Harnessing Biology Flashcards
What is selective breeding?
adapting an animals biological characteristics during breeding
Why does selective breeding happen?
to create animals with desired characteristics
How does selective breeding work?
-choose desired feature
-breed organism with that feature
-only select offspring with desired feature
-repeat
What is the aim of selectively breeding crops?
-give higher yields
-resistant to certain diseases
-resistant to pests
-better balance of nutrients
What features of animals are selectively bred?
-produce more meat, milk, eggs
-produce more/ better quality fur
-produce more offspring
-increased resistance to diseases and parasites
What factors do farmers attempt to control to maximise crop yield?
-light intensity
-CO2 conc
-temperature
What features of a greenhouse are useful for farmers?
-artificial heating
-artificial lighting
-artificial CO2 in air
-regular watering
Greenhouses and polythene tunnels provide enhanced…
conditions for plants to grow
GREENHOUSES: Why is it made out of glass?
-transparent
-allows natural light for photosynthesis
GREENHOUSES: Why is it a benefit that they can be heated easily?
increases enzyme activity
GREENHOUSES: What is the benefit of burning fossil fuels as a heating method?
-conc of CO2 and water vapour increase
-both factors needed for photosynthesis
-also reduces water loss from plant through transpiration
5 ways to increase crop yield
- use of fertilisers
- leguminous crops
- ploughing fields
- controlling soil pH
- controlling CO2, light + heat
What do fertilisers provide for crops?
elements to grow - e.g. nitrates for proteins, magnesium for chlorophyll
What are organic fertilisers?
made from faces of farm animals (manure) mixed with straw
What are inorganic fertilisers?
inorganic compounds, such as potassium nitrates or ammonium nitrates in specific amounts for optimum yield production
What are ADVANTAGES of organic fertilisers?
-improves soil structure
-greater range of minerals
-less cost for farmer
What are the ADVANTAGES of inorganic fertilisers?
-mineral ions release immediately (FAST ACTING)
-contents known
-easy to apply
What are the DISADVANTAGES of organic fertilisers?
-slow acting
-may contain pests
-bulkier, more difficult to apply
What are the DISADVANTAGES of inorganic fertilisers?
-can lead to eutrophication (as fertiliser is soluble)
-requires regular reapplication
What do leguminous crops have in their root nodules?
nitrogen-fixing bacteria
How do leguminous crops increase crop yield?
-converts nitrogen gas into ammonium
-releases ammonium into soil
What are pests?
organisms that reduce the yield of crops or stock animals
2 ways to control pests
-use pesticides
-biological control (using another organism to reduce number of pests)
What pesticide kills plant pests?
herbicides
What pesticide kills insects?
insecticides
What pesticide kills fungi?
fungicides
What pesticide kills molluscs (slugs, snails)?
molluscicides