• 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: an invasive species? (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: 10 % → 2 30 % → 7 50 % → 12 70 % → 17 90 % → 22 Which conclusion do the data support? (The data prove that light is the only factor that matters. / More daisies grow where light intensity is higher. / Light has no link with the number of daisies. / The tree eats the daisies.) → More daisies grow where light intensity is higher.Prompt: Look at how the number of daisies changes as light changes.
3. Grey squirrels were introduced to Britain and red squirrel numbers fell. What kind of factor are the grey squirrels for the red squirrels? (abiotic: temperature / biotic: competition and disease / abiotic: soil pH / not a factor at all) → biotic: competition and diseasePrompt: Are grey squirrels alive?

• 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: 12, 24, 48, 91, 149, 197, 228, 240, 238. Which value is closest to the carrying capacity? (91 / 120 / 240 / 480) → 240Prompt: The carrying capacity is where the population levels off.
2. A deer population grew from 500 to 625 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 6 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 200 to 210 in one year. What was the percentage growth rate? → 5 %Prompt: Find the increase.
2. Snowshoe hare and lynx populations rise and fall in cycles, with lynx peaks just after hare peaks. Why? (Hares eat lynx / Lynx and hares compete for grass / More hares feed more lynx; then lynx eat so many hares that hare numbers fall / The two species never interact) → More hares feed more lynx; then lynx eat so many hares that hare numbers fallPrompt: This is a predator–prey relationship.

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