BESC 201 10 25 2013 Lecture 23 Outline of Last Lecture I Soils Crops and Pests Outline of Current Lecture II Genetically Modified Food III Raising Animals for Food Livestock Poultry and Aquaculture IV The Growth of Sustainable Agriculture Current Lecture 10 25 2013 Genetically Modified Food The genetic modification of organisms that provides us food holds promise to enhance nutrition and the efficiency of agriculture while lessening impacts on the planet s environmental systems Foods can be genetically modified Genetic Engineering any process whereby scientists directly manipulate an organism s genetic material in the lab by adding deleting or changing segments of its DNA Genetically Modified GM Organisms organisms that have been genetically engineered using recombinant DNA Recombinant DNA DNA that has been patched together from the DNA of multiple organisms The goal is to place genes that produce certain proteins and code for certain desirable traits into organisms lacking those traits Transgenic an organism that contains DNA from another species Transgenes the genes that have moved between organisms Biotechnology the material application of biological science to create products derived from organisms The techniques geneticists use to create GM organisms differ from traditional selective breeding in several ways o Selective breeding mixes genes from individuals of the same or similar species whereas scientists creating recombinant DNA routinely mix genes of organisms as different as viruses and crops o Selective breeding deals with whole organisms living in the field whereas genetic engineering works with genetic material in the lab o Traditional breeding selects from combinations of genes that come together on their own whereas genetic engineering creates the novel combinations directly These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute What are the impacts of GM crops Because Gm technology is rapidly changing and because its large scale introduction into our environment is recent there remains much that we don t yet know The adoption of insect resistant GM crops appears to reduce the use of chemical insecticides but farmers planting herbicide tolerant crops tend to use more herbicide because their crops can withstand it A company s GM crops are tolerant to herbicides that the same company manufactures and profits from o Whereas the Green Revolution was a largely public venture the gene revolution promised by GM crops is largely driven by the financial interests of corporations selling proprietary products Precautionary Principle the idea that one should not undertake new action until the ramifications of that action are well understood Raising Animals For Food Livestock Poultry and Aquaculture Our food choices are also energy choices Eating meat is far less energy efficient than relying on a vegetarian diet and leaves a far greater ecological footprint Feedlot agriculture has benefits and costs Feedlots huge warehouses or pens designed to deliver energy rich food to animals living at extremely high densities Feedlots offer one overarching benefit for environmental quality Taking cattle and other livestock off rangeland and concentrating them in feedlots reduces the grazing impacts they would otherwise exert across large portions of the landscape Livestock produce prodigious amounts of manure and urine and their waste can pollute surface water and groundwater The crowded conditions under which animals are often kept necessitate heavy use of antibiotics to control disease The overuse of antibiotics can cause microbes to become resistant to the antibiotics Livestock are also a major source of greenhouses gases that lead to climate change We raise seafood with aquaculture Aquaculture the cultivation of aquatic organisms for food in controlled environments Many aquatic species are grown in open water in large floating net pens Others are raised in ponds or holding tanks Aquaculture is the fastest growing type of food production Reduces fishing pressure on overharvested and declining wild stocks Consumes fewer fossil fuels and provides a safer work environment than does commercial fishing Can produce prodigious amounts of waste both from the farmed organisms and from the feed that goes uneaten and decomposes in the water If farmed aquatic organisms escape into ecosystems where they are not native they may spread disease to native stocks or may outcompete native organisms for food or habitat The Growth of Sustainable Agriculture Organic agriculture is booming Organic Agriculture agriculture that uses no synthetic fertilizers insecticides fungicides or herbicides Benefits lower input costs enhanced income from higher value produce and reduced chemical pollution and soil degradation The main obstacle for consumers to organic foods is price Locally supported agriculture is growing Another component of the move toward sustainable agriculture is an attempt to reduce fossil fuel use from the long distance transport of food Farmers Market consumers buy meats and fresh fruits and vegetables in season from local producers Community Supported Agriculture CSA consumers pay farmers in advance for a share of their yield usually a weekly delivery of produce Welcome alternative to taking out loans and being at the mercy of the weather