Antibiotic resistance

Plesiosaurs are extinct animals that lived in the ocean.

Figure 5 shows what scientists think a living plesiosaur may have looked like.

Scientists think that the plesiosaur had smooth skin.

Suggest why the scientists cannot be certain what the skin of the plesiosaur was like.

Explain how structure A in Figure 5 helped the plesiosaur survive in the ocean.

Plesiosaurs may have moved rapidly upwards to hold their heads above the water surface to search for prey.

What type of adaptation was the rapid upwards movement?

Tick () one box.

Scientists use fossils to estimate when different types of plesiosaur existed.

Figure 6 shows when three types of plesiosaur existed.

When did plesiosaur A first evolve?

Use Figure 6.

Determine how many million years plesiosaur B existed for.

Use Figure 6.

The exact year of extinction of all plesiosaur species can only be estimated.

Which are two reasons why?

Tick () two boxes.

What evidence from Figure 6 shows that plesiosaur C might have evolved from plesiosaur B ?

Tick () one box.

Evolution can be studied using evidence from:

• fossils

• antibiotic-resistant bacteria.

Suggest two reasons why it is easier to study evolution in bacteria than to study evolution using fossils.

Give one reason why doctors are concerned about antibiotic-resistant bacteria.

Figure 8 shows an evolutionary tree.

Which species in Figure 8 is most closely related to lions?

Tick (✓) one box.

Tigers are more closely related to snow leopards than to jaguars.

Draw a line on Figure 8 to show the evolution of tigers.

Label the line ‘Tiger’.

What is represented by species R on Figure 8 ?

Tick (✓) one box.

Complete the sentence.

Choose the answer from the box.

Evolution occurs by the process of.

Species can become extinct.

Give two possible causes of extinction.

Fossils are used to study the evolution of some species.

Suggest one reason why fossils are used to study evolution.

Some bacteria have evolved to be resistant to penicillin.

Penicillin is an antibiotic.

How has the process of evolution produced bacteria that are resistant to penicillin?

Write the stages, A, B, C, D and E in the correct order.

The first stage has been completed for you.

A The bacteria with mutations are more likely to survive.

B The population of bacteria is exposed to penicillin.

C The mutation for resistance to penicillin is passed on to offspring.

D Variation in the population of bacteria is caused by mutation.

E The surviving bacteria reproduce.

New antibiotics are not likely to control the spread of bacteria that are resistant to antibiotics.

What are two reasons why?

Tick (✓) two boxes.

It is estimated that 99.9% of all species that have ever existed are now extinct.

Why is the percentage of species that are extinct only an estimate? Tick (✓) one box.

What evidence is used to study species that have become extinct?

A bacterium called Clostridioides difficile (C. difficile) can infect the human digestive system. C. difficile can multiply and produce toxins. The toxins cause diarrhoea. Doctors are concerned that new strains of C. difficile may evolve. Antibiotics may not be able to kill these new strains. Explain how the evolution of antibiotic resistant C. difficile can be slowed down.

It is estimated that 99.9% of all species that have ever existed are now extinct.

Why is the percentage of species that are extinct only an estimate? Tick (✓) one box.

What evidence is used to study species that have become extinct?

A bacterium called Clostridioides difficile (C. difficile) can infect the human digestive system. C. difficile can multiply and produce toxins. The toxins cause diarrhoea. Doctors are concerned that new strains of C. difficile may evolve. Antibiotics may not be able to kill these new strains. Explain how the evolution of antibiotic resistant C. difficile can be slowed down.

There is a need to grow enough food for all the people in the world. Growing enough food affects habitats and biodiversity.

What is meant by the term biodiversity?

Peat bogs are being destroyed because peat is used by humans. Destroying peat bogs also reduces biodiversity.

Give one use of peat taken from peat bogs.

Explain why the use of peat is harmful to the environment. Do not refer to biodiversity in your answer.

Intensive farming, where a single crop is grown on a large area of land year after year, is more cost effective for farmers. It is efficient to use fertilisers and to burn the waste so the land is ready to use the next year. Planting a single crop reduces biodiversity. Suggest two ways that this type of farming can damage the environment. Do not refer to biodiversity in your answer.

Most of the world’s production of antibiotics is used in farming. Antibiotics are given to animals to prevent the spread of disease.

Explain how the widespread use of antibiotics in farming is a threat to human life.

Pseudomonas bacteria cause infections in hospital patients.

A new strain of Pseudomonas bacteria has evolved. This new strain can only be killed by one antibiotic called fluroquinolone.

Scientists want to prevent the new strain of Pseudomonas from spreading in the human population.

Explain the advice doctors should be given to prevent the spread of the new strain.

Pseudomonas bacteria cause infections in hospital patients. A new strain of Pseudomonas bacteria has evolved. This new strain can only be killed by one antibiotic called fluroquinolone. Scientists want to prevent the new strain of Pseudomonas from spreading in the human population. Explain the advice doctors should be given to prevent the spread of the new strain.