12 HARNESSING BIOLOGY Flashcards
Describe how to use selective breeding to get animals/plants with the desired characteristics
- Choose individulas with desired feature
- Let only these individuals reproduce
- Choose offspring with desired feature
- Led only these individuals reproduce
- Repeat for generations
How can polythene tunnels and glasshouses be used to increase the yield of certain crops
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- Transparent material allows suffecient natural light for photoysnthesis
- Addigtional lighting gives a ‘longer day’ during winter
- Greenhouse effect raises temperature of glasshouse
- Burning fossil fuels or wood raises temperature when external temperature is too low (also produced CO2 and water vapour)
- Water vapour maintains a moist atmosphere, so reduces water loss by transpiration
What is the aim of polythene tunnels and glasshouses
Increase the rate of photosynthesis and increase yield by finding optimum conditions
Advantages to using organic fertiliser
- Greater range of minerals
- Improves soil structure
- Less cost to farmer
- Releases minerals over a longer time
Disadvantages to inorganic fertiliser
- Can lead to eutrophication as it is soluble
- Requires regular application
Advantages to inorganic fertiliser
- Mineral ions release immediately - fast acting
- Contents known
- Easy to apply
Advantages to inorganic fertiliser
- Mineral ions release immediately - fast acting
- Contents known
- Easy to apply
Disadvantages to organic fertiliser
- Slow acting - must be decomposed first
- Bulkier - more difficult to apply
- May contain pests
Disadvantages to organic fertiliser
- Slow acting - must be decomposed first
- Bulkier - more difficult to apply
- May contain pests
How could pesticies damage ecosystems
Passed up the food chain, and become concentrated in the top tissues of carnivores
How does biological control work
- Use a predator
- Never eradicates the pest only reduces to a level where they no longer cuase significant economic damage
Advantages of pesticides
- Reduces pest population instantly
- Can kill the whole population of pests
Disadvantages of pesticides
- Cost - need regular application
- Not specific - could kill other organisms
- Pest can come resistant to chemical
- Chemical can conocentrate in all organisms higher up the food chain
Disadvantages of pesticides
- Cost - need regular application
- Not specific - could kill other organisms
- Pest can come resistant to chemical
- Chemical can conocentrate in all organisms higher up the food chain
Disadvantages to biological control
- Takes time to reduce pest population
- Not all population killed
- Expensive if re-populating is required
Disadvantages to biological control
- Takes time to reduce pest population
- Not all population killed
- Expensive if re-populating is required
Advantages to biological control
- Organism only introduced once - will reproduce
- Only one cost for initial introduction
- Pest specific
- Pest will not become resistant
- No effect on other animals in food chain
Advantages to biological control
- Organism only introduced once - will reproduce
- Only one cost for initial introduction
- Pest specific
- Pest will not become resistant
- No effect on other animals in food chain