Thermodynamics Overview

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Questions and Answers

What type of bacteria are primarily involved in the sulfur cycle?

Facultative anaerobes

Non-sulfur photosynthetic bacteria

Chemosynthetic bacteria

Green and purple sulfur bacteria (correct)

Which process does anaerobic respiration NOT involve?

Use of organic compounds as electron acceptors

Functioning in the absence of oxygen

Reduction of inorganic compounds

Use of gaseous oxygen as an electron acceptor (correct)

How much energy is typically lost at each transfer in a food chain?

80 to 90% (correct)

50 to 60%

10 to 20%

100 to 110%

What characterizes a detritus food chain?

Begins with dead organic matter Signup and view all the answers

Which type of bacteria can function both with and without oxygen?

Facultative anaerobes Signup and view all the answers

Which statement about food chains is true?

Food chains are interconnected, forming food webs. Signup and view all the answers

What role do chemotrophic bacteria play in their ecosystem?

They serve as primary producers. Signup and view all the answers

What defines a grazing food chain?

Starts from green plant base Signup and view all the answers

What is the main process that converts nitrogen into various chemical forms?

The nitrogen cycle Signup and view all the answers

What percentage of Earth's atmosphere is comprised of nitrogen?

78% Signup and view all the answers

Which of the following processes is NOT part of the nitrogen cycle?

Oxygenation Signup and view all the answers

How do human activities impact the nitrogen cycle?

Altering nitrogen levels dramatically Signup and view all the answers

What form of nitrogen is primarily found in the atmosphere?

Nitrogen gas (N2) Signup and view all the answers

Which of the following best describes the role of bacteria in the nitrogen cycle?

Facilitate processes like fixation and denitrification Signup and view all the answers

Which of the following forms of nitrogen is NOT a dissolved form?

Organic nitrogen in living plankton Signup and view all the answers

What effect does nitrogen scarcity have on ecosystems?

Limits primary production Signup and view all the answers

What does the equation ΔE = q + w represent?

The change in internal energy of a system based on heat and work Signup and view all the answers

When does the internal energy of a system increase?

When the surroundings do work on the system Signup and view all the answers

Which of the following best describes kinetic energy?

Energy possessed by a body due to its motion Signup and view all the answers

What does the second law of thermodynamics state about entropy?

Entropy always increases in isolated systems Signup and view all the answers

Which of the following processes results in negative values for q and w?

Heat flowing out of the system and work done by the system on the surroundings Signup and view all the answers

How is potential energy defined?

Energy possessed by a body by virtue of its position and internal stresses Signup and view all the answers

What happens to energy when water is raised against gravity?

It is transformed into potential energy Signup and view all the answers

What is a characteristic feature of isolated systems, according to the second law of thermodynamics?

They tend towards thermal equilibrium and increased entropy Signup and view all the answers

What is the primary process by which plants produce oxygen?

Photosynthesis Signup and view all the answers

Which rock type is primarily formed from the cooling and solidification of magma?

Igneous Signup and view all the answers

What role does the lithosphere play in the oxygen cycle?

It contains oxygen-rich minerals and organic content. Signup and view all the answers

How does respiration by animals affect the carbon cycle?

It increases the amount of carbon dioxide in the atmosphere. Signup and view all the answers

Which process primarily drives the changes in the rock cycle?

Plate tectonics Signup and view all the answers

What percentage of the hydrosphere is oxygen by volume?

33% Signup and view all the answers

Which of the following is a primary agent affecting the sedimentary cycle?

Erosion Signup and view all the answers

What happens to igneous rocks during the rock cycle?

They can subduct and melt. Signup and view all the answers

What do the prefixes ‘steno-‘ and ‘eury-‘ refer to in ecological terms?

Narrow and wide ranges of tolerance Signup and view all the answers

What is the optimum zone in the context of Shelford’s Law of Tolerance?

The zone that supports maximum growth and development Signup and view all the answers

Which of the following terms describes a habitat that has a wide range of conditions that an organism can tolerate?

Euryecious Signup and view all the answers

What is the role of salinity in aquatic ecosystems according to Shelford’s Law of Tolerance?

It influences the distribution of both marine and estuarine species. Signup and view all the answers

Which of the following best describes the critical minimum zone?

The lowest limit where growth is inhibited Signup and view all the answers

In terms of temperature tolerance, which of the following species would be classified using the term ‘stenothermal’?

Species that require a narrow temperature range Signup and view all the answers

How is the concept of tolerance important in determining species abundance and distribution in ecosystems?

It helps predict how species will compete for resources. Signup and view all the answers

What does the 'euryhaline' term refer to concerning organisms in aquatic ecosystems?

Species with a wide tolerance to salinity levels Signup and view all the answers

Study Notes

Thermodynamics

The first law of thermodynamics states: ΔE = q + w, where ΔE is the change in internal energy, q is heat flow, and w is work done on the system.
Heat (q) and work (w) are processes that change a system's internal energy. Positive values indicate energy added to the system; negative values indicate energy leaving.
Heat energy is molecular vibration and motion. Sunlight absorbed by land and water creates temperature differences, driving airflow (kinetic energy) which can perform work (e.g., pumping water). This work converts kinetic energy into potential energy (stored energy).
Kinetic energy is energy of motion; potential energy is stored energy.

Entropy and the Second Law of Thermodynamics

The second law of thermodynamics states that the entropy of an isolated system always increases. Isolated systems tend towards thermal equilibrium (maximum entropy). The universe’s entropy only increases.

Photosynthetic Bacteria

Largely aquatic (marine and freshwater).
Play a minor role in organic matter production; important in mineral cycling.
Green and purple sulfur bacteria are obligate anaerobes (require no oxygen) and significant in the sulfur cycle.
Non-sulfur photosynthetic bacteria are facultative anaerobes (can function with or without oxygen) and can be heterotrophs (obtain energy from other sources) in the absence of light.

Chemosynthetic Bacteria

Considered "producers".
Intermediate between autotrophic (make their own food) and heterotrophic (depend on others) organisms.
Produce food via chemical oxidation of inorganic compounds (e.g., ammonia to nitrite, nitrite to nitrate, sulfide to nitrate, ferrous to ferric iron).

Respiration Types

Aerobic respiration: uses oxygen as the final electron acceptor.
Anaerobic respiration: uses an inorganic compound (other than oxygen) to accept electrons.
Fermentation: an anaerobic process using an organic compound as the final electron acceptor.

Food Chains and Webs

Food chain: transfer of energy from plants through a series of organisms (80-90% energy lost at each transfer).
Grazing food chain: starts with plants, progresses to herbivores and then carnivores (can be predator or parasitic chains).
Detritus food chain: starts with dead organic matter, decomposers, and then detritus feeders and their predators.
Food webs are interconnected food chains.

The Nitrogen Cycle

The conversion of nitrogen between its chemical forms through biological and physical processes.
Key processes: fixation, ammonification, nitrification, and denitrification.
Atmospheric nitrogen (78%) is largely unavailable for biological use.
Human activities have significantly altered the global nitrogen cycle (fossil fuels, fertilizers, wastewater).
Nitrogen exists in dissolved (organic and inorganic) and particulate forms in aquatic systems.

The Oxygen Cycle

The oxygen cycle is interconnected with the carbon and hydrogen cycles.
Primarily driven by photosynthesis (plants releasing oxygen) and respiration (animals consuming oxygen).
The lithosphere (Earth's crust) stores oxygen in biomass, organic matter, and mineral deposits. Weathering releases trapped oxygen.
The hydrosphere (water bodies) contains dissolved oxygen supporting aquatic life.

The Rock Cycle

Describes the dynamic transitions between sedimentary, metamorphic, and igneous rocks.
Driven by plate tectonics and the water cycle.
Rocks change as they encounter different environments.
Most elements and compounds follow a basic sedimentary cycle pattern involving erosion, sedimentation, mountain building, volcanic activity, and biological transport.

Shelford's Law of Tolerance

An organism's presence and success depend on a complex of conditions.
Absence or failure can be due to deficiency or excess of any single factor beyond tolerance limits.
Species existence, abundance, and distribution are determined by whether physical/chemical factors fall within their tolerance range.
Terms like "steno-" (narrow) and "eury-" (wide) describe tolerance levels (e.g., stenothermal vs. eurythermal for temperature).
The zone of tolerance includes an optimum zone (best growth), a critical minimum zone (growth inhibited), and a critical maximum zone (growth ceases).

Salinity in Aquatic Ecosystems

Salinity is a major factor in the distribution of marine, estuarine (brackish water), and freshwater species. It fundamentally shapes aquatic ecosystem structure and function.

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Description

This quiz explores key concepts in thermodynamics, including the first and second laws, energy changes, and entropy. Dive into the fundamental principles governing energy transformations and systems. Understand the role of heat and work in internal energy and learn about photosynthetic bacteria.