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* http://labspace.open.ac.uk/mod/oucontent/view.php?id=426185§ion=1.2.4 | * http://labspace.open.ac.uk/mod/oucontent/view.php?id=426185§ion=1.2.4 | ||
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=Teacher's Notes= | |||
Science Book: living environment p. 56 | |||
Topic: Animal populations and ecosystems | |||
==Introductory activity 1:==BRAINSTORM (whole class) | |||
Q. What factors affect animal population numbers in the wild? | |||
Probe – positive and negative factors | |||
Responses – food availability, pollution, weather conditions, water levels, disease, predators, etc | |||
Encourage pupils to build on what others have said and to say whether they agree with peer comments (building dialogue skills). | |||
==Introductory activity 2:==LOOKING AT GRAPHS (pairs/groups) | |||
Project or print the two graphs in figures 19 & 20. Look at the graphs of human and great tit populations and discuss: | |||
Q. Tell the story of the graphs; what do they show? | |||
Q. What factors might explain the changes in numbers over time? | |||
Brief plenary. | |||
Teacher note: text between and after the graphs | |||
==Activity 3:== A case study – Rabbits grazing on the North and South Downs of England (whole class teaching and discussion) | |||
Show Fig. 22 Colonising chalk downlands and talk through it using Q&A. | |||
E.g. Why might ground be completely bare? (clearing for agriculture, over-grazing, fire, volcano, quarrying) | |||
What happens over time? | |||
Introduce succession as a predictable sequence of change. Point to grassland, shrubland, woodland. Chalk grassland would become woodland if left… why hasn’t that happened in the Downs? | |||
What is the role of the rabbit (or sheep)? Grazing prevents trees developing… | |||
Why do farmers and vegetable growers install rabbit-proof fences? | |||
Why do certain plants increase and others decrease in number when rabbits are present? | |||
Human intervention: tell the story of myxomatosis and its devastating effect on the rabbit population. (Play the song “Bright Eyes” if you want!) Explain that it ultimately died out. | |||
What other animals might have been negatively affected by the virus? Why? | |||
- predators of rabbits, grassland dwelling birds, rabbit hole inhabitants | |||
What animals might have been positively affected by the virus? | |||
- competitors | |||
What happens when there are no animals grazing? | |||
Discuss the positive effects of grazing – biodiversity. | |||
The above Qs can be discussed in groups to get pupils thinking. | |||
Teacher note: text p. 58-61 | |||
Concept map: Whole class activity 4 (see Fig. 24) mapping interrelationships between rabbits and other organisms on downland | |||
This could be done on the IWB as it exploits the interactive nature of the technology. Provide each organism as a labelled object on the board. Ask pupils to suggest links. You may want them to work on this in groups at tables first (using paper or min-whiteboards), with one group then demonstrating their representation on the IWB, for constructive critique and extension by others. | |||
Introduce the notion of natural selection after this. Teacher note 1 – p.62. | |||
Q. What other examples of natural selection can you think of? | |||
Managing the downlands - Teacher note 2 – p.62. | |||
Conclusion: change in ecosystems upsets the whole balance… fragility and instability | |||
How much interference should humans make to protect one species or habitat? | |||
[[Category:Primary]] [[Category:Secondary]][[Category:Science]][[Category:Teacher Education]][[Category:External Resource]] | [[Category:Primary]] [[Category:Secondary]][[Category:Science]][[Category:Teacher Education]][[Category:External Resource]] | ||
