Population Dynamics: TEAS Practice Question with Answer & Explanation

Understanding Population Growth and Birth Rates

In demographic studies—a common topic on the TEAS 7 Science section—population growth is primarily determined by the relationship between the crude birth rate and the crude death rate. To understand why a country with high infant mortality would still have a growing population, we must look at how these variables interact.

Why Choice C is Correct

For a population to grow, the number of individuals being born must be greater than the number of individuals dying. In developing nations—often categorized as being in Stage 2 of the Demographic Transition Model—several factors contribute to this:

• Replacement Motivation: High infant mortality often leads to higher birth rates, as families may have more children to ensure that some survive to adulthood to support the family.
• Cultural and Economic Factors: In many developing regions, children are seen as an economic asset (providing labor), leading to larger family sizes.
• Delayed Decline: While medical advancements may start to lower the overall death rate, the birth rate often remains high for several generations, causing a "population explosion."

Analysis of Incorrect Choices

• Choice A: If birth and death rates were equal, the population would reach Zero Population Growth (ZPG). This does not align with the scenario of an "expanding population."
• Choice B: If birth rates were lower than death rates, the population would be shrinking (negative growth). This is typically seen in highly developed nations with aging populations, such as Japan or parts of Europe.
• Choice D: While emigration (people leaving a country) does affect total population, the question asks for the "demographic trend" most likely observed in a growing nation with high infant mortality. Typically, these nations have high natural increase (births minus deaths) that outweighs emigration.

TEAS Concept: The Demographic Transition

The TEAS exam often tests your ability to interpret how social or biological factors influence human populations.

1. Stage 1: High birth, high death (Stable, small population).
2. Stage 2: High birth, falling death (Rapidly growing population—found in many developing nations).
3. Stage 3: Falling birth, low death (Slowing growth).
4. Stage 4: Low birth, low death (Stable, large population).

Memory Tip

Think of a population like a bathtub: The faucet (Births) is adding water, and the drain (Deaths) is removing it. If the water level is rising (Growing Population), the faucet must be flowing faster than the drain is emptying!