the idea that not approximately equal amounts, students remember B4.3 Explain how the emergence everyone gets ill. including green pasta), which what happens. Students of resistant organisms Challenge students to are models for insects. They should, though, be supports Darwin’s theory of explain why not everyone design a table in which to aware that the process evolution including antibiotic gets the cold and record the numbers of each is continuous. resistance in bacteria. introduce the idea that different colour of pasta shape. Correct misconceptions this is partly due to The shapes are then spread as they arise. The most inherited variation – out in an open, grassy area. common ones revolve some people are One student is ‘the bird’ and is around the idea that the naturally immune to given a pair of tongs/forceps. environment directly some colds/diseases. The student has 2 minutes to causes organisms to pick up as many pasta shapes change. It is worth as possible. Students count dwelling on the first 2) Sketch a normal the numbers of each colour ‘stage’ of evolution to distribution curve on the returned and calculate ensure that students board and tell students percentages. Students should realise that genetic that it shows variation in find that red, orange and variation is ever present beak length in a yellow pasta pieces are more and that natural population of sandpipers. readily found than green selection cannot work if The birds dig with their pieces, although this will be there is no genetic beaks to find small slightly dependent on the variation to start with. animals to eat. Ask colour of the grass at the time students to suggest why of doing the investigation. Digital: Evolution of there are more birds with antibiotic resistence the middle beak length Students repeat their presentation and very few with either experiment to improve the very short or very long repeatability of the data. beaks. Elicit the idea that Students then calculate mean conditions in the percentages returned for each environment make it colour. They then use this data easiest for birds with to draw pie charts. Ask them to speculate on the
B4.3 Explain how the emergence of resistant organisms supports Darwin’s theory of evolution including antibiotic resistance in bacteria. the idea that not everyone gets ill. Challenge students to explain why not everyone gets the cold and introduce the idea that this is partly due to inherited variation – some people are naturally immune to some colds/diseases. 2) Sketch a normal distribution curve on the board and tell students that it shows variation in beak length in a population of sandpipers. The birds dig with their beaks to find small animals to eat. Ask students to suggest why there are more birds with the middle beak length and very few with either very short or very long beaks. Elicit the idea that conditions in the environment make it easiest for birds with approximately equal amounts, including green pasta), which are models for insects. They design a table in which to record the numbers of each different colour of pasta shape. The shapes are then spread out in an open, grassy area. One student is ‘the bird’ and is given a pair of tongs/forceps. The student has 2 minutes to pick up as many pasta shapes as possible. Students count the numbers of each colour returned and calculate percentages. Students should find that red, orange and yellow pasta pieces are more readily found than green pieces, although this will be slightly dependent on the colour of the grass at the time of doing the investigation. Students repeat their experiment to improve the repeatability of the data. Students then calculate mean percentages returned for each colour. They then use this data to draw pie charts. Ask them to speculate on the students remember what happens. Students should, though, be aware that the process is continuous. Correct misconceptions as they arise. The most common ones revolve around the idea that the environment directly causes organisms to change. It is worth dwelling on the first ‘stage’ of evolution to ensure that students realise that genetic variation is ever present and that natural selection cannot work if there is no genetic variation to start with. Digital: Evolution of antibiotic resistence presentation
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