Human Impact Flashcards
(16 cards)
Ways Humans influence the environment
- Using Pesticides & fertilisers
- Greenhouse gases and Combustion
- Deforestation
- Sewage into rivers and seas
Impact of Greenhouse Gases / Combustion
- The earths average temperature increases
- Causes sea level rise
- Cause more extreme weather
- More frequent forest fires
- Releases CO2
Impact of Deforestation
- More CO2 in the atmosphere which cannot be absorbed by the trees
-There is a loss of biodiversity
-The soil degrades which means it is weaker and can easily be weathered and eroded
-Causes Global Warming
Impact of Pesticides and Fertiliser
- Loss of biodiversity - in fields and farms - can also leach into lakes
- Eliminates some essential food sources for animals
- Can cause human birth defects etc.
- Causes soil degradation and compaction of soil - plants cant grow as well
Impact of Sewage
- Water borne Diseases
- Threatens biodiversity
Causes coastal erosion and loss of habitats - Risks to human heath
- Risks to aquatic ecosystems -contaminates water habitats
- Harmful substances kills animals
Why use Greenhouses or Polytunnels
To maximise the yield from a crop plant.
What can be controlled in a Greenhouse/Polytunnel
- CO2 - diffusers/paraffin burners to encourage more photosynthesis
- Sunlight - artificial UV lights
- Minerals - fertiliser/manure or crop rotations
- Water - irrigation systems
- Temp - only greenhouse - traps heat
Why use fertilisers
Added minerals to increase the growth rate which increases the overall yield.
Contain high concentrations of nitrogen and other mineral ions
Eutrophication Process (1-7)
1) Fertilisers are washed off the land and leach into ponds/lakes
2) Algae use fertilisers to reproduce = algal bloom
3) The algae prevent light form penetrating so submerged plants can’t photosynthesis
4) Plants die
5) Bacteria decompose dead plants
6) Bacteria reproduce and respire using up more of the waters oxygen
7) Water becomes completely anoxic and all life will die
Pollution of Water by Sewage Process
1) Sewage with high levels of nitrate containing compounds get into the water sources - this pollutes them
2) Bacteria and micro-organisms increase rapidly so more are respiring
3) Increased respiration lowers O2 concentration so other aquatic organisms find it hard to respire
4) Aquatic organisms die and decay providing more nutrients causing more bacteria to grow a vicious circle
5)Pathogenic water causes diseases.
Different Pesticides
Herbicides - kills weeds
Insecticides - kills insects
Fungicides - kill fungi
Molluscicides - kill molluscs (slugs/snails)
Biological control
Using other organisms rather than a toxic chemical to reduce the number of the pest.
A natural enemy to keep the the pest down in its numbers.
What is Bioaccumulation
When a toxic chemical is consumed and can’t be gotten rid of. If a lot is consumed it will stay and build up in size over time
What is Biomagnification
When an organism eats another with the toxin. Over time it builds up as they have to eat more and it is passed onto the next part of the food chain which eat even more of their prey which increases the % of toxin in the body which continues to increase the toxin concentration
What is DDT / why used / impact
Chemical Pesticide which was cheap to make and buy and it was very effective. It affects all animals in the food chains and they bio magnify up the food chain
4 advantages of Biological Control
- No need to keep doing it - the control organism will reproduce and it will continue happening.
- Very specific
- One time investment
- Self sustaining
- Better for the environment
