Biology - Sunday 9th April Flashcards
What is eutrophication?
What two gasses cause acid rain?
Sulphur dioxide
Oxides of Nitrogen
How are oxides of nitrogen formed?
Nitrogen and Oxygen naturally exist in the air. In car engines it can get so hot that the Oxygen and Nitrogen actually react together to form Oxides of Nitrogen. Oxides of Nitrogen cause acid rain.
How is sulfur dioxide formed?
Combustion of sulfur impurities in hydrocarbon fuels results in the formation of sulfur dioxide.
What is peat and what are the consequences of its destruction?
Peat bogs are the result of thousands of years of plant water that has been unable to decay fully due to acidic conditions and a lack of oxygen. They are very wet areas of land without trees in which many types of moss grow. They are acidic and often have very low levels of nutrients. Here decomposition is very slow and peat is formed from partially decayed plants. Peat is a very useful fuel and is also a natural compost. When it is burned or it decays it releases carbon dioxide into the atmosphere, adding to air pollution. Peat bogs also provide habitats to many different species of plants, animals and microorganisms, so their destruction (either for the land or for the peat itself) is reducing biodiversity.
For many years peat was removed from bogs for gardeners to add to their soil or to burn as fuel. This dramatically reduced biodiversity. Because peat takes such a long time to form, it is a non-renewable energy resource like fossil fuels.
Peat bogs are a very important store of carbon. We call them carbon sinks. If all the peat was removed and burned this would quickly release a huge volume of carbon dioxide into the atmosphere and contribute to the greenhouse effect.
Explain how global warming has an impact on biodiversity.
Ice caps may melt, increasing sea levels and flooding lowlands. This could destroy habitats so reducing biodiversity.
Organisms may be able to live in alternative countries or be excluded from other due to temperature changes.
The migration of birds, mammals etc may be affected.
If animals an plants cannot adapt to the new conditions they may be threatened with extinction, reducing biodiversity.
Describe three sources of pollution.
Pollution can occur:
- in water, from sewage, fertiliser or toxic chemicals
- in air, from smoke and acidic gases
- on land, from landfill and from toxic chemicals.
How is biomass lost from one energy level to the next?
- Light reflects off plants or misses the plants completely.
- Some light energy heats up the plants.
- Not all parts of an organism are eaten e.g. roots and bones.
- Some biomass is lost as waste. Some of the food consumed cannot be digested so is lost as faeces. N.B Decomposers can utili thhe biomas, but they do not normally appear in food chains or pyramids.
- Lots of the biomass is used for respiration so it is not available to be passed along the food chain. The energy released is used for movement, heating the body etc and some is lost to the environment.
What is food security?
Which factors affect food security?
Food security is having enough food to feed a population.
Biological factors which are threatening food security include:
- Increasing birth rate
- Changing diets in developed countries means scarce food resources are transported around the world
- New pests and pathogens that affect farming
- Environmental changes that affect food production, such as widespread famine occurring ins one countries if rain fails
- The cost of agricultural inputs
- Conflicts that have arisen in some parts of the world which affect the availability of water or food.
Describe and evaluate the advantages and disadvantages of modern farming techniques.
- Livestock raised in small pens and cages means
- Adv: Livestock use less energy for movement, leaving more energy available for growth
- Dis: Keeping animals confined in such small spaces is seen as unethical by many people. Disease can spread easily as many animals are kept very close together.
- Livestock fed antibiotics in their food.
- Adv: Antibiotics prevent diseases and bacterial infections in livestock.
- Dis: Scientists think this may be leading to antibiotic resistant in bacteria.
- Monocultures
- Adv: Farmers only grow a single crop type across a vast areas of land as this maximises the amount of food produced and their profits.
- Dis: Monocultures only support a low level of biodiversity.
- Fertiliser use
- Adv: Increases plant growth and therefore maximises food production.
- Dis: Runoff occurs from agricultural land if fertilisers are applied in too high a concentration causing fertilisers to enter watercourses which can lead to eutrophication and eventually the death of aquatic systems.
- Hedgerow removal
- Adv: This has made fields bigger and easier to maintain with big farm machinery.
- Dis: Reduces biodiversity as hedgerows provide a habitat for al larger number of species.
What is coronary heart disease?
In coronary heart disease layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
How are stents useful in coronary heart disease?
Stents are used to keep the coronary arteries open.
How are statins useful in coronary heart disease?
Statins are widely used to reduce blood cholesterol levels which slows down the rate of fatty material deposit.
What is the definition of health?
State of physical, mental and social well-being and not merely the absence of disease.
Can you give some examples of how different types of diseases can interact.
- Defects in the immune system mean that an individual is more likely to suffer from infectious diseases.
- Viruses living in cells can be the trigger for cancers.
- Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma.
- Severe physical ill health can lead to depression and other mental illness.
