Environmental science chapters 6 & 7

A modern example of biological control is the use of the Bacillus thuringiensis (Bt) soil bacterium, which produces a protein that kills many caterpillars and some fly and beetle larvae.

- Bt spores can be sprayed directly on plants. - The gene responsible for producing the protein has been genetically engineered into crop plants, allowing them to produce the poison

There are many economic and societal factors that affect fertility in a nation.

-Access to contraceptives -Acceptance of contraceptive use -Level of women's rights -Cultural influences, such as television programs -Level of affluence -Importance of child labor -Availability of governmental support for retirees

Wealth can produce even more severe environmental impacts than poverty

-Affluence is built on unsustainable levels of resource consumption. -The addition of 1 person from a wealthy country like the U.S. has the same impact as 3.4 Chinese, 8 Indians, or 14 Afghans.

Beginning in 1940, the Green Revolution introduced new technology, crop varieties, and farming practices to the developing world.

-Began with Norman Borlaug, a Nobel Prize-winning scientist who introduced new strains of wheat to Mexico, India, and Pakistan

Infant mortality rates are closely tied to a nation's level of industrialization.

-China, for example, saw its infant mortality rate drop from 47 children per 1000 live births in 1980 to 16 children per 1000 live births in 2013.

Weathering and the accumulation of organic matter are influenced by: Soil is renewable, but at a very slow rate

-Climate: Warm, moist climates accelerate most weathering processes. -Organisms: Plants and decomposers add organic material. -Topography: Hills and valleys affect exposure to sun, wind, and water, and influence soil movement. -Parent material: Its composition influences soil formation. -Time: Soil formation can take centuries, decades, or millennia.

Intercropping involves planting alternating bands of different crops.

-Cover crops can be used to reduce wind erosion, and legumes can be used to restore nitrogen.

Water has the most erosive power when it moves downhill, so farmers may use contour plowing and plow sideways across a hillside.

-Each furrow runs perpendicular to the hill's slope, serving as a small dam that stops water flow.

Individuals with the gene will survive and reproduce at greater rates, creating a new generation with a much higher rate of carrying the gene.

-Eventually the pesticide becomes ineffective and must be replaced by a new one. This is called the "pesticide treadmill."

Overnutrition, receiving too many calories per day, has grown in developing countries due to the abundance of cheap junk food and sedentary lifestyles.

-Excess weight leads to heart disease, diabetes, stroke, some forms of cancer, and other health issues.

The number of people suffering from food insecurity has decreased since the 1960s.

-Food security is the guarantee of an adequate, safe, nutritious, and reliable food supply.

The doubling time of a country's population can be estimated by taking the number 70 and dividing it by the annual percentage growth rate.

-Global doubling time is 70 / 1.2%, or 58 years. -China's doubling time prior to the one-child policy was 70 / 2.8%, or about 25 years. It is now about 140 years.

Pollination is the process by which male plant sex cells (pollen) fertilize female plant sex cells (ova, or egg cells).

-Grasses and conifer trees are pollinated by wind. -Plants with bright flowers attract animals (pollinators), which transfer pollen as they move from flower to flower.

Parent material is the base geologic material in a particular location. This may include:

-Hardened lava or volcanic ash. -Sediment deposited by glaciers or flowing water. -Wind-blown dunes. -Bedrock, the mass of solid rock that makes up most of the Earth's crust.

Industrial agriculture introduced large-scale mechanization and fossil fuel consumption into agriculture

-Higher rates of irrigation, synthetic fertilizers, and chemical pesticides -Greater prevalence of monocultures, where farmers grow vast areas of single crops in orderly rows

IPAT model represents how our total impact (I) on the environment results from the interaction of population (P), affluence (A), and technology (T). I = P × A × T

-Increased population means more individuals take up space, use resources, and generate waste. -Affluence leads to greater per capita resource consumption. -Technology can increase impact by enhancing our ability to exploit resources or decrease impact by improving efficiency.

The artificial provision of water beyond what is received by precipitation is irrigation.

-Irrigation is necessary with water-intensive crops (like rice) and in areas with dry climates. -Irrigation is the largest use of water by humans, making up 70% of all fresh water withdrawn.

Some developing countries are so overpopulated that they may not be able to complete a transition, creating demographic fatigue.

-Many sub-Saharan African countries, given their high populations and prevalence of HIV/AIDS, are in this position. •The demographic transition has occurred in many European countries, Canada, the U.S., Japan, and other countries.

traditional agriculture, the work of cultivating, harvesting, and distributing crops was performed by human and animal muscle power.

-Most farmers planted polycultures, mixtures of different crops in small plots of land.

Industrialization, improved women's rights, and health care have decreased TFR in many nations in recent years.

-Nearly every European nation has a TFR below (2.1) replacement level. -Europe's rate of natural increase, which only includes birth and death rates, was between 0% and 0.1% in 2015.

The industrialization of agriculture has boosted worldwide production of food and fiber immensely, but has also brought increased pollution and resource depletion.

-Organic farming decreases efficiency, but also has far fewer environmental impacts.

Malnutrition is a shortage of specific nutrients, such as lipids, proteins, vitamins, or minerals.

-People with protein-deficient diets can develop kwashiorkor, which causes bloating of the abdomen, deterioration of hair, mental disability, and other issues. -Protein deficiency and a loss of calories can lead to marasmus. -A deficiency of iron leads to anemia.

Feedlots can also produce more intensive pollution due to the release of highly concentrated waste

-Pollution is rich in nitrogen and phosphorous, so it contributes to eutrophication. -Feedlot waste contains bacterial and viral pathogens. -Hormones, antibiotics, and other drugs administered to animals may also be excreted.

Sustainable agriculture must meet the triple bottom line of social, economic, and environmental dimensions

-Provide food security -Be profitable to famers and ranchers -Conserve resources for future agriculture

Soil degradation is the deterioration in quality and productivity of soil. Causes include:

-Soil erosion -Nutrient depletion -Water scarcity -Salinization -Waterlogging -Chemical pollution -Changes in soil structure and pH -Loss of organic matter from soil

Soil is a system consisting of disintegrated rock, organic matter, water, gases, nutrients, and microorganisms.

-Soil is derived from rock, but shaped by microorganisms. -50% mineral matter, 5% organic matter, and 45% pore space.

One approach to sustainable agriculture is organic agriculture, which involves food-growing practices that do not include synthetic pesticides, fertilizers, hormones, or antibiotics.

-The Organic Food Production Act of 1990 established national standards by which foods can be labeled as organic.

China is not the only country with population issues; India lacks similar stringent policies and will soon become the most populous country.

-The current world population is over 7.4 billion, with most of the growth occurring in poorer nations.

The soils of the Amazon rainforest are much less agriculturally productive than those in Iowa or Kansas.

-The higher amount of precipitation quickly leaches nutrients out of the topsoil and E horizon.

The cultural gender preference for male children, coupled with the one-child policy, has resulted in roughly 116 Chinese boys born for every 100 girls.

-The leading hypothesis is that many parents are using ultrasounds to determine the gender of their unborn fetus, and then selectively aborting females.

Since the Green Revolution, farmers have increasingly relied on nutrients from inorganic fertilizers

-These nutrients are more quickly leached, creating other environmental problems.

In recent decades, falling growth rates in many countries has led to an overall decline in the global growth rate.

-This is primarily due to a steep drop in birth rates. •Immigration and emigration also significantly impact the population of individual nations.

Most of the next billion people added to the human population will come from developing countries, meaning that:

-Those countries will continue to be economically strained. -Environmental degradation will continue due to poverty.

In the late 19th and early 20th centuries, farmers moving into the Western Plains of the United States began plowing up native grassland plants in favor of wheat.

A severe drought in the 1930s worsened the impacts, causing the region's strong winds to erode millions of tons of topsoil.

A pest is any organism that damages crops or livestock

A weed is any plant that competes with crops

Sustainable agriculture maintains healthy soil, clean water, pollinators, and other vital resources. -The overall approach is to mimic the way natural ecosystems function. -Low-input agriculture is an approach that uses less amounts of fossil fuels, water, pesticides, fertilizers, growth hormones, and antibiotics than are used in industrial agriculture.

Achieving sustainable agriculture requires an understanding of the soil, water, nutrients, and pollinators that underpin agriculture.

Agriculture provides our most basic daily needs - from the cotton in our clothes to the food on our plates.

Agriculture is also responsible for some of our biggest impacts on the environment, making the development of sustainable practices essential.

Crop rotation is the process of farmers alternating the type of crop grown from one season to the next.

Alternating with legumes can boost soil nitrogen, and crop rotation also breaks pest and disease cycles seen with continuous planting.

Based on these difference in energy conversion efficiencies, a footprint of land area, water weight, and CO2 equilvants has been calculated for producing 1 kg of edible protein for each animal.

Animal agriculture accounts for 14.5% of our greenhouse gas emissions—more than driving.

A big part of the public debate is that every person relies on food for survival and genetic modification of rice, corn, soy, and wheat essentially forces people to consume biotech products.

Another concern is that a few large companies such as Monsanto, Bayer, Dow, DuPont, and BASF control GM technology. -These companies 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.

Due to plummeting wild fish populations and increasing demand for seafood, aquaculture, the cultivation of aquatic organisms in controlled environments, may be the answer.

Aquaculture increases food supplies and protein sources, increasing overall food security. -Also helps to reduce overfishing of wild fish and the unintended catch of other organisms called bycatch. Negative consequences include antibiotic overuse, degradation of coastal ecosystems, and spreading disease or invasive species into nearby ecosystems

The average food product sold in a U.S. supermarket travels at least 1600 km (1000 mi) from the farm.

At farmers' markets, consumers buy meats and produce from local producers

An organism that contains DNA from another species is called a transgenic organism. -The genes that move between them are called transgenes.

Biotechnology creates products derived from organisms.

Death rates decline during the transitional stage, due to improved food production and health care.

Birth rates remain high as society has not yet adjusted to the new economic conditions. -Overall population growth rate is very high.

Our population growth is largely due to technological, agricultural, and sanitation advances that reduced death rates. Can this growth continue?

British economist Thomas Malthus argued that the number of people would eventually outgrow the available food supply. -Paul and Anne Ehrlich of Stanford University made similar warnings in their 1968 book, The PopulationBomb.

Farm to Table and Back Again - at Kennesaw State University

Campus dining services, such as at Kennesaw State University, are becoming leaders with "closed-loop" culinary sustainability programs. -KSU runs three farms, producing much of the produce consumed by the students. -Uneaten food waste is composted and returned to the soil as fertilizer.

Organic fertilizers are made of the remains or wastes from organisms, including manure, crop residue, charcoal, fresh vegetation, and compost.

Compost is a mixture produced when decomposers break down organic matter in a controlled environment

Birth control includes all efforts to reduce the frequency of pregnancy.

Contraception is a deliberate attempt to prevent pregnancy despite engaging in sexual intercourse. -Many family-planning organizations provide free or discounted condoms, spermicides, hormonal treatments, or surgical sterilization. -Rates of use range from 84% in China and the U.K. to less than 10% in some African nations.

Industrialized countries tend to have the highest life expectancy increases due to a drop in infant mortality; life expectancy is the average number of years a person in an age group is expected to live.

Countries still industrializing will pass through a series of stages of economic and cultural change called the demographic transition.

Food production has intensified as a result of the "Green Revolution."

Despite these improvements, population growth still depletes resources, stresses social systems, and degrades the natural environment.

Much of the world's population lives in drylands, arid and semi-arid environments that cover about 40% of the Earth's land surface

Drylands are prone to desertification, a land degradation where more than 10% of productivity is lost. - Wind and water erosion are the biggest causes.

Every time that one organism consumes another, only about 10% of the energy moves to the next trophic level. -Feeding grain to a cow and eating beef from the cow result in loss of most of the grain's energy to the cow's metabolism.

Eating lower on the food chain (a more vegetarian diet) is more energy-efficient and reduces our ecological footprint

Poorer societies tend to have higher population rates than wealthier ones.

Economic factors are tied closely to population growth. -Poverty exacerbates population growth. -Rapid population growth worsens poverty.

In order to reduce fertility rates, women must be given equality in decision-making power and access to education and job opportunities

Equal rights also lead to women having the ability to make reproductive decisions themselves, leading to further drops in fertility rates and overall better care for children.

Erosion is the removal of material from one place and its transport to another by wind or water. -When eroded material is left at a new location, it is called deposition.

Erosion and deposition are natural processes, but are occurring at accelerated rates due to agriculture. - This removes topsoil at faster rates, quickly depleting soil of nutrients and organic matter.

Access to family planning gives women control over their reproductive window, the time at which they can become pregnant

Family planning is a key approach for controlling population growth

Feedlots are huge pens designed to provide high-energy feed to animals living in high densities. -These are also known as factory farms or confined animal feeding operations (CAFOs).

Feedlots have the benefit of being more economically efficient and reducing grazing impacts by the animals

comparing Age structure diagrams

For example, Nigeria's large concentration of individuals in young age groups predicts a much greater population growth rate than Canada.

Genetic engineering refers to any process where scientists directly manipulate an organism's genetic material (DNA).

Genetically modified (GM) organisms (GMOs) contain recombinant DNA, meaning it has been produced from multiple organisms.

•Births and immigration add individuals to a population. •Death and emigration remove individuals from a population.

Global decreases in infant mortality rates, the frequency of children dying in infancy, have played a large role in population growth. -Historically, families would have many children as "insurance" against the likelihood of one or more of them dying in infancy due to poor nutrition, disease, and exposure.

The amount of biologically productive land available to us is called biocapacity.

If humanity's ecological footprint exceeds biocapacity, it is termed overshoot, which leads to an ecological deficit. -If the footprint is less than biocapacity, there is an ecological reserve.

Fertilizers are substances that contain essential nutrients for plant growth

Inorganic fertilizers are mined or synthetically manufactured

The current population size is about 7.3 billion, spread among 200 nations. -The United Nations predicts that by 2050, the global population will surpass 9.7 billion.

Many other demographic aspects determine environmental impact besides size.

As global wealth and commerce have increased, so have the production and consumption of meat, milk, eggs, and other animal products.

Meat production has grown more than fivefold since 1950, and per capita meat consumption has doubled

Despite improved food production, 800 million people suffer from undernutrition, receiving fewer calories than the minimum dietary requirement

Most people who are undernourished live in developing countries, although 49 million people are classified as "food insecure."

Chemical pesticides tend to become less effective over time as pests evolve resistance to them.

Most pests occur in huge numbers, so it is likely that a few have genes that detoxify or metabolize a given pesticide

Conservation tillage reduces the amount of plowing, since it leaves soil surfaces bare and exposed to wind.

No-till farming eliminates tilling altogether. -Farmers leave crop residues behind, keeping the soil covered with plant material year-round. •Temporary cover crops can be planted during times when the main crop is not growing.

People make land more vulnerable to erosion in three ways: -Overcultivating fields through poor planning or excessive tilling (plowing). -Grazing rangeland with more livestock than it can support. -Clearing forests on steep slopes.

One study determined that U.S. croplands lose about 2.5 cm (1 in.) of topsoil every 15-30 years.

Precision agriculture involves monitoring soil nutrient levels and only applying specific types of fertilizer when needed.

Organic fertilizer use is embraced, because it provides additional benefits, such as improving soil structure, nutrient retention, and water-retaining capac

If livestock populations do not exceed the carrying capacity, rangelands can still be functional ecosystems. -Without adequate regeneration of plant biomass, the result is overgrazing.

Overgrazing exposes soil and makes it vulnerable to erosion. -In a positive feedback loop, soil erosion makes it more difficult for native plants to grow, perpetuating the problem.

The most obvious alternative to chemical pesticides is biological control or biocontrol, where natural predators or parasites are introduced to eliminate the pest.

Parasitoid wasps, for example, are natural enemies of many caterpillars

During the pre-industrial stage, death rates are high due to widespread disease, rudimentary health care, and unreliable food supplies.

People compensate for high infant mortality by having many children. Birth control is not available. -Population growth, overall, is stable.

Pesticides include synthetic chemicals that kill insects (insecticides), plants (herbicides), and fungi (fungicides). -Nearly 400 million kg of ingredients from pesticides are applied in the United States each year.

Pesticides also kill nontarget organisms, including predators and parasites of pests and pollinators.

One effective way to reduce water use is to better match crops and climate. - Government subsidies in some arid areas have made water artificially inexpensive

Plants only use about 40% of the water applied by irrigation on average. - Switching to drip irrigation can also reduce water use

•Tropical farmers may practice swidden agriculture, where they cultivate a plot for a few years and then move on to another. -If enough time is allowed, the soil and forest can recover.

Plots are often burned first, a practice called slash-and-burn agriculture.

During the industrial stage, employment opportunities increase for women and birth control becomes more widely available, decreasing birth rates.

Population growth slows and begins to stabilize

demography

Principles of population ecology can be applied to the study of statistical changes in the human population

Most biotech crops so far have been engineered for insect resistance and herbicide tolerance, primarily benefiting large-scale industrial farmers and not poor rural ones

Proponents of GM crops argue they can: -Enhance food security and reduce poverty. -Alleviate pressure to clear forests and grasslands. -Conserve water by reducing the need for irrigation. -Improve nutrition with crops that contain key nutrients (such as golden rice and vitamin A). -Reduce pesticide use.

•Total fertility rate (TFR) is the average number of children born per woman during her lifetime.

Replacement fertility is the TFR that keeps the size of a population stable. For humans, this is 2.1.

Colony collapse disorder is a phenomenon where a majority of worker bees in a hive disappear, endangering the queen and developing larvae.

Restoring bee populations will require establishing more wildflowers and flowering shrubs near farm fields and highways and decreasing the use of chemical insecticides

Waterlogging occurs when irrigation oversaturates the soil to the point where water drowns plant roots, depriving them of gases.

Salinization is the buildup of salts in surface soil layers as a result of irrigation.

Ecologically, scientists are concerned that GMOs will interbreed with their wild relatives, transferring new genes into the wild population

Some feel we should adopt the precautionary principle and not proceed further until the effects of GM crops are fully understood.

Many nations spend billions in subsidies to promote unsustainable practices, such as growing water-thirsty crops in desert regions. -In the United States, one-fifth of an average farmer's income comes from subsidies.

Subsidies help to stabilize and secure the income of farmers, but they also lead to land being cultivated that otherwise would not be. -This artificially increases food production, lowering prices for other farmers.

The O horizon contains organic matter deposited by organisms

The A horizon is topsoil, a mixture of inorganic mineral components with humus mixed in from above. -Topsoil is the most nutritive part of soil for plants and is vital for agriculture.

the E horizon tends to be the most heavily leached, losing minerals and organic matter.

The B horizon contains the minerals leached from above.

Every 5-6 years, the U.S. Congress passes legislation called the Farm Bill that guides agricultural policy.

The Conservation Reserve Program, first established in the 1985 Farm Bill, pays farmers to convert damaged cropland to conservation reserves.

Farm to Table and Back Again - at Kennesaw State University

The KSU dining commons was designed with sustainability in mind. -Floor-to-ceiling windows provide daytime lighting. -Food is prepared to order or in small batches, minimizing waste. -Dishwashing systems have high water and energy efficiency. -Water bottle refilling stations reduce plastic waste. -Recycling and composting programs divert over 44,000 pounds of waste per month from the landfill. -Biodiesel is generated from used cooking oil.

The population growth stabilizes or begins to shrink during the post-industrial stage.

The United States is in this stage, although it has higher birth rates due to an increased immigration rate

Soybeans account for more than half of the GM crops grown worldwide

The United States, Brazil, Argentina, India, and Canada accounted for 90% of production in 2017

In response, the U.S. government passed the Soil Conservation Act of 1935, which established an agency that worked with farmers to combat erosion

The agency today is known as the Natural Resources Conservation Service and employs trained experts called extension agents to assist farmers

Biocontrol organisms have, in some cases, become invasive and harmed nontarget organisms

The cactus moth, a natural predator employed in Australia to fight prickly pear cactus, was also used in Caribbean countries, but has spread into the United States and is now consuming native cacti

Farm to Table and Back Again - at Kennesaw State University

The farms are also designed to maximize sustainability. -Chemical pesticide and synthetic fertilizer use is minimized. -Hydroponic stations supplied by rainwater produce herbs, lettuce, and shiitake mushrooms. -Off-campus food sources are kept local whenever possible. •This and other university operations help to serve as models for nationwide agriculture reforms that could change how food is produced and delivered.

Shelterbelts are rows of trees or shrubs that serve as windbreaks

The trees can also provide habitats and fruit

•The global population is older than in past years. -The median age today is 28; in 2050, it is predicted to be 35.

This creates strain in social welfare programs in some countries, as fewer young workers are supporting more elderly.

Integrated pest management (IPM) combines biocontrol, chemical pesticides, habitat alteration, crop rotation, transgenic crops, alternative tillage methods, and mechanical pest removal.

This has been highly effective in Indonesia, which increased rice production while cutting pesticide subsidies and overall pesticide use

The naturally occurring sex ratio at birth for human populations is 106 males born per every 100 females born.

This is likely an evolutionary adaptation to the increased mortality rate faced by males at all ages. •In China, age distributions have become increasingly skewed.

Age structure diagrams, also called population pyramids, describe the relative numbers of individuals at each age class within a population.

This is valuable in predicting the future growth of a population.

Some areas in the most affected regions of the Dust Bowl lost 10 cm (4 in.) of topsoil in just a few years

Thousands of farmers in this area were forced off their land

Family planning

is the effort to plan the number and spacing of one's children.

Demographers

study several characteristics of the human population: -Size -Distribution -Age structure -Sex ratio -Rates of birth, death, emigration, and immigration

The C horizon is partially weathered parent material

the R horizon is bedrock; parent material.

Demography is the study of the human population

•A pyramid with a wide base denotes a large proportion of pre-reproductive age people and the potential for rapid future growth. •A pyramid with an even age distribution indicates a stable population. •A pyramid with a higher proportion of post-reproductive age adults indicates a shrinking population.

About 80% of Americans buy organic food at least occasionally, and most retail groceries offer it.

•Both production and demand for organic foods have grown, with some governments offering financial incentives to convert to organic agriculture.

•Parent material is broken down into smaller particles by weathering. -Physical weathering results from wind, rain, freezing, and thawing. -Chemical weathering occurs as water or gases chemically alter rock. -Biological weathering involves living things, such as lichens producing acid or tree roots rubbing against rock.

•Further biological activity deposits organic matter in the form of decomposed organisms or waste. -Partially decomposed organic matter is called humus and is very productive for plant life.

•The movement and sorting of soil particles creates distinct layers called soil horizons. -The entire cross-section of soil is the soil profile.

•Generally, the degree of weathering and concentration of organic matter decrease as one moves downward in a soil profile. Minerals dissolved or suspended in water can be transported downward in a process called leaching

Agriculture is the practice of raising crops and livestock for human use and consumption. -Most of our food and fiber is obtained from cropland, land used to raise crops for human use. -Rangeland, or pasture, is land used for grazing livestock.

•Growing crops and raising animals require inputs of resources - soil, sunlight, water, nutrients, and pollinators. •Today, more than 1 out of every 3 acres of land on Earth is used to produce food and fiber.

Case Study: Will China's New "Two-Child Policy" Defuse Its Population "Time Bomb"?

•In 1970, China instituted a population control program that restricted most couples to a single child. •Efforts included increased accessibility to contraceptives and abortion, rewards for single-child families, and fines and social scorn for those with more children. -Fertility rates dropped from 5.8 to 1.6 children per woman. The growth rate dropped from 2.8% to 0.5%.

The human population continues to grow

•The human population is currently growing at a rate of 88 million per year; that is 2.8 people added every second. -The human population did not reach 1 billion until after 1800. -A billion people are currently being added about every 12 years.

Case Study: Will China's New "Two-Child Policy" Defuse Their Population "Time Bomb"?

•The one-child policy created problems - the population's labor force shrank, the percentage of elderly increased, and there were too few women. -The decrease in young workers has made it difficult for employers and may affect the economy. -The culturally increased value of male children combined with the one-child policy led to selective abortion and the killing of female children. -The male-to-female ratio is unbalanced, creating large numbers of young men who cannot marry.

Case Study: Will China's New "Two-Child Policy" Defuse Their Population "Time Bomb"?

•The population "time bomb" of an aging population with skewed male-to-female ratios has led to a change in Chinese policies. -In 2013, if either member of a married couple was an only child, then the couple was granted permission to have two children. -In 2015, the one-child policy was immediately altered to a two-child policy. •It is unclear how many Chinese couples, who are now used to greater wealth and an urban lifestyle, will decide to grow their families.