 All right, and we're back and welcome. I'm Mr. Ruscha. All right, this is our second lesson in our human geography unit. In our last lesson, we talked about culture and how it describes everything we are and everything we do. But if we're going to be talking about human geography, obviously we're going to have to be talking about humans. If we're going to talk about humans, we have to start talking about population. And that's what we're going to be talking about today. We're going to be talking about population geography. And what is population? Well, quite frankly, population just simply is how many people are there. For example, in the United States, there is 328 million people, large population. But we also have something called population density. And quite frankly, this population density is an average of how many people are there per every square mile or every square kilometer of the country. And just because your country has a large population doesn't mean that it's going to have a high population density. For example, let's take the comparison between the United States and Bangladesh. Once again, the United States has nearly 330 million people. It's the third most populated country in the world. However, the United States is a huge country for spanning over 3.8 million square miles. Now compare that to Bangladesh, which has about the half the population as the United States that are right about 165 million people. However, unlike the United States, Bangladesh is actually a fairly small country. It's only about 50,000 square miles. So while the United States has a population density of 94 people per every square mile, the population density in Bangladesh is an astounding 3,277 people for every square mile. Bangladesh is really crowded and that's pretty much what population density tells you. Now the study of populations is called demography. Now the word demography is very similar to another word that you probably know, which is democracy. Now you'll see that the first portion of the word, both of these, comes from the Greek word, which means demos, which actually is the Greek word, which means people. Now if we look at the word demography, we see that the last portion of the word comes from the Greek word graphia, which means to describe. Just like geography is the description of the world, demography is the description of the people. And we can see the actual definition here that demography is the study of the statistics or the numbers, such as birth, death, income, literacy, the incidence of disease and other numbers, which illustrate the changing structure of human populations. Now when we use demography to describe a population, it studies really two things that everyone has to do. We all have to be born and unfortunately we all have to die. Now those two numbers that we look at when we start tracking babies, this is birth rates and the fertility rate. Now a birth rate is the number of live births for every 1,000 population. So for example, if your country was a very small country with only 10,000 people and you had 20 babies that were born in the year, your birth rate would be 2.0. Now a related number to birth rate is the fertility rate. Now the fertility rate is the average number of children that women in a country will have in their lifetime. And we see that there is a relationship between fertility rate and birth rate. If you have a country with a higher fertility rate, you're going to have a higher birth rate. Now not only does demographic start to tell us things about the population, it also helps us describe which countries are more likely to be rich and what countries are more likely to be poor. Now we'll be talking about something called the Human Development Index in our next lesson, but essentially developing countries are poor countries and developed countries are rich countries like the United States. And here what we find is if you're in a developing country or a poor country, you're going to have a much higher birth rate. For example, the African country of Niger has a birth rate of about 45 and a half while the United States has a birth rate of just about 12 and a half. And another rich country, Japan has a birth rate is actually under eight babies born for every 1,000 population. We also see the same thing in our fertility rates. The country in Niger, every woman in Niger on average is going to have almost seven kids while the United States, the average women will only have 1.87. Now how do you get a fracture? Well remember this is just an average. Now if I have to track the number of babies, that also means that demography will have to track the number of people that die. And we do this through two numbers as well. We have something called a mortality rate and an infant mortality rate. Now both of these terms have the word mortality which comes from the word mortalis, which means mortal or subject to death. Now a mortality rate is essentially the mere opposite of a birth rate, where a birth rate tells us the number of births per every 1,000 population and mortality rate is the number of deaths per 1,000 population. So in our small country of only 10,000 people, if I have 20 people who die in a year, our mortality rate is going to be 2.0. Now what's interesting is now unlike birth rates and fertility rates where we see a great difference between poor countries and rich countries, we really don't see that as much with mortality rates. For example, the poor African country Lothoso has a mortality rate of about 14.9 and even really poor Afghanistan has a mortality rate of just about 14, which isn't all that much greater than say Germany, which has a mortality rate of 11.42. Now while you don't have a great difference between rich countries and poor countries mortality rates, we do have a huge difference when we start looking at infant mortality rates. Now infant mortality rates tracks the number of babies who are born who die before their first birthday. But unlike mortality rates and birth rates, which is of a 1,000 population, a infant mortality rate is actually the number of children who die before their first birthday for every 1,000 births. So if you look at our infant mortality rates of our poor countries and our rich countries, at the top of the infant mortality rates is Afghanistan, which has an infant mortality rate of just about 115. This means that in Afghanistan, 11.5% of all the children that are born will die before being able to blow out their first candle. But we'll see that other poor countries also have very high infant mortality rates. Now this is in stark contrast to our developed or rich countries, such the United States, which has an infant mortality rate of under six, or even Japan that has an infant mortality rate of just about two. It's a huge difference. Now if we start taking our birth rate and mortality rate, we get something called the rate of natural increase. For example, if I take the birth rate of the United States and subtract from it the mortality rate, what I get is a rate of natural increase of 4.34. Now in our poor countries, even though you have a high mortality rate because you have a high birth rate, we see a much larger rate of natural increase. For example, we can see that Niger, which has a rate of natural increase of 22.2. But we can also look at countries such as Japan, where in Japan you actually have more people who are dying than you have being born. And what this means is Japan actually has a shrinking population of 1.58. Now because of this disparity of the rate of natural increase between rich countries and poor countries, we actually see a huge difference in the projected world population growth. In this chart here, we have in red are your rich countries or your developed countries. We actually see that the population change within these countries really isn't very much. But if we look at the countries in blue, those are our poor countries, we see that their population is increasing much, much, much faster. Now a tool that demographers and geographers and other social scientists will use to be able to study the population of different countries is something known as a population pyramid. This is a graphic device that shows the sex and age distribution of a population. Now essentially, a population pyramid is two sets of bar graphs and the left side of a population pyramid will have the male population divided in age groups of usually about five years for every one of these bars, with the youngest being at the bottom and the oldest being at the top. On the right side of the population pyramid, we have the same thing for the female population. Now if you look at this population pyramid of the African country of Sudan, we find very quickly that has far more people who are younger than they do older. This is what we call a Christmas tree or a triangle population pyramid. Now when we start analyzing a population pyramids, the important age to look at is the age of 45 because most reproduction is done by those individuals under 45 years old. So if you have a population pyramid such as this one which is Sudan, we find that most of the population is under 45 years old or is within the range where they can still reproduce and have more babies. So when you have a population pyramid like this where majority of a population is actually under 45 years old, we see a high birth rate, we see high growth rates and short life expectancy. This is usually what we're going to find in our developing countries or our poor countries. Then we have a population pyramid like this which we call the box. Now if you'll see basically the population that is above 45 years old and the population that is below 45 years old is about the same. So what we find with a box population pyramid, this is going to be a developed nation such as the United States or Australia. Now here we find is low infant mortality rate, we have a low population growth rate and long life expectancy. This is a indicator of a developed or a rich country. Now we also have a population pyramid which we can call the cup. Japan and Germany are an example of a cup type population pyramid. Here you see that the majority of the population is older than 45 and since there's more people over 45, you don't have as many people having babies, you're actually going to have a shrinking population. This too happens in a developed or a rich country. Now when we talk about the population trends of a country, so far what we talked about is the natural rate of increase, but there's one or the thing that can change the population of a country and that is migration. Now migration is the movement of people to a new area or a country in order to find better work or better living conditions. Now there are two terms that we're going to be talking about throughout this course anytime we talk about migration. There are push factors and there are pull factors. Push factors are those factors that cause people to leave their homeland. Pull factors are those things that pull or attract people to a location and it's really easy to determine what is a push factor and what's a pull factor. Push factors are always, always going to be bad things. Examples of push factors might be war, famine, economic distress, oppression, natural disasters. These are all reasons why people decide, hey listen I no longer want to live here, I need to look for somewhere else to live, which brings us to pull factors. Just as push factors are always bad, pull factors are always going to be good. And examples of pull factors of things such as better economic opportunities, more jobs, a better political condition, the weather is better, or there is established ethnic communities. People like to go move where there's people that are very similar to them. These are things which will cause people to move to a country called the pull factor as opposed to things that are pushing you out of the country called the push factor. Alright so what we've done is we've talked about population, we talked about what population is and how that compares to population density, we talked about some of the demographics such as birth rates and fertility rates and mortality rates and infant mortality rates and how those all combine to be able to have something called the rate of natural increase and then we looked at population pyramids and how they can be used to analyze population and then we looked at the factors of migration which causes populations from move around the world. Alright in our next lesson we're going to talk about how we can use these demographics and start determining what is the human development index of these different countries. Alright but until then, keep on learning.