Life on Earth - Food production T6 Flashcards
Two alternatives to using pesticides
Introduction of a natural predator and GM crops
What are genetically modified crops?
GM crops are crops that have had their genome altered so that they can be resistant to some pests and grow more abundantly to increase yield.
Substance added to soil to improve nitrate levels
Fertilisers
How plants absorb and use nitrates
Plants absorb and use nitrates through their roots and they’re used to produce proteins for healthy growth.
Problems associated with leaching
Leaching can cause algal blooms.
These happen by a huge rainstorm for example, washes fertiliser into water bodies. This will then cause the algae population to rapidly. These algal blooms will cover waterbodies, stopping sunlight getting to the water dwelling plants from photosynthesis then they will stop producing oxygen meaning fish will die and bacteria will have plenty of food. This is how an ecosystem can die due to algal blooms.
What are pesticides?
Chemicals sprayed on crops to remove a pest by killing weeds, insects and other organisms that reduce yield.
Examples include fungicides - kill fungi, insecticide- kills insects
What is bio accumulation?
When a top predator will accumulate a lot of a poisonous substance as the volume of that substance has increased up the food chain. Going from negligible levels to potent levels.
For example DDT bioaccumulating in birds as it is absorbed by plants, eaten by insects eaten by small rodents then they are eaten by predatory birds.
Why are GM crops more environmentally friendly than conventional crops?
Some pesticides will not have been used on the crops as they are already resistant to a pest - meaning less potentially harmful chemicals will be used on the crop and its environment.
What is biological control?
Introduction of a natural predator or disease to decrease the number of pests. For example wasps introduced to reduce the number of aphids.
What are fertilisers?
Chemicals put in soil to increase nitrate content of foil so plants grow better.
Arguments against GM crops
Potential negative effects on the environment.
Potential negative effects on human health.
Argument for GM crops
Crops can grow more abundantly and be more nutritious. Exceptionally helpful when an increased food yield is essential.
Arguments for pesticides
Allow crops to grow more abundantly die to the removal of pests - essential chemicals n current times due to the increased demand for higher food yields
Arguments against pesticides.
Potential bioaccumulation in top predators.
Potential build up of harmful chemicals in humans.
