Inputs vs. Outputs
Inputs vs. Outputs is a Grade 7 science skill from Amplify Science California, Chapter 1: Stability and Change in Populations. Students learn that population change is determined by the balance between births and deaths, and that a population increase definitively tells us births exceeded deaths over a sustained period, focusing investigation on whether births increased or deaths decreased to find the underlying cause.
Key Concepts
To explain the population explosion, we apply the rules of dynamics. Since the population increased , we know for a fact that the number of births was greater than the number of deaths for a sustained period.
The investigation now focuses on finding the cause: did births go up (more food?), or did deaths go down (fewer predators?)?
Common Questions
What determines population change in an ecosystem?
Population change is determined by the balance between inputs (births) and outputs (deaths). If births exceed deaths over a sustained period, the population increases.
What does a population increase tell scientists?
A population increase definitively tells scientists that the number of births was greater than the number of deaths for a sustained period. The investigation then focuses on identifying why.
How do scientists investigate why a population exploded?
Scientists ask two questions: Did births go up (perhaps due to more food?) or did deaths go down (perhaps due to fewer predators?). Each explanation leads to different areas of investigation.
What textbook covers population dynamics for Grade 7?
This topic is covered in Amplify Science California, Grade 7, Chapter 1: Stability and Change in Populations.