BIO - 4d. Human Influences on the environment

what 3 mineral ions do plants need and what do they need them for

nitrate - needed to make amino acids, to build proteins for growth and repair

magnesium - needed to make chlorophyll for photosynthesis

phosphates - to make DNA

sources of carbon dioxide and explain

burning fossil fuels - we burn them to release stored chemical energy to generate electricity

deforestation - CO₂ is absorbed by plants via photosynthesis, less trees = less CO₂ absorbed

sources of methane

cattle/ agriculture - fermentation by microorganisms in stomach of cattle

rice paddy fields - fermentation by bacteria in rice fields

landfill - decomposition of waste buried in the ground by microorganisms

nitrous oxide

agriculture

fertilisers - when nitrogen-based fertilisers are added to soil, some soil bacteria break them down releasing nitrous oxide

vehicle emissions - cars release nitrous oxide through the exhaust, during the combustion of gas and diesel

Chloroflurocarbons or CFCs

refrigeration | - CFC are only produced by human activities, they do

air conditioning system | not occur naturally

fire extinguishing system |

What is the greenhouse effect

long wave radiation is absorbed by greenhouse gases, instead of escaping to space. This traps heat and increases the temp. of the Earth

explain the 4 steps of the green house effect

• short-wave infrared radiation from the sun reaches earth

• some is absorbed by the earth’s surface and then emitted again as longer wavelength IR radiation

• greenhouse gases absorb and then re-emit some of this long-wavelength radiation

• heating up the earth’s surface

What is the Enhanced Greenhouse effect or Global warming

Idea that human emissions of greenhouse gases are leading to an enhanced GE, causing global temps. to increase more

name 3 consequences of global warming

• sea levels rise, due to melting ice caps

• flooding of low-lying land

• extreme weather e.g. droughts

• changes in weather patterns

• changes in ecosystems

• local/ global extinction of species

if a cows stomach contains microorganisms to digest plant cell walls why are they useful

Cellulose is found it plant cell walls, it releases energy for respiration

suggest why more attempts are being made to limit the release of CO₂ into the atmosphere than the release of water vapour

Humans can control CO₂ levels e.g. using renewable energy

2 ways to release the limit of CO₂ into the atmosphere

• reduce the use of fossil fuels

• using more renewable energy sources e.g. solar

• using public transport, walking, cycling

• reducing deforestation

2 effects global warming could have on an animals habitat

• sea levels rising, due to melting polar ice

• extreme weather such as wildfires which can destroy forest ecosystems

• spread of disease

• change in food chains

What is eutrophication

The addition/ leaching of nutrients into water bodies, typically containing ammonium or nitrate from fertilisers

• these excess nutrients are a form of water pollution as it can destroy aquatic ecosystems

Eutrophication explanation in 6 steps

• excessive nutrients from fertilisers are leached from the soil into the water

• this nutrients (e.g. nitrates and phosphates) cause aquatic plants to flourish and grow rapidly

• They also cause rapid algal growth/ bloom on the surface of the water

• Algal bloom prevents sunlight from reaching aquatic plants near the bottom of the river causing them to die. Reducing the amount of O₂ in the water as photosynthesis is reduced.

• The dead plants are decomposed by bacteria and the respiration of these bacteria reduces oxygen in the water, this reducing the remaining O₂ avaliable for fish and other aquatic animals

• without O₂ these fish and aquatic animals will die

What are some alternative substances to chemical fertilisers

• manure

• compost

• seaweed

• bone

• blood