Ecology Unit

Abiotic factors

Abiotic factors

the non-living physical and chemical attributes of a system, for example light or temperature in an environment.

Autotroph

an organism that uses solar energy or chemical energy to manufacture the organic compounds it needs as nutrients from simple inorganic compounds obtained from its environment.

Biotic factors

attributes in an ecosystem that refer to living organisms.

Chi-squared test

a statistical test of the fit between a theoretical frequency distribution and a frequency distribution of observed data for which each observation may fall into one of several classes.

Community

formed by populations of different species living together and interacting with each other.

Consumers

heterotrophs that feed on living organisms by ingestion.

Crossbreeding

when members of different species breed together.

Detritivores

heterotrophs that obtain organic nutrients from dead organisms by internal digestion.

Ecosystem

community of different species interacting with each other and with the chemical and physical factors making up the non-living environment.

Heterotroph

an organism that gets its organic nutrients by feeding on autotrophs or other heterotrophs.

Inorganic nutrients

chemical elements, compounds, and other substances necessary to sustain life processes that are not chemically carbon-based.

Interbreeding

when two members of the same species mate and produce offspring.

Mesocosm

an experimental tool that brings a small part of the natural environment under controlled conditions.

Population

a group of organisms of the same species who live in the same area at the same time.

Quadrat sampling

square or rectangular plot of land, a quadrat, marked off at random to isolate a sample and determine the percentage of vegetation and animals occurring within the marked area.

Random numbers

a number chosen by a random sampling from a table or generated by a computer.

Saprotrophs

heterotrophs that obtain organic nutrients from detritus by external digestion.

Species

groups of organisms that can potentially interbreed to produce fertile offspring.

Sustainable communities

communities that are capable of being maintained at a steady level without exhausting natural resources or causing severe ecological damage.

autotroph

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

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

pyramid of energy

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.

anaerobic organisms

occur in the absence of oxygen or do not require oxygen to live. For example, anaerobic bacteria produce energy from food molecules without the presence of oxygen.

autotroph organisms

that use solar energy or chemical energy to manufacture the organic compounds they need as nutrients from simple inorganic compounds obtained from their environment.

biomass

the total mass of living matter within a given unit of environmental area.

carbohydrates

any of a large group of organic compounds, including sugars and polysaccharides, such as cellulose, glycogen, and starch, that contain carbon, hydrogen, and oxygen, with the general formula (CH2O)n. They are an important source of food and energy for animals.

carbon dioxide

a colourless, odourless, incombustible gas present in the atmosphere and formed during respiration, the decomposition and combustion of organic compounds, and in the reaction of acids with carbonates.

carbon flux

the flow of carbon from one carbon pool to another.

fossilized organic matter

when remains of organisms of a past geologic age have been preserved in a fossil form.

gigatone

equivalent to a one billion tonnes.

limestone

a sedimentary rock consisting mainly of calcium carbonate, deposited as the calcareous remains of marine animals or chemically precipitated from the sea.

methane

an odourless, colourless, flammable gas. It is the major constituent of natural gas, which is used as a fuel, and is an important source of hydrogen and a wide variety of organic compounds.

peat

a compact, brownish deposit of partially decomposed vegetable matter saturated with water, it found in uplands and bogs in temperate and cold regions and used as a fuel.

waterlogged soil

a soil that is soaked or saturated with water.

aerosol

a collection of tiny solid or liquid particles in the atmosphere that can come from natural sources (such as wildfires) or people's activities (such as burning fossil fuels). Some aerosols make the atmosphere warmer because they absorb energy. Others have a cooling effect because they reflect sunlight back into space.

biofuel

a type of fuel produced from plants or other forms of biomass. Examples of biofuels include ethanol, biodiesel, and biogas.

biomass

material that comes from living things, including trees, crops, grasses, and animals and animal waste. Some kinds of biomass, such as wood and biofuels, can be burned to produce energy.

climate change

a significant change in the Earth's climate, including changes in weather patterns, the oceans, ice and snow, and ecosystems around the world.

climate

the average weather conditions in a particular location or region at a particular time of the year. Climate is usually measured over a period of 30 years or more.

coral reef

a marine ridge or reef consisting of coral and other organic material consolidated into limestone.

fossil fuel

a type of fuel created over millions of years as dead plant and animal material becomes trapped and buried in layers of rock, and then heat and pressure transform this material into a fuel deep within the Earth. Examples of fossil fuels include coal, oil, and natural gas.

global warming

the increase in temperature near the surface of the Earth as a result of natural causes. However, the term is most often used to refer to recent and on-going warming caused by people's activities.

greenhouse gases

natural or man-made gases that trap heat in the atmosphere and contribute to the greenhouse effect. Greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, and fluorinated gases.

infrared radiation

a type of electromagnetic radiation. The Earth gives off energy in the form of infrared radiation, which is not visible to the naked eye and feels like heat to the human body.

long wave radiation

radiation emitted in the spectral wavelength greater than 4 µm corresponding to the radiation emitted from the Earth and atmosphere.

nitrous oxide

a colourless, odourless greenhouse gas that occurs both naturally and as a result of people's activities. Major sources include farming practices (such as using fertilizers) that add extra nitrogen to the soil, burning fossil fuels, and certain industrial processes.

ozone

a gas made up of three atoms of oxygen bonded together. High in the atmosphere, ozone naturally shields the Earth from harmful ultraviolet radiation and closer to the Earth's surface is a pollutant that is formed by other pollutants that react with each other. Ozone is also a greenhouse gas.

radiation

energy that travels in the form of a particle or a wave and exists in many different forms, such as electromagnetic radiation, X-rays, ultraviolet radiation, infrared radiation, and visible light.

ultraviolet radiation

a type of electromagnetic radiation, not visible to the naked eye that is produced by the sun. Most UV radiation is blocked by ozone high in the Earth's atmosphere, but some of it reaches the Earth's surface and can lead to skin cancer and eye damage.

water vapor

water that is present in the atmosphere as a gas, and as a greenhouse gas it plays an important role in the natural greenhouse effect.