1. Chapter 15-Food and Agriculture
Feeding the World

2. Humans and Nutrition Famine- Widespread starvation (Ex: Ethiopia)
Food for energy (calories) and as building material for body tissue
Malnutrition- When the body does not have enough Calories (1 kilocalorie) or variety of foods to fulfill needs
Ex: Amino acid deficiency

3. Famine

5. Major Nutrients in Human Foods

6. Sources of Nutrition Diet- the type and amount of foods eaten
Balanced diet = HEALTHY

7. Diets Around the World Vary by region
Developed nations= more foods (high in proteins and fats
U.S. - almost 1/2 Calories from meat, fish, and oils

8. The Ecology of Food Farmland replaces natural ecosystems
Food efficiency- quantity produced on a given area of land w/ limited inputs of energy and resources
More energy and resources required for animals
Meat - more nutrients per gram

9. The Ecology of Food Yield- amount of food produced in a given area
Researchers interested in organisms that can survive in various climates w/out chemicals and large amounts of water

10. World Food Problems
Food production not increasing fast enough with human pop. growth
Malnutrition result of poverty, war and political strife (transportation problems)
Drought- prolonged period during which rainfall is below average
No irrigation
Seeds not available
Soil degradation

11. The Green Revolution
Worldwide crop yield increases ;new variety and techniques
B/w 1950 and 1970, Mexican wheat up eight-fold; India doubled rice
Neg. effects: large amts of water, chemicals, and machinery; crop decline- degradation and overuse
Subsistence farmers- grow only enough food for local use; can’t afford machinery/chemicals

13. Chapter 15- Food and Agriculture
Section 2- Crops and Soil

14. Agriculture Arable land- land that can be used to grow crops
Plowing- mixes nutrients loosens soil particles, and uproot weeds
Fertilizers- enrich soil with nutrients for better health and growth of plants Irrigation- bringing in water for crops
Chemicals used to kill pests

15. Agriculture Traditional Modern Farmer or animal pulled plow
Manure used as fertilizer
Weeds removed by hand
Water flowed through ditches
Modern
Machine plows
Synthetic chemical fertilizers
Weeds removed by machines
Overhead sprinkler and drip systems

16. Traditional Vs. Modern

17. Fertile Soil: The Living Earth
Fertile soil can support the growth of healthy plants.
Topsoil- Organically rich surface layer
Living organisms, rock particles, water, air, and organic material (decomposing)
Soil forms from rocks broken into smaller fragments by water, wind, and chemical weathering (rock minerals react to form new chemicals)
Temperature changes allow for rocks to crack and break
1000s of years for centimeters of soil

18. Soil Composition Surface Litter Topsoil Zone of Leaching Subsoil
Rock Particles
Bedrock

19. Soil Erosion Wearing away of rocks or soil by wind and water
Half of original US topsoil lost in last 200 years
Farming increases

20. Land Degradation
Human activity or natural processes damage the land to the point of being inable to support the ecosystem.
Desertification- Land in which arid or semiarid areas become more desert-like because of human activity or climatic changes.
Ex: Sahel, N. Africa used to plant crops and allow land to lie fallow for a few years to replenish; Increase in pop. caused fallow periods to be shorter or none at all. Large areas can not support crops anymore and have desertified

21. Sahel, N. Africa

22. Soil Conservation Soil erodes downhill- soil-retaining terraces
Contour plowing on gentler slopes
No-till farming- Harvest a crop without turning soil so remains hold soil in place
Leaves soil packed causing lower crop yields

23. Enriching the Soil
Organic matter such as manure and leaves was traditionally added
Inorganic fertilizers have doubled food production in 50 years
Nitrogen, Phosphorous, Potassium
Erosion pollutes waterways with these
Modern way is combining inorganic fertilizers and compost (partly decomposed organic material)
Some garbage can form compost

24. Compost

25. Salinization The accumulation of salts in the soil CA and AZ
Irrigation from river or groundwater; saltier than rain
Raises groundwater levels
Evaporation leaves salts behind
Prevent by lining irrigation canals or water heavily

26. Pest Control Insects eat 13% of crops in N. America
Tropical areas worse
33% worldwide
Pest- any organism that occurs where it is not wanted or occurs in large enough numbers that it causes ecological damage
Wild plants naturally protected

27. Agricultural Pests

28. Pesticides Chemicals used to kill insects, weeds, and other crop pests
Can harm beneficial wildlife, plants, insects, and people
Pests can evolve a resistance after prolonged use
500 species worldwide
Cancer rates and nervous disorders are higher in agricultural areas that use pesticides as well as factories that produce them
Persistent- Does not break down quickly or easily
Accumulates in water and soil
Biomagnification
Ex: DDT and Bald Eagle

29. Biological Pest Control
The use of living organisms to control pests
India tried 1st; prickly pear cactus and American beetle
Pathogens- organisms that cause disease
Bacillus thuringiensis (Bt) kills caterpillars
Plant defenses- plants bred for chemical compounds and physical barriers
“VNT” resistant to certain pests
Defensive chemicals from plants used
In-home sprays
Less harmful
Biodegradable

30. Pest Management Integrated Pest Management Disrupting insect breeding
Growth regulators
Chemicals interfere with some stage of life cycle
Ex: Monthly flea meds
Pheromones
Chemicals produced by one organisms to affect the behavior of another
Used to confuse insects
Can also make insects sterile with x-rays or chemicals
Integrated Pest Management
Modern method of controlling crop pests
Reduce pests without elimination
Different program for each pest
Biological method first
Cultivation second
Insecticides last

31. Engineering a Better Crop
Traditional: Save seeds from best plants with fewest pests
Modern: Genetic Engineering- genetic material in living cell is modified for medical or industrial use
Can isolate genes from one organism and implant in another
Genetically modified plants (GM)
Ex: inserting a bacterium insecticide gene
Problems:
Products not fully tested
Genes transferred to wild plants

33. Sustainable Agriculture
Low-input farming
Minimizes use of energy, water, pesticides, and fertilizers
Planting productive, pest-resistant crops

34. Chapter 15- Food and Agriculture
Section 3- Animals and Agriculture

35. Domesticated Animals Less energy required to raise animals
Basis for protein in diet
Domesticated- Bred and managed for human use
About 50 animal species
Chicken, sheep, cattle, honey bees, silkworms, fish, and shellfish
Goats, pigs, and buffalo

36. Food from Water Fish are important food source
Overharvesting- catching or removing more organisms than a population can replace
No-fishing zones improve after a few years
Necessary for fish markets to prosper

37. Aquaculture
The raising of aquatic organisms for human use or consumption
Began in China 4,000 yrs ago
Catfish, oysters, salmon, crayfish and rainbow trout
23% of seafood
20% of protein from fish and other aquatic organisms
Ranch- raise fish to release
Fish return to birthplace to breed
Captured, bred and re-released
Fish farms have many small ponds with circulating water
Can create waste/pollution, deplete local water supply
Few cases damaged sensitive wetlands

38. Aquaculture

39. Livestock
Domesticated animals that are raised to be used on a farm or to be sold for profit
Used for leather, wool, eggs, meat, draft animals to pull equipment and manure

40. Ruminants Cattle, sheep, and goats
Cud-chewing with 3 to 4 chambered stomachs
Cud- Regurgitated food that is rechewed to increase digestion
Special microorganisms allow digestion of plant materials
Common in N. America, India, and Africa for meat, milk, blood, dung and work power

42. Poultry
Domesticated birds raised for meat and eggs; good source of amino acids
Chicken production increased more than any other livestock since 1961
Farms are cramped, artificial environment

43. Poultry

44. Poultry Ducks and geese Integrated system in China Meat
Droppings fertilize rice paddies
Irrigation of mulberry trees, home of silkworms, occurs from ponds
Plant materials and filtered sewage dumped as food for carp and other fish