Principles of Sustainability and Environmental Science

Posted on Aug 25, 2024 in Geology

1. Principles of Sustainability

1.1 What are three principles of sustainability?

A. Environmental Science: A study of connections in nature.

  1. Ecology: Studies relationships between living organisms and their interaction with the environment.
  2. Environmentalism: A social movement.

B. Nature’s Survival Strategies: Three principles of sustainability.

  • Life depends on solar energy.
  • Biodiversity provides natural services.
  • Chemical/nutrient cycling means there is little waste in nature.

C. Key Components of Sustainability:

  • Life depends on natural capital, natural resources, and natural services.
  • Many human activities can degrade natural capital.
  • Solutions are being found and implemented.
  • Sustainability begins at personal and local levels.

D. Resource Classification:

  1. Perpetual Resource: Continuously renewed.
  2. Renewable Resource: Replenished in days to several hundred years.
  3. Sustainable Yield: The highest rate at which a renewable and non-renewable resource can be used indefinitely without reducing its available supply.
    1. Nonrenewable Resources: Exist in fixed quantities.
      • Exhaustible energy (coal and oil).
      • Metallic minerals (copper and aluminum).
      • Nonmetallic minerals (salt and sand).

Sustainable Solutions: Reduce, Reuse, Recycle.

2. Ecological Footprints and Environmental Problems

2.1 How are our ecological footprints affecting the earth?

  1. Environmental/Natural Capital Degradation: Is occurring.
  2. Pollution Sources:
    1. Point Sources: Single, identifiable sources (e.g., smokestack).
    2. Nonpoint Sources: Dispersed and often difficult to identify (e.g., lawn runoff).
  3. Tragedy of the Commons: Overexploiting shared renewable resources.
    1. In 1968, biologist Garrett Hardin called the degradation of openly shared resources the tragedy of the commons.
    2. Reducing Degradation:
      1. Reduce use by government regulations.
      2. Shift to private ownership.
  4. Ecological Footprints: Our environmental impacts.
    1. Per Capita Ecological Footprint: The average ecological footprint of an individual in a given country or area.
    2. Ecological Deficit: The ecological footprint is larger than the biological capacity to replenish resources and absorb wastes and pollution.
  5. IPAT Model: Another environmental impact model.
    1. In the early 1970s, scientists Paul Ehrlich and John Holdren developed the IPAT model.
    2. I (environmental impact) = P (population size) x A (affluence/person) x T (technology’s beneficial and harmful effects).
  6. Case Study: China’s new affluent consumers.

2.2 Why do we have environmental problems?

  1. Four Basic Causes of Environmental Problems:
    1. Population growth.
    2. Unsustainable resource use.
    3. Poverty.
    4. Excluding environmental costs from market prices.
  2. Poverty’s Harmful Effects:
    1. One in every five people live in extreme poverty (< $1.25 a day), and more are susceptible.
  3. Differing Views on Environmental Problems and Solutions:
    1. Planetary Management Worldview: Holds that we are separate from and in charge of nature.
    2. Stewardship Worldview: Holds that we can and should manage the earth for our benefit, but that we have an ethical responsibility to be caring and responsible managers.
    3. Environmental Wisdom Worldview: Holds that we are part of, and dependent on, nature and that nature exists for all species, not just for us.

2.3 What is an environmentally sustainable society?

  1. Protecting Natural Capital: Environmentally sustainable societies protect natural capital and live off its income.
    1. Increase reliance on renewable resources.
    2. Protect Earth’s natural capital.
  2. Collaborative Problem Solving:
    1. Trade-off Solutions: Provide a balance between the benefits and the costs.

Individuals matter, especially in the success of bottom-up grassroots action.

3. The Scientific Process and Ecosystems

3.1 What do scientists do?

  1. Scientific Process: Important features are skepticism, reproducibility, and peer review.
    1. Results that have not been widely tested or are not widely accepted can be called tentative or frontier science. At this stage, disagreement among scientists is common and leads to advancement.

3.2 What are the major components of an ecosystem?

  1. Ecosystem Components:
    1. Consumers/Heterotrophs: Get their nutrients by feeding on other organisms or their remains.
    2. Consumers can be herbivores (feed on plants), carnivores (feed on animals), or omnivores (feed on both plants and animals).
    3. Detritivores (Detritus Feeders): Feed on waste or dead bodies.

Usable energy decreases with each link in a food chain or web.

  1. Less high-quality energy is available to organisms at each succeeding feeding level because when chemical energy is transferred from one trophic level to the next, about 90% of the energy is lost as heat.
  2. Ecosystem Productivity:
    1. Gross Primary Productivity (GPP): The rate of an ecosystem’s producers converting energy into biomass.
    2. Net Primary Productivity (NPP): The rate that producers use photosynthesis to store biomass minus the rate at which they use energy for aerobic respiration. NPP measures how fast producers can provide biomass needed by consumers in an ecosystem.
    3. Ecosystems and aquatic life zones differ in their NPP. The three most productive systems are swamps and marshes, tropical rainforests, and estuaries. The three least productive are tundra, desert scrub, and extreme desert.

3.3 What happens to matter in an ecosystem?

  1. The Carbon Cycle:
    1. Carbon is the basic building block of carbohydrates, fats, proteins, DNA, and other compounds.
    2. Carbon circulates through the biosphere, hydrosphere, and atmosphere.
    3. Producers, consumers, and decomposers circulate carbon in the biosphere.
  2. The Nitrogen Cycle: Bacteria in action.
    1. Nitrogen gas (N2), which makes up 78% of the atmosphere, cannot be used directly by most living organisms.
      1. Nitrogen Fixation: Specialized bacteria convert gaseous nitrogen to ammonia.
      2. Nitrification: Specialized bacteria convert ammonia in the soil to nitrite ions and nitrate ions; the latter is used by plants as a nutrient.
      3. Ammonification: Decomposer bacteria convert detritus into ammonia and water-soluble salts.
      4. Denitrification: Anaerobic bacteria in soggy soil and bottom sediments of water areas convert NH3 and NH4+ back into nitrite and nitrate ions, then into nitrogen gas and nitrous oxide gas, which are released into the atmosphere.
  3. The Phosphorus Cycle:
    1. Phosphorus does not cycle through the atmosphere.

3.4 How do scientists study ecosystems?

A. Direct Study: Some scientists study nature directly.

  1. Geographic Information Systems (GIS)

C. The Need for More Data: We need to learn more about the health of the world’s ecosystems.

  1. We need more baseline data about components and physical and chemical conditions to determine how well the ecosystem is functioning and anticipate how best to prevent harmful environmental changes.

4. Biodiversity and Its Importance

4.1 What is biodiversity and why is it important?

A. Biodiversity: A crucial part of the Earth’s natural capital.

  1. Components of Biodiversity:
    1. Species Diversity: The number and variety of the species present in any biological community.
      1. A species is a set of individuals that can mate and produce fertile offspring. Every organism is a member of a certain species.
      2. Species diversity estimates range from 8 million to 100 million.
    2. Genetic Diversity: The variety of genes found in a population or in a species.
    3. Ecosystem Diversity: Refers to the Earth’s variety of deserts, grasslands, forests, mountains, oceans, lakes, rivers, and wetlands.
    4. Functional Diversity: Includes a variety of processes such as energy flow and matter cycling occurring within ecosystems.
  2. INDIVIDUALS MATTER: Edward O. Wilson: A champion of biodiversity.
    1. Started with studying ants then widened his focus to include the entire biosphere.
    2. Proposed the hypothesis that humans have a natural affinity for wildlife and wild places—biophilia (or love of life).
    3. Helped develop the theory of island biogeography, which examines how species diversity on islands is affected by the sizes and locations of the islands. This theory has been important in the creation of wildlife preserves.
    4. Wrote The Diversity of Life, which put together the principles and practical issues of biodiversity.
    5. Writes and lectures about the need for global conservation efforts and is promoting the goal of completing a global survey of biodiversity.

4.2 How do speciation, extinction, and human activities affect biodiversity?

  1. Evolution of New Species:
    1. Speciation: The process where one species splits into two or more different species.
    2. Geographic Isolation: Occurs when different groups of the same population of a species become physically isolated from one another for a long period of time.
    3. Reproductive Isolation: Occurs when mutation and change by natural selection operate in the gene pools of geographically isolated populations.
  2. Extinction:
    1. Biological Extinction: The process by which an entire species ceases to exist.
    2. Local Extinction: Occurs when a population of a species becomes extinct over a large region, but not globally.
    3. Endemic Species: Found in only one area and are thus especially vulnerable to extinction.
    4. Background Extinction: Has occurred over most of Earth’s history.
  3. Mass Extinctions:
    1. Fossil and geological evidence indicate that there have probably been five mass extinctions during the past 500 million years.
    2. Mass extinctions have been followed by an increase in species diversity as new species have arisen to occupy new habitats or to exploit newly available resources.
    3. There is growing evidence that we are experiencing the beginning of a new mass extinction, with much of the increase in extinctions and loss of biodiversity due to human activities.

4.3 What roles do species play in an ecosystem?

  1. Ecological Niche:
    1. An ecological niche is a species’ way of life in an ecosystem, everything that affects its survival and reproduction.
  2. Predator-Prey Interactions:
    1. Coevolution: Occurs when two different species interact over a long period of time and changes in the gene pool of one species can lead to changes in the gene pool of the other.
    2. Some bats and moths have coevolved.

5. Population Growth and Limits

5.1 What limits the growth of populations?

A. Population Dynamics: Populations can grow, shrink, or remain stable.

  1. Population change = (births + immigration) – (deaths + emigration).

C. Limits to Growth: No population can grow indefinitely: J-Curves and S-Curves.

  1. Environmental Resistance: The combination of all factors that act to limit the growth of a population.
  2. Carrying Capacity: Environmental resistance largely determines an area’s carrying capacity, the maximum population of a given species that a particular habitat can sustain indefinitely.
  3. Exponential Growth: Starts slowly but then accelerates as the population increases. It occurs when a population has essentially unlimited resources to support its growth. A graph of population size over time of an exponential growth has a J-shaped curve.
  4. Logistic Growth: Occurs when the growth rate decreases as the population becomes larger and nears the carrying capacity of its environment because resources such as food, water, and space begin to dwindle.
  5. Population Stabilization: Population size may stabilize at or near the carrying capacity of its environment. The result is a sigmoid (S-shaped) population growth curve.