b18: biodiversity and ecosystems

Question 1

what is biodiversity

Answer 1

the variety of all the different species of organisms on earth or within an ecosystem

Question 2

what is the advantage of high biodiversity

Answer 2

ensures stability of ecosystems by reducing the dependence of one species on another

Question 3

how are humans trying to maintain biodiversity

Answer 3

• breeding programs
• protection of rare habitats
• reintroduction of hedgerows
• reduction of deforestation and carbon dioxide emissions
• recycling recourses

Question 4

why are more recourses being used and more waste produced by humans

Answer 4

rapid growth in human population and increase in the standard of living

Question 5

where does pollution occur

Answer 5

water
air
land

Question 6

how are humans reducing the land available for other organisms

Answer 6

building
quarrying
farming
dumping waste

Question 7

what are the negative impacts of the destruction of peat bogs

Answer 7

• reduces amount of available habitat, causing decrease in biodiversity
• burning or decay of peat releases carbon dioxide into the atmosphere

Question 8

why have humans carried out large-scale deforestation in tropical areas

Answer 8

• provide land for cattle and rice fields
• grow crops for biofuels

Question 9

what is food security

Answer 9

having enough food to feed a population

Question 10

what are the biological factors threatening human security

Answer 10

• rapid population growth and increased birth rate
• new pests and pathogens
• changing diets in developed countries
• environmental changes
• conflicts
• costs of agricultural inputs

Question 11

how can the efficiency of food production in farming be increased

Answer 11

• limits movements of animals
• control temperature of surroundings
• feed animals high-protein foods
• give animals antibiotics
• regularly use fertilizers, herbicides, and pesticides

Question 12

what gases are increasing in atmospheric levels and contributing to global warming

Answer 12

carbon dioxide and methane

Question 13

how can fish stocks be maintained at a sustainable level

Answer 13

controlling net sizes and introducing fishing quotas