A

Abiotic Factor: The physical, chemical and other non-living components of the environment that an organism lives in. These factors include all aspects of climate, geology, and atmosphere that affect ecological systems. Compare biotic factor.

Abyssopelagic Zone: 'Abysso' meaning 'no bottom', this zone of the ocean begins 4000 m below the surface of the ocean and extends down to the sea floor. This zone is home to a variety of unique critters that are specially adapted to the inhospitable conditions that these depths create. Visit the Abyssopelagic Zone on OceanLink to learn about life in the abyss.

Adaptation: Any change in the structure or function of an organism which makes it better suited to its environment. For example, the torpedo body shape of a tuna allows for fast swimming in the open ocean.

Allele: One of the alternative forms of a particular gene. Each gene is comprised of two alleles, one inherited from the father and one from the mother. However, within a population, many alleles may exist for one gene. Hair colour in humans is a great example! See also genes.

Autotroph: An organism that synthesizes organic molecules from inorganic starting materials through photosynthesis or chemosynthesis. Autotrophs are ecologically important as primary producers as they ultimately provide energy for all heterotrophic organisms. See also chemosynthesis, photosynthesis; compare heteroptroph.

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B

Bathypelagic Zone: The zone of the ocean that extends from 1000m to 4000m below the surface of the ocean. Visit the Bathypelagic Zone on OceanLink for pictures and cool facts about life at this depth.

Benthic: Refers to organisms that live on or in the ocean bed. Benthic epifauna are organisms that live on the ocean floor or upon bottom objects sch as sea anemones and barnacles, whereas benthic infauna are organisms that live within the surface sediments such as clams and worms. Compare pelagic.

Bioaccumulation:> The process whereby pollutants are taken up, retained and concentrated in the cells of plants and animals.

Biodiversity: The variation in life on Earth reflected at all levels, from various ecosystems and species, to the genetic variation within a species. See also ecosystem diversity, species diversity, genetic diversity.

Bioluminescence: Meaning living (bio) light (luminescence) is the light produced by living organisms and the emission of such biologically produced light. Also commonly referred to as 'phosphorescence'. For more info, visit the Salty Science Seaweeds Page.

Biotic Factor: A living component of the environment which arises from and affects living organisms (distinct from physical factors). For example, the interaction between predators and prey is a biotic interaction. Compare abiotic factor.

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C

Chemosynthesis: The process whereby chemical energy is used to make organic compounds from inorganic compounds. One example is the oxidation of ammonia to nitrite by nitrifying bacteria. Compare photosynthesis.

Chromosome: A linear sequence of genes wound up with proteins into a single unit that is found in the nucleus of cells. See also DNA, genes.

Community: A naturally occurring group of plants and animals that live within a certain environment and interact with each other. Communities are often defined by a dominant species (e.g. kelp forest community) or the major physical characteristics of the area (e.g. mud flats).

Conservation Biology: A field of science that deals with threats to biodiversity. The goals of conservation biology are to investigate human impacts of biodiversity and to develop approaches to prevent extinction through stewardship of entire biological communities.

Convergent Evolution: The development of similar structures in organisms that do not share recent common ancestor (e.g. eyes of squid and humans). Compare divergent evolution; see also evolution.

Cryptic Colouration: >To protect themselves against predators, many animals acquire colouring and markings to match and conceal them in their usual surroundings. For example the nudibranch (sea slug), Rostanga pulchra, is practically indiscernible from the red sponges on which it lays its eggs.

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D

Diatoms: Microscopic algae with plate-like structures composed of silica.

Decomposer: An organism which gains energy by breaking down the final remains of living things. Predominantly bacteria and fungi, decomposers are important in freeing the last of minerals and nutrients from organics and recycling them back into the food web. See also decomposition; compare detrivore.

Decomposition: The biochemical process where biological materials are broken down into smaller particles and eventually into basic chemical compounds and elements. See also decomposer.

Detritus: Dead organic matter of plant or animal. See also detrivore.

Detrivore: An organism that feeds on large bits of dead and decaying organic matter. What detrivores leave behind is used by decomposers. Crabs and seabirds are examples of detrivores. Compare decomposer; see also detritus.

Divergent Evolution: The evolution of one species to a number of different forms. Compare convergent evolution; see also evolution.

DNA: Deoxyribonucleic acid. The primary genetic material of a cell that makes up genes and chromosomes. See also genes, chromosome.

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E

Ecology: The study of the physical and biological interactions between an organism and its natural environment.

Ecological Niche: The role a plant or animal plays in its community. The niche of an organism is defined by what it eats, its predators, salt tolerances, light requirements etc. Two species cannot live stably in the same habitat if they occupy identical niches.

Ecosystem: A community of plants, animals and other organisms that are linked by energy and nutrient flows and that interact with each other and with the physical environment. Rain forests, deserts, coral reefs, and grasslands are examples of ecosystems.

Ecosystem Diversity: The diversity of biological communities and their physical environment. Diversity is determined by the species composition, physical structure and processes within an ecosystem. This is the highest level of biodiversity. See also biodiversity; compare species diversity, genetic diversity.

Effluent: Industrial or urban waste discharged into the environment.

Endangered: A species or ecosystem that is so reduced or delicate that it is threatened with or on the verge of extinction. Compare extinct, extirpated, threatened, vulnerable.

Endemic: An animal or plant species that naturally occurs in only one area.

Environment: All of the physical, chemical, and biological factors in the area where a plant or animal lives.

Epilithic: A term for organisms that live attached to rocks.
Latin translation: epi = upon, lith = rock. This term is general to terrestrial and marine habitats, ie. some lichens are epilithic.

Epipelagic Zone: see Photic Zone.

Eutrophication: Enrichment of a water body with nutrients, resulting in excessive growth of phytoplankton, seaweeds, or vascular plants, and often depletion of oxygen.

Evolution: The process by which a species' structural and behavioural characteristics change over many generations, sometimes in response to changes in environmental conditions. "New" species develop in this way. For example, scientists think that whales gradually evolved from land animals. See also convergent evolution, divergent evolution.

Extinct: A species which no longer exists. The Stellar sea cow is an example of a species which once lived on the Pacific's East Coast and is now extinct. Compare extirpated.

Extirpated: A species no longer existing in Canada, but occurring elsewhere on Earth. Compare extinct.

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F

Fertilization: The joining or fusion of the male gamete (sperm) and the female gamete (egg) to form a zygote during sexual reproduction. See also gamete, zygote.

Food Chain: A linear sequence of organisms that exist on successive trophic levels within a natural community, through which energy is transferred by feeding. Primary producers capture energy from the environment (through photo- or chemo-synthesis) and form the base of the food chain. Energy is then passed to primary consumers (herbivores) and on to secondary and tertiary consumers (carnivores and top carnivores) (e.g. phytoplankton -> zooplankton -> herring -> salmon -> killer whales). Once they die, these organisms are in turn consumed and their energy transferred to detrivores and decomposers. Compare food web.

Food Web: A non-linear network of feeding between organisms that includes many food chains, and hence multiple organisms on each trophic level. For example, both sharks and tuna eat herring, and sharks also eat tuna. Visit and tour around the Pacific Northwest Food Web on the OceanLink website.

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G

Gamete: A mature reproductive cell that is capable of fusing with another gamete of the opposite sex to form a zygote. Male gametes are typically known as sperm and female gametes a typically known as eggs. See also fertilization, zygote.

Generalist: A species that can live in many different habitats and can feed on a number of different organisms. For example, shore crabs on the Pacific coast live in a wide variety of habitats, such as mud, sand and rock, and feed on everything from the algae growing on rocks to invertebrates to detritus. Compare specialist.

Genes: The hereditary material coded in cells that determine how an organism will look and behave. A gene is a single unit located on a chromosome and is thereby passed from one generation to the next. Genes are what make each species and individual unique. For example, genes are responsible for hair colour and texture in humans. See also chromosome, DNA.

Genetic Diversity: The genetic variation that occurs within a population or species. For example, there are several different colour dog whelk shells and ochre sea stars. See also biodiversity; compare ecosystem diversity, species diversity.

Genotype: The genetic makeup of an organism. The actual appearance of an individual (the phenotype) depends on the interaction between different forms (or alleles) of genes and between the genotype and the environment. Compare phenotype.

Gillnet: A net set upright in the water to catch fish by entangling their gills in its mesh.

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H

Habitat:The immediate space where an animal or plant lives and has food, water and protection. Habitat loss, which includes the destruction, degradation, or fragmentation of habitats, is the primary cause of decreasing biodiversity.

Herbivore: A plant-eating animal. Sea urchins re a good example of a marine herbivore as they feed on kelp. See also heterotroph, primary consumer.

Hermaphrodite: An animal that has both male and female reproductive organs. Nudibranchs (sea slugs) are a good example o a hermaphrodite.

Heterotroph: An organism that is unable to synthesize organic compounds (and thus its energy) from the environment and therefore fulfils its energy requirements by feeding on other organisms or organic matter. Compare autotroph.

Homogeneous: Similar or uniform structure or composition throughout.

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I

Inorganic: Part of or derived from non-biological material. A chemical compound that does not include a carbon chain. Compare organic.

Introduced Species:> An organism that has been brought into an area, usually by humans, where it does not normally occur. Introduced species often compete with and cause problems for native species. Introduced species are also called exotic, nonnative, and alien species. See also invasive species, native species.

Invasive Species: An introduced species that out-competes native species for space and resources. Scotch Broom is an invasive species that out-competes local vegetation and results in a monoculture, and hence a decrease in local diversity. See also introduced species, native species.

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J

K

Keystone Predator: The dominant predator or the top predator that has a major influence on community structure. For example, sea otters are a keystone predator in kelp beds. Sea otters eat urchins that feed on kelp which house a huge diversity of other organisms. If sea otter populations are lowered in an area the kelp beds are generally reduced and urchin barrens appear.

Keystone Species: A species that has a major influence on community structure.

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L

M

Mesopelagic Zone: Also called the "twilight zone" of the ocean, this area from 200m to 1000m in depth, is bordered by the photic zone above and darkness below. It's in this zone where you start to see bioluminescence on all sorts of animals. Visit the Mesopelagic Zone on OceanLink to learn about the animals unique to these depths.

Morphology: The form and structure of an organism, in particular its outside features.

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N

Native Species: A species that occurs naturally in an area (i.e. is not introduced). Compare introduced species, invasive species.

Natural Selection: The main mechanism of evolutionary change. In a given population of organisms, there are heritable traits that enable some members to contribute a larger number of offspring than others. If these offspring also have a greater reproductive success, then the genetic composition of the population is altered, thus evolution. See also selection pressure.

Nekton: Pelagic organisms that are free-swimming and so whose movements are independent of the tides, currents and waves. Such animals include fish, whales, squid, crabs and shrimps. The distribution of nekton is limited by temperature and nurtient supply and decreases with decreasing depth. Compare benthic, plankton.

Nonrenewable Resource: A resource that is in limited supply and can't be replenished by natural processes, at least not for thousands of years or more. Fossil fuels are nonrenewable resources. Compare renewable resource.

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O

Organic: Part of or derived from living organisms. Or a chemical compound that contains carbon as an essential component. Compare inorganic.

Over-consumption: The use of resources at a rate that exceeds the ability of natural processes to replace them.

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P

Pelagic: Refers to the plants and animals that live in the water column or in the open waters of the ocean rather than the ocean floor (see benthic). Life is found throughout the pelagic zone, however is more concentrated at shallower depths. Pelagic organisms can be further divided into the plankton and nekton. Compare benthic.

Pesticides: Chemical products used to reduce or eliminate unwanted organisms, regarded as "pests". Pesticides are often used on gardens, agricultural land, roadsides, and golf courses to eliminate species considered undesirable or damaging.

Phenotype: The physical appearance of an individual that is the result of that individual's genotype and the interaction of the genotype with the environment during development. Hence, individuals with the same genotype may have different phenotypes in different environments. Compare genotype.

Phosphoresence: see Bioluminescence.

Photic Zone: The surface layer of the ocean that is penetrated by sunlight. The photic zone is the layer of the ocean that has been explored the most as it is relatively easy to access with conventional diving equipment. In the photic zone phytoplankton flourish and it is where the fish, marine mammals, and marine invertebrates that most people are familiar with are found. Light can penetrate down to approximately 200m which marks the end of the photic zone. Also referred to as the Sunlight Zone or the Epipelagic Zone.

Photosynthesis: A chemical process whereby plants and algae use a sun's energy to make sugars (organic compounds) from carbon dioxide and water (inorganic compounds). See also autotroph, chemosynthesis.

Phylum: The broadest classification for animals. Compare species.

Phytoplankton: The plant and algae component of the plankton; the primary producers of almost all marine food webs. Compare zooplankton.

Plankton: Pelagic organisms that float through the water column, not attached to any substrate and unable to move against the currents and tides. Plankton can be further divided into phytoplankton and zooplankton, meroplankton and holoplankton. Compare nekton.

Population: The number of individuals of a particular species that live within a defined area.

Predator: An animal that hunts and kills other animals for food.

Prey: An animal that is used by other animals for food.

Primary Consumer: A heterotrophic, herbivorous organism that feeds directly on a primary producer. Urchins are a primary consumer as they feed on kelp. See also heterotroph, food chain; compare secondary consumer.

Primary Producer: An autotrophic organism that makes complex organic compounds from inorganic compounds through the process of photosynthesis or chemosynthesis. For example, phytoplankton synthesize sugars (organic compounds) from carbon dioxide and water(inorganic compounds) using energy from the sun. Phytoplankton is one example of a marine primary producer. See also autotroph, food chain.

Primary Production: Synthesis of organic matter by plants, which is the main source of energy and nutrition for other consumers in the ecosystem (e.g. herbivores). See also chemosynthesis, photosynthesis.

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Q

Quadrat: An ecological sampling unit that consists of a square frame of known area. The quadrat is used for quantifying the number or percent cover of a given species within a given area. See also transect.

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R

Renewable Resource: A resource that can be replenished through natural processes within a human life span, if it is soundly managed. Compare nonrenewable resource.

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S

Secondary Consumer: A heterotrophic, carnivorous organism that feeds on a primary consumer. Herring feeding on zooplankton are an example of a secondary consumer. See also food chain, heterotroph, primary consumer.

Selection Pressure: A measure of the effectiveness of natural selection in altering the genetic composition of a population. See also natural selection.

Specialist: A species with a very narrow range in habitat or food requirements. For example, the Marbled Murrelet nests in old-growth forests on thick branches high up in the forest canopy. Compare generalist.

Speciation: The evolution of one or more species from an existing species.

Species: A group of organisms that differ from all other groups of organisms and that are capable of breeding and producing fertile offspring. This is the smallest unit of classification for plants and animals. Compare phylum.

Species Diversity: A measure of both species abundance and species richness. An area that has a large number of species and many representative individuals from each species is more diverse than an area that has only a single species. See also biodiversity; compare ecosystem diversity, genetic diversity.

Species Abundance: The total number of individual of a species within a given area or community. Compare species richness.

Species Richness: The number of different species that exist within a given area or community. Compare species abundance.

Substrate: The material upon or within which a plant or animal live or grows (e.g. rocky or sandy substrate). See also benthic.

Sunlight Zone: see Photic Zone.

Sustainable: A sustainable way of life is one in which human needs are met without diminishing the ability of other people, wild species, or future generations to survive.

Symbiosis:< An interaction between two different species where either both, one or neither of the organisms benefit from the relationship. Many symbiotic relationships are obligatory (e.g. tropical reef building corals and their algal symbiont).

Systematics: The area of biology that deals with the diversity of living organisms, their relationships to each other through evolution, and their classification. Can also be referred to as taxonomy.

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T

Taxonomy: The theory and practice of describing, naming and classifying plants and animals. See also systematics.

Threatened: A species likely to become endangered if limiting factors are not reversed. Compare endangered, extinct, extirpated, vulnerable.

Transect: A straight line placed on the ground along which ecological measurements are taken. If an ecologist wanted to sample the diversity of intertidal organisms in the intertidal, he/she would place a number of transects perpendicular to the shore and take samples at predetermined interval lengths. See also quadrat.

Trophic levels: The energy levels or steps in a food chain or food web: primary producer, primary consumer, secondary consumer, tertiary consumer etc.

Twilight Zone: see Mesopelagic Zone.

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U

V

Vulnerable: A species of special concern because of characteristics that make it particularly sensitive to human activities or natural events. Compare endangered, extinct, extirpated, threatened.

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W

Water Cycle: The continuous circulation of water from the atmosphere to the earth, including the ocean, and back to the atmosphere through condensation, precipitation, evaporation, and transpiration.

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X

Y

Z

Zooplankton: Animal component of the plankton that feed on phytoplankton and other zooplankton (primary consumers). Compare phytoplankton.

Zygote: A fertilized egg. Or the diploid cell that results from the joining of two haploid gametes (sperm and egg) during sexual reproduction, that will cleave to form an embryo. See also fertilization, gamete.

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References

Lincoln, R., Boxshall, G., Clark, P. 1998 A Dictionary of Ecology, Evolution and Systematics - 2nd ed. Cambridge University Press, Cambridge.

Norse, Elliott A. 1993 Global Marine Biological Diversity: A strategy for building conservation into decision making. Island Press , Washington, DC.

Oxford. 1990 A Concise Dictionary of Biology. Market House Books, Oxford University Press, Toronto.

Toothill, Elizabeth (ed.). 1998 The Facts on File Dictionary of Biology. Charles Letts & Co. Ltd., New York.

World Wildlife Federation. 1996 WOW! Windows on the Wild. World Wildlife Federation, pp.26.

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