Food security exists when all people, at all times, have physical and economic access to sufficient safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life.
Anthropogenic Biomes
Homo sapiens left Africa between 125000 and 60000 years ago
As they moved across the world they adapted to different biomes
Only remained in a biome if it could provide sufficient food for survival
Some civilisations have disappeared because they over exploited the biome by overusing scarce water and over grazing crops, leading to soil erosion and declining food supplies
Most terrestrial biomes have been altered by humans fore food and settlement. These actions have altered natural systems, productivity cycles and energy flows
Altering biomes for agriculture can have a long term effect on an area’s ecological processes
Biomes: Net primary productivity
Net primary productivity is the rate at which ecosystem producers capture and store energy as biomass
NPP indicates plant productivity and measures the rate at which plants can convert carbon dioxide and water into energy
When energy is exchanged from plants to animals or from animals to animals through consumption, this is known as a food chain
Main abiotic controls of NPP are temperature, radiation and water
Over time, the NPP of ecosystems changes due to natural and anthropogenic factors such as fire, wind, insect and pests outbreaks, changes in soil nutrients, changes in light levels and changes in climatic/atmospheric conditions
Anthropogenic changes to the land have resulted in changed NPP
As people continue to alter Earth’s biomes, scientists question how the terrestrial and aquatic biomes will continue to supply food for an increasing population
Changing biomes for food
Since prehistoric times, people have been hunting and gathering food in their environments
Over 4000 years ago, the Agricultural Revolution moved humans from foraging for food to farming food