Carrying capacity: J-shaped and S-shaped growth
Grade 9 Science Worksheet - Building Confidence

Circle the best answer.
Ari reads the graph. Which words describe the shape of the line?
- S-shaped: it climbs, then levels off
- Flat: the number stays near one height
- J-shaped: it climbs faster and faster
- Straight: the same number is added each day
Bo reads the graph. Which words describe the shape of the line?
Yeast in a test tube (model data). Time (hours) across, 0 to 10, a mark every 2. Yeast cells (thousands) up, 0 to 100, a mark every 20. Yeast cells joins (0, 10), (1, 21), (2, 37), (3, 54), (4, 67), (5, 74), (6, 78), (7, 79), (8, 80), (9, 80), (10, 80) with straight pieces. Yeast in a test tube (model data). Time (hours) across, 0 to 10, a mark every 2. Yeast cells (thousands) up, 0 to 100, a mark every 20. Yeast cells joins (0, 10), (1, 21), (2, 37), (3, 54), (4, 67), (5, 74), (6, 78), (7, 79), (8, 80), (9, 80), (10, 80) with straight pieces. Yeast in a test tube (model data) 0 2 4 6 8 10 0 20 40 60 80 100 Time (hours) Yeast cells (thousands) Yeast cells - Straight: the same number is added each hour
- J-shaped: it climbs faster and faster to the end
- Falling: the number gets smaller each hour
- S-shaped: it speeds up, then levels off
Esme reads the graph. Room and food stay plentiful for one group. Which line fits that group?
Two groups of duckweed (model data). Time (days) across, 0 to 5, a mark every 1. Plants (number) up, 0 to 80, a mark every 20. Line A joins (0, 2), (1, 4), (2, 8), (3, 16), (4, 32), (5, 64) with straight pieces. Line B joins (0, 2), (1, 6), (2, 14), (3, 29), (4, 44), (5, 54) with straight pieces. Two groups of duckweed (model data). Time (days) across, 0 to 5, a mark every 1. Plants (number) up, 0 to 80, a mark every 20. Line A joins (0, 2), (1, 4), (2, 8), (3, 16), (4, 32), (5, 64) with straight pieces. Line B joins (0, 2), (1, 6), (2, 14), (3, 29), (4, 44), (5, 54) with straight pieces. Two groups of duckweed (model data) 0 1 2 3 4 5 0 20 40 60 80 Time (days) Plants (number) Line A Line B - Line B, because it levels off, which shows room and food are plentiful
- Line B, because it has more plants on day 3, 29 against 16
- Neither line, because plentiful food gives a flat line
- Line A, because it is J-shaped
Jun reads the graph. What is the carrying capacity of the pond?
Frogs in a pond (model data). Time (years) across, 0 to 7, a mark every 1. Frogs (number) up, 0 to 80, a mark every 20. Frogs joins (0, 6), (1, 14), (2, 27), (3, 41), (4, 52), (5, 57), (6, 59), (7, 60) with straight pieces. Carrying capacity joins (0, 60), (7, 60) with a straight piece. Frogs in a pond (model data). Time (years) across, 0 to 7, a mark every 1. Frogs (number) up, 0 to 80, a mark every 20. Frogs joins (0, 6), (1, 14), (2, 27), (3, 41), (4, 52), (5, 57), (6, 59), (7, 60) with straight pieces. Carrying capacity joins (0, 60), (7, 60) with a straight piece. Frogs in a pond (model data) 0 1 2 3 4 5 6 7 0 20 40 60 80 Time (years) Frogs (number) Frogs Carrying capacity - 80 frogs
- 7 frogs
- 6 frogs
- 60 frogs
Read this first
Snails in a garden tank (model data)
week snails 0 4 1 9 2 17 3 28 4 38 5 44 6 48 7 49 8 50 Luz reads the table. About what carrying capacity does the tank show?
- 100 snails
- 50 snails
- 4 snails
- 8 snails
Bacteria in a flask with plenty of food (model data)
hour bacteria 0 50 1 100 2 200 3 ? Ren reads the table. The count doubles each hour. How many bacteria are there at hour 3?
- 300 bacteria
- 800 bacteria
- 400 bacteria
- 600 bacteria
Duckweed on a pond (model data)
day plants 0 4 1 8 2 16 3 32 Tala reads the table. How many plants were added between day 2 and day 3?
- 4 plants
- 16 plants
- 8 plants
- 32 plants
Three groups of bacteria (model data)
group day 0 day 1 day 2 day 3 A 10 20 30 40 B 10 20 40 80 C 10 30 90 270 Zee reads the table. Which group doubles each day?
- Group A and Group B, because both have 20 on day 1
- Group A, because it goes up by 10 a day
- Group B, because 20, 40 and 80 each double
- Group C, because it triples, 30 to 90 to 270
Yeast in a test tube with a fixed amount of sugar (model data)
hour yeast cells (thousands) sugar left (grams) 0 4 100 1 10 85 2 22 60 3 34 25 4 38 8 5 38 2 Noah reads the table. What change in the table explains why the yeast count levels off?
- The sugar left falls from 100 to 2 grams, so the yeast run low on food
- The sugar left stays high, so food is not short
- The yeast count rises from 4 to 38, so the sugar grows too
- Yeast settle at 38 thousand cells in any test tube
Kira reads the graph. In weeks 0 to 3 the line climbs a bit more each week. Why?
Sunflower seedlings in a plot (model data). Time (weeks) across, 0 to 8, a mark every 1. Seedlings (number) up, 0 to 100, a mark every 20. Seedlings joins (0, 8), (1, 16), (2, 28), (3, 44), (4, 59), (5, 69), (6, 74), (7, 77), (8, 79) with straight pieces. Carrying capacity joins (0, 80), (8, 80) with a straight piece. Sunflower seedlings in a plot (model data). Time (weeks) across, 0 to 8, a mark every 1. Seedlings (number) up, 0 to 100, a mark every 20. Seedlings joins (0, 8), (1, 16), (2, 28), (3, 44), (4, 59), (5, 69), (6, 74), (7, 77), (8, 79) with straight pieces. Carrying capacity joins (0, 80), (8, 80) with a straight piece. 0 1 2 3 4 5 6 7 8 0 20 40 60 80 100 Time (weeks) Seedlings (number) Seedlings Carrying capacity - The seedlings are already at the carrying capacity
- Each week the same number of seedlings is added
- The count is nearest its limit, so growth is fastest
- Few seedlings share plenty of room and light, so growth is almost J-shaped