(geography essay)

First, the main factors affecting population growth

Economic factors:

The role of economic factors in natural population growth mainly lies in that it determines the conditions for population proliferation and survival, and affects the natural population growth rate by changing the birth rate and death rate. Under normal circumstances, when the population cannot meet the demand of economic development for labor, the reproduction of the population itself will be stimulated; When the population exceeds the total consumption provided by economic development, the reproduction of the population itself will be suppressed. At the level of modern productive forces, the natural growth rate of population often decreases with the improvement of economic level. Economic factors also have an important influence on the mechanical growth of population. Under normal circumstances, economically developed or rapidly developing areas have a kind of attraction and cohesion to the population, and the mechanical growth of the population is positive; On the contrary, areas with backward or slow economic development will repel and disperse the population, and the mechanical growth of the population is generally negative.

Cultural factors:

This factor affects the natural growth of population. With the improvement of scientific and cultural level, the natural growth rate of population tends to decline, especially in modern society, which is mainly manifested in three aspects: first, due to the extension of people's education years, the average age of marriage will be delayed accordingly; Second, the more advanced the scientific and cultural level, the richer people's physiological knowledge, parenting knowledge and health care knowledge, which will help reduce infant mortality; Third, the higher people's scientific and cultural level, the more they pay attention to the improvement of their own and future generations' various qualities, and spend their limited income on cultivating children into modern people with higher scientific and cultural quality.

Medical and health factors:

The progress of medicine and the development of medical and health undertakings have a direct impact on the birth rate and death rate. First of all, it reduces the mortality rate caused by various diseases, thus reducing the population mortality rate and prolonging the average life expectancy of the population; Secondly, it has a positive effect on birth control and eugenics.

Second, the world population distribution

The geographical distribution of population is the spatial expression of population growth process. It is a complex social phenomenon, that is, it is deeply influenced by natural conditions and is restricted by social, economic and political systems.

Uneven distribution of population in the world Due to the differences in natural environment and economic development level among countries in the world, the geographical distribution of population is unbalanced. The spatial distribution of the world population is divided into densely populated areas, sparsely populated areas and basically underdeveloped areas without population. According to statistics, the most densely populated area on the earth accounts for about 7% of the land area, but it has 70% of the world's population, and more than 90% of the world's population is concentrated in 10% of the land. The population distribution of different continents is also very different. Europe and Asia account for about 32.2% of the total land area of the earth, but their population accounts for 75.2% of the world's total population. Especially in Asia, where 60% of the world's population lives. Africa, North America and Latin America account for about half of the world's land area, but their population is less than 1/4 of the world's total population. Oceania is vast and sparsely populated. So far, there are no permanent residents in Antarctica. Europe and Asia have the highest population density, with an average of more than 90 people per square kilometer, while Africa, Latin America and North America have an average of less than 20 people per square kilometer. Oceania has the lowest population density, with an average of only 2.5 people per square kilometer. There are also obvious differences in the distribution of world population according to latitude and height: the mid-latitude zone in the northern hemisphere is the concentrated distribution area of world population, with nearly 80% of the world population distributed between 20 and 60 north latitude, while the population in the southern hemisphere only accounts for more than 1 1% of the world population; The vertical distribution of the world's population is also unbalanced. More than 55% of the population lives in low-lying areas below 200 meters above sea level, and the land area is less than 28%. With the trend of productivity concentrated in coastal areas, the population will also be concentrated in coastal areas. At present, the proportion of population in coastal areas within 200 kilometers from the coasts of all continents has obviously exceeded its area proportion, and the trend of population growth in coastal areas will continue to develop. From a national perspective, the same is true. At present, there are about 200 countries and regions in the world, among which there are 1 countries with a population over 1 billion. They are China, India, USA, Indonesia, Russian Federation, Brazil, Japan, Nigeria, Pakistan and Bangladesh. The total population of these 10 countries exceeds 310.50 billion, accounting for about 60% of the world's total population. In addition, there are some countries with very small populations in the world, such as Nauru (7,000), Andorra (50,000), San Marino (23,000), Monaco (30,000) and Vatican (1.380). In terms of population density, Monaco has the largest population density, with 20,000 people per square kilometer, 4,300 people in Singapore, Vatican 1.920, Malta 1.654, 38+0 and so on. The country with the lowest population density in the world is French Guiana (1 person). Mongolia (1), Namibia (2), Libya (2), Mauritania (2), Iceland (2), etc.

The population is increasingly concentrated in cities. Since modern times, the world population has become more and more concentrated in cities, which makes the global population distribution present some dense points of different sizes. In the 1990s, more than 49% of the world's total population was concentrated in cities.

The most densely populated and sparsely populated areas in the world can accurately reflect the actual distribution of population from the regional distribution map of population. The most densely populated areas in the world are as follows: ① Coastal plain along the lake. Especially in some areas with winding coastlines and excellent ports, or in the estuaries of some big rivers. For example, the east coast of the Asian continent, south Asia, the Baltic coast of Europe, the Atlantic coast, the Mediterranean coast, the Gulf of Guinea in Africa, the Boshua coast of America, the Florida and Mexico coasts, the California coast of the Pacific Ocean, the Seattle-Vancouver (Canada) region, the Great Lakes region, Brazil-Venezuela coast, Argentina-Uruguay coast, Chile-Peru coast and the southeast coast of Australia. (2) The middle and lower reaches or estuary deltas of some big rivers flowing into the three oceans. East Asia and South Asia are particularly prominent. ③ In some temperate and tropical islands and peninsulas. The island is surrounded by the sea and the peninsula is surrounded by the sea on three sides. If the location is moderate and there is an excellent harbor, it will often become an economically developed and densely populated area. ④ Some inland places with rich mineral resources. Due to the development of mining industry and the construction of railways and highways, it has become an industrial center and formed a town group; ⑤ On some inland plateaus in tropical and subtropical regions. Because of the high terrain, it is not as hot and humid as the plains or lowlands, and the tropical diseases that endanger people's health are greatly reduced, such as the Mexican Plateau, the Brazilian Plateau, the Peruvian Plateau, and the East African Plateau. ⑥ Oasis areas in the desert, etc. There are the following types of sparsely populated areas in the world: ① areas in the bipolar circle; (2) the vast virgin forest zone between 50 degrees north latitude and the Arctic Circle in the northern hemisphere; (3) Desert and Gobi areas near the Tropic of Cancer and in temperate continents; ④ Tropical rain forest area; ⑤ Mountain area.

Third, the important reason of population growth.

Marx's population theory holds that people have duality. People are consumers on the one hand and producers on the other. As consumers, human beings are unconditional and absolute, and they have to consume the means of subsistence from birth to death. As production, people are relative and conditional. First of all, there must be certain age conditions. Old people and children can only be consumers, not producers. Secondly, it is difficult for disabled people and patients to become producers if they have certain physical conditions; Third, as producers, people should own or use certain means of production. In addition, as a producer, you must master certain production experience and production technology. Therefore, the growth of population should be compatible with the growth of material resources. If this is done, both large and small populations will promote production. If the population growth is greater than the growth of material resources, a part of the surplus population can not be combined with the means of production, it will change from producers to consumers, increasing the social burden; If the population growth is slower than the growth of material resources, part of the means of production cannot be combined with the population, and the resources are not fully developed, which will also affect the development of production. The so-called population problem is that population growth is incompatible with the growth of material resources, which affects the growth rate of national economic development and the improvement of people's living standards. Marx believes that through population self-regulation, human beings can completely unify the production of material materials with their own production.

So now people should have family planning, so that the world population can live in harmony with nature and society.