Mutations and evolution in bacteria | Combined science

Starter quiz

True or false? Bacteria are living organisms.

True ✓

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

True

False ✓
Which part of the bacterium is the DNA?

A

B ✓

C

D

none – bacteria do not have DNA
‘Evolution’ refers to …

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

… changes in the common characteristics of a species over generations. ✓

… mating to produce offspring.

… passing genetic information from one generation to the next.
Match each keyword to its correct definition.

genetic variant

⇔

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

mutation

⇔

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

natural selection

⇔

the process by which most scientists believe evolution occurs ✓
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.

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

'microorganisms' ✓
The Oak pupils are discussing evolution. Who is correct?

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

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

True

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

cell.

chromosome.

genetic variant. ✓

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

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

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.

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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.

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.

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.