Environmental Science Test 2

Human population Growth

populations have rised in most countries

-worldwide population growth =1.2%

-The rate of population growth is slowing, but the population is still increasing in number.

- Global populations grow by over 80 million each year.

-exponential growth by a fixed % accelerates increasing populations.

-UN predicts 9.8 million for us by 2050

- medicine has made mortality lower in both infants and humas.

Replacement fertility

TFR that maintains a stable population

Doubling time

70 divided by growth rate= years

Migration

the movement of humans among

total fertility rate

average number of children born per women during her lifetime

Explain how human pop., affluence, and tech affect the environment

-Affluent societies have enormous resource consumption and waste production

-The richest 1/5 use 85% of the world’s resources.

-more people=more resources=more waste/ consumption/space

-more tech=lower mortality=more people

Demography:

The application of population ecology to the study of change in human population

Describe the concept of demographic transition

-        A stable pre-industrial state of high birth and death rates changes to a stable post industrial state of low birth and death rates

-        1. Pre-industrial most of human history /Both b &d high Stable

-        2. Transitional Stage: D decreases due to increased food and medical care. B increase due to do used to new condition/ Big acceleration of pop size

-        3. Industrial Stage:b rates start to drop women work children less valuable more expensive

-        4. Post industrial: B & d low & stable

Family planning

effort to plan the # and spacing of one’s children

Birth control

controlling the number of children born

Contraception

deliberate prevention of pregnancy through a variety of methods

Status of women and affluence in pop growth

Fertility rates drop when women: gain access to contraceptives, family planning programs, and education.

Increasing affluence lowers fertility

Poorer status has higher population growth rates.

What do population pyramids reveal about human population growth?

-Population pyramids help us predict future population growth or population number. If there are a lot of old people compared to young people, population will drop. If there are a lot of young people compared to old it will grow significantly. If the pyramid is balanced, the population will be stable.

sex ratio

ratio of males in females: 106 males for every 100 females. China= 116 to 100

Describe the global trends and reasons for urban population growth

Urbanization: the movement of people from rural to urban areas.

-Ag surpluses allowed people to leave their farms.

-Industrial Revolution created jobs/opportunities in cities based on new technology.

-Since 2009, more people are living in urban areas than in rural areas.

- Developing nations are urbanizing rapidly: rural decreasing while urban increasing.

-Suburbs: mid-20^th century very appealing with more space, less crime, better schools.

Define sprawl and discuss its causes and consequences

-Sprawl: spread of low-density development outward from an urban center

-Causes: more room, desires,

-Consequences: ugly, environmentally harmful and inefficient

-Transportation: people are forced to drive more cars. (more traffic accidents and fossil fuels burned)

-Pollution: carbon dioxide, ozone, smog, acid rain, from autoreliance

-Health: promotes physical inactivity because driving replaces walking. Increased obesity and higher blood pressure,

-land use: less forests, fields, farmland, ranchland

-Economics: can drain tax dollars from existing communities.

Evaluate transportation options, urban parks, and green buildings

-Smart growth: city planning tat limits sprawl and maintains/ improves resident life.

-building up, energy efficient buildings, transportation options, parks provide air purifying and recreation and greenery

What is transit-oriented development?

-Compact communities arrayed around stops on transit lines

What are green buildings (LEED certified)?

-Leadership in Energy and Environmental Design= leading sets of standards for certification as a green building.

• Summarize major approaches to managing waste, and compare and contrast the types of waste we generate

Waste: any unwanted material or substance that results from a human activity or process.

-Municipal solid waste: nonliquid waste from homes, institutions, and small businesses.

-Generate 4.4 pounds of trash per day

- electronic waste: 300 million devices per year

-reduce, reuse, recycle

Discuss the nature & scale of the waste dilemma

We are producing more waste than is sustainable for the earth. Trash will cover the earth eventually if we don’t stop. Though the growth of waste has leveled off, still super unsustainable.

Evaluate approaches for reducing waste

-Composting: conversion of organic waste into mulch/humus through decomposition.

-Recycling: collecting materials that can be broken down and reprocessed to manufacture new items.

-Financial incentives: pay as you throw/ bottle bills = paid for returning bottle

Describe landfills & incineration as conventional waste disposal methods

-Landfills: NIMBY=not in my backyard, end up in poor minority neighborhoods or countries.

-Leachate: liquid from trash dissolved by rainwater.

What are the three steps of recycling?

-collection and processing of recyclable materials by municipalities and businesses.

- Use of recyclable materials by industry to manufacture new products.

-Consumer purchase of products made from recycled materials.

Do you think the ‘pay-as-you-throw’ and bottle bill financial incentives are a good idea?

Yes, money rules the world and money would need to be used for people to stop. Also, I think both tactics are very effective and not really controversial so people would support them.

Learn the factors that underpin agriculture, and outline how ag has developed

Agriculture: The practice of raising crops and livestock for human use and consumption

-38% of Earths land is devoted to ag

-if sustainable, it can promote healthy soils, yield food, clean water, stop erosion, help pollinators, feed livestock.

-Factors include: physical, biological, human and economic factors.

-Developed from traditional, self-sustaining practices to a business.

-Forced: Conservation Reserve Program (1985): farmers are paid to put highly erodible land in conservation reserves

Explain the importance and fundamentals of soil science

-Soil: the complex mixture of organic and inorganic components: made of dead/living organisms, decaying material, nutrients, particle from parent material (rock), habitat for earth worms, insects, etc.

-caused by weathering: Physical 9wind/rain, freeze/thaw; Chemical parent material chemically altered. Biological organisms produce soil

-Soil color= indicates composition and fertility. - Black or dark brown =  rich in organic matter- Pale gray or white = low organic content/leaching

-Soil texture = determined by particle size From smallest to largest: clay, silt, sand

-Soil pH = pH of soil, tells us if it’s acidic or basic.

Describe the importance of water, nutrients, and pollinators, and assess solutions to challenges with each

• -Water: Water is essential for photosynthesis, plant growth, and transporting nutrients within plants.

• It maintains soil moisture and supports livestock health.

• Reliable water supply determines where crops can be grown and how productive they are.

Challenges:

• Drought due to climate change.

• Overuse of rivers and groundwater for irrigation.

• Pollution from fertilizers and waste reduces clean water availability.

Solutions:

• Efficient irrigation systems (e.g., drip irrigation) to reduce water waste.

• Rainwater harvesting and water storage during wet seasons.

• Drought-resistant crop varieties bred through selective breeding or genetic engineering.

• Improved water management policies to prevent over-extraction of rivers and aquifers.

Nutrients

Importance:

• Plants require nutrients (e.g., nitrogen, phosphorus, potassium) to grow, develop roots, and produce seeds.

• Healthy soil rich in organic matter improves crop yields and resilience.

Challenges:

• Soil nutrient depletion from continuous cropping.

• Overuse of chemical fertilizers, causing water pollution (eutrophication) and soil degradation.

• Loss of soil organisms from heavy tillage.

Solutions:

• Crop rotation and cover crops to naturally restore soil nutrients.

• Organic fertilizers (manure, compost) to build soil structure and fertility.

• Precision farming to apply the right amount of fertilizer only where needed.

• Reduced tillage to maintain soil microorganisms and prevent erosion.

Pollinators

Importance:

• Many crops (e.g., fruits, nuts, vegetables) depend on pollinators such as bees, butterflies, birds, and bats for seed and fruit formation.

• About 1/3 of global food production relies on animal pollination.

Challenges:

• Habitat loss from expanding farmland and urban development.

• Pesticides (especially neonicotinoids) harming pollinator health.

• Climate change altering flowering times and pollinator behavior.

• Spread of diseases in honey bee populations.

Solutions:

• Creating pollinator-friendly habitats (wildflower strips, hedgerows, natural field borders).

• Reducing pesticide use, especially during flowering periods.

• Supporting diverse farming systems (e.g., agroforestry, mixed cropping).

• Conservation programs to protect wild pollinator species.

Promoting bee health research and sustainable beekeeping practices.

• Analyze causes/impacts of soil erosion & land degradation, and discuss solutions

-Soil degradation: a decline in quality & productivity.- From deforestation, industrial agriculture, overgrazing, clearing forests on steep slopes, overcultivation fields(ie. Excessive tilling)

-Desertification = fertile lands become desert.  Dust Bowl = 1930s drought + erosion caused “black blizzards” of topsoil

-Erosion: loss of soil by wind or water

-Solutions: crop rotation, contour farming=plowing perpendicular to slope, terracing= slopes of steps, conservation tillage=not till or limited till.

-Irrigation= artificially supplying water for ag.

-Salinization= build-up of salts in soil

-Water logging= too much waterdrowns roots.

Drip irrigation: reduces water waste, reducing salinization.

How does traditional agriculture differ from industrialized agriculture?

Traditional agriculture: biologically powered ag using human and animal muscle power. Hand tools and simple machines. Allowed people to settle in one place. Often more polyculture

Industrial agriculture: using large scale mechanization and fossil fuels to boost yields. Also uses pesticides, irrigation, and fertilizers. Often monoculture

Diff: traditional=sustainable, industrial not so much.

Explain the challenges of feeding a growing human population

-Undernutrition = not obtaining enough daily calories: 1/3 of the global population lives on < $2 per day • 49 million Americans are food insecure

-Overnutrition = receiving too many calories daily: • Developed countries – abundant, cheap junk food + sedentary lives. • 1/3 of Americans are obese. Health concerns? Cardiovascular

ID the pros and cons of the Green Revolution

-Boosted yields, made farming easier/ more efficient. Cured a lot from starvation. Movement to introduce new technology, crop varieties, and farming practices to the developing world in the 1940s - Wheat, rice, corn

-Con: relies on synthetic fertilizers, peticides, machinery, irrigation. Monoculture decreased biodiversity.

Discuss how we raise animals for food, and assess the impacts of meat consumption

eating meat is less energy efficient than eating crops. 90% of energy is lost when we move from one trophic level to next. Eating lower on the level means more food for all.

-some animals also convert gain to meat more efficiently.

-Feedlots (factory farms) = Concentrated Animal Feeding Operations (CAFOs) • Huge warehouses or pens deliver food to animals living at extremely high densities, dosed liberally with antibiotics to control disease

-Aquaculture: raising aquatic organisms for food in a controlled environment.

-Livestock ag can pollute the water & air • Manure and urine causes eutrophication and waterborne pathogens sicken people. • Antibiotic use contributes to resistance • Contributes 14.5% of the emissions driving climate change (more than automobiles!

Pro:more efficient

less parasites

less stress

controlled water quality

quicker transportation to restaurant/destination

less pressure on wild organisms/endangered species

less global ocean pollution

reliable protein source

Con: inhumane

unnatural feed/uses grain

overproduction/waste

fecal waste

uses antibiotics to stop disease spread

Describe the science of genetic engineering

- Genetic Engineering = scientists directly manipulate an organism’s genetic material in the lab by adding, deleting, or changing DNA.

 • Example –Roundup Ready soybeans have a bacterial gene that makes them insensitive to the pesticide in Roundup.

No registered health risks, crop weed hybridization worry, no labeling laws on GMO

Analyze the nature, growth, & potential of organic ag

-Organic Ag: Food-growing practices that use no synthetic fertilizers, insecticides, fungicides, or herbicides. Its booming.

sustainable agriculture = doesn’t deplete soil, pollute water, and reduces fossil fuel inputs. Can be practiced in the same way, in the same place, far into the future.

 Farmers’markets = provide fresh, locally grown food

 • Community-supported agriculture (CSA) - Consumers pay farmers in advance- Consumers get fresh food- Farmers get a guaranteed inco

Explain the goals of environmental health & ID major enviro health hazards

-Plastics contain numerous synthetic molecules that can be released when they break down. • Ex. BPA and Phthalates (hormone mimics) Over 90% of Americans have detectable BPA and phthalates in their urine.

-Environmental health = assesses enviro factors that influence human health & quality of life

Types of hazards

Physical: occurs naturally in environment. Ex. UV radiation from sun

Chemical: synthetic and natural chemicals hazardous to health

Biological: results from interactions among organisms. Ex. COVID infection

Cultural: results from where we live, socioeconomic status, occupation, and behavioral choices. Ex. housing, food selection/diet, fireworks,

Describe the prevalence of toxins in our environment

-Toxicology = examines the effects of poisonous substances on humans and other organisms

-Toxicant = any toxic substances (poison).  'The dose makes the poison'

Phalates and BPAs, Radon: a highly toxic, radioactive gas that is

colorless and undetectable without special kits, Asbestos = a mineral that insulates, muffles sounds, and resists fire:scars lung tissue and lungs can stop functioning, Lead poisoning = caused by lead, a heavy metal: Damages brain, liver, kidneys, stomach,. Causes learning and behaviour problems and can lead to death, Polybrominated diphenyl ethers (PBDEs) = has fire retardant properties: mimics hormones and affects thyroid hormones: may cause cancer, synthetic industrial chemicals everywhere.

Explain the movements of toxic substances & how they affect organisms and Ecosystems

-Toxicants in the body can be excreted, degraded, or stored

-Biomagnification: concentrations of toxicants become magnified as they move up the food chain Ex. DDT and Raptors

• Compare the philosophical approaches to risk and how they relate to policy

-Risk = the probability (likelihood) that some harmful outcome will result from a given action, event, or substance

Risk management = decisions and strategies to minimize risk • Comparing costs and benefits is hard

Benefits are economic and easy to calculate. Health risks (costs) are hard to measure probabilities of a few people suffering and lots of people not.

Innocent-until-proven-guilty approach: assumes a substance is harmless. Pros/cons :cheaper to get material out /could be posioning people

Precautionary principle: assumes a substance is harmful until it shown to be harmless. Pros/cons?

Expensive, takes a long time/ saving health