Biodiversity And Ecosystems Flashcards
How does an increasing birth rate affect food security?
In many less developed countries the birth rate is still increasing. Eg because of a lack of contraception. This threatens food security as there is not enough food to go around.
How does changing diets in developed countries affect food security?
People continually look for new, interesting foods. As a result, food sources are transported around the world to provide variety for people to already have plenty to eat. This can deprive local people of traditional food.
Communities depend on buying food rather than buying it.
How does new pests and pathogens affect food security?
There has been an increase in new pests and pathogens as a result of global travel and climate change.
How do environmental changes affect food security?
In recent years, both droughts and flooding have increased. During drought, crops don’t grow, animals die and people starve. When there are floods, crops also fail to grow and the crops rot.
How does the cost of agricultural inputs affect food security?
Scientists in the developed world can produce crops genetically engineered to withstand droughts or floods, or to produce a very high yield. This has increased the cost of seed. Also, the fertilisers, irrigation systems and pesticides than can increase yields all cost money to buy.
How do conflicts affect food security?
Rising food prices can also lead to increased food insecurity, as people fear they will not be able to feed their families.
Conflicts usually arise as a result of power struggles often fuelled by religious or racial tensions. Concerns over food security can add to the mix.
How can food chains be used to make food production more efficient?
By the time the food reaches us, most of the biomass from the plant has been used up from the animals we eat.
To increase the growth of their livestock, farmers sometimes feed animals to animals. This high-protein food increases the growth rate. Eg ground up fish is often part of the commercial pig and chicken feed and is also the food in fish farms. This adds an extra stage to the food chain, making the chain less efficient.
The most energy-efficient way to use this is to grow plants and eat them directly. Every extra stage that is introduced results in less biomass at the end of the chain and so less food to go around the human population.
Reducing the number of stages in food chains could dramatically increase the efficiency of our food production.
How can artificially managing food production make food production more efficient?
Farmers want to get the maximum possible increase in biomass from animals as effectively as possible.
This can be done by:
Limiting the movement of food animals which reduces the need for respiration and so they have biomass available for their food growth.
Controlling the temperature of the surroundings so the animals do not have to use much biomass in respiration for keeping warm or cooling down.
How can farming fish make food production efficient?
Used as a source of protein food worldwide. The fish are often specifically bred for fast growth. They live in cages and are fed high protein food
Fish farming helps to protect wild stocks and produces cheap protein food.
However, there are ethical concerns.
How can managing the oceans lead to more sustainable food production?
It is important to maintain fish stocks at a sustainable level where breeding continues successfully.
Many k these large fish grow for years before breeding. If they are all taken, people fish for smaller, younger fish, but there are no more breeding animals to replace them.
How can the problem of overfishing be tackled?
Controlling the size of the holes in the nets so only the biggest fish are caught.
Band on fishing in the breeding season.
Quotas - strictly enforced limit on how many fish can be caught. However, if they catch more the fish are often already dead and just thrown over board.
What role does biotechnology have in making food production sustainable?
Scientists are trying to develop new ways of growing food and developing new food. Genetically modified crops are being developed to give bigger yields or improved nutrition.
Modern biotechnology enables large quantities of microorganisms to be cultured in industrially controlled vats.
Eg scientists were able to make a proteins from fungus, called mycoprotein.
What is biodiversity?
Biodiversity is a measure of the variety of all the different species of organisms on earth, or within a particular ecosystem.
Why is it good to have biodiversity?
It ensures the stability of ecosystems. It reduces the depended of one species on another for food, shelter, and then the maintenance of the physical environment.
What effect does the increasing population have on land and resources?
More and more land is used for building houses, shops, industrial sites and roads on. This destroys the habitats of other living organisms and reduces biodiversity.
We use billions of acres of land around the world for farming. Wherever people farm, the natural animal and plant populations are destroyed.
We dig up vast areas of land for quarries to obtain rocks and metal ores, reducing the land available for other organisms.
The waste produced by humans polluted the environment and processing it takes up lan, affecting biodiversity.
How do people pollute the land?
Sewage - soil can become polluted with unpleasant chemicals and gut parasites.
Household hazardous industrial waste goes into landfill sites. This causes toxic chemicals to be spread.
Farming - herbicides and pesticides can be washed into rivers. This can cause them to become part of food chains, and more of the toxins build up as you go up the food chain. This is known as bioaccumulation.
Toxic chemicals can poison the souls for miles around. Eg Chernobyl nuclear accident in 1986.
What is bioaccumulation?
When toxins build up in animals in a food chain, animals at the top have the most poisons.
How do humans pollute water?
When water is polluted with fertilisers or sewage, bacteria and water plants grow quickly. This quick growth uses up oxygen in the water and leaves little oxygen for other organisms.
Therefore, the fewer organisms in a stream, the more polluted the water is.
How can you test the pollution levels of water?
We can take a sample of aquatic animals at various places. Each sample is then checked to see which animals are found. A score is given to each sample, and the lowest scoring area is the most polluted.
Indicator species can also be used to see how polluted an area is. Eg mayfly larvae are only found in areas with lots of oxygen. However, worms need little oxygen and can survive in very polluted water.
How is acid rain formed?
When fossil fuels are burnt in vehicles and factories, acid ages are formed. Fossil fuels often contain sulfur impurities, which react with oxygen when they burn to form sulfur dioxide gas. Sulfur dioxide gas can cause breathing problems. Acidic sulfur dioxide and nitrogen oxides also dissolve in rainwater and react with oxygen in the air to form dilute sulphuric acid and nitric acid. This produces acid rain, which can have a ph of 2.0.
What are the effects of acid rain?
Can kill leaves, buds, flowers and fruits.
Can destroy roots if it soaks into the soil.
If it goes into water sources, the become slightly acidic and lakes and streams can become dead as plants and animals can no longer survive.
Sometimes it falls as ‘acid snow’. This can be more damaging because all the acid is released in the first meltwater of spring. This causes an acid flush that magnified the effect of acid rain.
