An example of a mutation in bacteria that could be helpful to humans (e.g. ability to digest man-made waste).
An example of a mutation in bacteria that is dangerous to humans (e.g. antibiotic resistance).
Explanations of examples at the genetic level using ideas about mutation, natural selection and asexual reproduction.
Explanations to include why advantageous genetic variants become more common in the bacteria over generations.

Common misconception

Pupils may think that bacteria are not living organisms and/or do not evolve. Pupils may also think that all bacteria are harmful.

The lesson explores two examples of evolution in bacteria, explaining each example through mutation, reproduction and natural selection.

Keywords

Natural selection - Organisms that are better adapted to their environment are more likely to survive, reproduce and pass on their genes to their offspring.
Micro-organism - Microscopic living thing, such as a bacterium or an amoeba.
Mutation - A change in the nucleotide base sequence in the DNA of the genome.
Genetic variant - A region of DNA in which the sequence of nucleotide bases has been changed.
Asexual reproduction - A form of reproduction in which a cell divides to produce two genetically identical cells.

The lesson explores one example of a mutation in bacteria that could be helpful to us (the ability to digest plastic waste, to challenge the misconception that all bacteria are harmful), and one example that is not helpful (antibiotic resistance, because of its importance to public health).

Teacher tip

Equipment

None required.

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Video

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Worksheet

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Starter quiz

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6 Questions

Q1.

True or false? Bacteria are living organisms.

Correct answer: true

false

Q2.

True or false? All bacteria are harmful to humans because they cause diseases.

true

Correct answer: false

Q3.

Which part of the bacterium is the DNA?

Correct answer: B

none – bacteria do not have DNA

Q4.

‘Evolution’ refers to …

… changes in an organism’s characteristics during its lifetime.

Correct answer: … changes in the common characteristics of a species over generations.

… mating to produce offspring.

… passing genetic information from one generation to the next.

Q5.

Match each keyword to its correct definition.

Correct Answer:genetic variant,a region of DNA in which the nucleotide base sequence has been changed

a region of DNA in which the nucleotide base sequence has been changed

Correct Answer:mutation,a process that changes the nucleotide base sequence in a region of DNA

a process that changes the nucleotide base sequence in a region of DNA

Correct Answer:natural selection,the process by which most scientists believe evolution occurs

the process by which most scientists believe evolution occurs

Q6.

Put the steps in the correct order to explain how an organism evolves by natural selection.

1 - A mutation changes the nucleotide base sequence in the organism’s DNA.

2 - Variation is caused by the changes in the nucleotide base sequence in the DNA.

3 - This may cause the organism to have a new adaptation, giving it an advantage.

4 - The organism competes more successfully for food and other resources.

5 - The organism is more likely to survive and reproduce.

6 - The genetic variant made by the mutation is passed to the organism’s offspring.

Exit quiz

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6 Questions

Q1.

Microscopic living things such as bacteria and amoeba are known as .

Correct Answer: microorganisms, micro-organisms, micro-organism, microorganism

Q2.

The Oak pupils are discussing evolution. Who is correct?

Correct answer: Andeep: All living organisms evolve, including microorganisms.

Jun: Only humans and other animals such as finches and tortoises evolve.

Laura: Animals and plants evolve, but bacteria don’t because they’re too small.

Q3.

Bacteria divide to make two identical cells in the process of reproduction.

Correct Answer: asexual

Q4.

True or false? Some antibiotics have evolved to be resistant to bacteria.

true

Correct answer: false

Q5.

Bacteria can gain a new ability when mutation in their DNA creates a new ...

cell.

chromosome.

Correct answer: genetic variant.

offspring.

Q6.

The Oak pupils are discussing evolution in bacteria. Who is correct?

Alex: Many bacteria have deliberately evolved to try to kill us!

Correct answer: Izzy: It’s just random. New abilities just appear because of random mutations.

Sam: Some bacteria have evolved new abilities because they want to help us.