1. APES Unit 5 Human Populations and Food
Ch. 7 – Human Populations
Ch. 11 – Feeding the World
by - Natalie Tarpein

2. Pop clock:
World Population Video:

3. Earth’s Carrying Capacity
Innovations lead to increased K for humans – arrows, ox- driven plows, mechanical harvesters

4. Changes in Population Size
Births and Deaths
Immigration and Emigration
Net migration rate- the difference between immigration and emigration in a given year per 1,000 people in the country.

5. Changes in Population Size

6. Life Expectancy
Life expectancy- the average number of years that an infant born in a particular year in a particular country can be expected to live, given the current average life span and death rate of that country.
Infant mortality and child mortality

7. Age Structure
Age structure diagrams (population pyramids)- visual representations of age structure within a country for males and females.

8. The Demographic Transition
The theory of the demographic transition is the theory that as a country moves from a subsistence economy to industrialization and increased affluence, it undergoes a predictable shift in population growth.

9. The Stages of the Demographic Transition
Phase 1: (Subsistence) Slow to no population growth because there are high birth rates and high death rates which offset each other. - US and Western Europe prior to Industrial Revolution; Lesotho (south Africa; 23% infected with HIV)
Phase 2: (Preindustrial) Rapid population growth because birth rates remain high but death rates decline due to better sanitation, clean drinking water, increased access to food and goods, and access to health care. – China, India, many others; US in early 20th century
Phase 3: (Industrial) Stable population growth as the economy and educational system improves and people have fewer children. (fig ) – US and Canada now
Phase 4: (Postindustrial) Declining population growth because the relatively high level of affluence and economic develop encourage women to delay having children. Bigger elderly population. – Japan, UK, Germany, Russia, Italy

10. Family Planning
Family planning- the regulation of the number or spacing of offspring through the use of birth control.

11. Population momentum effect
Momentum of a growing population
Even after birth control is put into place, it takes a few generations to see a difference in population

12. The IPAT Equation Estimate the impact of human lifestyles on Earth
Impact= Population × Affluence × Technology

13. Ecological Footprints
Affluence - having a lot of wealth such as money, goods, or property. Global average 2.7

14. The Impact of Affluence
Gross domestic product (GDP)- the value of all products and services produced in a year in that country.
GDP is made up of consumer spending, investments, government spending, and exports minus imports.
A country’s GDP often correlates with its pollution levels (USA in 20th century)
However, as the GDP increases further, this correlation might reverse (Western Europe today; US soon)

15. Green Revolution techniques
1. Mechanization – replacement of humans with machines for farm labor (large farms outcompete small farms)
2. Irrigation – watering systems to increase crop growth rates or enable crops to grow
3. Fertilizers – Replacement or addition of nutrients in soil
4. Monocropping – large planting of a single species or variety; ex – cotton and wheat in the US; pine trees in forestry
5. Pesticides – use of substances to kill or control pests

16. Monocropping Dominant agricultural practice in the US
Improved productivity
Uniform machinery, fertilizers, and pesticides
Problems: soil erosion, pest problem vulnerability, reduction in local biodiversity

17. Irrigation Problems
Waterlogging
Salinization

18. Fertilizers Problems -use of fossil fuels to make them!
Organic fertilizers- natural
Inorganic fertilizers (synthetic)- This is usually done by combusting natural gas, which allows nitrogen from the atmosphere to be fixed and captured in fertilizer.
Problems
-use of fossil fuels to make them!
-runoff could lead to eutrophication

19. Pesticides
Two types:
Broad-spectrum pesticides- designed to kill many different types of pests.
Ex – dimethoate – kills almost all insects and mites
Selective pesticides- designed to kill a narrower range of organisms.
Ex – acequinocyl – kills only mites

20. Pesticides
Persistent Pesticides- pesticides that remain in the environment a long time (ex. DDT)
Bioaccumulation – builds up in fatty tissues of organisms (mercury)
Biomagnification – builds up in upper trophic levels of food chain (mercury)
-POPs – persistent organic pollutants
“Dirty Dozen” (DDT, PCBs, dioxins…)
Nonpersistent Pesticides- pesticide that breaks down relatively rapidly, usually in weeks to months.
Ex. Herbicide glyphosate - Roundup

21. Pesticide Treadmill, “Trap”
Pesticide treadmill- the cycle of pesticide development followed by pest resistance, followed by development of a new pesticide.
-Natural selection in action
Ex. – Roundup-ready crops  prompt resistance  weeds like pigweed in cotton crops  farmers use harsher pesticide - 2-4,D

22. Pesticide Problems May kill or harm beneficial organisms
Pollinators, ladybugs, plants, mammals
Toxicity to farmworkers
Risk to humans who ingest food treated with pesticides (more on this in next unit)

23. Benefits of Genetic Engineering
Greater yield
Greater food quality
Reductions in pesticide use
Reduction of world hunger by increased food production
Increased profits

24. Concerns with Genetic Engineering
Safety for human consumption
Effects on biodiversity
Regulation of genetically modified organisms
“Though knowing who to trust and what to believe regarding this topic is an ongoing battle, major health groups, including the American Medical Association and World Health Organization, have concluded from the research of independent groups worldwide that genetically modified foods are safe for consumers [4]. Regarding toxicity, this includes any dangers related to organ health, mutations, pregnancy and offspring, and potential for transfer of genes to the consumer.” - Megan Norris, PhD candidate, Harvard U.

25. Sustainable Agriculture
Techniques
Contour plowing- plowing and harvesting parallel to the land to prevent erosion.
Intercropping- two or more crop species are planted in the same field at the same time. Ex – Three sisters
Crop rotation- rotating crops species from season to season. Ex – corn first, then peas, then corn
Agroforestry- intercropping trees with vegetables. Reduces wind and soil erosion

26. No-till Agriculture
Helps prevent soil degradation by leaving crop residues in the fields and not tilling the land after each harvest.

27. Integrated Pest Management
Integrated pest management (IPM)- using a variety of techniques designed to minimize pesticide inputs
Crop rotation
Intercropping
Planting pest-resistant crop varieties (Yes, GMOs)
Creating habitats for predators
Limited use of pesticides

28. IPM training of farmers in Indonesia – farmers learned to determine the need for pesticides and cut their expenditures in half as well as improving yields

29. High-Density Animal Farming
CAFOs (concentrated animal feeding operations)- large structures where animals are being raised in high density numbers.
Pros
Farmers minimize land costs
improve feeding efficiency
Cons
Antibiotic-resistance
waste disposal
runoff
sad lives

30. More Sustainable Animal Farming
Free-range – chicken and beef not raised in CAFOs
Little to no antibiotics and meds
Less fossil fuels used in raising them
Waste is naturally processed
Living off the land, less supplements

31. Harvesting of Fish and Shellfish
Fishery- a commercially harvestable population of fish within a particular ecological region.
Fishery collapse- the decline of a fish population by 90% or more (30% of fisheries worldwide)
Bycatch- unintentional catch of non-target species.
Decrease in wild-caught fish
Increase in farmed fish

32. Fishing methods
Purse-seine nets to catch school of high value fish, like tuna – capture a million pounds of adult tuna; loss of a predator/keystone species when done intensively
Dredging – weighted net drags the bottom for fish that live on or close to the bottom; damages habitat
Bycatch has reduced shark and sea turtle populations

33. More Sustainable Fishing methods
Sustainable Fisheries Act – 1996 – shifted fisheries management to focus on conservation rather than economics
Success story – Alaska – commercial salmon fishery – Individual transferable quotas (ITQs) – right to catch an allowed amount; they’re transferable and can be sold
International cooperation – important because fish move and migrate across oceans.

34. Aquaculture
Aquaculture- the farming of aquatic organisms such as fish, shellfish, and seaweeds.
Good – alleviate some fisheries problems; provide protein for undernourished
Bad – environmental problems like dirty water pumped out with disease, feces, antibiotics; escapees
In eastern US, almost all of the catfish, trout, shrimp, and salmon produced this way

35. Energy Subsidies