Population Growth Trends - Middle School Earth and Space Science
Card 1 of 25
What is the formula for population change using births, deaths, immigration, and emigration?
What is the formula for population change using births, deaths, immigration, and emigration?
Tap to reveal answer
$\Delta P = (B - D) + (I - E)$. Change equals births minus deaths plus immigration minus emigration.
$\Delta P = (B - D) + (I - E)$. Change equals births minus deaths plus immigration minus emigration.
← Didn't Know|Knew It →
Which graph shape best matches exponential population growth: straight line or J-shaped curve?
Which graph shape best matches exponential population growth: straight line or J-shaped curve?
Tap to reveal answer
J-shaped curve. Exponential growth curves upward sharply, resembling the letter J.
J-shaped curve. Exponential growth curves upward sharply, resembling the letter J.
← Didn't Know|Knew It →
What term describes growth that increases faster as the population gets larger?
What term describes growth that increases faster as the population gets larger?
Tap to reveal answer
Exponential growth. Growth rate proportional to current population size creates acceleration.
Exponential growth. Growth rate proportional to current population size creates acceleration.
← Didn't Know|Knew It →
What term describes growth that adds about the same number of people each year?
What term describes growth that adds about the same number of people each year?
Tap to reveal answer
Linear growth. Linear growth adds a constant number of individuals per time period.
Linear growth. Linear growth adds a constant number of individuals per time period.
← Didn't Know|Knew It →
What does it mean when the slope of a population graph becomes steeper over time?
What does it mean when the slope of a population graph becomes steeper over time?
Tap to reveal answer
The growth rate is increasing (accelerating). Steeper slope indicates faster population increase per unit time.
The growth rate is increasing (accelerating). Steeper slope indicates faster population increase per unit time.
← Didn't Know|Knew It →
What does a slope of $0$ on a population-versus-time graph indicate?
What does a slope of $0$ on a population-versus-time graph indicate?
Tap to reveal answer
Population is staying constant. Zero slope means no change in population over time.
Population is staying constant. Zero slope means no change in population over time.
← Didn't Know|Knew It →
What does a negative slope on a population-versus-time graph indicate?
What does a negative slope on a population-versus-time graph indicate?
Tap to reveal answer
Population is decreasing over time. Downward slope means population decreases as time progresses.
Population is decreasing over time. Downward slope means population decreases as time progresses.
← Didn't Know|Knew It →
What does a positive slope on a population-versus-time graph indicate?
What does a positive slope on a population-versus-time graph indicate?
Tap to reveal answer
Population is increasing over time. Upward slope means population increases as time progresses.
Population is increasing over time. Upward slope means population increases as time progresses.
← Didn't Know|Knew It →
Which graph shape best matches logistic population growth: J-shaped curve or S-shaped curve?
Which graph shape best matches logistic population growth: J-shaped curve or S-shaped curve?
Tap to reveal answer
S-shaped curve. Logistic growth starts fast then slows, creating an S shape.
S-shaped curve. Logistic growth starts fast then slows, creating an S shape.
← Didn't Know|Knew It →
Which trend is shown when a line graph becomes steeper over time for population vs. year?
Which trend is shown when a line graph becomes steeper over time for population vs. year?
Tap to reveal answer
The growth rate is increasing. Steeper slope indicates faster population increase per time unit.
The growth rate is increasing. Steeper slope indicates faster population increase per time unit.
← Didn't Know|Knew It →
Which option best describes a positive population growth trend on a time-series graph?
Which option best describes a positive population growth trend on a time-series graph?
Tap to reveal answer
An upward slope (population increases over time). Rising line shows population growing over time.
An upward slope (population increases over time). Rising line shows population growing over time.
← Didn't Know|Knew It →
What does the term carrying capacity mean on a logistic population growth graph?
What does the term carrying capacity mean on a logistic population growth graph?
Tap to reveal answer
Maximum population an environment can support long term. Resources and space limit how many organisms can survive sustainably.
Maximum population an environment can support long term. Resources and space limit how many organisms can survive sustainably.
← Didn't Know|Knew It →
Which trend is shown when a population graph rises and then levels off near a maximum value?
Which trend is shown when a population graph rises and then levels off near a maximum value?
Tap to reveal answer
Logistic growth (S-shaped curve). Growth slows as population approaches environmental limits.
Logistic growth (S-shaped curve). Growth slows as population approaches environmental limits.
← Didn't Know|Knew It →
What does it mean when the slope of a population graph becomes less steep over time?
What does it mean when the slope of a population graph becomes less steep over time?
Tap to reveal answer
The growth rate is decreasing (decelerating). Less steep slope indicates slower population increase per unit time.
The growth rate is decreasing (decelerating). Less steep slope indicates slower population increase per unit time.
← Didn't Know|Knew It →
Identify the trend if a population graph rises quickly at first, then slows as it nears a limit.
Identify the trend if a population graph rises quickly at first, then slows as it nears a limit.
Tap to reveal answer
Growth is slowing due to limiting factors (logistic). Resources become limited as population nears carrying capacity.
Growth is slowing due to limiting factors (logistic). Resources become limited as population nears carrying capacity.
← Didn't Know|Knew It →
Using $\Delta P = (B-D)+(I-E)$, find $\Delta P$ if $B=50$, $D=30$, $I=10$, $E=5$.
Using $\Delta P = (B-D)+(I-E)$, find $\Delta P$ if $B=50$, $D=30$, $I=10$, $E=5$.
Tap to reveal answer
$25$. $(50-30)+(10-5) = 20+5 = 25$ net population change.
$25$. $(50-30)+(10-5) = 20+5 = 25$ net population change.
← Didn't Know|Knew It →
Calculate doubling time using the Rule of $70$ if annual growth rate is $1%$.
Calculate doubling time using the Rule of $70$ if annual growth rate is $1%$.
Tap to reveal answer
$70$ years. $\frac{70}{1} = 70$ years for population to double.
$70$ years. $\frac{70}{1} = 70$ years for population to double.
← Didn't Know|Knew It →
Calculate doubling time using the Rule of $70$ if annual growth rate is $2%$.
Calculate doubling time using the Rule of $70$ if annual growth rate is $2%$.
Tap to reveal answer
$35$ years. $\frac{70}{2} = 35$ years for population to double.
$35$ years. $\frac{70}{2} = 35$ years for population to double.
← Didn't Know|Knew It →
What is the doubling time formula using annual growth rate $r$ (as a percent) with the Rule of $70$?
What is the doubling time formula using annual growth rate $r$ (as a percent) with the Rule of $70$?
Tap to reveal answer
$t_d \approx \frac{70}{r}$. Dividing 70 by growth rate percent approximates doubling time.
$t_d \approx \frac{70}{r}$. Dividing 70 by growth rate percent approximates doubling time.
← Didn't Know|Knew It →
Identify the trend when the population values rise, then level off near a maximum.
Identify the trend when the population values rise, then level off near a maximum.
Tap to reveal answer
Logistic growth approaching carrying capacity. Population approaches but doesn't exceed environmental limits.
Logistic growth approaching carrying capacity. Population approaches but doesn't exceed environmental limits.
← Didn't Know|Knew It →
Identify the trend when a table shows the same population increase in each equal time interval.
Identify the trend when a table shows the same population increase in each equal time interval.
Tap to reveal answer
Constant-rate growth (linear). Equal increases per time interval create a straight line.
Constant-rate growth (linear). Equal increases per time interval create a straight line.
← Didn't Know|Knew It →
Identify the trend when a table shows larger population increases in each equal time interval.
Identify the trend when a table shows larger population increases in each equal time interval.
Tap to reveal answer
Accelerating growth (often exponential). Each interval's increase is larger than the previous one.
Accelerating growth (often exponential). Each interval's increase is larger than the previous one.
← Didn't Know|Knew It →
What is the formula for average rate of change on a population graph from $(t_1,P_1)$ to $(t_2,P_2)$?
What is the formula for average rate of change on a population graph from $(t_1,P_1)$ to $(t_2,P_2)$?
Tap to reveal answer
$\frac{P_2-P_1}{t_2-t_1}$. Slope formula: change in population divided by change in time.
$\frac{P_2-P_1}{t_2-t_1}$. Slope formula: change in population divided by change in time.
← Didn't Know|Knew It →
What is the formula for percent change in population from old to new?
What is the formula for percent change in population from old to new?
Tap to reveal answer
$%\text{ change}=\frac{\text{new}-\text{old}}{\text{old}}\times 100%$. Measures relative change as percentage of original value.
$%\text{ change}=\frac{\text{new}-\text{old}}{\text{old}}\times 100%$. Measures relative change as percentage of original value.
← Didn't Know|Knew It →
Calculate percent change if population goes from $50$ million to $55$ million.
Calculate percent change if population goes from $50$ million to $55$ million.
Tap to reveal answer
$10%$. $\frac{55-50}{50}\times 100% = \frac{5}{50}\times 100% = 10%$
$10%$. $\frac{55-50}{50}\times 100% = \frac{5}{50}\times 100% = 10%$
← Didn't Know|Knew It →