Composition of most human foods
Carbohydrates, proteins, lipids
Carbohydrates
sugars and starches - metabolized readily by cellular respiration
cellular respiration
the energy of biological molecules is transferred to ATP, which is used to run normal bodily functions
Proteins
large, complex molecules made of amino acids that perform several critical roles in the body, including building up muscle, and making DNA
Lipids
fats and oils - provide body with high levels of energy, hormones, essential component of cell membranes
Minerals
(ex. iron, iodine, calcium) that are essential for a normally functioning human body - ingested in the form of dissolved salts in food and water
Vitamins
complex biological molecules that living cells require in small quantities - help regulate metabolism and normal functioning of human body
Major food sources for humans
100 plants (mostly just 15 cereals) provide 90% of food humans consume - dependence on so few species makes us vulnerable to food shortages
Animals provide us with protein
Long-term solution to food supply problem
stabilization of the human population
famine
a temporary but severe food shortage caused by drought, war, flood, or another catastrophic event
World grain carryover stocks
the amounts of rice, wheat, corn, and other grains remaining from previous harvests, as estimated at the start of a new harvest
food security
a goal in which all people have access at all times to adequate amounts and kinds of foods needed for healthy, active lives
Reasons for drops in world grain stocks
environmental conditions: high temperatures, falling water tables, droughts
declining investments in agricultural research to improve crops and livestock
increase in amount of meat being eaten with improved lifestyles means more grain used to feed these a
Main cause of malnutrition and under-nutrition
poverty
chronic hunger is more common in rural areas than urban areas
infants, elderly, and children are most susceptible to poverty and chronic hunger
Amartya Sen
Nobel peace prize winner who observed that the leading cause of hunger and famine in the world is the type of government: Democratic governments are more likely to get people fed in hard times than totalitarian regimes.
One solution to food problems is fo
Industrialized Agriculture
(high-input agriculture) Modern agricultural methods, which require a large capital input and less land and labor than traditional methods
Produces high yields, so requires less land
Subsistence Agriculture
Traditional agricultural methods, which are dependent on labor and a large amount of land to produce enough food to feed oneself and one's family
requires a lot of energy, but from humans and animals rather than fossil fuels
Shifting cultivation
a form of subsistence agriculture in which short periods of cultivation are followed by longer periods of fallow in which the land reverts to forest
Slash-and-burn agriculture
one of several distinct types of shift agriculture in which small patches of tropical forest are cleared to plant crops
Nomadic herding
livestock is supported by land too arid for successful crop growth, so herders must continually move livestock to find adequate food for them
Intercropping
form of subsistence agriculture that involves growing several different crops on the same field - some crops grow more plentifully together than as monocultures
Polyculture
a type of intercropping in which several kinds of plants that mature at different times are planted together
Genetic diversity
variation in genes that contribute to a species' long-term survival by providing tools of adaption in changing environments
Domestication
The process of taming wild animals or adapting wild plants to serve humans; domestication markedly alters the characteristics of the domesticated organism
By restricting production to a few strains of the domesticated organism, the crop or animals becomes
germplasm
any plant or animal material that may be used in breeding - being collected by many countries to preserve older, more diverse forms of plants
International Treaty on Plant Genetic Resources for Food and Agriculture
limits the genetic materials that agricultural companies are allowed to patent and affirms the rights of farmers to save, use, exchange, and sell farm-saved seeds.
Increasing crop yields
greater knowledge of plant nutrition has led to fertilizers that promote plant growth, as well as pesticides to control weeds and insects
Breeders have created better varieties of plants that have higher yields
The Green Revolution
in the mid-20th century people noticed what a problem food shortages were, and recognized that more food was needed for growing populations
The Green revolution is known as using modern cultivation methods and the high-yielding varieties of certain stable
Increasing livestock yields
through use of hormones and antibiotics, animal production increases
Hormones
usually administered by ear implants, regulate animals' bodily functions and promote faster growth
Antibiotics
addition of low doses to feed for chickens, pigs, and cattle increase growth
evolution leads to development of increasing resistance to antibiotics
Genetic Engineering
The manipulation of genes, for example, by taking a specific gene from a cell on one species and placing it into a cell of an unrelated species, where it is expressed
Differs from traditional breeding methods in that desirable genes from any organism can
The safety of genetic engineering
a lot of evidence says that GM crops are safe for human consumption - more research is required
The Cartagena Protocol on Biosafety
provides appropriate procedures in the handling and use of GM organisms
Controversy over GM food
should it be labeled?
legitimate scientific concern
can it harm natural ecosystems?
Problems with Industrialized agriculture
Harm of ecosystems which causes them to not be able to provide ecosystem services
Use of fossil fuels increases air pollution
Replaces traditional family businesses
Resistance to pesticides are increasing in weeds, insects
Land degradation
Water over-cons
Land degradation
The natural or human-caused process that decreases the future ability of the land to support crops or livestock
Habitat Fragmentation
The breakup of large areas of habitat into small, isolated patches
Sustainable Agriculture
Agricultural Methods that maintain soil productivity and a healthy ecological balance while having minimal long-term effects
No pesticides, crop rotation, conservation tillage (maintains soil quality), organic fertilizers
integrated pest management
IPM - incorporate a limited use of pesticides with such practices as crop rotation, monitoring for pest problems, use of disease-resistant varieties, and biological pest controls
Organic Agriculture
The use of no inorganic fertilizers or pesticides
Agro-ecosystem
The agricultural ecosystem
Second Green Revolution
The trend from intensive techniques that produce high yields to methods that focus on long-term sustainability of the soil
Problems in the Fish Industry
No nation has legal claim to the ocean, so they are more prone to overuse as less regulation
Most serious problem is the over-harvesting of organisms (large predatory fish have declined by 90% since 1950s)
Sophisticated fishing methods locate multitudes o
longlines
fishing lines with thousands of baited hooks
Purse-seine nets
huge nets set out by small powerboats to encircle large schools of tuna and other fishes
Trawl net
a weighted, funnel-shaped net pulled along the bottom of the ocean to trap bottom-feeding fish and shrimp - destroy the ocean floor habitat
Drift Nets
plastic nets that entangle thousands of fishes and other marine organisms - many countries have banned them, but they are still used illegally
Undernourished
people who receive fewer calories than needed
Malnourished
people who are not receiving enough of a specific, essential nutrient such as protein or Vitamin A
Marasmus
common early in child's life
caused by malnutrition
progressive emaciation - slow growth, wasting of muscles
Kwashiorkor
malnutrition resulting from protein deficiency
Over-nourished
people who eat food in excess of what is required
bycatch
The fishes, marine mammals, sea turtles, seabirds, and other animals caught unintentionally in commercial fishing catch - dumped back into the ocean, but most soon die after this ordeal
Magnuson-Stevens Fishery Conservation and Management Act
required the regional councils and the National Marine Fisheries Service to protect essential fish habitat for more than 600 fish species, reduce overfishing, rebuild populations of overfished species, and minimize bycatch
Aquaculture
The growing of aquatic organisms for human consumption
Farmers control the diets, breeding cycles, and environmental conditions of their ponds or enclosures
Practiced inland, in estuaries, and in the ocean
Domestication of aquatic animals proves difficult