B18 Flashcards
what is biodiversity
the number of different species in an area
why is biodiversity good
- ensures a stable ecosystem
- reduces the dependency of 1 species on another
- food and shelter
what are some of the impacts humans have on earth
- global warming and climate change
- deforestation
- building buildings
- pollution
what 3 things have lead to the human population growing
- no natural predators
- enough food
- curing diseases
how do humans reduce land for other animals
- farming, building, quarrying, landfill
what is pollution
- the addition of substances to the environment which may be harmful
how can humans pollute the water
- sewage, fertilizer and chemicals going into the water
how can humans pollute the land
from landfill and toxic chemical from things like pesticide
how can humans pollute the air
from smoke and acidic gases
what is bioaccumulation
when toxics build up in a food chain
what is eutrophication
when water becomes too filled with algae which blocks the sunlight and may lead to oxygen depletion
what are the steps leading to eutrophication
1- nutrients from fertilizers get washed into a lake
2- the nutrients cause aquatic plants to flourish like algae
3- the algae block the sunlight which means that plants at the bottom cant photosynthesise and so they die and so the oxygen in the water depletes
4- dead plants are broken down by decomposers using up even more oxygen
5- the ecosystem dies
what are bioindicators
things which indicate how polluted water is
what is combustion
the scientific word for burning
what is a combustion reaction
when a substance reacts with oxygen from the air and transfers energy to the surroundings as heat and light
what is a combustion reaction
when a substance reacts with oxygen from the air and transfers energy to the surroundings as heat and light
how is acid rain formed
nitric acid and sulphuric acid are produced from factories when they burn fossil fuels and react with oxygen in the air to produce nitrogen dioxide and sulphur dioxide then get blown from 1 place to another by the wind. they get dissolved in rain and snow in the clouds and then cause the rain to turn slightly acidic
what is deforestation
when natural forests are burnt through burning or slashing methods
what are some of the reasons for deforestation
- land for cattle
- land for farming crops
- land for biofuels