General and Population Ecology

Vocabulary practice flashcards generated from lecture notes covering General Ecology, Population Ecology, and Plant Population Dynamics.

Ecology

The scientific study of the distribution and abundance of organisms, and their interactions with the environment.

Equilibrium Paradigm

The classical idea in ecology that natural ecosystems are usually in a state of equilibrium and will return to equilibrium if disturbed, which has been challenged by evidence supporting non-equilibrium states.

Organismal Ecology

The subfield of ecology concerned with how individual organisms interact with their abiotic and biotic environment, such as behavioral navigation or physiological adaptation.

Population

A group of freely interbreeding individuals belonging to the same species that occupy the same habitat at a given time.

Community

An assemblage of populations of different species living and interacting together in the same place at the same time.

Ecosystem

An interacting assemblage of living organisms in a given area together with nonliving environmental components such as water, light, nutrients, soil, and seasonality.

Ecological Time Scale

The timeframe over which ecological processes occur, ranging from days to millennia, which is shorter than the evolutionary time scale but overlaps with it as populations evolve.

Weather

The specific set of temporary abiotic conditions, such as temperature, rainfall, sunlight, and humidity, affecting a given area at a specific time.

Climate

The long-term overall pattern of weather conditions in a region evaluated over decades, centuries, or millennia.

Biomes

Broad geographic assemblages of plant and animal communities defined primarily by the dominant vegetation type.

Hadley Cell

A global atmospheric circulation pattern driven by rising warm, moist air at the solar equator that sheds moisture and descends as cool, dry air around $30^\text{o}$ North and South latitude, forming desert belts.

Tundra

A polar or high-elevation biome characterized by a very short growing season, lack of trees, precipitation mostly as snow, and vegetation dominated by lichens, annual grasses, and low shrubs.

Taiga (Coniferous Forest)

A widespread biome at high latitudes or elevations dominated by cone-bearing trees like pine, spruce, and fir, featuring cool to warm summers and freezing winters.

Desert

A biome characterized by low annual rainfall (generally under $30\text{\thinspace cm}$ per year), high temperature fluctuations between day and night, and vegetation adapted for extreme water conservation.

Grasslands

A widespread biome dominated by grasses and forbs where fire, grazing herbivores, and seasonal droughts inhibit the growth of trees and shrubs.

Temperate Deciduous Forest

A mid-latitude biome with moderate rainfall, distinct winter seasons prohibiting photosynthesis, and dense stands of trees that shed their leaves annually.

Tropical Rain Forest

The most productive and biodiverse biome on Earth, located near the equator with high precipitation, constant warm temperatures, and pronounced stratification of broad-leafed evergreen trees.

Pelagic Zone

The open water column of the ocean where light penetrates the upper meters to support photosynthetic algae, with organisms existing as floating or free-swimming nekton.

Abyssal Zone

The deep ocean layer completely devoid of sunlight that relies on organic nutrients falling from upper zones to sustain life.

Anthromes

Anthropogenic biomes created by human-dominated land use that modify pre-existing natural ecosystems into semi-natural, agricultural, or settled landscapes.

Geographic Range

The entire geographic area within which individuals of a given species may potentially be found.

Cosmopolitan Species

A species that possesses an exceptionally wide, worldwide geographic range.

Endemic Species

A species restricted to a single, localized, or geographically small area.

Population Density

The number of individuals of a population per unit area or unit volume.

Clumped Dispersion

A spatial pattern in which individuals aggregate in dense patches due to localized resource distribution, safety, social structures, or limited seed dispersal.

Regular Dispersion

A uniform spatial distribution pattern resulting from intense negative interactions among individuals, such as competition for root space or territorial behavior.

Random Dispersion

An unpredictable spatial pattern of individuals that occurs when strong attractive or repulsive interactions are absent.

Intrinsic Rate of Increase ($r$)

The instantaneous per capita growth rate of a population, calculated as per capita birth rate ($b$) minus per capita death rate ($d$).

Exponential Growth Model

A population growth model that assumes continuous growth under ideal conditions with constant per capita rates, expressed as $N(t) = N_0 e^{rt}$.

Carrying Capacity ($K$)

The maximum population size of a species that a specific environment can sustain indefinitely given available limiting resources.

Logistic Growth Model

A population growth model incorporating environmental resistance and carrying capacity, formulated as $\frac{dN}{dt} = r_{\text{max}} N \frac{K - N}{K}$.

Demography

The statistical study of population age structures, birth rates, reproductive strategies, and death rates.

Cohort

A specific group of individuals born during the same time interval that are followed throughout their lives.

Type I Survivorship Curve

A convex survivorship curve where mortality is low in early and middle age and high among old individuals.

Type II Survivorship Curve

A linear survivorship curve reflecting a constant probability of mortality across all age groups.

Type III Survivorship Curve

A concave survivorship curve marked by extremely high juvenile mortality, with survivors exhibiting high survival rates later in life.

Producers

Autotrophic organisms that manufacture their own carbohydrate food from inorganic nutrients and solar energy through photosynthesis.

Primary Consumers

Herbivorous animals or plant parasites that obtain energy by directly ingesting primary producers.

Biomass Pyramid

A graphical representation showing the progressive reduction in caloric content or dry weight biomass at higher trophic levels in an ecosystem.

Ephemeral (Annual)

A plant that completes its full life cycle from seed germination to seed production in less than one year.

Biennial

A plant that lives for two years, growing vegetatively in the first year and flowering, setting seed, and dying in the second year.

Perennial

A plant that lives for many years and typically undergoes repeated reproductive cycles.

Semelparous Reproduction

A life history tactic where an organism devotes a large portion of its reserves to a single massive reproductive effort before dying.

Iteroparous Reproduction

A life history strategy in which an organism reproduces repeatedly over multiple cycles across its lifespan.

Mast Years

Intermittent years during which iteroparous plant species produce unusually high quantities of seeds or fruits.

Monoecious

A plant species that possesses both male and female reproductive structures on the same individual plant.

Dioecious

A plant species in which individual plants carry strictly male or strictly female reproductive structures.

r-selected Species

Species adapted to unstable or frequently disturbed environments that emphasize rapid growth, small body size, early maturity, and high reproductive output.

K-selected Species

Species adapted to stable, competitive habitats characterized by large body size, slow development, long lifespan, and repeated low-effort reproduction.

Macroenvironment

The broad, regional environmental conditions defined by prevailing climate, latitude, and elevation.

Microenvironment

The immediate, localized abiotic environment directly surrounding an organism or structure.

Xerophytes

Plants equipped with structural, anatomical, or physiological adaptations to survive in arid habitats.

Epiphytes

Non-parasitic plants that grow anchored upon other plants for mechanical support while deriving moisture and nutrients from the air and rainfall.

Thermoperiod

The degree of difference between maximum daytime temperature and minimum nighttime temperature within a 24-hour cycle.

Ecotype

A genetically distinct population within a widespread species that is locally adapted to specific regional microenvironmental conditions.

Competition

A negative biotic interaction where two or more populations suffer reduced growth or survival due to an insufficient supply of a shared limiting resource.

Amensalism (Allelopathy)

An interaction where one species inhibits or harms another by releasing chemical compounds or metabolic byproducts into the environment.

Herbivory

The consumption of living plant tissue or plant parts by animals.

Mutualism

An interspecific interaction that increases the survival, growth, or fitness of both participating populations.

Commensalism

An interaction between species in which one partner gains benefits while the other is neither helped nor harmed.