• Quick retrieval from earlier learning (Living and non-living factors in an ecosystem). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Is this a biotic or an abiotic factor: number of pollinating insects? (abiotic (non-living) / biotic (living)) → biotic (living)Prompt: Does it come from a living organism?
2. Students placed quadrats in a line leading out from under a tree. Light intensity (% of full sunlight) → number of daisies: 90 % → 17 70 % → 13 50 % → 9 30 % → 5 10 % → 1 Which conclusion do the data support? (The data prove that light is the only factor that matters. / Light has no link with the number of daisies. / The tree eats the daisies. / More daisies grow where light intensity is higher.) → More daisies grow where light intensity is higher.Prompt: Look at how the number of daisies changes as light changes.
3. Lichens grow less well near busy roads. Which abiotic factor is the likely cause? (a new disease / air pollution such as nitrogen dioxide / competition with trees / the number of predators) → air pollution such as nitrogen dioxidePrompt: Lichens are used as indicators of air quality.

• Show a food web and ask what would happen if one animal disappeared.
• Share the objective: Population growth and carrying capacity. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: A population of yeast cells (thousands per cm³) was counted each day: 15, 30, 60, 114, 186, 246, 285, 300, 297. Which value is closest to the carrying capacity?
• Step 1: The population stops growing at about 300.
• Step 2: So the answer is: 300
• Answer: 300
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. A population of yeast cells (thousands per cm³) was counted each day: 8, 15, 30, 57, 93, 123, 143, 150, 149. Which value is closest to the carrying capacity? (57 / 75 / 150 / 300) → 150Prompt: The carrying capacity is where the population levels off.
2. A deer population grew from 200 to 250 in one year. What was the percentage growth rate? → 25 %Prompt: Find the increase.

• Students work on the student sheet. Circulate and check the first two answers of every student early.
• Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. A deer population grew from 500 to 600 in one year. What was the percentage growth rate? → 20 %Prompt: Find the increase.
2. Why does a population stop growing when it reaches carrying capacity? (Limiting factors such as food, space and disease balance births and deaths / The animals decide to stop breeding / Carrying capacity is always 100 / The population runs out of DNA) → Limiting factors such as food, space and disease balance births and deathsPrompt: What becomes scarce as numbers grow?

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-11.