DP Biology Vocabulary (SL & HL) - C4.2 Transfers of Energy and Matter

Autotroph (or producer)

an organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.

Biomass

the total mass of living matter within a given unit of environmental area, expressed in terms of living or dry weight per unit area.

Cell respiration

a series of metabolic processes that take place within a cell in which biochemical energy is produced from organic substances and stored as energy carriers (ATP) for use in the energy-requiring activities of the cell.

Chemical energy

energy released from a substance, or absorbed in the formation of a chemical compound, during a chemical reaction.

Ecosystem

a system that includes all biotic factors (living organisms) in an area as well as its abiotic factors (physical environment) functioning together as a unit.

Energy flow

the movement of energy around an ecosystem by biotic and abiotic means.

First consumer

the name given to an organism that feeds on the producer in a food chain. For example, a goat is considered a first order consumer since it eats green plants.

Food chains

a feeding hierarchy in which organisms in an ecosystem are grouped into trophic (nutritional) levels and are shown in a succession to represent the flow of food energy and the feeding relationships between them.

Heterotroph

an organism that obtains carbon by feeding on the organic material present in other organisms, living or dead.

Light energy

the energy produced or given off directly from the sun causing the growth of plants and the existence of most life forms.

Photosynthesis

the process in green plants and certain other organisms by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source.

Producer (or autotroph)

an organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.

Energy pyramids

a graphical model to show how the energy flows through a food chain, how the amount of energy is decreasing and becoming less available for organisms as it enters each trophic level, and how much of the energy in the ecosystem is lost to the atmosphere as heat.

Secondary consumer

an organism that feeds on primary consumers.

Trophic level

the position in a food chain occupied by a group of organisms with similar feeding modes.

Food web

A community of organisms where there are several interrelated food chains

Community

A group of interdependent organisms inhabiting the same region and interacting with each other

Decomposer

an organism, especially a soil bacterium, fungus, or invertebrate, that decomposes organic material.

Inorganic

Not formed from living things or the remains of living things. Generally not carbon based.

Photoautotroph

An organism that obtains energy from sunlight and carbon from CO2 by photosynthesis. These are typically plant species.

Chemoautotroph

An organism, typically a bacterium, that derives energy from the oxidation of inorganic compounds.

Oxidation reactions

Chemical reactions that involve the gain of oxygen or loss of hydrogen atoms (and their electrons)

Primary production

The amount of light energy converted to chemical energy (organic compounds) by autotrophs in an ecosystem during a given time period

Secondary production

The amount of chemical energy in food converted to new biomass during a given period of time

Carbon cycle

the series of processes by which carbon compounds are interconverted in the environment, chiefly involving the incorporation of carbon dioxide into living tissue by photosynthesis and its return to the atmosphere through respiration, the decay of dead organisms, and the burning of fossil fuels.

Carbon sink

A natural environment that absorbs and stores more carbon dioxide from the atmosphere than it releases, which offsets greenhouse gas emissions.

Carbon source

A body or process that releases carbon dioxide into the atmosphere

Combustion

A rapid reaction between oxygen and fuel that results in fire

Keeling Curve

a graph that plots the ongoing change in concentration of carbon dioxide in Earth's atmosphere since the 1950s

Nutrient recycling

The way in which elements are exchanged between the living and non-living components of an ecosystem

Carbon fixation

The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote).

Organic substance

Chemical compounds which contain carbon and come from a living system. E.g lipids, amino acids or ethanol

Anabolic

A metabolic process in which large molecules are built from small molecules. It's opposite term is catabolic.

Detritus feeders

Organisms that feed on small pieces of dead organic matter, typically Arthropods such as insects, annelids (worms) or molluscs such as snails.