Calculating Growth and Decline
Calculating Growth and Decline is a Grade 7 science concept from Amplify Science (California) Chapter 1: Stability and Change in Populations, introducing the fundamental mathematical rule of population dynamics. Population size increases when births outnumber deaths, and decreases when deaths outnumber births — a simple inequality that governs all population change.
Key Concepts
The size of a population changes based on a simple inequality. If the number of births is greater than the number of deaths, the population size will increase .
Conversely, if the number of deaths is greater than the number of births, the population size will decrease . This mathematical relationship is the fundamental rule of population dynamics.
Common Questions
What determines whether a population grows or shrinks?
The relationship between births and deaths determines population change. If births exceed deaths, the population grows. If deaths exceed births, the population shrinks. If they are equal, the population is stable.
What is the basic formula for population change?
Population change = births minus deaths. If this number is positive, the population increases; if negative, it decreases; if zero, the population is stable.
Why is the births vs. deaths comparison fundamental to ecology?
All population dynamics trace back to this simple inequality. Every factor — predators, food supply, disease, climate — ultimately influences population size by affecting either the birth rate, the death rate, or both.
What do Grade 7 students learn about population growth in Amplify Science?
In Chapter 1 of Amplify Science California Grade 7, students learn the foundational rule that birth and death rates drive population change, and apply this mathematical relationship to analyze how ecosystems maintain or lose stability.