unit 3 - made using online summery notes Flashcards
What is food security?
The ability of human populations to access food of sufficient quality and quantity.
What has led to concerns about food security?
The rapidly increasing human population and rising demand for food worldwide.
What is a key part of food security?
Access to food, including affordability.
What is sustainable food production?
Food production that meets current demands without negatively impacting the ecosystem and natural resources.
What are some common sources of human food?
- Cereals
- Potato
- Roots
- Legumes
What factors affect food production?
- Light availability
- Available nutrients
- Water in the soil
- Competition with other plants
What practices can increase food production efficiency?
- Control of limiting factors
- Planting higher yield strains
- Removing competition using pesticides
- Developing pest-resistant crops
Why is livestock production less efficient than crop production?
About 90% of energy is lost between trophic levels, making it more energy and water-intensive.
What is photosynthesis?
The process by which green plants trap light energy to make carbohydrates.
What happens when light strikes a leaf?
- 12% is reflected
- 5% is transmitted
- 83% is absorbed
What are the principal pigments involved in photosynthesis?
- Chlorophyll a
- Chlorophyll b
What is photolysis?
The process by which water is split into oxygen and hydrogen during photosynthesis.
What is the Calvin Cycle?
A series of enzyme-controlled reactions that fix carbon dioxide without requiring light.
What is the role of glucose produced in photosynthesis?
- Energy source for respiration
- Building material for cellulose
- Energy storage as starch
What is selective breeding?
Manipulating DNA of crops and animals to improve certain desirable characteristics.
What are plant field trials used for?
- Investigating performance of cultivars
- Assessing effects of environmental conditions
What is inbreeding?
Reproduction between closely related individuals to develop desired characteristics.
What is inbreeding depression?
A decline in vigor, size, fertility, and yield due to increased homozygosity for deleterious alleles.
What is crossbreeding?
Introducing new alleles by breeding individuals from different breeds to improve characteristics.
What is genetic sequencing?
A process to determine the precise sequence of DNA nucleotides in an organism.
What is monoculture?
The production of a single species of plant, often genetically identical.
What are the characteristics of annual weeds?
- Rapid growth
- Short lifecycle
- Large number of seeds
- Long-term seed viability
What are some common invertebrate pests?
- Molluscs (slugs and snails)
- Nematodes (microscopic worms)
- Herbivorous insects (e.g., aphids)
What are cultural control methods?
- Ploughing
- Timing of sowing
- Early weed removal
- Destruction of crop residue
- Cover crops
- Crop rotation