Download
1 / 73
730 likes | 821 Views
8- 1. Housekeeping Items. Any reactions to the film “Food Fight”?
E N D
Housekeeping Items • Any reactions to the film “Food Fight”? • Did anyone go to the water talk on Monday night? There are other events as part of International Development Week – last night they showed “Food Security: It’s In Your Hands” and “Voices of the River” from 6 to 9 in Building 200, Room 203. • Caitlyn was asking about difference in soils near where her parents live. I’ll pass around a book, “Soil Landscapes of BC,” with a few pages marked. The predominant soils in this part of the Island are humo-ferric podzols that result from the interaction between the glacial till (sand and gravel) and the organic matter shed by the dominant vegetation (Western hemlock, Douglas fir, and various shrubs).
Housekeeping Items • Cameron was asking about the “R” horizon of soil. It is a transitional zone of partially weathered bedrock. • Someone else asked about the flooding of Nile. It has largely ceased in the upper portion due to the Aswan Dam. • The VIU Sustainability Committee now has some cash for projects on campus; if you have ideas let me know. • Career Day: The Geography Department is hosting a Career Day! All students are welcome to attend. It will take place today from 1 to 2 in this room. • Anyone who is working on a major paper who would also like practice in presenting is welcome to present at the pre-WDCAG session on Friday, Feb. 22 from 11:30 to 2:30. Just notify Jeff Lewis. • If you haven’t turned in or e-mailed your outlines please do so today. • We’ll briefly go through the agriculture slides (also review on your own).
Upon successfully completing this chapter, you will be able to: • Outline the historical development of agriculture and the transition to industrialized agriculture • Explain the challenge of feeding a growing human population • Identify the main approaches and summarize the environmental impacts of the Green Revolution • Summarize the strategies and impacts of pest management and the importance of pollination
Upon successfully completing this chapter, you will be able to (cont’d): • Describe the science and evaluate the controversies associated with genetically modified food • State the importance of crop diversity and some approaches to preservation • Assess the positive and negative aspects of feedlots and aquaculture for raising animals for food • Summarize the main goals of sustainable agriculture
Central Case: GM maize and Roundup-Ready Canola “Worrying about starving future generations won’t feed them. Food biotechnology will…At Monsanto, we now believe food biotechnology is a better way forward.” – Monsanto company advertisement See also the film, “The World According to Monsanto” “I never put those plants on my land. The question is, where do Monsanto’s rights end and mine begin?” – Percy Schmeiser
Central Case: GM maize and Roundup-Ready Canola (cont’d) • Schmeiser charged with reusing or growing patented seed without a contract • Schmeiser claimed the seeds blew onto his field from the neighbor’s adjacent field • The courts sided with Monsanto for a patent violation, a fine of $238 000 • An appeal to the Supreme Court of Canada recognized the violation but exempted the fine because the farmer had not benefitted from the seeds • Canada was the first nation to prohibit patents on higher organisms (e.g. mice)
The Race to Feed the World • World’s population will swell to 9 billion by the middle of this century • Agricultural land covers 38% of Earth’s land surface • Agriculture: practice of raising crops and livestock for human use and consumption • Cropland: land used to raise plants for human use • Rangeland: land used for grazing livestock 8-10
Agriculture first appeared around 10,000 years ago • Agriculture was invented independently by different cultures
Agriculture first appeared around 10,000 years ago (cont’d) • Agriculture is a form of intensification – a way to increase the productivity and carrying capacity of a given unit of land • Traditional agriculture = biologically powered agriculture, using human and animal muscle power • Subsistence agriculture = families produce only enough food for themselves
Industrialized agriculture is more recent • Industrialized agriculture = using large-scale mechanization and fossil fuels to boost yields • Vast fields of single types of crops – monoculture • Occupies about 25% of the world’s croplands
Food security = the guarantee of an adequate, reliable, and available food supply to all people at all times No guarantee that agricultural production will continue to outpace population growth Since 1985, world grain production per person has fallen by 9% World’s soils are in decline A significant portion of the planet’s arable land has already been brought into production Countries like China and Saudi Arabia are buying up arable land in Africa to help provide for their own food security at the possible expense of those who live in those nations We are producing more food per person
We face undernourishment, overnutrition, and malnutrition Undernourishment = people receive less than 90% of their daily caloric needs Mainly in developing countries Overnutrition = receiving too many calories each day In Canada, 48% of adults exceed their healthy weight and 14% are obese Malnutrition = a shortage of nutrients the body needs The diet lacks adequate vitamins and minerals
Green revolution = increases in agricultural productivity during mid- to late twentieth century Increased food production Devoting more energy Greatly increasing use of irrigation, fertilizers, and pesticides Extensification = bringing more land into production Intensification = better productivity per unit of land The Green Revolution led to dramatic increases in agricultural productivity
The green revolution has had both positive and negative impacts • Positive effects on natural resources • Reduced pressure to convert natural lands • Prevented deforestation and habitat conversion • Negative effects on natural resources • Intensive use of water, fossil fuels, chemical fertilizers, and pesticides • Pollution • Erosion • Salinization • Desertification
The green revolution has had both positive and negative impacts (cont’d) • Fertilizer Impacts • Inorganic – or industrial fertilizers are mined or synthetically manufactured mineral supplements (nitrogen, phosphorus, and potassium) • Organic – natural materials such as animal manure, crop residues, fresh vegetation, compost • Runoffs can lead to phytoplankton blooms and pose human health risks
The green revolution has had both positive and negative impacts (cont’d) • Irrigation Impacts • Agriculture main reason for extraction and use of fresh water worldwide • Efficiency is quite low as only 43% of the water applied gets used by plants • Can lead to waterlogging and salinization of soils • Drip irrigation is one possible solution
The green revolution has had both positive and negative impacts (cont’d) Monoculture Impacts Large expanse of a single crop More efficient, increases output Devastates biodiversity Susceptible to disease and pests Contributes to a narrowing of human diet: 90% of our food comes from 15 crop species and 8 livestock species
Pests and Pollinators Insects, fungi, viruses, rodents, and weeds that eat or compete with our crops have taken advantage of the ways we cluster food plants into agricultural fields Pest = any organism that damages valuable crops Bigger problem in monoculture Weed = any plant that competes with crops
What a pest! Compare the concept of a pest or weed species with that of alien and invasive species. At what point should a species be considered a pest? Does it have to cause damage to human interests? What if it causes harm only to natural ecosystems? How should pest species be managed? weighingtheissues
Thousands of chemical pesticides have been developed Pesticides = poisons that target pest organisms Insecticides = target insects Herbicides = target plants Fungicides = target fungi 91% of pesticide sales are for agricultural purposes 85% of pesticides sold in Canada are herbicides
Pests evolve resistance to pesticides Usefulness tends to decline with time as pests evolve resistance to pesticides Small fraction of insects and microbes have genes that confer some degree of immunity to a given pesticide If an insect survives pesticide, resistance is passed through their genes to insect offspring Evolutionary arms race: chemists increase chemical toxicity to compete with resistant pests
Biological control pits one organism against another Biological control (Bio-control) = uses a pest’s natural predators to control the pest
Biocontrol agents themselves may become pests No one can predict the effects of an introduced species The agent may have “non-target” effects on the environment and surrounding economies Removing a bio-control agent is harder than halting pesticide use Due to potential problems, proposed bio-control use must be carefully planned and regulated
IPM combines biocontrol and chemical methods Integrated Pest Management (IPM) uses multiple techniques to suppress pests Biocontrol Chemicals, when necessary Population monitoring Habitat alteration Crop rotation and transgenic crops Alternative tillage methods Mechanical pest removal
We depend on insects to pollinate crops Pollination = male plant sex cells fertilize female sex cells Value of insect pollination services in Canada is $1.2 billion Globally one mouthful in three requires insect pollination Bees pollinate 73% ofcultivars Flowers are evolutionary adaptations to attract pollinators
Conservation of pollinators is vital Bees devastated by parasites and Colony Collapse Disorder North American farmers regularly hire beekeepers to bring colonies to their fields To conserve bees and other pollinators: Reduce or eliminate pesticide use Plant flowering plants
Genetic modification of organisms depends on recombinant DNA • Genetic engineering = laboratory manipulation of genetic material • Creates a genetically modified (GM) organism • Recombinant DNA = DNA patched together from the DNA of multiple organisms
Biotechnology is impacting our lives Biotechnology = the material application of biological science to create products derived from organisms Transgenic organism = an organism that contains DNA from another species Transgenes = the genes that have moved between organisms Biotechnology has helped us create medicines, clean up pollution, understand the causes of cancer, dissolve blood clots after heart attacks, and make better beer and cheese
Genetic engineering is like, and unlike, traditional breeding • Similar: • Both alter gene pools for preferred characteristics • Both apply to plants and animals • Different: • Traditional breeding uses genes from the same species • Selective breeding deals with whole organisms, not just genes • In traditional breeding, genes come together on their own
GM foods and you Have you have ever eaten a food product that contained genetically modified organisms? If you live in North America, the answer is almost certainly “yes.” As much as 70% of the food products on shelves in North American grocery stores contain at least some GM ingredients. Check your kitchen cupboards for any foods that contain products or ingredients made from corn, soy, or canola. The probability that some of those ingredients came from genetically modified plants is very high. The European Union requires labelling of foods that contain GM ingredients. Do you want your food to be labelled? Would you choose foods based on whether they are organic or genetically modified? weighingtheissues
Biotechnology is transforming the products around us • Most GM crops today are engineered to resist herbicides, others to resist insects+ • Three-fourths of the world’s soybean plants are transgenic, as are one out of every four corn plants and over half of all cotton plants • Globally, GM foods grew on 134 million hectares of farmland, producing $10.5 billion worth of crops
What are the impacts of GM crops? • As GM crops expanded, scientists, citizens, and policy makers became concerned • Dangerous to human health • Escaping transgenes could pollute ecosystems and damage nontarget organisms • Pests could evolve resistance • Could ruin the integrity of native ancestral races • Interbreed with closely related wild plants • Critics argue that we should adopt the precautionary principle
Debate over GM foods involves more than science • Ethical issues play a large role • People don’t like “tinkering” with “natural” foods • With increasing use, people are forced to use GM products, or go to special effort to avoid them • Multinational corporations threaten the small farmer • Research is funded by corporations that will profit if GM foods are approved for use • Crops that benefit small, poor farmers are not widely commercialized
Debate over GM foods involves more than science (cont’d) • The future of GM foods seems likely to hinge on social, economic, legal, and political factors as well as scientific ones • Transnational spats will surely affect the future direction of agriculture, but consumers and the government’s of the world’s developing nations could exert the most influence in the end • India and Brazil approve of GM crops • China is expanding use of transgenic crops
Crop diversity provides insurance against failure • Preserving native variants protects against crop failure • Monocultures are vulnerable, so wild relatives contain genes that could provide resistance to disease and pests • We have already lost a great deal of genetic diversity in crops • Wheat varieties in China dropped from 10,000 (1949) to 1,000 (1970s) • Mexico’s famed maize varieties number only 30% of what it was in the 1930s • Market forces discourage diversity in food’s appearance • Consumers prefer uniform, standardized food
Seed banks are living museums for seeds • Seed banks = preserve seed types as a living museum of genetic diversity • Seeds are collected and preserved, and periodically planted • Hand pollination preserves genetic distinctiveness • The Royal Botanic Garden’s Millennium Seed Bank in Britain aims to bank 20% of the world’s plants by 2020 • Norway has started a “doomsday vault” seed bank
Raising animals for food • Most people eat animal products • People don’t need to eat meat to live full, active, healthy lives • As wealth and commerce increase, so does consumption of meat, milk, and eggs • Global meat production has increased fivefold since 1950 • Per capita meat consumption has doubled
High consumption has let to feedlot agriculture • Pressure of global population has led to feedlots • Feedlots = Huge warehouses deliver energy-rich food to animals living at extremely high densities • Also known as “factory farms” or CAFOs • Necessary to keep up with meat consumption in Canada and the United States • Over ½ of the world’s pork and most of the poultry come from feedlots
High consumption has let to feedlot agriculture (cont’d) • Benefits of feedlots: • Greater production of food • Keeps up with high meat consumption • Reduces the impact of livestock on land (use less space) • Drawbacks of feedlots: • Contribute to water and air pollution • Poor waste containment may cause human disease • Cattle: steroids used to stimulate growth • Heavy uses of antibiotics to control disease
