The Rule of 70 states that doubling time is...

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $24.99Unlock all

Study for the Dual Enrollment Environmental Science Test. Prepare with flashcards and multiple choice questions, complete with hints and detailed explanations. Get ready for your exam!

Multiple Choice

The Rule of 70 states that doubling time is...

Explanation:
Doubling time is the time needed for a population to grow to twice its size at a constant growth rate. The Rule of 70 gives a quick estimate: doubling time ≈ 70 divided by the growth rate (as a percent per time unit). This comes from the exact formula t = ln 2 / ln(1 + r); for small growth rates, ln(1 + r) ≈ r, so t ≈ 0.693 / r, which is about 70/r when r is in percent. For example, at 2% growth per year, the population would double in about 35 years (70/2). The other options describe different population concepts (life expectancy, birth rate divided into total population, or carrying capacity) and do not tell how long it takes to double.

Doubling time is the time needed for a population to grow to twice its size at a constant growth rate. The Rule of 70 gives a quick estimate: doubling time ≈ 70 divided by the growth rate (as a percent per time unit). This comes from the exact formula t = ln 2 / ln(1 + r); for small growth rates, ln(1 + r) ≈ r, so t ≈ 0.693 / r, which is about 70/r when r is in percent. For example, at 2% growth per year, the population would double in about 35 years (70/2). The other options describe different population concepts (life expectancy, birth rate divided into total population, or carrying capacity) and do not tell how long it takes to double.

More Multiple Choice Questions
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy