Abiogenesis (Gr. a — not, without; bios — life; genesis — origin) — the theory of the origin of life from non-living matter (according to modern views, through chemical evolution of organic substances and increasing complexity of geochemical cycles).
Abiotic factors (Gr. a — not, without; bios — life) — a group of ecological factors associated in their origin with non-living nature.
Agrosystems (Lat. ager — land; Gr. systema — composed of parts, combination) — artificial agricultural ecosystems inhabited by plants and animals modified by humans.
Adaptation (Lat. adaptare — to adjust) — adjustment; the morphophysiological, behavioural, or other correspondence between organisms of a given species and their way of life.
Additive properties of a system (Lat. additio — addition) — properties of a system that can be determined as the sum of the corresponding properties of its subsystems.
Accessories (Fr. accessoire — auxiliary details) — a group of ecological factors whose action is not vitally necessary for organisms (in the classification of factors by their importance).
Allometric growth (Gr. allos — other, different; metron — measure) — unequal growth of body parts during organismal development. May be negative (slower growth of the head relative to the body in children) or positive (accelerated growth of horns in ruminant artiodactyls).
Albedo (Ger. Albedo — bright) — the reflective capacity of a surface, measured as a percentage. A perfectly black body has an albedo of 0%, while a surface reflecting all incident radiation has an albedo of 100%.
Altruistic behaviour (Lat. alter — other) — actions by an individual aimed at benefiting its conspecifics, associated with harm or risk to the individual itself.
Amensalism (Gr. a — not, without; Lat. mensa — table) — a type of relationship between populations or species in which one population experiences an unfavourable effect from another without affecting it in return. An extreme manifestation of competition.
Anabiosis (Gr. anabiosis — revival, return to life) — an adaptation of organisms to survive unfavourable external conditions (low temperature, absence of moisture, etc.). A state in which vital processes are slowed and visible signs of life are almost absent. When favourable conditions return, the organism reverts to normal vital functions.
Anaerobes (Gr. an — not, without; aer — air; bios — life) — organisms capable of living and developing in the absence of free oxygen. They may be obligate (existing only in the absence of oxygen) or facultative (capable of surviving in an oxygen-containing environment as well). They use organic or inorganic substances (nitrates, sulphur compounds, CO2) as oxidising agents.
Antibiotics (Gr. anti — against; bios — life) — chemical substances produced by fungi and bacteria that are capable of exerting toxic effects on other microorganisms even in small quantities. The term often also includes antimicrobial substances produced by higher plants (phytoncides) and animals. In medical practice, the antibiotic effect was first discovered for penicillin by A. Fleming in 1929.
Anthropogenesis (Gr. anthropos — human; genesis — origin) — the origin of humans in the course of evolution and their development as a species.
Anthropic factors (Gr. anthropos — human) — a group of ecological factors associated with human activity in transforming non-living and living nature. By origin they can be divided into technogenic and agrogenic factors. The term is sometimes used as a synonym for “anthropogenic factors.”
Anthropogenic factors (Gr. anthropos — human; Lat. genos — lineage, origin) — a group of ecological factors associated with the direct influence of humans, as living beings, on the environment. The term is sometimes used as a synonym for “anthropic factors.” See also section 5.2.
Range (area) (Lat. area — area, space) — the part of Earth’s surface within which a given taxon (species, genus, etc.) or community type is distributed and completes its full developmental cycle.
Archaebacteria (archaea) (Gr. archaios — ancient; bakteria — rod) — a group of prokaryotes differing from true bacteria (eubacteria) in a number of significant physiological and biochemical characteristics. Some representatives possess a special type of photosynthesis in which light quanta are absorbed not by chlorophyll but by bacteriorhodopsin. Archaebacteria include methanogens, sulphur-oxidising and sulphur-reducing thermophiles, halophiles, and thermoplasmas.
Autecology (Gr. autos — self; oikos — home, habitat; logos — science) — the branch of ecology concerned with the interactions of individual organisms with their environment. Synonyms: organismal ecology, factorial ecology, physiological ecology.
Aerobes (Gr. aer — air; bios — life) — organisms capable of living and developing only in the presence of free oxygen in the environment, used as an oxidising agent. They may be obligate (existing only in the presence of oxygen) or facultative (capable of surviving in an oxygen-free environment as well). Most eukaryotes are aerobic organisms.
Benthos (Gr. benthos — depth) — the aggregate of organisms living within and on the surface of the bottom substrate of marine and freshwater bodies. Includes plant (phytobenthos), animal (zoobenthos), bacterial, and lower fungal components.
Biomass (Gr. bios — life; Lat. massa — heap, mass) — the total mass of individuals of a species or of an organismal community. Expressed as dry or wet mass per unit area or volume of habitat (kg/ha, g/m², kg/m³, etc.). To relate it to energy flow in an ecosystem it is expressed in units of energy per unit surface area (J/m²).
Biotic factors (Gr. bios — life) — a group of ecological factors associated in their origin with living organisms.
Biotope (Gr. bios — life; topos — place) — an area of Earth’s surface with uniform values of abiotic factors, occupied by a particular biocenosis. An analogous concept is habitat.
Biogeochemical cycle (Gr. bios — life; ge — earth; chemeia — chemistry; kyklos — circle) — the set of relatively closed pathways of movement of substances and energy among the components of the biosphere, driven by the vital activity of organisms. The term was proposed by V. I. Vernadsky (1910–1912).
Biogeocenosis (Gr. bios — life; ge — earth; koinos — common) — a relatively uniform area of Earth’s surface with a particular type of vegetation and a defined composition of living (biocenosis) and non-living (geocenosis) components, united by cycling of matter and energy flow. The totality of biogeocenoses constitutes the biosphere. The concept is close to “ecosystem” but differs from it in having a defined spatial scale. The term was proposed in 1940 by V. N. Sukachev.
Biogenic elements (biogenes) (Gr. bios — life; Lat. genos — lineage, origin) — chemical elements that are permanently incorporated into organisms and fulfil specific biological functions. Approximately half of the elements commonly found in Earth’s crust belong to this category.
Biogeocenology (Gr. bios — life; ge — earth; koinos — common; logos — science) — the branch of ecology concerned with processes occurring in biogeocenoses. Synonym: ecosystem ecology.
Biosystem (Gr. bios — life; systema — composed of parts, combination) — a living system. May include both living and non-living components (for example, ecosystems include a habitat).
Biome (Gr. bios — life; Lat. -oma — suffix denoting an aggregate) — the aggregate of various groups of organisms and their habitat in a particular landscape-geographic zone, such as tundra, desert, etc.; a large regional ecosystem type.
Biosphere (Gr. bios — life; sphaira — sphere) — the shell of Earth whose composition and processes are determined by the activity of living organisms.
Biospherology (Gr. bios — life; sphaira — sphere; logos — science) — the branch of ecology concerned with processes occurring in the biosphere.
Biocenosis (Gr. bios — life; koinos — common) — the aggregate of living organisms jointly inhabiting a relatively uniform area; one of the components of a biogeocenosis. Its structure is stably maintained over time through interactions among all its components, primarily via trophic links. The term was proposed in 1877 by K. Möbius.
Struggle for existence — one of the central concepts of C. Darwin’s theory of evolution, by which he understood the totality of relationships between individuals and environmental factors. These relationships determine survival success and reproduction in the course of intraspecific and interspecific competition and other interactions among individuals and between individuals and the environment.
Vienna Convention for the Protection of the Ozone Layer — a convention for the cessation of production and sale of ozone-depleting substances. Concluded in 1985; developed further by the Montreal Protocol.
Species — the basic structural unit in the system of living organisms and a qualitative stage of their evolution. A universally accepted definition has not been developed. Typically the term refers to a group of populations of individuals capable of interbreeding to produce fertile offspring, inhabiting a defined range and sharing a number of morphophysiological characteristics and types of interactions with the environment.
Vicariants (Lat. vicarius — substitute, deputy) — species of plants and animals belonging to the same life form and occupying similar ecological niches in different geographical regions. They may be closely related or taxonomically distant (but similar through convergence).
Violent (Lat. violentia — force) — a strategy type (cenotype) distinguished by L. G. Ramensky. Analogous to the competitor (C-strategist) in Grime’s classification.
Viroids (Lat. virus — poison; Gr. eidos — form, appearance) — infectious agents consisting of a low-molecular-weight single-stranded circular RNA (molecular weight 150,000–170,000) that does not encode its own proteins. They cause diseases of plants and animals.
Gas exchange — the aggregate of processes by which organisms exchange gases with the surrounding environment. The composition of gases absorbed and released depends on the metabolic characteristics of the organism. The principal substances absorbed are O2, CO2, etc., while those released include CO2, O2, water vapour, and others.
-halinity (Gr. hals — salt) — a root used in terms describing tolerance to salinity.
Gause’s principle; law of competitive exclusion — two species occupying the same ecological niche cannot coexist stably in the same habitat; the coexistence of species is linked to the division of ecological niches. Formulated by the Russian biologist G. F. Gause on the basis of experiments on laboratory cultivation of ciliates in 1931–1935.
Hemipopulation (Gr. hemi — half; Lat. populus — people, population) — parts of a population occupying different ecological niches (for example, larvae and adults of dragonflies or frogs). The concept was introduced by V. M. Beklemishev.
Geochronological scale (Gr. ge — earth; chronos — time; logos — science; Lat. scala — ladder) — the sequence of time intervals corresponding to the sequence of sedimentary rock layers in Earth’s crust, used to describe Earth’s history. The best-known subdivisions of the geochronological scale are eras and periods.
Geocenosis (Gr. ge — earth; koinos — common) — the non-living part of a biogeocenosis.
Heterotrophs (Gr. heteros — other; trophe — nutrition) — organisms that use ready-made organic substances as their source of carbon and energy. These include all animals, fungi, most bacteria, and non-chlorophyllous terrestrial plants.
Gaia; Gaia hypothesis (Gr. Ge, Gaia — the goddess of the earth in ancient Greek mythology) — the concept, formulated in the 1970s by British chemist J. Lovelock and American biologist L. Margulis, of Earth as an integrated self-regulating system that maintains the conditions required for life on its surface.
-hygric (Gr. hygros — moist) — a root used in terms describing tolerance to moisture.
Hydrological cycle (Gr. hydor — water, moisture; logos — science; kyklos — circle) — the water cycle in nature. Driven by evaporation and transpiration.
Hyper- (Gr. hyper — above, over, beyond) — a prefix indicating an excess of the norm.
Hypo- (Gr. hypo — below, under) — a prefix indicating a reduction relative to the norm or location below a certain level.
Glycolysis (Gr. glykys — sweet; lysis — decomposition, dissolution) — the enzymatic anaerobic process of carbohydrate breakdown. Phylogenetically the most ancient pathway for glucose cleavage, it is widespread in nature and plays an important role in the metabolism of living organisms. It supplies the cell with energy under conditions of oxygen deficiency, and in obligate anaerobes it is the sole pathway for energy production.
Holophages (Gr. holos — whole; phagos — devouring) or true predators — exploiter organisms that kill their prey immediately.
Homeothermy (Gr. homoios — similar; therme — heat) — a type of thermoregulation in which an animal maintains a constantly relatively high body temperature by means of regulatory mechanisms controlling both its lower and upper boundaries.
Demographic pyramids (Gr. demos — people; grapho — I write) — one of the graphical methods for displaying changes in the age and/or sex composition of a population as presented in life tables. They allow the history of a given population to be traced.
Life tables (Gr. demos — people; grapho — I write) — a method of presenting data on changes in the age-sex composition of populations.
Demography (Gr. demos — people; grapho — I write) — the science of human population, its size and patterns of change, composition, and distribution over Earth’s surface.
Detritus (Lat. detritus — worn away) — organic matter in the process of decomposition, along with the microorganisms it contains. It plays an important role in the cycling of organic matter (detrital food chain), serves as a reservoir of biogenic elements, and is a constituent of soil.
Detrital food chain (Lat. detritus — worn away) or decomposer chain — a food chain whose base is detritus. Consists of detritivores and the predators that feed on them.
Detritivores (Lat. detritus — worn away; Gr. phagos — devouring) — animals that feed on detritus.
Dynamic characteristics of a population (Gr. dynamikos — pertaining to force; charakter — mark, feature) — characteristics of a population showing changes in its static characteristics over time. They include birth rate, mortality, and migration.
Dynamism (Gr. dynamis — force) — the state of continuous change characteristic of all levels of organisation of living matter. Examples of dynamism in biosystems include the death and reproduction of individuals within a population, and the mobility of cells and organisms.
Respiration — one of the basic functions of aerobic living organisms; the enzymatic oxidation of organic substances by oxygen with the release of energy. The term is sometimes also used to denote the gas exchange that supports respiration: the uptake of oxygen and the release of carbon dioxide by the organism.
Carrying capacity — the variable K in the logistic equation of population growth, characterising the equilibrium population size at which the population consumes all available resources.
Natural selection — the primary driving force of evolution; the preferential survival and/or reproduction of better-adapted individuals. The prerequisite for selection is organismal variability. The concept of natural selection was first developed by C. Darwin and, independently, by A. R. Wallace.
Life form — a stable complex of adaptations to a particular way of life, often expressed in a characteristic external appearance. Both related and unrelated organisms may belong to the same life form. Among the first to describe life forms (under the name “physiognomic types”) was A. von Humboldt; the widely known classification of plant life forms was proposed by C. Raunkiaer.
Life cycle (Gr. kyklos — circle) — the totality of all developmental phases through which an organism must pass before reaching maturity and being capable of giving rise to the next generation. A simple life cycle is characteristic of individuals with direct development (e.g., grasshoppers). A complex life cycle occurs in individuals that develop via metamorphosis. It may include development during the ontogeny of a single individual (e.g., the cockchafer) or development with alternation of generations and reproductive types (e.g., scyphozoan jellyfish, plants with sporophyte and gametophyte generations).
Life — a phenomenon of which our existence is one manifestation. It has no universally accepted definition. The definition proposed in this course: life is the maintenance and reproduction of characteristically highly ordered structures, which are perfected through evolution and are carried out in accordance with an internal programme by means of external sources of matter and energy.
Zooplankton (Gr. zoe — life; planktos — wandering) — see Plankton.
Variability — the property of living organisms to exist in different forms. It may be realised in individual organisms or cells during ontogenesis, or within a group of organisms across generations during sexual and asexual reproduction.
Information (Lat. informatio — explanation, account) — orderliness that can convey a certain meaning; any data transmitted by means of any carrier.
Carotenoids (Lat. cariotta — carrot; Gr. eidos — form, appearance) — yellow, orange, or red pigments of bacteria, fungi, and higher plants. They include carotenes, the orange-yellow accessory pigments of photosynthesis.
Kyoto Protocol — an international agreement aimed at a significant reduction in industrial CO2 emissions by 2010 relative to 1990 levels. Signed in 1997 as a supplement to the United Nations Framework Convention on Climate Change.
Coadaptation (Lat. coadaptatio — mutual adaptation) — the mutual adaptation of co-inhabiting species (e.g., clover and the bumblebees that pollinate it) to interacting with each other in the course of coevolution.
Commensal (Lat. com — with, together; mensa — table) — populations that derive benefit from populations of another species during commensalism.
Commensalism (Lat. com — with, together; mensa — table) — a type of relationship between populations or species. Direct or environment-mediated relations in which individuals of one species (the commensal) derive benefit from individuals of another species (the host). The presence of the commensal is neutral for the host. The commensal may obtain shelter, protection, a modified habitat, transport, or, most commonly, food from the host.
Compass reactions (It. compassare — to measure by steps) — a mode of orientation based on maintaining a constant angle between the direction of movement and light rays from natural light sources (sun, moon). When an artificial light source is selected instead, this may lead to movement in a tightening spiral (as when nocturnal moths fly toward a candle flame).
Convergence (Lat. convergere — to approach, converge) — the independent development of similar traits in taxonomically distant groups of organisms inhabiting similar environmental conditions. In similar habitats entire biocenoses may evolve comprising series of convergent species. Thus in Australia the evolution of marsupials produced species convergent with placental mammals (wolf — thylacine, mole — marsupial mole, etc.). The term was introduced by C. Darwin.
Competitor (Lat. conkurro — I run together, I clash) — a participant in competitive interactions. In Grime’s classification — C-type (competitor), spending most energy on maintaining adult organisms; dominant in stable communities. In Ramensky’s classification — violent.
Law of competitive exclusion — see Gause’s principle.
Consumers (Lat. consumo — I consume) — heterotrophic organisms that act in the food chain as consumers of organic substances produced by producers. First-order consumers are herbivores; second- and higher-order consumers are predators. See also Reducers.
Crust (geological) — the outer solid shell of Earth, including hard surface layers of sedimentary rocks and basalt-like materials, as well as the uppermost layers of the mantle. The structure of oceanic crust differs from that of continental crust.
Coevolution (Lat. co — together; evolutio — evolution) — the joint evolution of different species closely associated in the same biocenosis. Such relationships determine the mutual dependency of the interacting species: parasites and hosts, plants and herbivores, etc. The result of coevolution is coadaptations that ensure their coexistence and the integrity of the biocenosis as a whole.
Creationism (Lat. creatio — creation) — a concept regarding the origin of life (and, more broadly, the Universe) as an act of Divine creation. It is an article of faith, not a scientific theory. It is often combined with fixism — the belief in the immutability of species in their historical development. The scientific alternative to creationism is the hypothesis of abiogenesis as a result of natural evolution of non-living matter.
Survivorship curves — one of the graphical methods for displaying information about changes in numbers across different age groups as presented in life tables. R. Pearl distinguished three basic types; real survivorship curves of various organisms are combinations of these types.
Liebig’s law of the minimum — the growth and development of an organism is most strongly influenced by the resource whose proportional availability is at its minimum. Formulated in 1840 by the German agricultural chemist J. von Liebig.
Limiting factor (Lat. limitis — boundary, limit) — the ecological factor that exerts the greatest effect on the organism under consideration and thereby determines the limit of its development or distribution.
Macro- (Gr. makros — large) — a prefix denoting large size or the study of large objects.
Mantle (geological; Lat. mantus — covering, cloak) — the shell of Earth located between the crust and the core.
Meso- (Gr. mesos — middle, intermediate) — a prefix denoting a medium value or intermediate position.
Merophages (Gr. meros — part, portion; phagos — devouring) or grazing predators — exploiter organisms that consume only part of the prey, often without inflicting lethal damage.
Habitat — a constituent part of an ecosystem; the aggregate of its non-living components.
Metapopulation (Gr. meta — after, beyond; Lat. populus — people, population) — a long-lived population composed of short-lived subpopulations whose unity is maintained by exchange of migrants.
Migration (Lat. migratio — resettlement, movement) — regular movements of animals between different areas of Earth’s surface or different habitats. Periodic (daily, seasonal) and non-periodic (irregular mass movements of sedentary animals caused by changes in living conditions) migrations are distinguished. As a dynamic characteristic of populations it is associated with departure from one population (emigration) and entry into another (immigration).
Mycorrhiza (Gr. mykes — fungus; rhiza — root) — mutualism between fungal mycelium and the roots of a higher plant. Fungi decompose organic soil compounds inaccessible to the plant, facilitating phosphorus and nitrogen uptake and producing vitamins and growth stimulants, while themselves obtaining carbohydrates drawn from the plant’s roots.
Micro- (Gr. mikros — small) — a prefix used to denote objects of small size or a limited area of something.
Mutualism (Lat. mutuus — mutual) — obligate symbiosis. A mutually beneficial relationship between two populations or species in which they occur only together.
Modelling (Lat. modulus — measure, example) — the study of phenomena, processes, or systems of objects by constructing their models — analogously structured systems.
Model (Lat. modulus — measure, example) — a system created to study an original system. It must have a similar character of interaction among parts and thereby possess analogous emergent properties.
Montreal Protocol — an international agreement requiring a complete cessation of production and sale of chlorofluorocarbon substances that deplete the ozone layer, by 2010. Signed in 1987 as a supplement to the Vienna Convention.
Heredity — the property of organisms ensuring the continuity of traits between generations. Realised through reproduction, across generations, of a specific character of metabolism and ontogenesis under particular external environmental conditions.
Neutralism (Lat. neuter — neither one nor the other) — a type of relationship between populations or species in which they have no influence on each other, or in which such influence is negligible.
Nekton (Gr. nektos — swimming) — the aggregate of actively swimming aquatic animals capable of overcoming currents and covering large distances. These include fish, squid, cetaceans, pinnipeds, sea turtles, sea snakes, and others.
Obligate (Lat. obligatus — obligatory, necessary) — a term indicating the obligatory nature of certain conditions of existence (an obligate parasite is an organism for which a parasitic way of life is the only possible one).
Metabolism — the most important characteristic of biosystems. The totality of chemical transformations and movements of substances occurring in living systems that ensure their normal functioning.
-oxybiontic (Ger. Oxy — oxygen; Gr. biontos — living) — a root used in terms describing tolerance to dissolved oxygen content in water.
Oligo- (Gr. oligos — few, insignificant) — a prefix indicating adaptation to low values of the factor under consideration.
Ontogenesis (Gr. ontos — being; genesis — origin) — the individual development of an organism; the totality of its transformations from inception to the end of life.
Sedimentary cycle — the movement of elements (in particular, biogenic elements) from weathered rocks into sediments on the bottom of water bodies, and subsequently, through plate tectonics, their re-elevation to a surface accessible to weathering. The sedimentary cycle ensures the availability of most biogenic elements to living organisms.
Osmosis (Gr. osmos — push, pressure) — the diffusion of a solvent through a semi-permeable membrane toward a higher concentration of dissolved substances.
Osmotic pressure (Gr. osmos — push, pressure) — the external pressure that must be applied to a solution to halt the entry of pure solvent into it through a semi-permeable membrane.
Nature conservation — activities aimed at limiting the adverse effects of human activity on the environment.
Parasitism (Gr. parasitos — one who eats at another’s table) — a type of relationship between individuals, populations, or species. A form of exploitation in which a representative of one species (the parasite) uses a representative of another species as its habitat and food source, causing it a certain degree of harm.
Parasitoids (Gr. parasitos — one who eats at another’s table; eidos — form, appearance) — exploiter organisms that live freely but deposit their eggs in, on, or near a host. Their larvae develop inside the host, consuming it alive. The death of the host is inevitable but delayed.
Parasites (Gr. parasitos — one who eats at another’s table) — exploiter organisms closely associated with their host, drawing only part of its resources. They do not necessarily cause death. Obligate and facultative parasites are distinguished. Depending on their location on the host’s body, endo- and ectoparasites are recognised (many ectoparasites are more properly considered merophages). Development may take place entirely within the host or may include free-living stages or life cycles involving host alternation. Parasites are characterised by reduction of some organ systems (digestive, nervous, sensory) and elaboration of others (reproductive, attachment organs).
Greenhouse effect — the warming of a system whose surface transmits incoming electromagnetic radiation more readily than outgoing radiation. For example, Earth’s atmosphere is relatively transparent to solar light but traps (via greenhouse gases — H2O, CO2, CH4) the far-infrared radiation emitted by Earth.
Grazing food chain or food chain based on consumption — a food chain whose base is autotrophic organisms (producers). The second level consists of herbivores (first-order consumers); above them are predators (second- and higher-order consumers).
Patient (Lat. patientia — patience, endurance) — a strategy type (cenotype) distinguished by L. G. Ramensky. Analogous to the stress-tolerant (S-strategist) in Grime’s classification.
Plankton (Gr. planktos — wandering) — the aggregate of organisms suspended in the water column of marine and freshwater bodies. They are maintained in it by their small size, buoyancy, various outgrowths, and sometimes by the action of locomotory organs. Includes plant (phytoplankton), animal (zooplankton), and bacterial (bacterioplankton) components.
Population density — a static characteristic of a population defining the number of individuals per unit of space. Expressed as number per unit area or volume.
Poikilothermy (Gr. poikilos — varied; therme — heat) — a type of thermoregulation in which an organism does not maintain a constant body temperature by means of physiological thermoregulatory mechanisms. Survival under changing ambient temperatures is ensured by behavioural adaptations or changes in organismal state (hibernation, anabiosis, etc.).
Poly- (Gr. poly — many) — a prefix indicating adaptation to high values of the factor under consideration.
Population (Lat. populus — people, population) — the aggregate of individuals of the same species sharing a common gene pool and occupying a defined territory. See also section 4.1.
Allen’s rule — a pattern of intraspecific and interspecific (among closely related species) variability. It states that among related forms of homeothermic animals, those inhabiting colder climates have shorter protruding body parts (ears, legs, tail, etc.). The rule was formulated by J. A. Allen in 1877.
Bergmann’s rule — a pattern of intraspecific and interspecific (among closely related species) variability. It states that among related forms of homeothermic animals, those inhabiting colder climates have larger body sizes. The rule was formulated by C. Bergmann in 1847.
Gloger’s rule — a pattern of intraspecific and interspecific (among closely related species) variability. According to this rule, among related forms of homeothermic animals, those inhabiting warm and humid climates have brighter colouration than those inhabiting cold and dry climates. The rule was formulated by C. Gloger in 1833.
Tidal rhythms — adaptations of marine organisms inhabiting the intertidal zone to the influence of the Moon orbiting Earth; specifically to the lunar day (24 hours 50 minutes), during which two tidal cycles occur. The reproduction of some fish and polychaete worms, horseshoe crabs, the vertical migrations of plankton, and the activity of molluscs are synchronised with these rhythms.
Fitness — the correspondence between the characteristics of biosystems and the properties of the environment with which they interact. It cannot be achieved once and for all, since the environment changes continuously.
Producers (Lat. producens — producing, creating) — autotrophic organisms that create organic substances from inorganic ones by means of photosynthesis or chemosynthesis. Producers constitute the first trophic level of ecosystems (the base of ecological pyramids). The principal producers of aquatic and terrestrial ecosystems are green plants.
Prokaryotes (Lat. pro — before; Gr. karyon — nucleus) — organisms whose cells lack a nucleus. Prokaryotes are most commonly divided into two kingdoms: eubacteria (which include, among others, cyanobacteria) and archaebacteria.
Protocooperation (Gr. protos — first; Lat. cooperatio — cooperation) — a type of relationship between populations or species. A form of symbiosis characterised by facultative mutually beneficial relations between two populations.
Profane ecology (Lat. profanus — uninitiated, secular) — unscientific, often idealised notions about “Nature”; non-constructive condemnation of human characteristics and the consequences of human activity.
Irritability — the property of biosystems to respond to external or internal influences. It underlies adaptation to changing environmental conditions.
Reducers (decomposers) (Lat. reducens — returning, restoring) — organisms that feed on dead organic matter and subject it to mineralisation. These include organisms forming part of the detrital food chain (bacteria, fungi, some animals).
Requisites (Lat. requisitum — the necessary) — a group of ecological factors without which the existence of organisms is impossible (in the classification of factors by their importance).
Resources (Lat. resurgere — to recover, revive) — a group of ecological factors that are consumed by organisms and are thereby spent and exhausted.
Reproductive potential (Lat. reproducere — to reproduce; potens — capable of something) — the variable r in the logistic equation of population growth, characterising its capacity for increase.
Rhyniophytes (Rhyniophyta) — a division of extinct ancient vascular plants. Known from the Silurian to the Upper Devonian. They had smooth shoots with sporangia borne terminally or laterally. Leaves and roots were absent. Probable ancestors of ferns and fern allies.
Ruderal (Lat. ruderis — rubble, debris) or R-type — a strategy type distinguished by J. Grime. Organisms of this type replace violents in disturbed communities or exploit resources temporarily unused by other species. In Ramensky’s classification — explecrent (explerunt).
Self-regulation — the maintenance of constancy in the properties of biosystems. Ensured by the action of feedback mechanisms.
Seasonal rhythms — the response of an organism to regularly recurring changes in a complex of factors associated with the change of seasons. In temperate latitudes, in most organisms they are regulated by photoperiodism.
System (Gr. systema — composed of parts; combination) — an ordered whole consisting of interconnected parts. Systems may be material or abstract. Biosystems are of particular importance for ecology.
Symbiosis (Gr. symbiosis — living together) — a type of mutually beneficial relationship between populations or species. The basis may be trophic, spatial, or other relationships. Symbiosis may be facultative (protocooperation) or obligate (mutualism).
Synthetic theory of evolution (STE) (Gr. synthesis — combination; Lat. evolutio — development) — the theory that views evolution as the consequence of changes in allele frequencies in populations. It emerged in the 1930s–40s as the result of applying principles of population genetics to the description of evolutionary phenomena.
Synecology (Gr. syn — together; oikos — home, habitat; logos — science) — the branch of ecology studying supra-organismal systems.
Solar system — a stellar system comprising the star Sol (the Sun), nine planets orbiting it (including Earth), and various other components (asteroid belt and comets).
The Sun — a star of the yellow dwarf class. It consists of approximately 24% helium, 75% hydrogen, and 1% other elements. As a result of thermonuclear fusion occurring within the Sun, hydrogen is converted into helium, releasing energy that made possible the origin and development of life on Earth.
Community — an aggregate of living organisms of various species representing a certain ecological unity. Sometimes defined as the total aggregate of organisms inhabiting a particular area of Earth’s surface, thus serving as a synonym for “biocenosis.”
Environmental science (envarionmentology) — the study of characteristics of the habitat and the processes affecting it. Synonym: environmentology.
Station (habitat patch) (Lat. statio — place, station) — an area of Earth’s surface occupied by individuals of a given species and characterised by the ecological conditions necessary for them. Each species corresponds to a strictly defined set of stations, which may serve as a distinguishing feature. The term is more often used in relation to terrestrial organisms and is close to the more general concept of “habitat.”
Static characteristics of a population (Gr. statos — standing; charakter — mark, feature) — characteristics of a population that can be determined for a specific moment in time. These include abundance, sex composition, age composition, population density, and spatial distribution.
Steno- (Gr. stenos — narrow) — a prefix indicating a narrow tolerance range.
Stenobionts (Gr. stenos — narrow; bios — life) — organisms adapted to living in strictly defined environmental conditions.
Stress-tolerant or S-type (Lat. tolerant — patiently enduring) — a strategy type distinguished by J. Grime. Organisms of this type endure unfavourable conditions by exploiting resources in places where almost no other species compete for them. In Ramensky’s classification — patient.
Stromatolites (Gr. stroma — layer, bedding; lithos — stone) — fossilised formations with diverse internal layering resulting from the vital activity of cyanobacteria and bacteria. Known from the Archean. In modern tropical seas they form under conditions of frequently changing water salinity.
K-strategy (Gr. stratos — army; ago — I lead) — the adaptive strategy of species that spend most of the energy they obtain on maintaining the life of the individual. The name is associated with the constant K (carrying capacity) of the logistic equation of population growth. The r- and K-strategy typology was proposed by R. MacArthur and E. O. Wilson in 1967.
r-strategy (Gr. stratos — army; ago — I lead) — the adaptive strategy of species that spend most of the energy they obtain on reproduction. The name is associated with the variable r (reproductive potential) of the logistic equation of population growth. The r- and K-strategy typology was proposed by R. MacArthur and E. O. Wilson in 1967.
Sub- (Lat. sub — under) — a prefix denoting location below the level indicated by the root word (subpopulation); subordination or dependence of an action or object; location near what is indicated by the root word (subarctic).
Succession (Lat. successio — inheritance, succession) — the sequential replacement of communities within a single habitat. Primary and secondary, autotrophic and heterotrophic, autogenic and allogenic successions are distinguished.
Diel (circadian) rhythms — regularly recurring changes in the physiological states of an organism in accordance with daily periodicity. Regulators of these processes include changes in light regime, temperature, precipitation, humidity, wind, etc.
Lithospheric plate tectonics (Gr. tektonike — the art of building) — the branch of geology studying the mobility of plates in Earth’s lithosphere; the mobility of these plates itself.
Thermoregulation (Gr. therme — heat; Lat. regula — norm, rule) — an organismal function consisting in the ability to alter body temperature physiologically or through appropriate behaviour in a direction favourable for the organism.
Tolerance (Lat. tolerantia — patience) — the ability of an organism to withstand the effects of unfavourable environmental factors.
Topical relationships (Gr. topikos — place) — interspecific relationships (in V. M. Beklemishev’s classification) consisting in the modification of the habitat by one species in a favourable or unfavourable direction for other species.
Trophic relationships (Gr. trophe — nutrition) — interspecific relationships (in V. M. Beklemishev’s classification) based on feeding (feeding of individuals of one species on individuals of another or on their metabolic products).
Food chains (trophic chains) (Gr. trophe — nutrition) — pathways for the transfer and transformation of energy and matter in ecosystems, based on the feeding of organisms. From link to link in the chains, most potential energy is lost as heat; consequently the number of links most commonly does not exceed four or five. Since the diet of most species in a chain includes several other species, the term “trophic web” is more accurate. Constructing food chains helps assign their components to specific trophic levels. Food chains are divided into grazing chains and detrital chains.
Trophic level (Gr. trophe — nutrition) — the aggregate of organisms united by feeding type. The first level comprises autotrophs (producers); the second comprises herbivores (first-order consumers); the third and subsequent levels comprise predators feeding on them (second- and higher-order consumers). Organisms from different food chains that receive energy through the same number of links occupy the same trophic level. The proportional relationships among trophic levels can be depicted graphically as ecological pyramids.
Turgor (Lat. turgor — swelling, fullness) — the tense state of a cell wall created by the pressure of intracellular fluid. Owing to turgor, plant tissues possess elasticity.
Uniqueness (Lat. unicus — unique, exceptional) — the property of biosystems to be irreproducible and to differ from analogous systems.
Levels of organisation of biosystems — hierarchically subordinate levels at which manifestations of life are observed, from the molecular to the biospheric. For ecology, the organismal and supra-organismal (populational, ecosystemic, etc.) levels are of particular importance.
Conditions — a group of ecological factors that are not consumed and cannot be exhausted (though they may change) by organisms.
Fabric relationships (Lat. fabrica — workshop) — interspecific relationships (in V. M. Beklemishev’s classification) consisting in the provision of a habitat (lice in the human hair coat) or the “construction” of shelters (woodpeckers excavate cavities in which other animals live).
Facultative (Lat. facultas — capacity, possibility) — a term indicating the possibility and non-obligatory nature of certain conditions of existence (a facultative anaerobe is an organism that can live both in the presence and in the absence of oxygen).
Phycobilins (Gr. phykos — alga; Fr. bile — bile) — pigments of red algae and cyanobacteria. In cells they are contained in phycobilisomes. Absorbing in the green part of the spectrum, they participate in photosynthesis as accessory pigments, transferring absorbed energy to chlorophyll molecules. They include phycoerythrins (red pigments) and phycocyanins (blue pigments).
Phylogenesis (Gr. phylon — lineage, tribe; genesis — development) — the evolutionary history of a particular group of organisms or of life in general. The term was introduced by E. Haeckel in 1866.
Phytoplankton (Gr. phyton — plant; planktos — wandering) — see Plankton.
Phoric relationships (Gr. phoros — carrying) — interspecific relationships (in V. M. Beklemishev’s classification) consisting in the transport of individuals of one species by individuals of another.
Photonasties (Gr. photos — light; nastos — compressed) — movements of plant organs caused by changes in light intensity. Associated with growth processes and changes in turgor.
Photoperiodism (Gr. photos — light; periodos — circuit, rotation) — the response of organisms to the length of the photoperiod (day length), expressed in changes in growth and developmental processes. Widespread in organisms of the temperate zone.
Photoreactions (Gr. photos — light) — responses of an organism to visible light. Photoreactions must be distinguished from photoperiodism.
Photosynthesis (Gr. photos — light; synthesis — combination) — the formation by plants and some bacteria of organic substances from inorganic ones with the participation of solar light. Occurs by means of pigments, the most important of which is chlorophyll.
Phototaxis (pl. phototaxes) (Gr. photos — light; taxis — arrangement, order) — movement toward a light source (positive phototaxis) or away from it (negative phototaxis).
Phototropism (pl. phototropisms) (Gr. photos — light; tropos — turn, direction) — orientation with respect to a light source. Characteristic of sessile animals and plants. Growth movements lead to displacement toward the light (positive phototropism, characteristic of stems) or away from it (negative phototropism, as in roots).
Phototrophs (Gr. photos — light; trophe — nutrition) or photoautotrophs — bacteria and plants capable of photosynthesis. They draw upon the energy of light radiation and convert it into a form accessible to other organisms.
Photochemical reactions (Gr. photos — light) — reactions that occur under the action of light. These include photosynthesis, the synthesis of vitamin D, etc.
Chemosynthesis (Gr. chemeia — chemistry; synthesis — combination) — one type of autotrophic nutrition in bacteria, based on the assimilation of carbon dioxide through the oxidation of inorganic compounds.
Chemotrophs (Gr. chemeia — chemistry; trophe — nutrition), chemoautotrophs, chemosynthesisers, lithotrophs — bacteria whose autotrophic nutrition is based on the assimilation of carbon dioxide through the oxidation of inorganic compounds.
Chlorophylls (Gr. chloros — green; phyllon — leaf) — the green pigments of plants by means of which they capture light energy and carry out photosynthesis. The basis of the molecule is a magnesium–porphyrin complex. The molecule becomes physiologically active only in a form bound to protein. In the cell it is contained in chloroplasts and chromatophores. Types of chlorophyll differ in structural details and absorption spectra. Chlorophyll a is the principal pigment; the rest are accessory photosynthetic pigments.
Kingdom — one of the highest taxonomic ranks in modern systematics. One of the most widely used modern systems, proposed by R. Whittaker, distinguishes four kingdoms of eukaryotes (Plants, Animals, Fungi, and Protists) and one or two kingdoms of prokaryotes (Bacteria and Archaebacteria). Notably, at least some of these kingdoms are not separate evolutionary lineages but life forms whose similarity is related to a similar way of life.
Cenopopulation (Gr. kainos — new; Lat. populus — people, population) — a population inhabiting a particular biogeocenosis. The term is more often applied to plant populations.
Integrity — a necessary condition for considering any object as a system. It is the result of the interconnection and interdependence of parts of biosystems and the basis for the emergence of emergent properties in the system.
Circadian rhythms (Lat. circa — approximately; dies — day) — near-daily rhythms representing changes in organismal activity over a period of 20–28 hours. Regulated by the alternation of light and darkness. See also Diel rhythms.
Circannual rhythms (Lat. circa — approximately; annus — year) — annual cycles of organisms; typically controlled by day length.
Particular (special) ecology — the ecology of individual groups of organisms.
Shelford’s principle; principle of ecological tolerance — for any given condition, a tolerance range can be distinguished within which an optimal value exists. The more the condition deviates from the optimum, the stronger its unfavourable effect on the organism. Formulated in 1913 by the American ecologist V. E. Shelford.
Evolution (Lat. evolutio — development, unfolding) — the process of historical change in species and in the entire biosphere.
Eury- (Gr. eurys — broad) — a prefix indicating a broad tolerance range.
Eurybionts (Gr. eurys — broad; bios — life) — organisms capable of existing under highly diverse environmental conditions.
Exo- (Gr. exo — outside) — a prefix meaning outside, beyond. Same as ecto-.
Ecocline — succession observed in space. An example is the colonisation of a sandy beach on river meanders. At the edge such a beach is bare; further along it is covered with grass; further still it becomes colonised by shrubs. This spatial sequence corresponds to the stages of succession in time.
Ecological niche — the totality of all environmental factors within which the existence of a species in nature is possible. The term was proposed by J. Grinnell in 1917 to characterise the spatial distribution of species, which is close to the concept of “habitat.” In 1927 C. Elton defined the ecological niche as the position of a species in a community, emphasising the importance of trophic relationships. The modern concept developed on the basis of models proposed by G. E. Hutchinson (1957, 1965), according to which the ecological niche is a portion of an imaginary multidimensional space (hypervolume) whose individual dimensions correspond to the factors necessary for the normal life of the species.
Ecological environment — the totality of all objects and processes that can influence the biosystem under study, at the organismal or higher level; that which the biosystem interacts with and adapts to.
Ecological pyramids — a graphical representation of the proportional relationships among trophic levels. The base of the pyramid is always the producer level. Pyramids of numbers (number of individual organisms at each level), biomass (total quantity of living matter), and energy (magnitude of energy flow) are distinguished.
Ecological factor — an individual characteristic of the environment; a particular phenomenon, process, or property that can affect the organism under study.
Ecology (Gr. oikos — home, habitat; logos — science) — the science studying the interactions of organisms and supra-organismal systems with the surrounding environment; see also section 1.1.
Ecosystem (Gr. oikos — dwelling; systema — combination) — the unity of the aggregate of living organisms (community) and their habitat (environment), connected by exchange of matter, energy, and information. The concept was proposed by A. Tansley in 1935. Sometimes interpreted as applying only to relatively uniform areas of Earth’s surface and thus virtually identical to “biogeocenosis.” More often interpreted as a scale-independent concept applicable to biogeocenoses as well as to smaller (e.g., a drop of water) and larger (e.g., the biosphere) systems.
Explerent (Lat. explere — to fill) — a strategy type (cenotype) distinguished by L. G. Ramensky. Analogous to the ruderal in Grime’s classification.
Exploitation (Fr. exploitation — use, extraction of benefit) — asymmetric relationships between populations or species in which a change in the abundance of the prey population leads to an increase in the abundance of the exploiter population, while an increase in the exploiter’s abundance leads to a decrease in the prey’s abundance. The principal types are predation and parasitism in various forms.
Emergent properties of a system (Lat. emergere — to rise, to appear) — qualitatively new properties of a system absent in its isolated parts.
Environmentology (Eng. environment) — the science of the environment. Synonym: environmental science.
Endo- (Gr. endon — within) — a prefix meaning within, inside something. Same as ento-.
Energy (Gr. energeia — action, activity) — matter lacking rest mass, serving as the general measure of the quantity of motion and as the cause of changes in matter.
Energy subsidy (Lat. subsidium — help, support) — energy received from an additional source that reduces the costs of ecosystem self-maintenance and increases the proportion of energy entering production. For example, tides energetically subsidise coastal ecosystems by ensuring gas exchange and mixing of sediments.
“Nuclear winter” — a model of the possible consequences of a nuclear conflict, proposed in the 1980s by American researchers (led by C. Sagan) and Soviet researchers (led by N. N. Moiseev). It posits the injection into the upper atmosphere of large quantities of soot and smoke from nuclear explosions and the subsequent massive fires, primarily in cities. The consequence is the formation of an atmospheric screen blocking sunlight from reaching Earth and the subsequent extinction of humanity and the biosphere.