1. Key Area 1(a) : Food supply Unit 3: Sustainability and Interdependence

2. Food security and sustainability Why is food security an increasing issue in the human population? The human population is increasing more rapidly than food production. Less land is available for food production. What is meant by sustainable food production? Continuing production of food without causing damage or degrading the natural resources that were used to produce it. CfE Higher Biology Sustainability and Interdependence

3. Food security and sustainability Human populations have to access food and use this food over a sustained period of time. This is important because? Survival – avoid starvation Health – avoid malnutrition (safe and nutritious food have more benefits) CfE Higher Biology Sustainability and Interdependence

4. Food security CfE Higher Biology Sustainability and Interdependence QUANTITY Sufficient amounts of food QUALITY Nutritious and provides a balanced diet. ACCESS Economic means to obtain food. Food security

5. Factors affecting food security Complete the table to give explanations of these factors. CfE Higher Biology Sustainability and Interdependence Factors that underpin food security Explanation Sustainability Accessibility Availability Usage

6. Factors affecting food security CfE Higher Biology Sustainability and Interdependence Factors that underpin food security Explanation Sustainability A food source that is able to support populations, maintain its productivity and endure over time without causing any ill effects. Accessibility A food source that is easily available, near to where it is required and ready to use. Availability It is convenient, ready to use, easily obtained over long periods. Usage It is easy to use, process and manage.

7. Food security and sustainability Using the case study in the text book on page 226, answer the following questions. What reasons are there that present the challenge of providing a secure supply of food? What contributions has ‘biological science’ made to meeting this challenge? What other agencies could be involved in a more ‘interdisciplinary approach’ to food security. CfE Higher Biology Sustainability and Interdependence

8. Food security and sustainability What are the natural factors that can affect food production? Drought Pests Flooding Disease Desertification Insecticide resistance Write a short explanation of how each of these could effect food production. Use a named example where possible. CfE Higher Biology Sustainability and Interdependence

9. Food Production Natural resources are vital for food production. We need to find an appropriate balance between CfE Higher Biology Sustainability and Interdependence Providing enough sustainable quality food Preventing damage/further damage to the environment

10. Food Production – factors to consider CfE Higher Biology Sustainability and Interdependence SUSTAINABILITY Global warming Pollution Soil: erosion & fertility Deforestation Write the biological issue or impact each factor could have on the sustainability of current and future food production

11. Food Production Ultimately food production depends on plant growth. The main producers of human food are displayed below: CfE Higher Biology Sustainability and Interdependence

12. Food Production Small numbers of green plant species are relied on as main sources of food. These small numbers equate to approximately 95% of the worlds food supply. The earth itself, however, has at least 75000 species of edible plants. CfE Higher Biology Sustainability and Interdependence

13. Food Production Competition Weeds or too dense planting will slow growth Pests Decrease yield, either by feeding on crops or by making the plant less healthy Breeding higher yield cultivars Will increase yield, but some require more intensive farming methods and are more dependent on particular soil profiles and nutrients Disease Decrease yield as the plant is less healthy. May also produce food that is unsuitable for eating Soil profile The depth of soil / drainage etc will determine what type of crop you can grow Soil nutrients Plants need specific nutrient profiles. Some may need to be added using fertlisers. Can also use crop rotations

14. Food chains and energy loss The sun is the ultimate source of energy for most communities of living things. Green plants absorb some of the sun’s light energy to make their own food by photosynthesis. The other organisms in a food chain are consumers because they all get their energy and biomass by consuming and eating other organisms. Not all energy available to organisms at one stage can be absorbed by organisms at the next one. The amount of energy decreases from one stage to the next and only about 10% is passed on. CfE Higher Biology Sustainability and Interdependence

15. Pyramids of Numbers Pyramids of numbers can be produced based on a food chain and each layer in the pyramid is called a trophic level. Grass grass hopper frog snake hawk CfE Higher Biology Sustainability and Interdependence

16. Food chains and energy loss Draw a food chain where plants are consumed by humans. Draw another food chain where animals are consumed by humans. What can you deduce by comparing these two food chains? The shorter the food chain the greater the quantity of energy held in the food. The fewer the trophic levels the less energy lost. Therefore more food is generated per unit area of land when plant crops are grown. Livestock generates less food per unit of land. CfE Higher Biology Sustainability and Interdependence

17. Photosynthesis Write the summary equation for photosynthesis. Carbon+wateroxygen + glucose Dioxidesugar CO 2 +H 2 OO 2 +C 6 H 6 O 12 Other additional factors that are necessary for photosynthesis to take place are: sunlight and chlorophyll CfE Higher Biology Sustainability and Interdependence

18. Photosynthesis – getting the light When the light hits a leaf there are 3 things that can happen to it. It can be Absorbed (used in photosynthesis) Reflected Transmitted CfE Higher Biology Sustainability and Interdependence Reflected 12% Absorbed 83% but only 4% used in photosynthesis Transmitted 5%

19. Photosynthesis The light that is absorbed is absorbed by the pigments in the chloroplasts. CfE Higher Biology Sustainability and Interdependence Granum Starch grain Inner membrane Outer membrane Stroma Lamella

20. Photosynthesis This light is known as ‘visible light’ on the radiation spectrum. It covers a narrow band of wavelengths ranging from 380nm to 750nm. CfE Higher Biology Sustainability and Interdependence

21. Absorption Spectra What does Absorption mean? taking something in An absorption spectrum shows the specific wavelengths of light that are absorbed. In a leaf more than one pigment is involved in the absorption of light. These can be separated by using paper or thin layer chromatography. CfE Higher Biology Sustainability and Interdependence

22. Name the colours along the spectrum below and shade them in (ROYGBIV) Wavelength of light (nm) 700600 500 400 Violet Indigo BlueGreen Yellow Orange Red Wavelength of light (nm) 700 600 500 400 Shade in the spectrum below showing the areas where light is absorbed

23. Absorption spectra The absorption spectra shows how strongly the different pigments absorb at different wavelengths. From this information, why are chloroplasts green? They are green because they absorb every other colour apart from green. CfE Higher Biology Sustainability and Interdependence

24. Photosynthetic pigments CfE Higher Biology Sustainability and Interdependence It can also be shown by graphing the wavelength in nm (on the x-axis) against the relative absorbance (on the y- axis).

25. Photosynthetic pigments Chlorophyll a and b absorb mainly blue and red light. The other pigments, called carotenoids absorb other colours of light (including the blue-green region of the spectrum) and pass this energy on to the chlorophyll. These carotenoids are also called accessory pigments. CfE Higher Biology Sustainability and Interdependence

26. Photosynthetic pigments Why is it useful to the plant to have several different pigments? They can absorb more of the wavelengths of light. CfE Higher Biology Sustainability and Interdependence

27. Action spectra An action spectra shows the rate of photosynthesis at different wavelengths. CfE Higher Biology Sustainability and Interdependence

28. Spectra CfE Higher Biology Sustainability and Interdependence

29. Photosynthetic pigments A close correlation can be seen between the overall absorption spectrum for the leaf pigments and the action spectra for photosynthesis. The action spectra is made up of all the absorption spectra added together. It shows the amount of photosynthesis you get from each wavelength of light (all of the different pigments working together) CfE Higher Biology Sustainability and Interdependence

30. Separation of Photosynthetic pigments Pigments from leaves can be extracted using a suitable solvent. These can then be separated using either paper or thin layer chromatography. The different pigments can be identified by their position on the paper and their colour. Rf values can be calculated for each pigment. CfE Higher Biology Sustainability and Interdependence

31. Separation of Photosynthetic pigments Propanone is usually used as the extraction solvent. A mixture of propanone and petroleum ether is used as the chromatographic solvent. CfE Higher Biology Sustainability and Interdependence

32. Separation of Photosynthetic pigments CfE Higher Biology Sustainability and Interdependence