AP HUMAN GEO Unit 2 Review (EVERYTHING You NEED to Know!)

The video begins with an introduction to AP Human Geography Unit 2, emphasizing the importance of understanding population distribution and density. The speaker, Steve Heimler, offers a review guide to help students excel in their exams. He introduces the topic of population distribution, explaining that humans are not evenly distributed across the Earth's surface and that understanding the reasons behind this is crucial. The paragraph also briefly touches on physical and human factors that affect population distribution.

This paragraph delves into the factors that influence population distribution. It discusses physical factors such as climate, landform, and water bodies, and how they determine where people choose to live. For instance, harsh climates and mountainous terrains are less populated, while temperate climates and coastal areas are more populated. Human factors like culture, economy, history, and politics also play significant roles. The paragraph provides examples, such as the cultural significance of Israel and Palestine, economic migration for job opportunities, historical patterns like the African slave trade, and political motivations for moving to new regions.

The paragraph explains three methods geographers use to calculate population density: arithmetic density, physiological density, and agricultural density. Arithmetic density is the total population divided by the total land area. Physiological density considers only arable land, which reflects a population's ability to feed itself. Agricultural density focuses on the number of farmers relative to arable land, indicating the level of mechanization in farming. The paragraph highlights that these calculations provide different insights into the pressures populations place on their land and resources.

This section discusses the impact of population distribution and density on political, economic, social, and environmental processes. Population patterns affect political representation, economic development, public service accessibility, and environmental health. The concept of carrying capacity is introduced, which refers to the maximum population size that an environment can support. The debate around Earth's carrying capacity is complex, considering factors like climate, agricultural productivity, and resource consumption habits.

The paragraph focuses on population composition, particularly age structure and sex ratio. Age structure is the distribution of a population across different age groups, which helps geographers understand population growth or decline. The dependency ratio, a measure of non-working dependents to working-age population, is discussed as a crucial indicator of societal pressure. The sex ratio, comparing the number of males to females, is also significant. Population pyramids are introduced as a tool to visually represent age structure and sex ratios, with examples of different population growth trends.

This paragraph discusses population dynamics, which involves studying trends in population growth or decline through fertility rates, mortality rates, and migration. Fertility rates, including crude birth rate and total fertility rate, are crucial for predicting future population changes. Mortality rates, including crude death rate and infant mortality rate, reflect a population's death rate and access to healthcare. The rate of natural increase is calculated by subtracting the crude death rate from the crude birth rate. The paragraph also touches on the doubling time of populations and the factors influencing fertility, mortality, and migration, such as social, cultural, political, and economic factors.

The demographic transition model is introduced as a theoretical framework to explain population growth and changes over historical periods. The model consists of four stages, from pre-industrial high birth and death rates to post-industrial low birth and death rates. The model is based on the assumption that as societies industrialize, birth rates decrease, and death rates decrease, leading to population stabilization. A potential fifth stage of natural decrease is also mentioned, where birth rates fall below death rates. The limitations of the model are discussed, including its applicability mainly to European and American populations.

The epidemiological transition model focuses on changes in death rates over time due to diseases. The model has four stages, starting from high death rates due to infectious diseases to a phase where degenerative diseases become the main cause of death due to advances in medical technology. The fifth stage sees a re-emergence of infectious diseases due to drug resistance. The model is criticized for oversimplifying the causes of population change and not accounting for poverty's role in disease spread.

The Malthusian theory, proposed by Thomas Malthus, predicts a population crisis due to exponential population growth outpacing arithmetic food supply growth. Malthus suggested that measures like delayed marriage and fewer children could prevent overpopulation and subsequent famines. However, the theory was proven incorrect as technological advancements in agriculture allowed food production to keep up with population growth.

The consequences of population growth and decline are significant and multifaceted. For governments, managing population growth can involve policies to influence birth and migration rates. The changing roles of women, with increased access to education, healthcare, and employment, have led to decreased fertility rates. An aging population presents political, social, and economic challenges, including shifts in political power, increased need for elder care, and potential economic strain due to fewer working-age individuals.

Migration is driven by a combination of push and pull factors. Push factors, such as war, persecution, or natural disasters, force people to leave their homes, while pull factors, like job opportunities or better governance, attract them to new places. Intervening obstacles and opportunities can also affect migration patterns. The paragraph discusses two major categories of migration: forced migration, often due to crisis situations like war or persecution, and voluntary migration, which is a choice. Voluntary migration is further divided into seven categories: transnational, transhuman, internal, chain migration, step migration, guest workers, and rural to urban migration.

The effects of migration are far-reaching and impact political, economic, and cultural spheres. Politically, migration can shift the balance of power and lead to laws affecting immigration. Economically, immigrants can fill labor gaps and contribute to the economy, but their home countries may suffer from a brain drain. Culturally, immigrants bring their traditions, enriching the destination country's culture, but remittances can also change social structures in their home countries. The paragraph provides examples, such as the Bracero Program and the Chinese Exclusion Act, to illustrate these effects.