Back to the lesson plan builder
Lesson length30 min45 min60 min
Questions🔀 New questions

Print the plan for yourself; the student sheet prints on its own page after it.

Science lesson plan · 9th grade (Year 10 in England) · 45 minutes

Natural selection and resistance

Cells, genetics and evolution

CCSS NGSS.MS-LS4-4CCSS NGSS.HS-LS4-2CCSS NGSS.HS-LS4-4England: KS4 Combined Science: Evolution, inheritance and variation

Objective and success criteria

Students will: Natural selection and resistance.

  • I can answer questions on today's skill on my own, without help.
  • I can explain each step and say why it works.
  • I can check my answer and spot a mistake.

Before and after

Needs first: Evolution and fossil evidence; DNA, genes and chromosomes

Leads to: Evidence for evolution and how new species form; Allele frequencies with the Hardy–Weinberg equations

Materials: Microscope images or slides, Cell diagrams, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).

Warm-up · 5 min

  • Quick retrieval from earlier learning (Evolution and fossil evidence; DNA, genes and chromosomes). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Who is famous for the theory of evolution by natural selection? (Charles Darwin / Marie Curie / Isaac Newton / Albert Einstein) → Charles DarwinPrompt: He studied finches and tortoises on the Galápagos Islands.
  2. What shape is a DNA molecule? (a ring of six atoms / a cube / a double helix / a single straight line) → a double helixPrompt: It looks like a twisted ladder.
  3. Evolution: which statement is true? (Individual animals evolve during their own lifetime. / Dinosaurs and early humans lived at the same time. / Variation between individuals is needed for natural selection. / Humans evolved from modern chimpanzees.) → Variation between individuals is needed for natural selection.Prompt: Evolution is about populations over many generations.

Hook · 5 min

  • Show a microscope image of cells and ask what students think they are looking at.
  • Share the objective: Natural selection and resistance. Read the success criteria together.

I do: model it · 10 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: Before the Industrial Revolution most peppered moths were pale. Soot darkened tree bark, and dark moths became common. Why?
  • Step 1: Dark moths survived to breed more, so the dark allele became more common.
  • Step 2: So the answer is: Dark moths were better camouflaged, so fewer were eaten by birds
  • Answer: Dark moths were better camouflaged, so fewer were eaten by birds
  • Pause after each step and ask a student to say what comes next.

We do: guided practice · 10 min

  • Do these together. Students try each step on whiteboards before you reveal it.
  • Use the hints as prompts rather than giving the answer.
  1. Why should patients finish a course of antibiotics? (Because antibiotics kill viruses / To make their immune system weaker / To kill all the bacteria, so resistant ones are less likely to survive and spread / To make the antibiotic taste better) → To kill all the bacteria, so resistant ones are less likely to survive and spreadPrompt: Stopping early can leave the toughest bacteria alive.
  2. A population of 100 bacteria contains 1% that are resistant to an antibiotic. The antibiotic kills all the others. How many bacteria survive? → 1Prompt: Only the resistant ones survive.

You do: independent practice · 10 min

  • 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.

Exit ticket · 5 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. A population of 1000 bacteria contains 1% that are resistant to an antibiotic. The antibiotic kills all the others. How many bacteria survive? → 10Prompt: Only the resistant ones survive.
  2. What is selective breeding? (feeding animals more food / cloning one plant / animals choosing their own mates in the wild / humans choosing parents with useful characteristics to breed) → humans choosing parents with useful characteristics to breedPrompt: Farmers have done this for thousands of years.

Watch out for

  • Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
  • Remembering facts without the reason: ask "why?" and "what is the evidence?"

Support and stretch

Support

  • Review first: Evolution and fossil evidence.
  • Use concrete materials: microscope images or slides.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Move on to: Evidence for evolution and how new species form; Allele frequencies with the Hardy–Weinberg equations.
  • Explain a common mistake in writing and how to fix it.
  • Write a word problem that uses today's skill, then solve a partner's.

Homework and more practice

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-9.

Free lesson plan from eurekami.com/lesson-plan-builder

eurekami

Natural selection and resistance

Name

Date

Score/ 8

  1. Question 1

    What is selective breeding?

    • A. animals choosing their own mates in the wild
    • B. humans choosing parents with useful characteristics to breed
    • C. feeding animals more food
    • D. cloning one plant

  2. Question 2

    A population of 200 bacteria contains 2% that are resistant to an antibiotic. The antibiotic kills all the others. How many bacteria survive?

    Answer

  3. Question 3

    What is the original source of new variation in a population?

    • A. mutations in DNA
    • B. learning new skills
    • C. injuries
    • D. exercise

  4. Question 4

    A population of 1000 bacteria contains 5% that are resistant to an antibiotic. The antibiotic kills all the others. How many bacteria survive?

    Answer

  5. Question 5

    A population of 200 bacteria contains 5% that are resistant to an antibiotic. The antibiotic kills all the others. How many bacteria survive?

    Answer

  6. Question 6

    A population of 500 bacteria contains 10% that are resistant to an antibiotic. The antibiotic kills all the others. How many bacteria survive?

    Answer

  7. Question 7

    A population of 100 bacteria contains 2% that are resistant to an antibiotic. The antibiotic kills all the others. How many bacteria survive?

    Answer

  8. Question 8

    A population of 100 bacteria contains 5% that are resistant to an antibiotic. The antibiotic kills all the others. How many bacteria survive?

    Answer

Free from eurekami.com

for the adult only

Answer key: Natural selection and resistance

  1. 1. B. humans choosing parents with useful characteristics to breed

  2. 2. 4

  3. 3. A. mutations in DNA

  4. 4. 50

  5. 5. 10

  6. 6. 50

  7. 7. 2

  8. 8. 5