BIOL 327 Exam Preparation - Sampling, Distribution, and Population Dynamics

These flashcards cover key ecological concepts from the BIOL 327 course, including sampling methods, distribution models, population growth, species interactions, and landscape ecology.

Sampling

A technique used by ecologists to provide an estimate of population size with the smallest confidence limits at the lowest cost, as it is usually impossible to measure an entire population.

Systemic sampling

A method where samples are collected at regular intervals, such as traps placed every $5\,m$ along a transect line or at the corners of a quadrat; it is easier than random sampling but often produces biased results.

Simple random sampling

A sampling method where every sample unit has an equal probability of being selected; identified as the simplest way to achieve an unbiased sample.

Stratified random sampling

A method that involves dividing an area into different strata and sampling each stratum at random to ensure all habitat types are represented and reduce sampling bias.

Pseudo replications

The statistical error of treating non-independent variables as if they are independent, which reduces variance in the data and creates the illusion of a highly precise result.

Habitat stability

The requirement that a habitat provides the necessary conditions for survival, growth, and reproduction; the overlap of these abiotic conditions determines a species' potential niche.

Correlative models

Spatial distribution models that use species occurrence data and environmental variables to identify a climatic envelope and predict suitable habitats.

Mechanist models

Models that use physiology, tolerance limits, and development rates to predict distributions, such as Argentine ant development requiring approximately $445$ degree-days above $15.9^{\circ}C$.

Fundamental niche

The potential niche representing all climatic combinations where a species could persist if no other species (through competition, predation, etc.) affected it.

Realised niche

The actual locations in the world where a species exists within a climate suitable for persistence, often restricted by biological interactions like competition.

Facilitation

Any interaction that has a positive effect on the receiving party, which can be positive (mutualism), neutral (commensalism), or negative (antagonistic).

Lichens

A mutualistic interaction where fungi contain algae; the lichen receives sugars while the algae receives water and physical protection, allowing it to occupy an enhanced range of habitats.

Extent of occurrence (EOO)

The total area enclosed by the outermost known occurrences of a species; a small value suggests a greater extinction risk.

Area of occupancy (AOO)

The specific area occupied within a geographic range; it is considered a better indicator of presence, though its value reduces with finer resolution subunits.

Rapport’s rule

The observation that species at higher latitudes tend to have larger geographic ranges than species found in the tropics.

Exponential growth model

A density-independent population growth model featuring a constant per-capita growth rate and a j-shaped curve, typical of invasive species immediately after introduction.

Logistic growth model

A density-dependent growth model where population increase slows as it approaches the carrying capacity ($K$), producing an s-shaped curve.

Contest competition model

A form of density-dependent growth where dominant individuals monopolise resources, resulting in a fixed number of successful individuals and a stable carrying capacity.

Scramble competition model

A growth model where resources are shared among all individuals, potentially causing population crashes or boom-and-bust cycles when densities become extremely high.

Allee effects

A phenomenon where population growth is negative at low density due to factors like difficulty finding mates, reduced group defense, or poor cooperative survival.

Lotka–Volterra Predator–Prey Model

A mathematical model describing dynamics where the predator population depends on prey, prey grow exponentially in the absence of predators, and both populations cycle through time.

Predation rate

The number or proportion of prey consumed by predators per unit time, expressed as prey killed per predator or per unit area.

Type I Functional Response

A rare consumption pattern where prey consumption increases linearly with prey density because there are no handling time limits.

Type II Functional Response

The most common functional response where prey consumption increases rapidly but eventually levels off because handling time limits consumption.

Type III Functional Response

A consumption pattern that is low at low prey densities but increases rapidly at intermediate densities due to prey switching, learning, or search images.

Herbivory

The consumption of plant tissues by animals, mainly insects, which drives ecological and evolutionary interactions through plant defence and tolerance strategies.

Monophagous

Specialist herbivores that feed on a single plant type and evolve specific detoxification mechanisms to overcome plant defences.

Resistance

Plant traits, such as thorns (physical) or toxins (chemical), that reduce herbivore preference or performance to reduce damage.

Tolerance

The ability of a plant to maintain stable fitness levels and recover through growth or physiological changes despite experiencing herbivore damage.

Mutualism

An interaction where both species benefit through resource or service exchange, increasing the fitness of both partners; can be facultative or obligate.

Mycorrhizal mutualism

A relationship occurring in approximately $80\%$ of terrestrial plants where fungi receive carbon from plants while providing them with phosphorus and nitrogen.

Grime’s CSR model

A theory describing plant life-history strategies shaped by stress (factors limiting production) and disturbance (factors destroying biomass).

Competitor (C-strategy)

Plants adapted to low stress and low disturbance that exhibit high growth rates under good conditions but have few adaptations for stress.

Stress tolerator (S-strategy)

Plants adapted to high stress and low disturbance that possess specific adaptations to stress and exhibit slow but sustained growth.

Ruderal (R-strategy)

Plants adapted to low stress and high disturbance that feature early reproduction and good seed dispersal to exploit temporary habitats.

R*

Tilman's concept of the minimum resource requirement; the superior competitor is the species that can survive at the lowest resource level.

Omnivory

Feeding across multiple trophic levels, which blurs strict linear food chains and introduces cross-linkages in real ecosystems.

Bottom-up control

Community regulation where energy and nutrient availability limit producers, thereby affecting the entire ecosystem.

Top-down control

Community regulation where predators regulate the abundance of lower trophic levels, such as top predators exerting control over herbivores.

Janzen–Connell hypothesis

The idea that specialist enemies maintain diversity by causing higher mortality in seeds and seedlings near parent plants, preventing any one species from dominating.

SLOSS debate

The ecological debate over whether a 'Single Large Or Several Small' reserve design is better for maximizing biodiversity and managing extinction risk.