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?
- J-shaped: it climbs faster and faster
- Straight: the same number is added each day
- S-shaped: it climbs, then levels off
- Flat: the number stays near one height
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
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 - 6 frogs
- 80 frogs
- 60 frogs
- 7 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?
- 4 snails
- 100 snails
- 50 snails
- 8 snails
Pia reads the graph. What does the duck line do after it reaches the carrying capacity line?
Ducks on an island (model data). Time (years) across, 0 to 8, a mark every 1. Ducks (number) up, 0 to 60, a mark every 20. Ducks joins (0, 4), (1, 9), (2, 16), (3, 25), (4, 32), (5, 36), (6, 38), (7, 39), (8, 40) with straight pieces. Carrying capacity joins (0, 40), (8, 40) with a straight piece. Ducks on an island (model data). Time (years) across, 0 to 8, a mark every 1. Ducks (number) up, 0 to 60, a mark every 20. Ducks joins (0, 4), (1, 9), (2, 16), (3, 25), (4, 32), (5, 36), (6, 38), (7, 39), (8, 40) with straight pieces. Carrying capacity joins (0, 40), (8, 40) with a straight piece. Ducks on an island (model data) 0 1 2 3 4 5 6 7 8 0 20 40 60 Time (years) Ducks (number) Ducks Carrying capacity - It stays close to the carrying capacity line
- It keeps climbing in a J-shape
- It drops back to the first count
- It climbs fastest there
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?
- 32 plants
- 4 plants
- 16 plants
- 8 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, because it goes up by 10 a day
- Group A and Group B, because both have 20 on day 1
- Group B, because 20, 40 and 80 each double
- Group C, because it triples, 30 to 90 to 270
Milo reads the graph. Why does the line flatten near the carrying capacity?
Duckweed on a small pond (model data). Time (days) across, 0 to 12, a mark every 2. Duckweed plants (number) up, 0 to 120, a mark every 20. Duckweed plants joins (0, 5), (1, 10), (2, 21), (3, 37), (4, 56), (5, 74), (6, 86), (7, 93), (8, 97), (9, 99), (10, 99), (11, 100), (12, 100) with straight pieces. Carrying capacity joins (0, 100), (12, 100) with a straight piece. Duckweed on a small pond (model data). Time (days) across, 0 to 12, a mark every 2. Duckweed plants (number) up, 0 to 120, a mark every 20. Duckweed plants joins (0, 5), (1, 10), (2, 21), (3, 37), (4, 56), (5, 74), (6, 86), (7, 93), (8, 97), (9, 99), (10, 99), (11, 100), (12, 100) with straight pieces. Carrying capacity joins (0, 100), (12, 100) with a straight piece. Duckweed on a small pond (model data) 0 2 4 6 8 10 12 0 20 40 60 80 100 120 Time (days) Duckweed plants (number) Duckweed plants Carrying capacity - Duckweed has a fixed limit of 100 on any pond
- The plants stop growing once they are old
- Space and light get short as the plants crowd, so growth slows
- Nothing limits the plants, so the flat part is a graph slip
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
- The count is nearest its limit, so growth is fastest
- Few seedlings share plenty of room and light, so growth is almost J-shaped
- Each week the same number of seedlings is added