Chapter 7 Flashcards
What is the green revolution?*
It helped preserve biodiversity by preventing deforestation and habitat destruction
What is subsistence farming?*
Self-sufficient farming where farmers grow enough food to feed themselves and their families.
How much is food consumption predicted to increase by 2020?*
50%
How much is food production predicted to increase in the next two decades?*
40%
What are genetically modified crops?*
Crops that have had their DNA altered in a way that does not occur naturally
What does transgenics mean?*
The incorporation of desired traits into crop lines and animals.
4 commonly occurring GM crops
soybeans, corn, cotton, and canola
What are the benefits of GM organisms
disease resistance, drought tolerant, improved nutritional value, less allergens, more productivity
Environmental issues associated with GM crops
not considered safe by all people, not affordable everywhere, and affects non-target species
Roundup Ready
Genetically modified crops like soybeans and canola that are resistant to roundup.
How do pest populations develop resistance to pesticides?
The pests that survive the pesticide breed and produce a pesticide-resistant population.
What is food security?
The guarantee of an adequate, safe, nutritious, and reliable food supply available to all people at all times.
Undernutrition
Receiving fewer calories than the minimum dietary energy requirement.
Overnutrition
Consuming too many calories in a day.
Malnutrition
When a person fails to obtain enough proteins, lipids, vitamins, and minerals.
What is the root cause of hunger?
The root cause of hunger is poverty.
Causes of famine
Civil wars, drought, government incompetence, illiteracy, discrimination.
True or false, food aid alleviates chronic hunger, helps local agriculture, disrupts local economy, contributes to ecological deterioration, postpones the day of reckoning
True
What is soil?
A complex mixture of organic and inorganic components and is full of living organisms.
By volume, what does soil consist of?
50% mineral matter, 5% organic matter, the rest is air or water.
How long can it take to form 1 inch of soil?
Hundreds or thousands of years.
Distinguishing characteristics of soil (5)
Slow rate of nutrient and energy transfer, different textures demand different adaptions, near total reliance on decomposers, exclusive use of detritus, extreme susceptibility to disturbance and slow recovery times.
What is the parent material of soil?
The base geological material in a particular location.
What is soil texture?
The percentage of each type of particle found in the soil.
How big are sand particles?
Large
How big are silt particles?
Medium/small
How big are clay particles?
Small
Loam soil is approximately
40% sand, 40% silt, and 20% clay.
What is humus?
Partly decomposed organic matter. Has a high capacity for holding water and nutrients.
Why is humus important?
Without humus, it results in topsoil mineralization, loss of water holding and nutrient holding capacity, water infiltration, and aeration.
What defines productive soil? (7) low salt content
A good supply of nutrients, water & nutrient holding capacity, resists evaporation, porous structure, neutral ph, low salt content
Splash erosion
Impact of falling raindrops breaks up the clumpy structure of topsoil.
Sheet erosion
Erosion caused by running water.
Gully erosion
When erosion creates gullies by moving large amounts of soil.
6 things that can cause erosion
Overcultivating, overgrazing, construction, deforestation, salination, waterlogging.
What happens after soil erosion?
Loss of fertility and sedimentation.
Sedimentation
When eroding soil fills reservoirs, streams, estuaries, and bays.
Desertification
When water-holding capacity of soil is greatly diminished.
According to the TED talk, how can we prevent desertification?
We can use livestock and their predators to mimic nature.
How does vegetation prevent erosion?
It can slow runoff and allow it to flow above the soil. It can also help absorb impact from raindrops and roots hold soil together,