Environmental Science, Systems, Evolution, and Ecosystem Dynamics

Flashcard study set derived from lectures covering basic environmental science concepts, historical stages, systems principles, evolutionary processes, biological community dynamics, and thermodynamic/chemical cycles.

How is the term 'environment' defined in Environmental Science?

The circumstances or conditions that surround an organism or group of organisms, as well as the complex of social or cultural conditions that affect an individual or community.

What is the primary focus of Environmental Science as an interdisciplinary field?

It is the systematic study of our environment and our proper place in it, drawing on natural sciences, social sciences, and humanities to understand and resolve environmental problems created by humans.

What are the four distinct historical stages of environmental thinking?

Pragmatic Resource Conservation, Moral and Aesthetic Nature Preservation, Concern about Health and Ecological Damage (Modern Environmental Movement), and Global Environmentalism.

What was Gifford Pinchot's core policy regarding resource conservation?

Pragmatic Utilitarian Conservation, summarized as providing 'the greatest good for the greatest number for the longest time,' which is reflected today in the Multiple Use Policies of the USFS.

How did John Muir's view of nature conservation differ from Gifford Pinchot's?

John Muir advocated for Biocentric Preservation, arguing that nature deserves to exist for its own sake regardless of its degree of usefulness to humans.

What contribution did Rachel Carson make to the modern environmental movement in 1962?

She published the book Silent Spring, which awakened the public to the environmental threat posed by pesticides.

Who founded the Green Belt Movement in 1997 and what was its objective?

Wangari Maathai founded the movement in Kenya to organize poor rural African women to restore the local environment by planting trees while promoting justice and equality.

According to World Bank estimates in the text, how many people live below the international poverty line and at what daily income?

700 million people live below the international poverty line, earning less than $1.90 (U.S.) per day.

How does resource consumption in the United States compare to its percentage of the global population?

The U.S. makes up 4.6% of the world population, but consumes 20% of global oil production and generates 15% of carbon dioxide and 50% of toxic wastes.

What is the Brundtland (1987) definition of sustainable development?

Meeting the needs of the present without compromising the ability of future generations to meet their own needs.

What is the difference between inherent value and instrumental value?

Inherent value is an intrinsic right to exist or innate worth, whereas instrumental value means items have worth only because they are of use to or valued by another person.

What is environmental racism and what quantitative example is provided in the lecture notes?

Environmental racism is an inequitable distribution of environmental hazards based on race, such as Black children in the U.S. being 2 to 3 times more likely to suffer lead poisoning than White children at all income levels.

What is toxic colonialism?

The practice of targeting poor communities or communities of color in developing nations as waste disposal areas.

What does the scientific principle of empiricism state?

We can learn about the world by careful observation of empirical (real, observable) phenomena and expect to understand fundamental processes and natural laws by observation.

What is parsimony (Ockham's razor) in scientific methodology?

The rule that when two plausible explanations are equally reasonable, the simpler (more parsimonious) one is preferable.

What is the distinction between accuracy and reproducibility in scientific measurements?

Accuracy refers to the correctness of measurements, whereas reproducibility (or replication) refers to the repeatability of results.

Contrast deductive reasoning and inductive reasoning.

Deductive reasoning is logical reasoning from general principles to specific conclusions, while inductive reasoning is reasoning from many specific observations to produce a general rule.

At what probability threshold are ecological tests usually considered statistically significant?

When the calculated probability that observed results could have occurred by chance is less than $5\%$.

What is the difference between a natural experiment and a manipulative experiment?

A natural experiment involves observation of events that have already happened, while a manipulative experiment deliberately alters some conditions while holding all other variables constant.

How are dependent and independent variables plotted on a graph?

The dependent (response) variable is placed on the vertical (Y) axis, and the independent variable is placed on the horizontal (X) axis.

Define an open system versus a closed system.

An open system exchanges matter and energy with its surroundings, whereas a closed system is self-contained and exchanges no matter or energy with the outside.

Contrast a positive feedback loop with a negative feedback loop.

A positive feedback loop is a self-perpetuating process where an increase in a state variable leads to further increases in it; a negative feedback loop suppresses change within a system to help maintain stability.

What is a state shift in system dynamics?

A severe disturbance in which the system does not return to normal but instead results in significant changes in some of its state variables.

What are emergent properties of a system?

Characteristics of a whole, functioning system that are quantitatively or qualitatively greater than the sum of the system's individual parts.

What is a paradigm shift in science?

A major change in explanatory frameworks that occurs when a majority of scientists agree that an old explanation no longer works very well.

How does natural selection explain adaptation?

Natural selection is the process by which better-selected individuals pass their advantageous, inherited genetic traits to the next generation at a higher rate than individuals with less suitable traits.

How do Von Liebig's and Shelford's theories define critical limits on organism distribution?

Von Liebig proposed that the single factor in shortest supply relative to demand is the critical factor; Shelford expanded this by stating that each factor has minimum and maximum tolerance limits beyond which a species cannot survive or reproduce.

What is the difference between a generalist and a specialist ecological niche?

A generalist has a broad ecological niche (such as the brown rat), whereas a specialist has a narrow ecological niche (such as the giant panda).

What is Gause's principle of competitive exclusion?

No two species can occupy the same ecological niche at the same time; the species that is more efficient at using resources will exclude the other.

How does resource partitioning enable species coexistence?

Species coexist in a habitat by utilizing different parts of a single resource, such as swallows eating insects during the day and bats eating insects at night.

Contrast allopatric speciation and sympatric speciation.

Allopatric speciation occurs when a sub-population becomes geographically isolated from the main population; sympatric speciation occurs when organisms continue to live in the same place but become isolated by other means (such as chromosome doubling in ferns).

What are the three main patterns of natural selection on trait distribution?

Directional selection (shift toward one extreme of a trait), stabilizing selection (range of a trait is narrowed), and disruptive selection (traits diverge toward the two extremes).

Distinguish between Batesian mimicry and Müllerian mimicry.

In Batesian mimicry, a harmless species mimics the warning coloration of a harmful species to gain protection; in Müllerian mimicry, two harmful species evolve to look alike.

Define the three main forms of symbiosis.

Mutualism (both species benefit), Commensalism (one species benefits while the other is neither helped nor harmed), and Parasitism (one organism feeds on a host organism, benefiting at the host's expense).

What is the difference between a keystone species and an ecosystem engineer?

A keystone species plays a critical role in a community out of proportion to its abundance (e.g., tropical figs supplying fruit year-round), while an ecosystem engineer modifies, maintains, or creates habitats (e.g., earthworms altering soil structure).

Contrast primary succession and secondary succession.

Primary succession occurs when a community begins to develop on a site previously unoccupied by living organisms, whereas secondary succession occurs when an existing community is disrupted and a new one subsequently develops.

What are the four phases of Holling's adaptive cycle model of ecosystem change?

1) Rapid growth phase of primary succession, 2) Conservation phase of secondary succession and stability, 3) Release phase of rapid change due to disturbance, and 4) Reorganization phase of new growth and invention.

What does the principle of Conservation of Matter state?

Matter is neither created nor destroyed, but rather transformed from one form to another and recycled over and over.

Which four elements account for 96% of the mass of living organisms?

Oxygen, carbon, hydrogen, and nitrogen.

How do ionic bonds differ from covalent bonds?

Ionic bonds are formed by forces holding together ions of opposite charges (such as $Na^+$ and $Cl^-$), whereas covalent bonds form when atoms share electrons.

What occurs during oxidation and reduction chemical reactions?

Oxidation occurs when an atom gives up one or more electrons; reduction occurs when an atom gains one or more electrons.

What are the First and Second Laws of Thermodynamics?

The First Law states that energy is conserved (neither created nor destroyed); the Second Law states that with each successive energy transfer, less usable energy is available to perform work and entropy (disorder) increases.

What is chemosynthesis and what role do archaea play in it?

Chemosynthesis is the extraction of energy from inorganic chemical compounds bubbling from seafloor vents or hot springs, carried out by ancient archaea that represent one-third of all global biomass.

What is the balanced chemical equation for photosynthesis?

$$6\,H_2O + 6\,CO_2 + \text{solar energy} \rightarrow C_6H_{12}O_6 + 6\,O_2$$

What is the balanced chemical equation for cellular respiration?

$$C_6H_{12}O_6 + 6\,O_2 \rightarrow 6\,H_2O + 6\,CO_2 + \text{energy}$$

What is the 10% Rule in ecological pyramids?

Due to energy loss as heat in metabolic processes (Second Law of Thermodynamics), only about $10\%$ of energy or biomass is transferred from one trophic level to the next (e.g., $100\,kg$ clover to $10\,kg$ rabbit to $1\,kg$ fox).

In the carbon cycle, what is the difference between carbon sinks and carbon sources?

Carbon sinks are parts of the cycle that remove carbon dioxide from the atmosphere (e.g., live vegetation), while carbon sources are parts that release carbon dioxide into the atmosphere (e.g., burning fossil fuels).

How do nitrogen-fixing bacteria contribute to the nitrogen cycle?

They convert atmospheric nitrogen gas into ammonia ($NH_3$), which other bacteria then convert to nitrites and nitrates that plants take up to construct proteins.