APES ch 10: agriculture and sustainability

pollinator decline causes: insecticides

-A direct source of mortality is the vast arsenal of chemical insecticides we apply to crops, lawns, and gardens to kill pest insects. -All insects are vulnerable to these poisons, so when we try to control pests, we also end up killing beneficial insects such as bees. -Pollinators have suffered loss of habitat and flower resources for decades, but this has grown worse recently as weed-killers like Roundup have eliminated weeds from farm monocultures, depriving pollinators of a diversity of nectar and pollen sources.

Bt (bacillus thuringiensis)

-A widespread modern biocontrol effort has been the use of Bacillus thuringiensis (Bt), a naturally occurring soil bacterium that produces a protein that kills many caterpillars and some fly and beetle larvae. -Farmers spray Bt spores on their crops to protect against insect attack. -In addition, scientists have managed to isolate the gene responsible for the bacterium's poison and engineer it into crop plants so that the plants produce the poison.

food security

-Agricultural scientists and policymakers worldwide pursue a goal of food security, the guarantee of an adequate, safe, nutritious, and reliable food supply available to all people at all times. -The good news is that globally the number of people suffering from undernutrition has been falling since the 1960s. -The percentage of people who are undernourished has fallen even more.

benefits of industrialization and the Green Revolution on developing nations

-Along with the new grains, developing nations imported the methods of industrial agriculture. -They began applying large amounts of synthetic fertilizers and chemical pesticides on their fields, irrigating crops generously with water, and using more machinery powered by fossil fuels. -From 1900 to 2000, people increased energy inputs into agriculture by 80 times while expanding the world's cultivated area by just one-third. -Intensified agriculture saved millions in India from starvation in the 1970s and turned that nation into a net exporter of grain.

seed banks

-Another way to preserve genetic assets for agriculture is to collect and store seeds from diverse crop varieties. -This is the work of seed banks, institutions that preserve seed types as a kind of living museum of genetic diversity. -These facilities keep seed samples in cold, dry conditions to keep them viable, and they plant and harvest them periodically to renew the stocks.

aquaculture benefits

-Aquaculture increases food supplies and helps ensure reliable protein sources, thus improving people's food security. -Aquaculture also helps reduce fishing pressure on wild fish stocks, many of which, as we've discussed, are overharvested and declining. -Reducing fishing pressure also lessens bycatch, the unintended catch of nontarget organisms that results from commercial fishing. -Aquaculture consumes fewer fossil fuels and provides a safer work environment than does commercial fishing. -Fish farming can produce more fish -When practiced on a small scale by families or villages, as in much of the developing world, community-based aquaculture can be sustainable

growing consumption of animal products

-As wealth and global commerce have increased, so have humanity's production and consumption of meat, milk, eggs, and other animal products. -Worldwide, more than 30 billion domesticated animals are raised and slaughtered for food each year. -Global meat production has increased more than fivefold since 1950, and per capita meat consumption has doubled.

IPM (integrated pest management)

-Because both biocontrol and chemical control methods pose risks, agricultural scientists and farmers began developing more sophisticated strategies, trying to combine the best attributes of each approach. -Integrated pest management (IPM) incorporates numerous techniques, including biocontrol, use of chemicals when needed, close monitoring of populations, habitat alteration, crop rotation, transgenic crops, alternative tillage methods, and mechanical pest removal. -IPM has become popular in many parts of the world that are embracing sustainable agriculture. -Indonesia: promoting IPM

pesticides

-Because industrial monocultures limit the ability of natural enemies to control pest populations, farmers have felt the need to introduce some type of pest control to produce food economically at a large scale. -In the past half-century, most farmers have turned to chemicals to suppress pests and weeds. -In that time we have developed thousands of synthetic chemicals to kill insects (insecticides), plants (herbicides), and fungi (fungicides). -Such poisons are collectively termed pesticides.

pollinator decline causes: parasites and pathogens

-Bees are also being attacked by novel parasites and pathogens that, like many invasive species, have been moved around the world by human travel and trade. -In particular, two accidentally introduced parasitic mites have swept through honeybee populations in recent years, decimating hives and pushing beekeepers toward financial ruin.

industrialization of agriculture and food production

-By intensifying our inputs of energy and resources and by managing production efficiently at immense scales, we have increased our agricultural output beyond what any farmer or rancher of the past would have imagined. -Yet our high-input industrial agriculture also has brought pollution and resource depletion on unprecedented scales. -The environmental impacts of high-input industrial agriculture now threaten to roll back our gains, calling into question whether the industrial model can be sustained in the long term.

solutions to restore bee populations

-By retaining or establishing wildflowers and flowering shrubs in or near farm fields, farmers can provide bees a refuge and a source of diverse food resources. -these buffer strips protect against incursion of pesticides or GM material from neighbors, and conventional farmers sometimes plant buffer strips to protect streams and receive subsidies under conservation programs. -In addition, farmers can decrease their use of chemical insecticides by using biocontrol or integrated pest management. -Homeowners can help pollinators by reducing or eliminating the use of pesticides, tending gardens of flowering plants, and providing nesting sites for bees.

aquaculture risks

-Dense concentrations of farmed animals can incubate disease, which necessitates antibiotic treatment, results in expense, and can reduce food security. -Industrial-scale shrimp farming along tropical coastlines has destroyed large areas of valuable mangrove forest and has polluted coastal waters. -Indeed, aquaculture can produce remarkable amounts of waste, both from the farmed organisms and from feed that goes uneaten and decomposes in the water. -As with feedlot livestock, commercially farmed fish often are fed grain, which is energy-inefficient and can reduce food supplies for people. -Farmed fish are also sometimes fed fish meal made from wild ocean fish such as herring and anchovies, whose harvest may place additional stress on wild populations. -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.

undernutrition

-Despite our rising food production, nearly 800 million people worldwide do not have enough to eat. -These people suffer from undernutrition, receiving fewer calories than the minimum dietary energy requirement. -In most cases, poverty limits the amount of food people can buy. -Political obstacles, regional conflict and wars, and inefficiencies in distribution contribute significantly to hunger as well. -Most people who are undernourished live in the developing world. -49 million Americans as "food insecure," lacking the income required to reliably procure sufficient food.

landraces

-Every crop has a wild ancestral species from which it was domesticated, and most crops have had a complex evolutionary history, with people creating many landraces (variants adapted to local conditions) over the centuries. -The wild relatives of crop plants and their local landraces contain a diversity of genes that we may someday need to introduce into our commercial crops (through crossbreeding or genetic engineering) to confer resistance to disease or pests or to meet other unforeseen challenges.

raising/eating livestock and ecological footprints

-Every time that one organism consumes another, only about 10% of the energy moves from one trophic level up to the next. -Energy was used up as the cow converted the grain to tissue as it grew and as the cow conducted cellular respiration on a constant basis to maintain itself. -For this reason, eating meat is far less energy-efficient than relying on a vegetarian diet, and it leaves a far greater ecological footprint. -The lower on the food chain we eat, the smaller is our ecological footprint, and the more of us Earth can support.

challenges of organic farming

-Farmers face obstacles to adopting organic methods, however. -Foremost among these are the risks and costs of shifting to new methods, particularly during the transition period. -Australian farmers like Steve Marsh need to meet standards for three years before their products can be certified, and U.S. farmers face the same requirement. -The main obstacle for consumers is price.

feedlots: benefits

-Feedlots allow for economic efficiency and greater food production, and this makes animal products affordable to more people. -Taking cattle and other livestock off pastureland and concentrating them in feedlots reduces grazing impacts across large areas of the landscape. -Animals that are densely concentrated in feedlots will not contribute to overgrazing.

organic agriculture

-Food-growing practices that use no synthetic fertilizers, pesticides, hormones, or antibiotics—but instead rely on biological approaches such as composting and biocontrol—are termed organic agriculture.

benefits of GM crops

-Genetically engineered foods have long been promoted as a way to assist poor people in developing nations. -If crops can be made tolerant of drought or of salinized soils, then small farmers can more easily produce crops on marginal land and use less water -However, most of these noble intentions have not yet come to pass. -This is largely because the corporations that develop GM varieties cannot easily profit from selling seed to small farmers in developing nations. -Instead, most biotech crops thus far have been engineered for insect resistance and herbicide tolerance, which improve efficiency for large-scale industrial farmers who can afford the technology. -By increasing production of food and fiber while lowering costs, GM crops enhance food security and reduce poverty and hunger for millions of people. -By raising yields on existing farmland, GM crops alleviate pressure to clear forests and convert natural lands for agriculture, thus helping to conserve biodiversity, habitat, and ecosystem services. -GM crops that reduce fossil fuel use during cultivation help to lower greenhouse gas emissions and address climate change. -This meta-analysis calculated that, on average, researchers to that point had found that the adoption of GM crops increased yields by 22% and boosted farmers' profits by 68% while reducing chemical pesticide use by 37%).

GMOs and genetically modified foods

-Genetically modified foods are foods derived from genetically modified organisms (GMOs), organisms that are genetically engineered. -Genetic engineering uses recombinant DNA (DNA patched together from the DNA of multiple organisms).

monocultures

-Green Revolution -In today's conventional industrial agriculture, crops are planted in monocultures, large expanses of single crop types. -This makes planting and harvesting efficient and thereby increases output. -reduce biodiversity over large areas, because many fewer wild organisms are able to live in monocultures than in native habitats or in traditional small-scale polycultures. -Moreover, when all plants in a field are of the same species (and thus genetically similar), they are susceptible to viral diseases, fungal pathogens, or insect pests that can multiply and spread quickly from plant to plant.

feedlots: risks

-However, feedlot animals are generally fed grain grown on cropland. -This elevates the price of staple grains and can endanger food security for the poor. -Livestock produce prodigious amounts of manure and urine, and the highly concentrated waste from feedlots can pollute surface water and groundwater. -Rich in nitrogen and phosphorus, livestock waste is a common cause of eutrophication. -This waste may also release bacterial and viral pathogens that can sicken people

USDA organic

-In 1990, the U.S. Congress passed the Organic Food Production Act to establish national standards for organic products and facilitate their sale. -Under this law, the USDA in 2000 issued criteria by which crops and livestock can be officially certified as organic. -example of crop requirements: land free of prohibited substances for 3 years, crops not GM, no sewage sludge used -examples of livestock requirements: feed must be 100% organic, although vitamin and mineral supplements are ok, hormones and antibiotics prohibited, must have outdoor access

raising livestock and energy conversion efficiency

-In addition, some animals convert grain feed into milk, eggs, or meat more efficiently than others. -Scientists have calculated relative energy-conversion efficiencies for different types of animals and have used these to infer the area of land and weight of water required to produce 1 kg (2.2 lb) of edible protein from milk, eggs, chicken, pork, and beef. -The research illustrates that producing eggs and chicken meat requires the least land and water, whereas producing beef requires the most. -also accounts for pesticide applications, erosion, and antibiotics and pollution

evolutionary arms race: pests vs scientists

-In many cases, industrial chemists are caught up in an evolutionary arms race with the pests they battle, racing to intensify or retarget the toxicity of their chemicals while the armies of pests evolve ever-stronger resistance to their efforts. -Because we seem to be stuck in this cyclical process, it has been nicknamed the "pesticide treadmill."

malnutrition

-Just as the quantity of food a person eats is important for health, so is the quality of food. -Malnutrition, a shortage of nutrients the body needs, occurs when a person fails to obtain a complete complement of essential proteins, lipids, vitamins, or minerals. -Malnutrition can lead to disease.

low-input agriculture

-Low-input agriculture describes farming and ranching that use lesser amounts of pesticides, fertilizers, growth hormones, antibiotics, water, and fossil fuel energy than in industrial agriculture. -This approach seeks to reduce the costs of food production by allowing nature to provide ecosystem services (such as pest control, pollination, and fertilizer) that farmers using industrial methods must pay for themselves.

farmers markets

-Many proponents of sustainable agriculture call attention to the fossil fuel energy we use to transport food, and chemicals needed to keep food fresh -In response, increasing numbers of farmers and consumers are supporting local agriculture. -At farmers' markets, consumers buy meats and fresh fruits and vegetables in season from local producers. -These markets generally offer a wide choice of organic items and unique local varieties not found in supermarkets.

labelling GM foods

-More than 60 nations require that foods with genetically engineered ingredients be labeled so that consumers know what they are buying. -In contrast, the United States does not label GM foods, despite the fact that polls consistently show that a large majority of Americans would like their food to be labeled. -In California and several other states, ballot measures to mandate labeling of GM food have been defeated amid well-funded opposition from food, biotech, and pesticide industries. -Proponents of labeling argue that consumers have a right to know what's in the food they buy. -Opponents argue that labeling implies that labeled foods are dangerous, whereas research has not shown that to be the case. -They also say that labeling will entail expense and that consumers wishing to avoid GM foods can do so by buying certified organic foods. -GM foods removed from shelves in foreign labelling nations bc of avoidance: could pressure food producers to avoid using GM ingredients and farmers to avoid growing GM crops.

risks of GM crops

-Most scientists who harbor concerns over GMOs focus on potential ecological impacts. -Many conventional crops can interbreed with their wild relatives (domesticated rice can breed with wild rice, for instance), so there seems little reason to believe that transgenic crops would not also occasionally breed with wild strains. -Some scientists are concerned that in such an event, transgenes may be transferred from crops to other plants. -This could in theory "contaminate" the genomes of local landraces of crops. -In addition, if genes for glyphosate resistance are transferred to other plants, the genes from Roundup Ready "supercrops" could end up creating "superweeds." -Many experts feel we should proceed with caution, adopting the precautionary principle, the idea that one should not undertake a new action until its ramifications are well understood.

negative side of the Green Revolution

-On the negative side, the intensified use of fossil fuels, water, inorganic fertilizers, and synthetic pesticides has worsened pollution, topsoil erosion, and soil and water quality.

benefits of the Green Revolution

-On the positive side, intensifying the use of already-cultivated land reduced pressures to convert additional lands for cultivation. -Between 1961 and 2013, global food production more than tripled and per-person food production rose 48%, while area converted for agriculture increased only 11%. -In this way, the Green Revolution helped preserve biodiversity and natural ecosystems by preventing a great deal of deforestation and habitat destruction.

food growth vs human population growth

-Over the past half-century, our ability to produce food has grown faster than our global population. -Today many of the world's soils are in decline, and most of the planet's arable land has already been claimed. -Hence, even though agricultural production has outpaced population growth so far, we have no guarantee that this will continue.

monocultures and pests

-Pests pose an especially great threat to monocultures, because a pest adapted to specialize on a crop can move easily from plant to plant. -From the perspective of an insect that feeds on corn, grapes, or apples, encountering a grain field, vineyard, or orchard is like discovering an endless buffet. -In a natural ecosystem, each organism's population is kept in check by its predators, competitors, parasites, and pathogens—but in an industrial monoculture, the abundance of one type of food and the lack of other habitats can allow a pest population to flourish, unhindered by its natural enemies.

colony collapse disorder

-Researchers are finding that these multiple sources of stress seem to interact and cause more damage than the sum of their parts. -For example, pesticide exposure and difficulty finding food might weaken a bee's immune system, making it more vulnerable to parasites. -Any or all of these factors may possibly play a role in what is being called colony collapse disorder, a mysterious malady that for the past decade has destroyed up to one-third of all honeybees in the United States each year.

neonicotinoids

-Seed companies treat crop seed with neonicotinoids and they become systemic in the plant, dispersing throughout its tissues as it grows, and ending up in leaves, stems, flowers, fruit, and pollen. -"Neonics" make a plant toxic to insects; they kill insects that feed on the plant (as intended), but also harm bees pollinating the plant and predators that eat insects that feed on the plant (unintended consequences). -Neonicotinoids are also applied to plants chemically, and they may enter soil, water, and even plants that grow from treated soil, continuing to kill a diversity of organisms that pose no threat to crops.

CSA (community supported agriculture)

-Some consumers are partnering with local farmers in community-supported agriculture (CSA). -In a CSA program, consumers pay farmers in advance for a share of their yield, usually a weekly delivery of produce. -Consumers get fresh seasonal produce, while farmers get a guaranteed income stream up front to invest in their crops—a welcome alternative to taking out loans and being at the mercy of the weather. -Farmers' markets and community-supported agriculture help strengthen local economies while giving the consumer access to fresher foods.

sustainable agriculture

-Sustainable agriculture consists of farming and grazing that maintain the healthy soil, clean water, pollinators, genetic diversity, and other resources needed for the production of crops and livestock over the long term. -Reducing fossil fuel inputs and the pollution these inputs cause is a key aim of sustainable agriculture, and to many this means moving away from the industrial model and toward more traditional organic and low-input models. -even incorporating GMOs and livestock management

sustainable agriculture mimics natural ecosystems

-The best approach for making an agricultural system sustainable is to mimic the way a natural ecosystem functions. -Ecosystems operate in cycles and are internally stabilized with negative feedback loops. In this way they provide a useful model for agriculture.

biotechnology

-The creation of transgenic organisms is one type of biotechnology, the material application of biological science to create products derived from organisms. -Biotechnology has helped us develop medicines, clean up pollution, understand the causes of cancer and other diseases, dissolve blood clots after heart attacks, and make better beer and cheese.

feedlots and antibiotics

-The crowded conditions under which animals are kept in feedlots necessitate heavy use of antibiotics to control disease. -Overuse of antibiotics can cause microbes to evolve resistance to the antibiotics. -This makes the drugs less effective, and leads feedlot managers to increase dosages and switch to ever-stronger antibiotics. -Hormones are administered to livestock as well, and metals are added to feed to spur growth. -Livestock excrete most of these chemicals, which end up in wastewater and may be transferred up the food chain in downstream ecosystems. -Some chemicals that remain in livestock are transferred to us when we eat their meat.

aquaculture

-The cultivation of aquatic organisms for food in controlled environments, called aquaculture, is now being pursued with more than 220 freshwater and marine species, ranging from fish to shrimp to clams to seaweeds. -However, wild fish populations are plummeting throughout the world's oceans as increased demand and new technologies lead us to overexploit marine fisheries. -Many aquatic species are raised in open water in large, floating net-pens. -Others are raised in ponds or holding tanks. -Aquaculture is our fastest-growing type of food production; global output has increased 10-fold in just the past 30 years.

Green Revolution

-The desire for greater quantity and quality of food for the world's growing population led in the mid- and late-20th century to the Green Revolution, which introduced new technology, crop varieties, and farming practices to the developing world. -Agricultural scientists had realized that farmers could not go on forever converting additional land to increase production, so they devised methods and technologies to increase crop yields on existing cultivated land. -As a result, yields rose dramatically in industrialized nations. -greatly helped developing nations, introducing them to this new technology

biological control (biocontrol)

-The most obvious alternative has been to battle pests and weeds with organisms that eat or infect them. -This strategy, called biological control—often referred to as biocontrol—operates on the principle that "the enemy of one's enemy is one's friend." -Biological control is essentially an attempt to reestablish the restraining influence that predators and parasites exert over populations in nature.

doomsday seed bank: Norway

-This secured, refrigerated facility is built deep into a mountain in an area of permanently frozen ground. -The site has no tectonic activity, has little natural radiation or humidity, and is high enough above sea level to stay dry even if climate change melts all the planet's ice.

life-cycle analysis (and fossil fuels)

-To determine which alternative involves less energy use overall, one needs to conduct a life-cycle analysis, a quantitative analysis of the inputs and outputs across all stages of an item's production, transport, sale, and use. -In the most comprehensive life-cycle analysis of U.S. food production and delivery so far, researchers found that food miles from producer to retailer contributed just 4-5% of total greenhouse gas emissions of the entire process. -Fully 83% of emissions resulted from production at the farm or feedlot. -As a result, the average consumer can reduce his or her ecological footprint more effectively through dietary choices (such as eating more fruits and vegetables and less meat and dairy) than by eating locally sourced food, these researchers maintain.

GM crops and insecticides vs herbicides

-To understand the effects on pesticide use, however, we need to consider insecticides and herbicides separately. -Farmers who adopt insect-resistant Bt crops tend to use fewer insecticides because their crops do not need them; the insect resistance is already built into the plant. -In contrast, herbicide-tolerant GM crops tend to result in more use of chemical herbicides, because farmers often apply more herbicide (to make sure weeds are killed) if their crops can withstand heavier applications. -This rise in herbicide use is accelerating and the prime reason is that weeds are evolving resistance to herbicides, causing farmers to apply even more of them. -For years farmers have loved these Roundup Ready crops because they reduce labor and boost yields: Simply spray fields with Roundup, and the weeds die while the crops thrive. -However, widespread use of Roundup and other glyphosate-based herbicides is resulting in the evolution of resistance.

Green Revolution affected areas today

-Today, yields are declining in some regions targeted by the Green Revolution, likely due to soil degradation from the heavy use of fertilizers, pesticides, and irrigation. -Moreover, wealthier farmers with larger holdings of land were best positioned to invest in Green Revolution technologies. -As a result, many low-income farmers who could not afford these technologies were driven out of business and moved to cities, adding to the immense migration of poor rural people to urban areas of the developing world.

biocontrol agents: becoming pests and invasiveness

-When a pest is not native to the region where it is damaging crops, scientists may consider introducing a natural enemy of the pest from its native range, expecting that the enemy will attack it. -Alternatively, scientists may consider importing a biocontrol agent from abroad that the pest has never encountered, reasoning that the pest has not evolved ways to avoid the biocontrol agent. -In either case, this involves introducing an animal or microbe from a foreign ecosystem into a new ecological context. -In some cases biocontrol agents have turned invasive and become pests themselves. -When this happens, biocontrol organisms are more difficult to manage than chemical controls, because they cannot be "turned off" once they are set loose. -thus, biocontrol agents have to be studied carefully beforehand

organic agriculture is on the rise

-about 80% of Americans buy organic food at least occasionally, most retail groceries offer it, and Americans are the world's eighth- highest per-person consumers of organic food. -Production is increasing along with demand. -Although organic agriculture takes up just 1% of agricultural land worldwide, this area is rapidly expanding. -Europe boasts far more of this land -Government initiatives are assisting the growth of organic farming. -The European Union supports farmers financially during conversion. -The United States offers no such subsidy, which may explain why U.S. organic production lags behind that of Europe. -Government support is helpful, because conversion often means a temporary loss in income for farmers. -Once conversion is complete, though, studies suggest that reduced inputs and higher market prices generally make organic farming more profitable for the farmer than conventional methods.

Norman Borlaug and the Green Revolution

-began in the 1940s, when American agricultural scientist Norman Borlaug introduced Mexico's farmers to a specially bred type of wheat. -This strain of wheat produced large seed heads, was resistant to diseases, was short in stature to resist wind, and produced high yields. -Within two decades of planting this new crop, Mexico tripled its wheat production and began exporting wheat. -Borlaug took his wheat to India and Pakistan and helped transform agriculture there as well. -Soon many developing countries were doubling, tripling, or quadrupling their yields using selectively bred strains of wheat, rice, corn, and other crops from industrialized nations.

how have we increased food production specifically?

-by devoting more fossil fuel energy to agriculture -intensifying our use of irrigation fertilizers, and pesticides; -planting and harvesting more frequently; -cultivating more land; -developing (mostly through traditional crossbreeding, partly through genetic engineering) more productive crop and livestock varieties.

public debate over GMOs

-ethical and economic concerns have largely driven the public debate. -For many people, the idea of "tinkering" with the food supply seems dangerous or morally wrong. -Because every person relies on food for survival and cannot choose not to eat, the genetic modification of dietary staples such as corn and rice essentially forces people to consume biotech products or to go to unusual effort to avoid them. -concern that the global food supply is being dominated by a handful of large corporations that develop GM technologies -government regulators generally side with big business rather than small farmers. -much of the research into the impacts of GMOs is funded, conducted, or influenced by the corporations that stand to benefit if their products are approved. -So far, GM crops have not lived up to their promise of feeding the world's hungry. -Crops with traits that might benefit poor farmers of developing countries have not been widely commercialized, likely because corporations have little economic incentive to do so. -"gene revolution" promised by genetic engineering is largely driven by the financial interests of corporations selling proprietary products. -corporations patent the transgenes they develop and go to great lengths to protect their investments. -Today there is widespread concern that the burgeoning organic food market will be hindered if organic farms experience an influx of pollen or seed from GM plants

pest

-feed on crop plants -any organism that damages crops or livestock

genetic engineering vs traditional breeding (differences)

-first, 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, or spiders and goats. -Second, selective breeding involves whole organisms living in the field, whereas genetic engineering works with genetic material in the lab. -Third, traditional breeding selects from combinations of genes that come together on their own, whereas genetic engineering creates novel combinations directly in a more controlled way. -Thus, in traditional breeding, people use a process of selection acting on random mutations, whereas in genetic engineering, scientists use a process of mutation that is nonrandom and precisely directed.

pesticides: benefits

-have helped to greatly increase our food production. -They help us control pests in our homes, and they continue to protect millions of people in developing nations from insect-borne diseases such as malaria.

pesticides: risks

-health consequences for people. -Especially vulnerable are farm workers, who experience high levels of pesticide exposure, and children, whose brains and bodies are growing and developing. -We all encounter and ingest chemical pesticide residues when we eat non-organic produce we buy at the grocery store, and pesticides leave residues and breakdown products in the soil, water, and air, affecting organisms and ecosystems in many ways. -in the United States and most other nations, new chemical products are not thoroughly tested for health effects before being brought to market - commonly kill nontarget organisms, including the predators and parasites of the pests they are meant to target.

GM products today

-improved medicines (such as hepatitis B vaccine and insulin for diabetes) to designer plants and animals (including glow-in-the-dark pet goldfish). -In the United States today, roughly 90% of corn, soybeans, cotton, and canola consist of genetically modified strains, and close to half of these crops are engineered for more than one trait. -most GM crops today are engineered to tolerate herbicides, so that farmers can apply herbicides to kill weeds without having to worry about killing their crops. -Tolerance of herbicides and resistance to pests enables large-scale commercial farmers to grow crops more efficiently, and this is largely why sales of GM seeds to farmers have risen so quickly.

GHG emissions and livestock

-livestock are a major source of greenhouse gases that lead to global warming. - beef exerts the largest footprint. -Livestock release methane and nitrous oxide in their metabolism and waste. -Nitrous oxide is also released from certain crops used to feed animals, and from fertilizers applied to those crops. -Carbon dioxide is released to the atmosphere when forests are cleared for ranching or for growing feed, as well as when fossil fuels are burned to grow feed or transport animals. -represents 14.5% of the emissions driving climate change—a larger share than automobile transportation!

overnutrition

-many consume more than is healthy and suffer from overnutrition, receiving too many calories each day. -Overnutrition is a problem in developed nations such as the United States, where food is abundant, junk food is cheap, and people tend to lead sedentary lives with little exercise. -Excessive weight can lead to heart disease, diabetes, stroke, some types of cancer, and other health problems. -The growing availability of highly processed foods (which are often calorie-rich, nutrient-poor, and inexpensive) suggests that overnutrition will remain a challenge.

can organic agriculture feed the world?

-meta-analyses have found that organic agriculture, on average, tends to produce yields of roughly 80% of those of conventional agriculture. -So if yields from organic agriculture average 20% less than those of conventional industrial agriculture, can we feed the world with organic agriculture? -scientists point out that organic yields have been rising as farmers gain more experience, and could rise still further if organic agriculture were to receive the research funding that goes toward conventional agriculture -by protecting soil quality, organic farming keeps more acreage productive for farming over the long term than does conventional farming. -Moreover, experts argue that overall food production is not what limits our ability to feed the world. -crop goes to livestock feed, biofuels, and processed products like high-fructose corn syrup. -Politics and the logistics of transport limit food distribution, and one-third of all food intended for our consumption ends up going to waste. -Thus, by reducing waste, eating less meat, dealing with distribution problems, and prioritizing food for people, the world could easily be fed by organic agriculture even with lower yields, supporters maintain.

crop diversity (and lack thereof)

-monocultures: any single catastrophe might potentially wipe out an entire crop. -Monocultures also have narrowed the human diet by reducing the diversity of crops we grow -90% of the food consumed now comes from just 15 crop species and 8 livestock species -Mass-market forces: commercial food processors prefer items to be uniform in size and shape for convenience, and because consumers are often wary of what they perceive as unusual-looking food products. -Preserving the integrity of diverse native crop variants gives us a bulwark against the potential failure of our homogenized commercial crops.

pests evolve resistance to pesticides

-natural selection: organisms within populations vary in their traits. -Because most insects, weeds, and microbes can occur in huge numbers, it is likely that a small fraction of individuals may by chance already have genes that enable them to metabolize and detoxify a given pesticide. -These individuals will survive exposure to the pesticide, whereas individuals without these genes will not. -If an insect that is genetically resistant to an insecticide survives and mates with other resistant individuals, the genes for insecticide resistance will be passed on to their offspring. -As resistant individuals become more prevalent in the pest population, insecticide applications will cease to be effective and the population will grow.

kwashiorkor

-people who eat a diet high in starch but deficient in protein or essential amino acids can develop kwashiorkor. -Children who have recently stopped breast-feeding are most at risk for developing kwashiorkor, which causes bloating of the abdomen, deterioration and discoloration of hair, mental disability, immune suppression, developmental delays, anemia, and reduced growth.

weed

-plants that compete with crop plants for sun, water, and nutrients.

anemia and other malnutrition deficiency related illnesses

A deficiency of iron in the diet can lead to anemia, which causes fatigue and developmental disabilities; iodine deficiency can cause swelling of the thyroid gland and brain damage; and vitamin A deficiency can lead to blindness.

transgenic organism and transgene

An organism that contains DNA from another species is called a transgenic organism, and a gene transferred between them is called a transgene.

patent (GM crops)

Biotech companies also patent their seeds, meaning that if a farmer's crops are pollinated by a neighbor's GM crops, he may be sued for harvesting and replanting his own seeds.

feedlots

Feedlots, also known as factory farms or concentrated animal feeding operations, are huge pens designed to deliver energy-rich food to animals living at high densities. Today nearly half the world's pork and most of its poultry come from feedlots.

genetic engineering

Genetic engineering refers to any process whereby scientists directly manipulate an organism's genetic material in the laboratory by adding, deleting, or changing segments of DNA. -The goal is to place genes that produce certain proteins and code for certain desirable traits (such as rapid growth, disease resistance, or high nutritional content) into the genomes of organisms lacking those traits.

marasmus

Protein deficiency together with a lack of calories can lead to marasmus, which causes wasting or shriveling among millions of children in the developing world.