Ecology AQA Biology GCSE Triple Higher

Define biodiversity

The variety of different living species of organisms on Earth

What does human activity do to biodiversity

Reduce biodiversity and increase pollution by removing land available:

• Deforestation

• Land used for farming and cattle grazind

• Buidling industrial sites

• Minind (quarries)

• Landfill and waste

• Agribusiness

• Crops for biofuels

Why is high biodiversity important

Reduces the dependence of one species on another so they do not have limited options and limited effect if one species is lost.

Why do humans live longer

• Better technology and medical advancements

• Improved diets because of greater food availability and growth

• More luxuries and comfortable living due to technology

• No natural predators.

Leads to more waste produced

What is bioaccumulation and how does it lead to biomagnification

Bioaccumulation - small toxins build up inside organisms to dangerous levels. As other trophic levels eat it, they pass the toxic chemicals down until it gets built up much more higher up in the food chain, known as biomagnification

What are the causes and effects of water pollution

• Untreated sewage:
  - In places with lack of sewage systems
  - Sewage runs off into rivers and seas
  - Releases bacteria which start aerobically respirating and feeding on dead animals and plants which have died due to the toxic chemicals
  - Reduces dissolved oxygen levels in water
  - More fish and plants die

• Release of toxic chemicals like herbicides and pesticides

• Fertilisers run of into the water:
  - more underwater plant and algae on surface growth
  - blocks sunlight
  - Underwater plants die
  - Bacteria can rapidly reproduce and break it down.
  - Aerobically respire and reduce dissolved oxygen levels in water
  - Fish and plants die

What are the causes and effects of land pollution

• Landfills - waste. Destroy habitats

• Industrial development: buildings, quarries, farms.

• Toxic chemicals pollute soil and disturb its pH. Soil may become infertile

• Soil erosion

• Bodily waste - gut parasites

• Industrial waste

What are peat bogs and what are they used for

Contain large amounts of dead plants and animals that bacteria were not able to decompose due to the cool, wet, acidic conditions. Have trapped carbon and decay very slow.

• Produce cheap compost

• Burnt for energy -? release CO2

• Destruction of environment when obtaining them.

What are bioindicators

• Clean water: salmon, stonefly larvae

• Somewhat clean: shrimp, water lice

• Polluted: rat-tailed maggot, bloodworm

What are intertidal zones

regions at seashore above sea level at low tide and below at high. Habitats for Barnacles

What are the causes and effects of air pollution

• Burning fossil fuels. Release CO2, sulphur dioxide and nitrogen oxide

• When burning, sulphur and nitrogen impurities released which react with the oxygen. Dissolve in rain.

• Can cause acid rain which is dangerous and harmful to plants and animals. Roots destroyed, seeds won’t germinate, plants killed, limestone erosion, aluminium in soil activated which kills

• Acid rain pH lower than 5.5

• Normal rain also acidic due to CO2

  Clean flue gases before leaving atmosphere

• Use gas, not coal

• Smog: Smoke and chemicals. Haze of small particles and acidic gases

• Smoke pollution: particles damage lungs. Dimming effect and cooling of temp.

What are catalytic converters

convert SO2 and NO2 to CO2 (less harmful) in exhaust fumes

What is meant by peer-review

Detect false claims and make sure research published is valid

How does global warming happen

Increased CO2 and methane levels (greenhouse gases). These gases absorb Sun’s heat and trap it to keep surface warm. Too much means too much heat absorbed.

What is methane released by

• Rice fields

• Cows

What are the effects and environmental changes of global warming

• Affect migration patterns of animals

• Affect species distribution and ecosystem: more mosquitos moving away from equator

• SO2 and NO2 cause acid rain

• Reduce biodiversity as habitat loss

• Change in temp.

• Change in water

• Change in seasons

• Human interaction: pollution but also conservation and sustainability

• Natural disasters

• Geographical location: soil pH, plants and animals.

How can we maintain biodiversity

• Breeding programmes: restore endangered species to sustainable population. Must avoid inbreeding. Due to habitat loss

• Reforestation

• Recycling

• Reintroduction to field margins and hedgerows: Allows variety of birds, plants and animals. Soil erosion and infertility without it

• Reduction of deforestation and CO2 emissions

• Government taxes on putting material in landfill

• Protection and regeneration of rare habitats: protects biodiversity (coral reefs), E.g. reflooding wetlands. Game reserves and national parks

What is meant by trophic level

position of organisms on a food chain.

What is an apex predator

carnivores with no predators

How do decomposers release mineral ions back to soil

secrete enzymes in environment. Enzymes digest dead materials. Small soluble food molecules diffuse back into decomposer.

What is biomass

Weight. Needed for survival and cellular processes.

Why do we use ‘dry mass’ for calculating biomass

No water content and moisture content measured as it can vary widely for different organisms and produce inaccurate results.

How much light is actually absorbed for photosynthesis

1%

How much biomass is actually passed on from one trophic level to next

10%

How can biomass be lost

• Egestion - solids

• Excretion - liquids

• Cellular respiration (growth, movement, heating)

What is the difference between pyramid of biomass and pyramid of numbers

• pyramid of biomass: looks more like a pyramid. Bottom one biggest and top the smallest

• Pyramid of numbers: bottom the smallest(large tree), middle much bigger(lots of aphids), top a bit smaller than middle(ladybugs)

How to calculate efficiency of biomass

(biomass transferred to next level/biomass available at previous level) x 100

What in the food chain has the greatest biomass

Decomposers. Digest waste, dead plants and animals

What does it mean to have food security

Having enough food to feed a population

What are the factors affecting food security

• Increasing birth rate

• Changing diets in developed countries

• Climate change - unpredictable weather

• Cost of agricultural inputs

• Conflicts affecting access to water/food

What are the problems with free-range animals reared outside

• much of biomass used for keeping constant body temp, respiration, energy

• Slow growth

• More space

• Better quality

• Weather problem

• No heating/lighting costs

How long should food chains be

short with less stages

What is intensive farming

Agricultural farming methods aimed to maximise production and reduce amount of biomass lost in food chain

How is intensive farming done

• Feed animals high-protein food for fast growth

• restricted movement and limited space

• Controlling surrounding temp

What are the pros and cons of intensive farming

Pros:

• Less biomass lost = more food

• Eggs more easily harvested indoors

Cons:

• No animal welfare so ethical issues. Unnatural.

• Stress = more animal fights = bad for growth

• Risk of disease spreading quicker = anti biotic resistant bacteria may develop.

What is meant by sustainable fisheries

Maintain fish stocks at level which is sustainable and breeding continues otherwise some species may disappear.

• Control net size so small, immature fish not caught

• Strict quotas limiting amount of fish that can be caught of each species

• Ban fishing in breeding season

What is meant by biotechnology

Using living organisms and biological processes to to make products for industrial purposes

What are 2 examples of biotechnology

• Allow large quantities of microorganisms to be cultured for food

• GM bacteria: produce drugs (insulin) on larger industrial scale

What is meant by mycoprotein

Protein-rich food that can be eaten by vegetarians. Produced by fungus ‘Fusarium’. Grown on glucose syrup aerobically in fermentor and biomass harvested and purified.
Grow loads in small spaces so efficient.