate meets the edge of a continent and they push against each other, the heavier one sinks down and goes under the other one. So the…um...the oceanic plate is made of denser and heavier rock, so it begins to sink down under the continental plate and into the mantle.
Professor
Right. So the ocean floor would kind of slide under the edge of the continent. And once the ocean plate begins to sin k, it would be affected by another force –slab pull. Slab pull happens at the subduction zone.
So to continue our example…As the ocean floor plate begins to sink down into the mantle, it would drag or pull the entire plate along with it. So more and more of this plate, the ocean floor, would go down under the continent into the mantle. OK?
So, as I said, currently the Atlantic Ocean floor is spreading, getting wider, but some researchers speculate that eventually a subduction zone will occur where the oceanic plate meets the continental plate of the Americas.1f that happens, slab pull could draw the oceanic crust under the continent, actually causing the Americas to move eastward toward Europe and the ocean floor to get smaller. That is, the Atlantic Ocean would start to close up, narrowing the distance between the eastern edge of the Americas and Europe and Africa. So they form a single super continent.
Section2
Conversation 2— Credits for Internship
Narrator
Listen to a conversation between a Student and an Employee at the university center for off-campus study.
Student
Hi. I am Tom Arnold. I am supposed to pick up a packet from the regional center for marine research. I am doing an internship there this summer.
Employee
Yes. I have it right here. The mail carrier dropped it off a few minutes ago.
Student
Thanks. Um...l wanted to ask about getting credits for the internship. I don't know if…
Employee
I might be able to help you with that. Is there a problem?
Student
I just wanted to make sure the details have been corrected. The system should show that I am registered to earn four credits. But as of Friday, nothing was showing up yet. I was told it would be fixed this morning.
Employee
Well, I can check on the computer for you. Tom Arnold, right?
Student
Yes.
Employee
Well, it is showing credits…but only three.
Student
Really?! So now what? These all have to be finalized last week.
Employee
Well, yes. The course enrollment period ended last week. But since our office was supposed to get this straightened out for you before then... Let me see what I can do.
Uh...did the university give approval for you to earn four credits for this internship? Because the other Students at the center for marine research are only getting three.
Student
Um...l am pretty sure those other Students are doing the internship at the center's aquarium, taking classes in marine biology and then teaching visitors about the various displays. I am doing a special research internship with the center. We’ll be collecting data on changes to the seafloor out in the open ocean.
Employee
Oh. That sounds quite advanced.
Student
Well, the internship requires me to have scuba diving certification and to be a senior oceanography Student. I want to do advanced study in oceanography when I graduate. So I really want to get a sense of what real research is like.
Employee
I see. Now let's try and see if we can... Oh. OK. I see the problem. There are two kinds of internships listed here-regular and research. Yours is listed as regular so it is only showing three credits.
Student
Can you switch it?
Employee
Not yet. But it lists Professor Leonard as…
Student
She is in charge of all the internships.
Employee
She just needs to send an email so I have an official record. Then I can switch it. And that should solve everything.
Student
Great! And I know Professor Leonard is in her office this afternoon, so I can go there later. It will be such a relief to get all these paperwork completed.
Lecture3-Marine Biology — Coral Reefs & CoT starfish
Narrator
Listen to part of a lecture in a Marine Biology class.
Professor
We've been talking about the decline of coral reefs in tropical areas all over the world…um... how natural and man-made stresses are causing them to degrade, and in some cases, to die.
So now let's focus on a specific example of a natural predator that can cause a lot of damage to coral reefs-the Crown of Thorns, or CoT starfish. The Cot starfish is found on coral reefs in the tropical Pacific Ocean and it eats coral. Now, in small numbers, the starfish don't affect coral reefs dramatically. But periodically, starfish population explodes. And when that happens, the reefs can become badly damaged or even destroyed, something we are trying very hard to prevent. For example, during the 1960s, there was an outbreak of CoT starfish in the Great Barrier Reef, off the east coast of Australia. Luckily, the CoT starfish population gradually declined on its own and the reefs recovered.
But we were left wondering - what cause the population to increase so suddenly? Well, over the years, we've come up with a few hypotheses. All still hotly debated.
One hypothesis is that it's a natural phenomenon, that the starfish naturally undergo population fluctuations following particularly good spawning years.
There are also several hypotheses that suggest some sort of human activities are partly responsible, like fishing. There are fish and snails that eat starfish, particularly the giant triton snail, which is the main predator of the starfish. These fish and snails have themselves experienced a decline in population because of overfishing by humans. So with a decline in starfish predators, the starfish population can increase.
Another hypothesized human-related cause is fertilizer runoff. People use fertilizer for their crops and plants and a lot of it eventually makes its way from land into the seas. It's fertilizer, so it has a lot of nutrients. These nutrients have an effect on the starfish, because they cause an increase in the growth of phytoplankton. Phytoplankton are microscopic plants that grow in the ocean. Larval CoT starfish eat phytoplankton in their first month of life, so more fertilizer in the ocean means more phytoplankton, which means more starfish, bad for the reefs.
Now, the final hypothesis has to do with storm events.1f some reefs are destroyed by storms, starfish populations that inhabited those reefs would have to condense and concentrate on the reefs that are left. So this can cause a kind of mass feeding frenzy.
So we have ideas, but no real answer. And because we aren't sure of the causes for starfish population increases, it's difficult to prevent them. I mean, some progress has been made. For example, new survey techniques have enabled us to detect population increases when the starfish are quite young, so we can be ready for them. But meaningful progress requires much better evidence about the cause.
On the bright side, in all the research being done on causes, we have discovered something related to how starfish populations might affect coral reef diversity. We think that when reefs are damaged, after a few years, the fastest-growing corals repopulate the areas. And these fast-growing species can grow over the slower-growing species of coral, denying them light and preventing them from recovery. However, the faster-growing species are the preferred food of the CoT starfish. So when an outbreak of CoT starfish occurs, they thin out the fast- growing coral and may give the slower ones a chance to reestablish. So without the outbreak, the diversity of coral would be reduced.
Lecture4-Anthropology (the Botai People & Horses)
Narrator
Listen to a part of a lecture in an anthropology class.
Professor
So now that we've discussed how people in ancient societies tamed animals like cows and chickens for food and other uses. I'd like to talk about an ancient culture that domesticated horses. It's the Botai people.
The Botai culture thrived over 5,000 years ago in central Asia, in what is now northern Kazakhstan. Pretty much all of what we know about the Botai comes from three archaeological sites. And we learned that the Botai were able to build large perennial villages, sometimes with hundreds of homes. We also found horse bones at these sites and these can be traced back to the time of the Botai settlements. The climate that the Botai culture lived in...it was harsh. And the Botai people…they didn't really seem to have much in the way of agriculture going on. So their whole economy was really based on horses. And because horses can withstand the tough climate, they can survive ice storms and they don't need heated barns, the Botai people could settle in one place and rely on the horses for food, clothing and transportation.
Student
So the Botai were the first to domesticate horses?
Professor
Well, we are pretty sure that horses were first domesticated a bit earlier, to the northwest, in the area that is now Ukraine and western Russia. It's quite possible that some of those people later migrated east to Kazakhstan.
Student
But what exactly tells us that these Botai people, that the horses in their area were really domesticated?
Professor
As with most ancient history, there is not much that we can be certain about. But we know there was a significant population of wild horses in that area. So there were plenty of opportunities for the Botai people to find horses to domesticate.
We also know that horse milk was an important source of food for the Botai people. What? Milking a wild horse? Well, now, that would be impossible…to milk a wild horse. And then... there's the…
Oh. Yes? Eric.
Student
So you said last week that for some animals, like for dogs, there were physical changes taking place over the course of generations of dogs because of domestication. So can we tell from those horse bones if it was sort of the same for horses?
Professor
Actually, it wasn't. We know that horses have not changed a lot physically as a result of domestication. So those ancient horse bones don't tell us much about domestication. But…we've found that…um…we've found what maybe pens or corrals in the Botai settlements. And not too long ago, a new approach was used to find out if the Botai people were keeping horses. Soil samples from these pens or corrals show ten times the concentration of phosphorus.
Student
Um...phosphorus?
Professor
Yes. Phosphorus is a very significant indicator that horses, large numbers of horses were being kept in the settlements. You see, horse manure, horse waste is rich in phosphorus and also nitrogen compared to normal soil. But nitrogen is an unstable element. It can be washed out when it rains or it can be released to the atmosphere, whereas phosphorus combines with calcium and iron, and can be preserved in the soil for thousands of years.
The soil from the Botai settlement sites was found to have high concentrations of phosphorus and low nitrogen concentrations, which is important since it suggests that what we've got is really old, not something added to the soil more recently.
Student
Wait. So if horses have been there recently, there'd still be lots of nitrogen in the soil.
Professor
That's right. Yes. Karen.
Student
I just read an article. It said that one way to determine if there was an ancient fireplace at an archaeological site was to check the soil for phosphorus. So couldn't the phosphorus at the Botai sites just be from the frequent use of fireplaces?
Professor
You are absolutely right. However, when a fireplace leaves behind a lot of phosphorus in the soil, we'd also find an unusually high concentration of potassium. But the soil at the Botai settlements, it was found with relatively little potassium, which makes it far more likely that the phosphorus came from horses. OK?
Now, later on, people of the same region, northern Kazakhstan, started raising sheep and cattle. And that led to a more nomadic culture. Since sheep and cattle can't survive harsh climates, they needed to be taken south every winter. Moving around meant working harder but the trade-off was far richer, fattier milk year round and warm clothing from the sheep.
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