Unit 1- Ecosystems and Biogeochemical Cycles

10% rule

A rule of thumb stating that only about 10% of the energy at one trophic level is passed on to the next trophic level.

1st law of thermodynamics

The law stating that energy cannot be created or destroyed, only transferred or transformed.

1st, 2nd, 3rd order consumer

Consumers in an ecosystem classified based on their position in the food chain, with first-order consumers feeding on producers, second-order consumers feeding on first-order consumers, and so on.

2nd law of thermodynamics

The law stating that energy transfers result in a decrease in usable energy, often leading to increased entropy.

abiotic factor

Non-living factors in an ecosystem that can influence living organisms, such as temperature, water, sunlight, and soil.

abyssal zone

The deepest part of the ocean, characterized by very low temperatures, high pressure, and minimal light.

aerobic respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

ammonification

The process in which decomposers convert organic nitrogen into ammonia.

anaerobic respiration /fermentation

The process by which cells convert glucose into energy without using oxygen, often producing lactic acid or ethanol as byproducts.

assimilation

The process by which organisms absorb nutrients into their bodies for growth and maintenance.

autotroph

An organism that can produce its own food using light or chemical energy, such as plants through photosynthesis.

bathyal zone

The oceanic zone extending from the continental shelf to a depth of about 4,000 meters.

benthic zone

The bottom region of oceans, lakes, and rivers, inhabited by organisms such as algae, worms, and crustaceans.

biomass

The total mass of living organisms in a given area or volume.

biome

A large geographical region characterized by a specific type of climate, vegetation, and animal life.

biotic factor

Living factors in an ecosystem that can influence other organisms, such as predation, competition, and symbiosis.

biotic potential

The maximum reproductive capacity of a population under optimal environmental conditions.

brackish water

Water that is a mix of fresh and saltwater, often found in estuaries and coastal wetlands.

broadleaf evergreen

A type of tree that retains its leaves throughout the year and has broad, flat leaves.

carbon sink

A natural or artificial reservoir that absorbs more carbon from the atmosphere than it releases.

chemosynthesis

The process by which certain bacteria use inorganic compounds to generate energy without sunlight.

climate

The long-term patterns of temperature, humidity, wind, and precipitation in an area.

climate graph

A visual representation of a region's climate, typically showing temperature and precipitation patterns throughout the year.

climax community

A stable, mature community that undergoes little or no change in species over time.

Carbon Sink / Reservoir

A location where carbon is stored for an extended period, such as oceans or fossil fuels.

Carbon Sources

Places or processes that release carbon into the atmosphere, like combustion of fossil fuels.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Respiration

The process by which organisms exchange gases with their environment, primarily taking in oxygen and releasing carbon dioxide.

Ocean Sinks

Areas in the ocean where carbon is absorbed and stored for long periods, such as through the growth of algae and phytoplankton.

Burial

The process of organic matter being deposited and accumulating in sediment over time, effectively storing carbon.

Fossil Fuels

Natural fuels formed from the remains of living organisms, such as coal, oil, and natural gas.

Nitrogen Fixation

The conversion of atmospheric nitrogen into a form usable by plants, primarily ammonia, through natural or synthetic processes.

Assimilation

The process by which plants and animals incorporate nitrogen into their tissues from nitrogen-containing compounds.

Ammonification

The conversion of organic nitrogen into ammonia by decomposers like bacteria and fungi.

Nitrification

The conversion of ammonia into nitrites and then nitrates by soil bacteria, making nitrogen available for plants.

Denitrification

The process by which nitrates are reduced to nitrogen gas or nitrous oxide, returning nitrogen to the atmosphere.

Eutrophication

The excessive richness of nutrients in a body of water, often due to runoff from the land, leading to dense plant growth and depletion of oxygen.

Phosphorus Cycle

The movement of phosphorus between sources like rocks and sinks like sediments, crucial for biological systems as phosphorus is a limiting factor.

Hydrologic Cycle

The continuous movement of water between the Earth's surface and the atmosphere, driven by solar energy.

Primary Productivity

The rate at which solar energy is converted into organic compounds through photosynthesis, with gross and net primary productivity as key measures.

Trophic Levels

The hierarchical levels in an ecosystem, indicating an organism's feeding position in the food chain.

Food Web

A model showing interconnected food chains in an ecosystem, illustrating the flow of energy and nutrients among organisms.

Trophic Cascade

The ecological phenomenon where changes in the abundance of top predators in an ecosystem trickle down to affect the populations at lower trophic levels.