substances that release hydrogen ions (protons) in water.
the characteristic number of protons per atom of an element. Used as an identifying attribute.
the smallest unit of matter that has the characteristics of an element; consists of three main types of subatomic particles: protons neutrons and electrons.
substances that bond readily with hydrogen ions.
the populations of plants animals and microorganisms living and interacting in a certain area at a given time.
the total mass or weight of all living organisms in a given population or area.
the circulation and reutilization of carbon atoms especially via the process of photosynthesis and respiration.
places of carbon accumulation such as in large forests (organic compounds) or ocean sediments (calcium carbonate); carbon is thus removed from the carbon cycle for moderately long to very long periods of time.
organisms that mainly prey upon animals.
minute biological compartments within which the processes of life are carried out.
the process in which a cell breaks down sugar or other organic compounds to release energy used for cellular work; may be anaerobic or aerobic depending on the availability of oxygen.
potential energy stored in chemical bonds of molecules.
a molecule made up of two or more kinds or atom held together by chemical bonds.
Conservation of matter
in any chemical reaction matter changes form; it is neither created nor destroyed.
an organism that obtains energy and nutrients by feeding on other organisms or their remains.
fungi and bacteria that break complex organic material into smaller molecules.
organisms that consume organic litter debris and dung.
the scientific study of relationships between organisms and their environment. It is concerned with the life histories distribution and behavior of individual species as well as the structure and function of natural systems at the level of populations communities and ecosystems.
a specific biological community and its physical environment interacting in an exchange of matter and energy.
a molecule composed of one kind of atom; cannot be broken into simpler units by chemical reactions.
the capacity to do work (that is to change the physical state of motion of an object)
molecules usually proteins or nucleic acids that act as catalysts in biochemical reactions.
First law of thermodynamics
states that energy is conserved. It is neither created nor destroyed underneath normal conditions.
a linked feeding series; in an ecosystem the sequence of organisms through which energy and materials are transferred in the form of food from one trophic level to another.
a complex interlocking series of individual food chains in an ecosystem.
a form of energy transferred from one body to another because of a difference in temperatures.
an organism that eats only plants.
the natural process by which water is purified and made fresh through evaporation and precipitation. The cycle provides all the fresh water available for biological life.
electrically charged atoms that have gained or lost electrons.
forms of a single element that differ in atomic mass due to a different number of neutrons in the nucleus.
energy contained in moving objects such as a rock rolling down a hill the wind blowing through the trees or water flowing over a dam.
anything that takes up space and has mass.
all the energy and matter exchanges that occur within a living cell or organism; collectively, the life processes.
a combination of two or more atoms
the circulation and reutilization of nitrogen in both inorganic and organic places.
an organism that eats both plants and animals.
complex molecules organized around skeletons of carbon atoms arranged in rings or chains; includes biomolecules molecules synthesized by living organisms.
a value that indicated the acidity or alkalinity of a solution on a scale of 0-14, based on the proportion of H+ ions.
the movement of phosphorus atoms from rocks through the biosphere and hydrosphere and back to rocks.
the biochemical process by which green plants and some bacteria capture light energy and use it to produce chemical bonds. Carbon dioxide and water are consumed while oxygen and simple sugars are produced.
a group of individuals of the same species occupying a given area.
stored energy that is latent but available for use. A rock poised at the top of a hill or water stored behind a dam are examples.
an organism that synthesizes food molecules from inorganic compounds by using an external energy source; most producers are photosynthesis.
the synthesis of new organic material. That done by green plants using solar energy is called primary productivity.
an organism that feeds on the dead bodies of other organisms.
Second law of thermodynamics
states that with each successive energy transfer or transformation in a system, less energy is available to do work.
a population of morphologically similar organisms that can reproduce sexually among themselves but that cannot produce fertile offspring when mated with other organisms.
the chemical and physical reactions by which sulfur moves into or out of storage and through the environment.
step in the movement of energy through an ecosystem; an organism's feeding status in an ecosystem.