Ecology - Biodiversity Flashcards
What is “biodiversity”?
What area have a high and low biodiversity?
Biodiversity is a measure of how many different species of organisms live in the same geographical area.
High biodiversity = Tropical rainforests
Low biodiversity = Polar regions
What are the consequences of an increasing human population size?
- Food shortages
- Communicable diseases increase
- Pollution, deforestation and global warming
How does water pollution affect humans?
Water can be polluted by pathogens that cause communicable diseases, e.g.: salmonella and norovirus.
This occurs when sewage contaminates drinking water. Especially in 3rd world countries where the water supply is not transported away from sewage.
In which ways can chemicals pollute water and enter the food chain?
1) Chemicals from factories can enter local water supplies, e.g.: minimata disease from Japan. Mercury was found in zooplankton which bioaccumulated in the food chain.
2) Farmers overuse fertilisers which wash off fields and into ponds and lakes. This can speed up the growth of algae. Algae can produce a “bloom” which blocks light for photosynthesis.
Why is an “algae bloom” bad for all other life in the lake?
What is the name of the process this causes?
- Algae blocks light for photosynthesis for plants below.
- These plants die, and microorganisms decay the dead plant matter.
- The microorganisms respire and use up all the oxygen in the.
- Without oxygen, all animals such as fish and insects begin to die.
This process is called “Eutrophication”.
What other substances can contaminate the oceans?
1) Oil spills
2) Plastic rubbish (that does not decompose and can enter the foodchain)
What substances can pollute the air and what problems can this cause?
Waste gases from vehicles and factories which produce “particulates”.
Particulates form smog (a fog or haze) around major cities. Oxides of sulphur which come from burning fossil fuels and petrol can react with water to form sulphuric acid, which lowers the pH of water to form “Acid rain”, which can destroy entire forests.
What in “incomplete combustion” and why is it dangerous?
The burning of fuel without enough oxygen which produces carbon monoxide (CO), which is poisonous.
What is “recycling” and why is it important?
Changing a waste product into a new raw material to make another product.
Waste if often thrown into landfills or incinerators which make greenhouse gases and pollute the atmosphere
What is “deforestation”?
Why is deforestation bad?
The clearance of trees from an area that will then be used for other purposes such as farming or housing.
- Trees take up carbon dioxide for photosynthesis, so reduce greenhouse gases. Furthermore, trees are often burnt when they are cut down, releasing more CO2 and causing global warming.
- Deforestation also reduces the amount of living organism in an area so reduces biodiversity, and causes a lot of species to go extinct.
What is global warming and why has it occured?
A gradual increase in the average temperature of earth, due to increased emission of greenhouse gases.
What are the consequences of global warming?
- Freak weather incidences, e.g.: floods, heat waves and sea levels rising
- Species have to migrate away from regions where conditions once suited them.
- Droughts occur so we can no longer produce enough food
Why are “Greenhouse gases” called that?
Because they trap heat in the atmosphere just like a greenhouse traps heat.
Why are “Greenhouse gases” called that?
Because they trap heat in the atmosphere just like a greenhouse traps heat.
In what ways are people working to maintain biodiversity?
- Breeding programmes in zoos which reproduce animals carefully to prevent them from going extinct
- Conservation efforts (where ecosystems are protected) - e.g.: making national parks, which protect many areas of the world
