Population Growth Curves and Carrying Capacity · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Boom, Brake, Balance

Science · Organisms & Life Processes · ages 17-18
Name ______________________   Date ____________

  1. What is carrying capacity?

    • The maximum number a habitat can support over time
    • The number of young born each year
    • The speed of the exponential phase

  2. Put the phases of a growth curve in order.

    • Exponential, lag, stationary
    • Lag, exponential, stationary
    • Stationary, lag, exponential

  3. How do you estimate carrying capacity from a plotted curve?

    • Read the steepest slope of the rise
    • Count the years along the bottom axis
    • Read the level where the curve flattens out

  4. Which of these is a density-independent factor?

    • Disease racing through a crowd
    • Predators finding prey easily
    • A flood sweeping the field

  5. Which of these is a density-dependent factor?

    • Competition for food
    • A volcanic eruption
    • A hard frost

  6. How does exponential growth differ from logistic growth on a graph?

    • Exponential is S-shaped and logistic is J-shaped
    • Exponential is J-shaped with no limit while logistic is S-shaped toward K
    • Both level off at the same carrying capacity

  7. A frost kills the same fraction of ten voles as of ten thousand. That frost is density-dependent. This claim is true.

    Circle one:   True   False

  8. A deer herd stops growing while grass still covers the fields. Why?

    • Space is the only limit and it ran out
    • Food quality, waste, disease, and predators brake growth first
    • Births stop the moment any crowding starts
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Boom, Brake, Balance W1-mt_KX6rhHF5kj-s1

  1. The maximum number a habitat can support over time · Carrying capacity, labelled K, is the population the habitat can feed long term.
  2. Lag, exponential, stationary · Growth starts slow, explodes, then levels off at carrying capacity.
  3. Read the level where the curve flattens out · K is the level of the stationary phase, where the S-curve levels out.
  4. A flood sweeping the field · A flood kills the same fraction whether the field holds ten voles or ten thousand.
  5. Competition for food · Competition bites harder as crowding rises, so it depends on density.
  6. Exponential is J-shaped with no limit while logistic is S-shaped toward K · The J-curve keeps rising without limit, while the S-curve bends toward K.
  7. False · Equal fractions regardless of numbers means density-independent.
  8. Food quality, waste, disease, and predators brake growth first · Limiting factors bite through food, waste, and enemies long before room itself runs out.
Worksheet · LightMySky