AP Environmental Science Chapter 2 questions

1. What two problems did Arcata, California, solve with its constructed wetland?

The constructed wetland simultaneously beautified Arcata's blighted waterfront area and solved the sewage treatment problem of the town.

2. What are systems and how do feedback loops regulate them?

A system is a network of connected components and processes involving the flow of matter and energy from one part to the next. Feedback loops help to maintain stability in a system through either positive or negative feedback that can affect the population of another organism that is next in the chain.

3. Your body contains vast numbers of carbon atoms. How is it possible that some of these carbons may have been part of the body of a prehistoric creature?

The principle of conservation of matter states that matter is neither created nor destroyed, only transformed; as such, carbon atoms which probably formed part of some prehistoric plant or animal have been reused in many other different creatures in its history, of which humans unsurprisingly would also be a part of.

4. List six unique properties of water. Describe, briefly, how each of these properties makes water essential to life as we know it.

Water molecules are polar, allowing it to act as a nearly universal solvent in dissolving polar or ionic substances. This property is what enables cells to carry nutrients.

Water is the only inorganic substance to exist naturally as a liquid, allowing organisms to synthesize organic compounds that are liquid at room temperature. Water molecules exhibit cohesion to each other, and as a result has the highest surface tension of any natural liquid. This allows plants to draw water up through their stems using capillary action alone. Water expands when it freezes, which causes ice to be less dense than water. This permits aquatic life to exist under polar ice caps where the water is warmer than surface ice temperatures. Water has a high heat of vaporization, allowing many animals to cool off and maintain homeostasis through mechanisms of releasing water such as sweating which helps to carry off excess heat. Finally, water also has a high specific heat, which is what permits it to act as a moderator for global temperatures, keeping everything within limits suitable for life to exist.

5. What is DNA, and why is it important?

DNA, short for deoxyribonucleic acid, are strands of nucleotides that are the genetic blueprints for all living things. They contain directions for the growth and development of an organism as well as help in protein synthesis.

6. The oceans store a vast amount of heat, but this huge reservoir of energy is of little use to humans. Explain the difference between high-quality and low-quality energy.

Even though energy can be used repeatedly, as it flows through a system, more of it is released and dissipated. This is essentially the transformation of high-quality energy, which can be used to do work, to lower-quality energy that has increased entropy which lessens its usefulness and makes it harder to harness.

7. In the biosphere, matter follows circular pathways, while energy flows in a linear fashion. Explain.

Conservation of matter dictates that matter is neither created nor destroyed, only transformed. Because of that, while matter is constantly cycled through the environment in different states, at some point or another it will return to an earlier form and start the cycle again. Energy is also conserved in all systems; however the difference is that as it changes state, much of it is dissipated and thus, less useful energy is available higher up a chain.