B18 Biodiversity and Ecosystems Flashcards
What is the benefit of rich biodiversity?
It makes ecosystems more stable
3 different places 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.
Describe how water pollution can occur
Untreated sewage, chemicals from factories or fertilisers from farms can run of into rivers and streams. These cause dissolved oxygen levels to fall, killing aquatic organisms.
Describe how waste from human activities can pollute the air
Burning coal in power stations can release acidic gases, and cause acid rain. Burning can also release smoke. Air pollution can kill animals, reducing biodiversity
Describe how human waste can cause land pollution
Millions of tonnes of waste are dumped in landfills, which destroy habitats for plants and animals. Toxic chemicals can also leech out of landfills and pollute the soil
How is peat created?
By the incomplete decomposition of the remains of plants growing in waterlogged conditions.
What is peat used for?
As fertiliser, and as fuel for energy (as they contain a lot of trapped carbon)
How does the destruction of peat bogs reduce biodiversity?
It reduces the area of its (peat bog’s) habitat, reducing the variety of animals, plants and microorganisms that live there.
What are the disadvantages of extracting peat?
Reduced biodiversity Releases carbon dioxide when burnt, contributing to climate change Non renewable (used faster than it is formed)
Why would using peat alternatives be a pain
They are more expensive, and could cause food costs to rise - Understand the conflict between the need for cheap available compost to increase food production and the need to conserve peat bogs and peatlands as habitats for biodiversity and to reduce carbon dioxide emissions.
What type of field produces methane?
Paddy fields, that are used to grow rice as the bacteria in them produce methane
What is food security?
Having enough food to feed a population
A dairy farmer washes out his cow shed each day. The waste water contains urine
and faeces. The waste water overflows into a stream by mistake.
The waste water will have an effect on the plants and invertebrates living in the
stream.
Explain why
- Waste contains mineral ions (and organic matter)
- this increases growth of algae / water plants
- the plants / algae (underneath) die
- due to lack of light / photosynthesis / space
- decomposers / microorganisms feed on decaying matter or multiply rapidly
- the respiration of decomposers uses up all the oxygen
- so invertebrates die due to lack of oxygen
- this is called eutrophication
Explain why mixing peat with air releases CO2
decay / decomposition / rotting of peat
by microorganisms / bacteria / microbes / fungi / decomposers introduced when peat
is mixed with air
that respire using substances in peat as reactant
and using oxygen that is introduced when peat is mixed with air
How can fertilisers damage ecosystems?
They reduce dissolved oxygen levels, which can kill aqautic
Approximately a third of UK domestic rubbish is organic matter such as food waste and
gardening rubbish.
Many councils have started industrial composting schemes to decompose these wastes.
One product of the decomposition is compost (decaying organic matter).
Use this information and your own knowledge to suggest reasons why more councils
should be encouraged to start industrial composting schemes. [3]
Reduces Landfill
produces compost / fertiliser which can be sold
produces nutrients / fertiliser / minerals (ions) for plants
Describe two effects of global warming on the human population [6]
climate change
warmer/colder/drier/wetter
food production affected/starvation
mayor ecosystems destroyed/damaged
sea level rise
low land flooded
less food grown/starvation
homes/factories flooded
How do humans reduce the amount of land available for other plants and animals?
Building, quarrying, farming and dumping waste
Approximately how much biomass is transferred from one trophic level to another?
About 10%
In producers, how much incident light energy is transferred for photosynthesis?
about 1% of the incident energy from light for photosynthesis
Describe some reasons for losses of biomass
• not all the ingested material is absorbed, some is egested as faeces
• some absorbed material is lost as waste, such as carbon dioxide and
water in respiration and water and urea in urine.
- Large amounts of glucose used in respiration
Name biological factors that affect food security
the increasing birth rate has threatened food security in some
countries
• 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 in some countries if rains fail
• the cost of agricultural inputs
• conflicts that have arisen in some parts of the world which affect the
availability of water or food.
What is food security?
Having enough food to feed a population
