Soil and Population Geography Notes

Comprehensive practice flashcards covering soil composition, soil profiles, environmental impacts, demography, population pyramids, and development geography.

What is soil?

A layer of loose material on the earth's surface.

What are the five main ingredients that make up soil and their respective percentages?

Mineral matter ($43\%$), air ($25\%$), water ($25\%$), humus ($5\%$), and living organisms ($2\%$).

What two primary sources contribute minerals and nutrients to make soil fertile?

Minerals come from the parent rock, and nutrients come from the breaking down of plant litter and animals.

Why is soil classified as a non-renewable natural resource?

It takes approximately $400\text{ years}$ to form just $1\,\text{cm}$ of soil, meaning it cannot be replaced within a human lifespan and must be handled with care.

Which three soil characteristics influence what vegetation will grow and how well it will grow?

Depth, acidity (acid, neutral, basic), and drainage.

What is natural vegetation?

Any plant or tree that grows on its own, naturally, without any form of human interference.

How do farmers manage soil that is too acidic?

Farmers spread lime on the soil to reduce its acidity and make it more fertile.

How does vegetation cover reduce the rate of soil erosion and leaching?

Vegetation acts as an umbrella to reduce the impact of heavy rain on the soil, while plant roots bind the soil to protect it from erosion and mass movement.

What is leaching in soil profiles?

When rain falls, water passes through the soil, washing minerals, humus, and nutrients from the A horizon down into the B horizon.

What is a hardpan and under what conditions does it develop?

An impermeable layer formed in extremely wet conditions when minerals build up at the bottom of the A horizon and become cemented together, which can cause the soil to become waterlogged.

How do Brown Earth soils differ from Podzol soils?

Brown Earth soils form in well-drained lowlands under deciduous forests, are rich in humus, contain many living organisms, and are very fertile. Podzol soils form in poorly drained uplands under coniferous forests, are low in humus, contain few living organisms, and are infertile.

What are the distinct layers of a soil profile from the surface down to solid rock?

Organic layer, A horizon (topsoil), B horizon (subsoil), C horizon (parent material), and Bedrock.

What is one major reason life expectancy is low in developing countries?

Limited access to healthcare, including a lack of public hospitals or proper medical treatments, which causes many people to die at a young age.

What is a population pyramid?

An easy-to-read diagram that shows the sex and age breakdown of a population.

Which cohort makes up the working age group, and what is its economic responsibility?

Individuals aged $15\text{--}64$, who pay taxes that fund essential public services and welfare payments such as education, healthcare, children's allowances, and pensions.

Which cohorts are classified as dependants in a population?

Children aged $0\text{--}14$ and adults aged $65+$, who often do not work and rely on the working age group.

What infrastructure adjustments should a government plan if a population pyramid has a wider base?

Build more schools, hire more teachers, and establish more child areas to accommodate the growing younger population.

What changes must be planned if a population pyramid displays a larger cohort aged $50\text{--}59$ transitioning into the $60+$ bracket?

Build more and better residences for the elderly, provide higher pensions, and supply better medicines and healthcare.

How did the Agricultural and Industrial revolutions contribute to historic increases in life expectancy?

Agricultural improvements increased food supplies; technological advancements created jobs that provided income for food, shelter, and medical care; and medical discoveries allowed people to fight infections and disease.

What is a census and how do governments utilize it?

An official process that counts and records the number of people living in a country, used to determine population levels and plan investments in services like schools, hospitals, and communications.

What is the difference between birth rate and death rate?

Birth rate is the number of live births per thousand of population in any given year, whereas death rate is the number of recorded deaths per thousand of population in any given year.

What is the definition of fertility rate?

The average number of children born to a woman during her lifetime.

What does child mortality rate measure?

The number of children under the age of 5 who die for every $1{,}000$ children born.

What is a megacity?

A city with more than $10\text{ million}$ inhabitants.

What is sanitation?

Facilities to dispose of human waste in a safe way, such as sewerage systems and toilets.

What is family planning?

The awareness of birth control, and the planning and spacing of the number of children that a family might want.

What is demography?

The study of human population.

How does soil function as a carbon sink to help regulate global climate?

It absorbs and removes $CO_2$ from the atmosphere.

What are the four forms of land over-exploitation listed in the notes?

Deforestation (clearing a wide area of trees), overgrazing (excessive grazing causing grassland damage), over-cropping (exhausting land by continuously growing crops), and desertification (the spread of dry, infertile, sandy soils).

Why did global population size remain relatively steady for most of human history?

Birth rates and death rates were both very high due to wars, epidemics, diseases, famine, poor diets, poor health and safety standards, high infant and maternal mortality, and a lack of death/disease control.

What are the key economic traits that define developed countries compared to developing countries?

Developed countries have highly advanced, diversified economies with high per capita incomes, sophisticated infrastructure, strong social services, and rely primarily on the service sector. Developing countries have lower average incomes, less industrialization, and often rely on primary commodity exports.

Why does increasing levels of education slow population growth in developing regions?

When children and young adults stay in school longer and pursue careers, they wait longer before having children, which leaves less reproductive time and leads to falling birth rates.

What characterizes a progressive population pyramid?

A triangular shape that narrows toward the top because the birth rate increases each year, resulting in a large young base.