Unit A Exam Study Guide: Energy Flow and Biogeochemical Cycles

A comprehensive set of vocabulary flashcards covering energy flow, thermodynamics, water properties, and biogeochemical cycles for the Unit A Exam.

Trophic Levels

The distinct stages in a food chain or web, ranging from the producer level to the tertiary consumer level.

Ecological Pyramids

Models used to identify the flow of energy, biomass, or numbers of organisms; energy pyramids always decrease upwards, while biomass and numbers pyramids can sometimes appear inverted.

Rule of 10

The principle of trophic efficiency stating that only approximately $10\%$ of the energy from one level is transferred to the next higher level.

Laws of Thermodynamics (Energy Flow)

Scientific principles explaining why energy decreases at each trophic level due to heat loss, which ultimately limits the length of food chains.

Predation

A biological interaction where one organism, the predator, kills and eats another organism, the prey.

Competition

An ecological interaction where organisms or species vie for the same limited resources in an ecosystem.

Parasitism

A relationship between species where one organism (the parasite) lives on or in another organism (the host), causing it some harm.

Hydrogen Bonding

The type of chemical bond that explains why water molecules stick together and results in various unique properties of water.

Cohesion

The property of water that causes molecules to stick together due to hydrogen bonding.

Density Anomaly (Ice)

A property of water where ice floats because it is less dense than liquid water, a characteristic essential for ecosystem survival.

Carbon Cycle Reservoirs

Storage locations for carbon including the atmosphere, biosphere, lithosphere, and hydrosphere.

Deforestation (Atmospheric Impact)

An activity that alters the carbon cycle by changing the composition of atmospheric gases.

Nitrogen Fixation

The process carried out by nitrogen-fixing bacteria to convert atmospheric nitrogen into a form usable by plants.

Nitrification

The biological process in the nitrogen cycle where ammonia is converted into nitrites and nitrates.

Denitrification

The process in the nitrogen cycle that returns nitrogen to the atmosphere.

Decomposers

Organisms responsible for the recycling of nutrients within an ecosystem by breaking down dead organic matter.

Sedimentation

A process in the phosphorus cycle where phosphorus is deposited into long-term storage in rocks or ocean floors.

Phosphorus Cycle Storage

The movement of phosphorus between short-term reservoirs (biological organisms) and long-term storage (sedimentary rock).

Gaia Hypothesis

The theory that the Earth and its biological systems behave as a single self-regulating entity to maintain environmental conditions.

Negative Feedback

A mechanism within the Gaia Hypothesis that works to maintain carbon balance and stabilize the environment.

Positive Feedback

A mechanism where a change in a system triggers a response that intensifies or increases that change.