Natural Science Concepts

Species are genetically distinct organisms that can successfully interbreed

Populations are spatially or temporally defined subsets of species that may interact with other populations and disperse or move between other subsets of that species

Predator prey interactions Consume or being consumed by organisms of other species within a food web. The degree of this interaction is determined by the functional response.

Food webs are spatially or temporally defined subsets of populations that interact through predator/prey interactions.

Ecosystems are spatially or temporally defined food webs and the abiotic environment that the organisms interact with

Functional response is the shape of the predator/prey relationship between two populations. The shape of this response is generally a saturating function, i.e. a predator can only eat so much prey until it either becomes satiated or has to spend more time handling it prey than actually consuming it. This creates a non-linear relationship which gives rise to complex dynamics in food webs and ecosystems

Green water is the water is the part of precipitation that returns to the atmosphere through evaporation or that drives plant growth (transpiration) and thus is a major source of water vapor released into the atmosphere and thus an important source of precipitation

Blue water is the fresh water that accumulates in streams, rivers, lakes and ground.

Biodiversity genetic, population, species and habitat variation(s). Most commonly refers to a measure of species richness, either numbers or some abundance weighted measure to take account of the degree of dominance/rareness between species.

Attractor A set of conditions towards which a dynamical system evolves over time. An attractor is often a point, but can also be a curve, a manifold, or a more complicated set with a fractal structure known as a strange attractor. Also known as an equilibrium point.

Critical threshold The point that separates two dynamic regimes. Also known as a tipping point or a bifurcation.

Regime The set of system states that lead to a particular attractor, or represent fluctuations around a specific attractor. Within this set of states the system self organizes into a specific structure and behaves in essentially the same way. Also known as a domain of attraction, basin of attraction or stable state.

Feedback loop A set of cause and effect relationships that form a closed loop, so that a change in any particular element eventually feeds back to affect the element itself. Feedback loops can either be damping (also known as negative or balancing) or amplifying (also known as positive or reinforcing).

Hysteresis The tendency of a system to remain in the same state when conditions change due to lag effects and system memory. As a consequence the critical threshold for a forward shift from Regime A to B often differs from the critical threshold for a return shift from Regime B to A.

Regime shift A large, abrupt, persistent change in the structure and function of a system that occurs when a critical threshold is crossed and the system shifts from one dynamic regime to another. Also known as a critical transition or a phase shift.

Resilience The magnitude of change or disturbance that a system can tolerate before undergoing a shift to an alternate regime.

System state The condition of a system at a particular point in time, described in terms of specific variables such as pH or population size.