Use Of Biological Resources Flashcards
Yield definition
The amount of produce harvested
Poly tunnels and greenhouses can be used to increase the yield of certain crops. How can they control light?
Artificial lighting or shade covers
How can polytunnels control temperature
Heaters or ventilation
How can polytunnels control water
Irrigation systems
How can polytunnels control wind
Ventilation or fans
How can polytunnels tunnels control soil minerals
Fertilisers and minerals put in water
How can polytunnels control CO2
Wood burner to produce CO2 for photosynthesis
How do polytunnels control pollinators
Bee homes of safe insects
How can polytunnels control competitors and herbivore pests
By keeping them out of the polytunnels or using weed killer
What is the chemical control of pests
Using pesticides of weed killers to get rid of pests and weeds
What is biological control of pest
Putting predators that kill pests in or using parasites that weaken or cause disease in pests
What are the advantages of chemical control
It is specific
It can biodegrade or wash out
It is cost effective (until pests become resistant)
It is quick
What are the disadvantages of chemical control?
Can effect non target species Chemicals may get into food product People involved must wear suits as chemicals are toxic Could bio accumulate Not qualified as organic
What are the advantages of biological control
It is specific
It can reproduce by itself
Pests don’t become resistant
Natural can label as organic
What are the disadvantages of biological control
If too successful it can exhaust the food supply and switch prey
Not as quick
Does not completely remove pest
Control organism may become pest
May switch prey
Takes time for predators to become established.
Crop definition
Plants grown commercially for food on a large scale
What are intraspecific predators and interspecific predators?
IntRAspecific predators are predators within a species e.g. Salmon eating salmon
IntERspecific predators are different species e.g. Seals, sharks, birds or dolphins eating salmon
What is water quality affected by?
Oxygen and waste material
How is oxygen in water controlled in fish farms
In ponds or tanks water can be mechanically agitated or recirculated by pumps so more oxygen dissolves into the water
In cages in open water, water is oxygenated by natural tides and movement or plants (such as algae) that give off oxygen from photosynthesis
How is waster material in water controlled in fish farms and what are the dangers of waster material building up
Waste material accumulate from nitrogenous excretory products of fish(mostly ammonia). In too high levels and concentrations of ammonia it can be toxic and kill. It is controlled by water circulation
How is selective breeding used to improve fish yield
Superior individuals are selected for breeding to provide the next generation.
Entirely female fish stocks can be made as male fish become aggressive and their flesh quality decline when they get older.
How is feeding controlled to get a higher yield of fish?
Feeding is small, frequent and high in protein.
How are intraspecific predators controlled
Fish can be separated according to size or age in order to reduce competition and danger of bigger older fish eating small younger fish
How are interspecific predators controlled?
Nets prevent predators from getting inside the fish farm. Or measures are taken to kill the predators