Glossary: Essential ECO-01 Terminology

Term	Definition
Ecology	Study of interactions between organisms and their environment
Abiotic factors	Non-living physical/chemical environmental components
Biotic factors	Living components of the environment (organisms)
Population	Group of individuals of the same species living in the same area at the same time
Natality (b)	Birth rate — number of new individuals added per unit time
Mortality (d)	Death rate — number of individuals lost per unit time
Intrinsic rate (r)	r = b - d; net reproductive rate per individual per unit time
Carrying capacity (K)	Maximum population size an environment can sustainably support
Exponential growth	J-shaped population growth under unlimited resources; dN/dt = rN
Logistic growth	S-shaped population growth with carrying capacity; dN/dt = rN $\frac{K-N}{K}$
Mutualism	+/+ interaction; both species benefit
Competition	-/- interaction; both species harmed
Predation	+/- interaction; predator benefits, prey killed
Parasitism	+/- interaction; parasite benefits, host harmed (not immediately killed)
Commensalism	+/0; one benefits, other unaffected
Amensalism	-/0; one harmed, other unaffected
GPP	Gross Primary Productivity — total energy fixed by photosynthesis
NPP	Net Primary Productivity = GPP - Respiration
Lindeman's efficiency	~10% energy transfer between trophic levels (10% law)
Detritus	Dead organic matter that serves as substrate for decomposition
Fragmentation	Physical breakdown of detritus by detritivores
Leaching	Percolation of water-soluble nutrients from detritus into soil
Catabolism	Enzymatic degradation by bacteria/fungi
Humification	Formation of dark, resistant humus
Mineralization	Release of inorganic nutrients from humus
Humus	Dark, resistant organic matter formed during decomposition
Biogeochemical cycle	Pathway of chemical elements through biotic and abiotic compartments
Ecological succession	Sequential community replacement over time leading to climax community
Primary succession	Succession beginning on bare, lifeless substrate
Secondary succession	Succession on previously vegetated, disturbed substrate
Xerosere	Primary succession on bare dry rock
Hydrosere	Succession in water bodies (aquatic succession)
Climax community	Final, stable, self-perpetuating community at end of succession
Pioneer species	First colonizers of an uninhabited area (crustose lichens in xerosere)
Batesian mimicry	Harmless species mimics harmful model for protection
Mullerian mimicry	Multiple harmful species share warning coloration
Diapause	Developmental arrest in zooplankton/insects during unfavourable conditions
Resource partitioning	Division of resources by competing species to enable coexistence