Question | Answer |
What is food security? | The ability of a human population to access food in sufficient quantity and quality. This maintains a healthy population and helps avoid malnutrition and starvation |
What does an increasing human population and concern for food lead to? | there is a continuing demand for increased food production. |
What is meant by sustainable food production? | it does not degrade the natural resources on which agriculture depends. |
What is Availability? | Existence of food in sufficient quantities and of appropriate quality over time. |
What is Sustainability? | Degree to which food security can be guaranteed over extended periods of time and not degrade the natural resources on which agriculture depends. |
What is Accessibility? | Sufficient economic and infrastructure resources to get available food resources. |
What are the main producers of human food? | Only a small number of green plant species such as sugar cane, cereals (wheat and maize, rice and legumes) |
Plant breeders manipulate heredity and are seeking to develop crops with? | Higher nutritional values. Higher yields. Resistance to pests and diseases. Physical characteristics for harvesting and rearing (large fruit). Ability to thrive in particular environmental conditions. |
How does energy loss in food chains explain why livestock produce less food per unit area than plant crops? | Due to loss of energy between trophic levels - (the shorter the food chain, the greater the quantity of energy held in food) |
Why has there been a major increase in concern about food security in recent years? | The growing population requires food - we will be unable to provide enough/ |
What is a trophic level? | The next level in a food chain. |
What do plants convert in photosynthesis? | Light energy --> Chemical energy |
What is Net assimilation? | Mass increase due to photosynthesis (-) loss in respiration. |
Why is net assimilation measured by the (increase in dry mass) per unit leaf area. | Because the water content of a living organism (especially plants) can vary greatly over a short period of time. |
Why is net assimilation measured by the increase in dry mass (per unit leaf area.) | to measure the rate of production. Allows comparison of different species. |
What is biological yield? | The total plant biomass produced (dry mass) |
What does biological yield demonstrate? | The productivity in the ecosystem. |
What is economic yield? | The mass of desired product produced (dry mass) |
What does the economic yield demonstrate? | The productivity for market |
What is harvest index? | (dry mass of economic yield) / (dry mass of biological yield) |
What does harvest index useful for? | to show efficiency of production (conversion allows comparison of efficiency between different crops e.g maize and barely) |
What are the 3 fates of light? | Absorbed, Reflected, Transmitted. |
Why are chloroplasts green? | The green light is not absorbed, but it is reflected and transmitted |