Human Impact On The Environment Flashcards
Why do we need an increased food yield ?
Increasing human population
State 4 ways food yield can be increased
Use of fertilisers
Use of pesticides
Use of biological control
Genetically modified crops
What can be caused when fertilisers run from fields into nearby water ?
Algal blooms
What effect does algal blooms have on plants in the water and why ?
The plants die as algal bloom blocks out the light so they cannot photosynthesise
What happens to the algae and plant when they die ?
They are decomposed by bacteria which use up the oxygen supply in the water
What effect does the reduction in oxygen have ?
It causes fish and other life to die so biodiversity decreases
What is an indicator species ?
Species that by their presence or absence indicate the levels of pollution
What is the problem with applying pesticides to crops ?
Organisms can eat these crops and and the pesticides accumulate in their bodies
What happens as pesticides are passed along the food chain ?
Toxicity increases and can reach lethal levels
What is a biological control ?
The introduction of a natural predator to control pest species
Describe what a GM crop is
A crop that has been genetically modified to increase yield
