BIOL 1 -- Mr. Sage -- Lesson One -- Barstow Community College

HUMANS AND SUSTAINABILITY: AN OVERVIEW

Chapter 1

Environmental Problems, Their Causes, and Sustainability

Summary

1. All life depends on energy from the sun, solar capital, and the resources and ecological services of the earth, natural capital, to survive. An environmentally sustainable society provides for the current needs of its people without undermining the ability of future generations to do the same.

2. The world’s population is growing about 1.2% per year, which adds about 77 million people per year. Economic growth increases a country’s capacity to provide goods and services to its people. Economic development uses economic growth to improve standards of living. Globalization is a process of increasingly interconnecting people through social, economic, and environmental global changes.

3. The earth’s main resources are perpetual resources like solar energy, renewable resources like forests and fresh water, and nonrenewable resources like oil and gas. The resources can be depleted or degraded by overuse, by waste, by pollution, and by man’s increasing "ecological footprint."

4. The principle types of pollution are air, water, soil, and food pollutants. We can prevent pollution or clean up pollution. Prevention is far preferable because cleaning up pollution often causes additional pollutants in another part of the environment.

5. The basic causes of today’s environmental problems are population growth, wasteful use of resources, the tragedy of the commons, poverty, poor environment accounting, and ecological ignorance. They are interconnected because of political and economic practices that are not equitable for various populations, in resource consumption and in technological applications.

6. The world’s current course is not sustainable. Environmental sustainable development encourages environmentally beneficial forms of economic growth and discourages environmentally harmful growth.

Key Questions and Concepts

1-1 What is an environmentally sustainable society?

CORE CASE STUDY. The human population is growing exponentially, consuming vast amounts of resources. It is uncertain how many people the earth can sustain, particularly in light of the pollution they create.

A. Environmental science studies how the earth works, our interaction with the earth, and the methods/procedures we use to deal with environmental problems.

B. Environmental science considers everything that affects a living organism.

C. Ecology studies relationships between living organisms and their environment.

D. Environmentalism is a social movement dedicated to protecting life support systems for all species.

E. A path toward sustainability includes five subthemes that are addressed throughout the text:

1. Natural capital—natural resources and services that keep us and other species alive.

2. Natural capital degradation—when human activities use renewable resources unsustainably.

3. Solutions—are sought to degradation of natural resources.

4. Trade-offs—or compromises are made to resolve conflicts.

5. Individuals matter—to search for solutions to environmental problems.

F. Life and economies depend on solar capital (energy from the sun) and natural capital.　

1-2 How can environmentally sustainable societies grow economically?

A. Economic growth provides people with the goods and services needed.

1. Gross domestic product (GDP) is the market value for goods and services produced within the country.

2. Standard of living is the GDP divided by total population at midyear.

B. Economic development is improving living standards through growth. Most developed countries have high industrialization and high per capita income. Developing countries have moderate to low income.

1. Economic developments reflect good and bad economic news.

a. Poverty produces harmful environmental effects.

2. Developed countries enjoy a higher standard of living.

a. Longer life expectancy.

b. Decrease in infant mortality.

3. Environmentally sustainable development rewards sustainable activities and discourages harmful activities.

1-3 How are our ecological footprints affecting the earth?

A. Natural capital/natural resources are those in the environment or those obtained from the environment: food, water, air, shelter petroleum, etc.

B. Material resources we get from the environment are classified as perpetual, renewable, or nonrenewable.

1. A perpetual resource is renewed continuously, like solar energy.

2. Sustainable yield is the highest rate of use on an indefinite scale without degradation or depletion.

3. Environmental degradation occurs when use of resources exceeds rate of replacement.

C. The Tragedy of the Commons describes the overuse or degradation of freely available resources such as ocean pollution, abuse of national parks, air pollution, etc. No one individual owns these free-access resources.

D. What is our ecological footprint, our impact on the environment?

1. The per capita ecological footprint is the biologically productive land and water needed to supply renewable resources and absorb waste for each individual.

2. Humanity’s ecological footprint exceeds by about 39% the earth’s ecological capacity (or biocapacity) to replenish its renewable resources and absorb the resulting waste products and pollution.

E. What are nonrenewable resources?

1. Nonrenewable resources are those that exist in fixed quantity or stock in the earth’s crust. The resource is economically depleted when it costs too much to obtain what is left.

2. These resources include energy resources (oil, coal, natural gas), metallic mineral resources (copper, iron, aluminum, etc.), and nonmetallic minerals like salt, clay, sand, and phosphates.

3. There are solutions for an economically depleted resource.

a. Try to find more of the resource.

b. Recycle the resource.

c. Waste less.

d. Use less.

e. Try to develop a substitute for the resource.

CASE STUDY: The number of affluent consumers will soon double, as people in underdeveloped countries attain a middleclass lifestyle. China is already a leading consumer of many resources, and its economy and population are continuing to grow at a rapid rate. Thus, its ecological footprint and overall level of resource consumption are expected to continue to grow.

1-4 What is pollution and what can we do about it?

A. Pollutants are chemicals at high enough levels in the environment to harm people or other living organisms.

1. Pollutants may enter the environment naturally (e.g., volcanic eruptions) or through human activities.

2. Point sources of pollutants are single, identifiable sources.

3. Non-point sources are dispersed.

4. Three unwanted effects of pollutants are:

a. They can disrupt or degrade life-support systems of any organism.

b. They damage human health, wildlife, and property

c. They can produce nuisances in the form of noise, smells, tastes, and sights.

B. Solutions: What can we do about pollution?

1. We use two basic approaches to deal with pollution.

a. Pollution prevention/input pollution control reduces or eliminates production of pollutants.

b. Pollution cleanup/output pollution control cleans up or dilutes pollutants after they have been produced.

c. Problems with pollution clean up include:

1) Temporary bandage without long-term pollution control technology, like the catalytic converter.

2) Pollutant is removed but causes pollution in another place: burning garbage/burying it.

3) Expensive to reduce pollution to an acceptable level. Prevention is less expensive.

1-5 Why do we have environmental problems?

A. Five major causes of environmental problems are:

1. Population growth.

2. Wasteful Resource use.

3. Poverty.

4. Poor environmental accounting.

5. Ecological ignorance.

B. Affluence is the addiction to over-consumption of material goods.

1. Symptoms: high debt level, declining health, increased stress, more bankruptcies.

2. Solutions: admit the problem, shop less, avoid malls and other shopping addicts.

3. Toynbee’s law of progressive simplification: transfer energy and attention to the nonmaterial side of life.

C. Affluence of developed countries can lead to environmental improvements.

1. Money is available for technological improvements.

2. Since 1970, air and water are cleaner than previously.

3. Money was spent on environmental improvements.

D. Environmental worldviews and ethics determine the way people view the seriousness of environmental problems.

1. Your environmental worldview is your assumptions and values about the world and your role.

a. The planetary management worldview holds that nature exists to meet our needs.

b. The stewardship worldview holds that we mange the earth, but we have an ethical responsibility to be stewards of the earth.

c. The environmental worldview holds that we are connected to nature and that nature exists for all species equally.

CASE STUDY: Chattanooga, Tennessee, was once one of the most polluted cities in the United States. In the mid-1980s civic leaders gathered together community members to identify problems and brainstorm solutions. After years of encouraging zero-emission industries, implementing recycling programs, and renovating much of the city, Chattanooga is an example of what can be accomplished when cities build their social capital.

1-6 What are four scientific principles of sustainability?

A. There are four major components of earth’s natural sustainability

1. Reliance on solar energy.

2. Reserve biodiversity.

3. Population control.

4. Nutrient recycling.　

Key Terms (Chapter 1)

developing countries (p. 11)

ecological footprint (p. 14)

ecology (p. 7)

economic development (p. 10)

environment (p. 6)

environmental degradation (p. 12)

environmental ethics (p. 20)

environmental science (p. 6)

environmental wisdom worldview (p. 20)

environmental worldview (p. 20)

environmentalism (p. 8)

environmentally sustainable economic development (p. 11)

environmentally sustainable society (p. 9)

exponential growth (p. 5)

gross domestic product (GDP)
(p. 10)

input pollution control (p. 17)

natural capital (p. 9)

nonpoint sources (p. 16)

nonrenewable resources (p. 13)

output pollution control (p. 17)

per capita ecological footprint
(p. 14)

per capita GDP (p. 10)

perpetual resource (p. 12)

planetary management worldview (p. 20)

point sources (p. 16)

pollution (p. 16)

pollution cleanup (p. 17)

pollution prevention (p. 17)

poverty (p. 18)

recycling (p. 13)

renewable resource (p. 12)

resource (p. 12)

reuse (p. 13)

social capital (p. 20)

solar capital (p. 9)

stewardship worldview (p. 20)

sustainability (durability)
(p. 8)

sustainable yield (p. 12)

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Chapter 4: Evolution and Biodiversity

Summary;

1. Life emerged on the earth through two phases of development: a chemical evolution of the organic molecules, biopolymers, and systems of chemical reactions to form the first cells and the biological evolution from single-celled prokaryotic bacteria to single-celled eukaryotic creatures, and then to multicellular organisms.

2. Evolution is the change in a population’s genetic makeup over time. Evolution forces adaptations to changes in environmental conditions in a population. The diversity of life on earth reflects the wide variety of adaptations necessary and suggests that environmental conditions have varied widely over the life of the earth.

3. An ecological niche is a species’ way of life or its functional role in a community. Everything that affects its survival and reproduction (temperature tolerance, water needs, space needs, interactions with other organisms, etc.) is a part of that niche. The ecological niche helps a population survive by the adaptive traits that its organisms have acquired.

4. Extinction of species and formation of new species constantly change the biodiversity of the earth.

5. In the future, evolution will continue to influence our environment. Man’s use of artificial selection and genetic engineering to evolve species may have unintended consequences because evolution is a long, slow process and is unpredictable.

What is biodiversity and why is it important?

CORE CASE STUDY. Alligators act as a keystone species, yet their numbers were seriously compromised by over-hunting. Their activities provide important habitat for fish and avian species. They also control populations by their feeding behaviors. In 1967 the alligator was placed on the endangered species list and has made a dramatic recovery.

Biodiversity is the variety of species, genes, ecosystems, and ecosystem processes.

1. Species diversity, genetic diversity, ecosystem diversity, and functional diversity.

4-2 Where do species come from?

A. Evolution is the change in a population’s genetic makeup over time.

B. Populations evolve by becoming genetically different.

C. All species descend from earlier, ancestral species—theory of evolution.

1. Over time, a population’s gene pool changes when mutations (beneficial changes) in DNA molecules are passed on to offspring.

a. Mutations are random changes in the structure/number of DNA molecules in a cell.

b. Mutations occur in two ways.

1) Gene DNA is exposed to external agents like X-rays, chemicals (mutagens), or radioactivity.

2) Random mistakes that occur in coded genetic instructions.

D. Natural selection occurs when members of a population have genetic traits that improve their ability to survive and produce offspring with those specific traits.

1. For natural selection to evolve in a population, three conditions are necessary:

a. The population must have genetic variability.

b. The trait must be heritable, capable of being passed from one generation to another.

c. The trait must enable individuals with the trait to produce more offspring than individuals without the trait; this is differential reproduction.

2. Adaptation or adaptive traits are heritable traits that help organisms to survive and reproduce better under prevailing environmental conditions.

CASE STUDY. Humans have thrived so well as a species because of their strong opposable thumbs, ability to walk upright, and complex brain. These adaptations may not prove as beneficial as the environment continues to change, though our powerful brain may allow us to live more sustainably in the future.

E. Natural selection can only act on existing genes and is limited by reproductive capacity.

4-3 How do geologic processes and climate change affect evolution?

A. Processes such as the shifting of tectonic plates, volcanic eruptions, and earthquakes influence earth’s climate and in turn affect evolution by removing and/or isolating habitats and species.

B. Long-term climate changes relocate ecosystems, thus determining where certain species can live.

C. Asteroids and meteorites have caused environmental stress and mass extinctions.

4-4 How do speciation, extinction, and human activities affect biodiversity?

A. Natural selection can lead to development of an entirely new species.

In speciation, two species arise from one when some members of a population cannot breed with other members to produce fertile offspring. Speciation occurs in two phases:

1. Geographic isolation, physical separation for long time periods.

2. Reproductive isolation.

B. When population members cannot adapt to changing environmental conditions, the species becomes extinct.

C. When local environmental conditions change, some species will disappear at a low rate; this is called background extinction.

D. Mass extinction is a significant rise in extinction rates above the background extinction level. Usually, 25–70% of species are lost. Recent evidence suggests that there have been two mass extinctions on earth. There appear to have been three mass extinctions on earth.

4-5 What is species diversity and why is it important?

A. Species diversity is the number of species (richness) combined with their relative abundance (evenness).

B. Species rich communities tend to be more stable and more productive.

4-6 What roles do species play in ecosystems?

A. Ecological niche is a species’ way of life in an ecosystem, everything that affects its survival and reproduction.

1. The niche includes the members’ adaptations; its range of tolerance for physical and chemical conditions, its interactions with other components of the ecosystem, and its role in energy flow and matter recycling.

2. The fundamental niche is the full potential range of conditions and resources a species could potentially use. Its realized niche is the part of the potential niche that allows a species to survive and avoid competition with other species for the same resources.

B. Some species have broad ecological roles and are termed generalist species.

C. Some species have narrow ecological roles and are termed specialist species.

CASE STUDY. Cockroaches are the ultimate generalists. The can survive extreme conditions and have a wide variety of adaptations that allow them to avoid predation. By contrast, many species are narrow specialists, though they sometimes have an advantage in their environment because they have few competitors.

D. Niches can be occupied by native or non-native species.

E. Indicator species provide early warning of ecosystem damage because they have a narrow range of tolerance.

CASE STUDY. Amphibians are indicator species that are declining globally. Factors affecting their survival include habitat loss, drought, pollution, increase in UV radiation, parasites, fungal diseases, climate change, overhunting, and introduction of non-native species. Their role as indicator species is cause for alarm on a global scale.

H. Keystone species have a large affect on maintaining balance within an ecosystem.

1. Can be, but are not necessarily, pollinators and top predators.

2. Foundation species create and enhance habitats that benefit other species.

CASE STUDY. Sharks are keystone species that have been overlooked by conservation efforts because of human bias. They tend to be considered dangerous and have gone without protection despite being heavily fished for their valuable fins. They also commonly drown in fishing nets. Shark populations have been declining since the 1970s, and scientists are now calling for a ban on shark finning in international waters.