As populations grow, the need for increased food production is greater

On a global scale we produce enough food to adequately feed all of the world’s population

Tens of millions continue to suffer from starvation and undernourishment each day minimum critical diet 9900 J = approx

2200 cal

There are two forms of malnutritionunder nourishmentover nourishment

Causes of world hunger are complexsome regions of world have fertile

soils and favourable climatesothers have poor soil conditionsdroughtfloodingand other harsh conditions that limit

the ability to grow foodpoverty

Humans depend on...grain products livestockocean fisheries It is estimated by the Worldwatch

Institute that yield thresholds are being met.

Within the oceans, over fishing has depleted stocks beyond estimated sustainable yields Populations may not recover If significant reductions are not met

globally, can cause a severe prolonged collapse of stocks

10 billion animals used for livestock! Livestock ranching has led to forest

degradation 36% of world’s grain goes to feed livestock livestock wastes are implicated in the

pollution of waterways▪ proliferation of toxic algal blooms▪ loss of fish species▪ water loss (to livestock, and to fresh water

supplies)

Being converted to non-agricultural uses....▪ Housing, industry

soil degradation▪ deforestation exposes soil▪ loss of roots of living plants that would

retrieve nutrients from deeper layers of soil disrupt nutrient cycles▪ salinization▪ accumulation of excess of salts in soil that restricts

water and essential nutrients that plants can withdraw from the soil

Ecologists often use energy pyramids to visualize transfer of food energy from one trophic level to the next through a food chain

Much of the energy is lost at each trophic level and this energy cannot be recaptured 

Approximately only 10% of energy in one organism is transferred to an organism in the next trophic level

Top consumers receive a small fraction of available energy from the producers

Humans can obtain more energy from consuming producers directly than from other consumers

Urban Sprawl Growth of low density development on

the edges of cities and townsAquifers

Porous, water-saturated layers of sand, gravel, or bedrock that can store and yield significant volumes of water

Precipitation and runoff enter recharge zones and percolate gradually down to an aquifer

Despite it’s recognized ecological importance to southern Ontario, the moraine is at risk from having to accommodate housing developments

supply is not limitless less that 1% of Earth’s water is fresh

waterhuman activities negatively

affect the supply that does exist livestock operations have been

introduced into rural Canadacontamination from livestock wastes

and poor regulation of monitoring procedures and chlorination equipment has led to tragedies (Walkerton)

water supplies polluted by fertilization of cropland, pesticides, acid precipitation, and runoff from storm water off of soiled pavement, industrial wastes (most of which are toxic), mine tailings, household waste water, and raw sewage all lead to critical health concerns regarding the scarcity of clean water for drinking and irrigation.

Cellular respiration of bacterial populations increases, depleting oxygen from the water. This harms other aquatic organisms

Phosphates and nitrates from fertilizers and sulfates from laundry detergent support cellular respiration of some algae and plants, (algal bloom) further depleting oxygen sources for other organisms

Heat produced by power plants and other industrial processes also reduces the amount of dissolved oxygen that can exist in water

(aka) Acid deposition A mixture of Sulfur

dioxide and nitrogen oxide pollutants that can reach earth’s surface in the form of rain, gas, or solid particles.