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GCSE
OCR Gateway
Natural selection and evolution
Genetic variation, as well as changes in the environment, cause characteristics of organisms to change over time. This process of natural selection leads to the evolution of new species.
Part of
Biology (Single Science)
Genes, inheritance and selection
quiz
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Evidence for evolution - antibiotic resistance in bacteria
Antibiotic resistance
Bacteria can evolve quickly because they reproduce at a fast rate. Mutations in the DNA of bacteria can produce new characteristics. A random mutation might cause some bacteria to become resistant to certain antibiotics, such as penicillin. Antibiotics usually kill bacteria, but in this case the mutation means the bacteria cannot be destroyed by the antibiotic. The emergence of antibiotic resistance in bacteria is an example of natural selectionleading to evolution.
Development of antibiotic resistance
Penicillin was the first antibiotic to be produced on a mass scale in the 1940s. It is derived from Penicillium fungi, shown here growing on an agar plate.
Many new types of antibiotics were discovered during the 1950s and 1960s, but the rate of discovery has slowed greatly more recently. Many scientists even stopped looking for new antibiotics, as they felt it was unnecessary.
Recent concerns about increasing antibiotic resistance have created a drive for new antibiotics. However, their development is costly and takes a long time. Some scientists fear that we are fighting a losing battle against antibiotic resistant bacteria, which may ultimately lead to people dying from simple infections.
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GCSE Subjects
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