7.8.9.10

Ecology in Action

Evolutionary puzzle

Possession of a trait that, on the surface, appears to be maladaptive

Demography

The quantitative study of the size and structure of populations, and of how populations change over time.

Endangered Species

Any species that is in danger of extinction through all or a significant portion of its range.

Iteroparous

Having multiple reproductive efforts over the course of a lifetime

K-selected species

Species whose individuals compete effectively for resources in predictable and stable environments, and whose populations tend to be at or near their carrying capacity

Life history traits

Species whose individuals compete effectively for resources in predictable and stable environments, and whose populations tend to be at or near their carrying capacity

Phenotypic plasticity

An ability to change phenotypes (in developmental, physiological or behavioral traits) in response to different environments

Predator saturation

An antipredator adaptation in which prey populations occur at high densities, thereby reducing the probability of a particular individual being eaten by predators

r-selected species

Species with potentially high reproductive rates that are most successful in unpredictable environments including those that have been recently disturbed by catastrophic events such as fires or floods

reproductive effort

The amount of resources an organism allocates to a reproductive event

Resource allocation

The quantity of key resources, such as energy and nutrients, that a parent can devote to reproduction

Resting metabolic rate

The amount of energy used by an organism over a given time period while at rest in a thermally neutral environment.

Semelparous

Having only one reproductive effort over the course of a lifetime

Clumped dispersion

Pattern in which individuals are more likely to be situated near other individuals within the habitat

Dispersal

The movement of individuals from one location to another location

Dispersion

Spatial pattern of distribution of individuals within a population

Fundamental niche

The potential set of environmental conditions and resources in which a species can survive, grow, and reproduce

GIS

A system designed to store, display, and analyse the locations and characteristics of Earth's spatial features.

Human footprint

A global map that shows human influence on the land surface

invasive species

A non-native species that is introduced into a new habitat, and that often adversely affects numerous species in the new habitat

migration

The back-and-forth intentional movement of individuals or populations between two locations

Niche

The set of environmental conditions and patterns of resource availability, in which a species can survive, grow, and reproduce

Random dispersion

Pattern in which each individual within a population has an equal probability of occupying any given space in the habitat

Realized niche

The set of environmental conditions and resources in which a species can survive, grow, and reproduce in the presence of competitors and predators

Recruitment

The addition of new individuals to a population

Sensitivity (of a model)

The number of correct positive predictions divided by the total number of positive occurrences

Specificity (of a model)

The number of correct negative predictions divided by the total number of negative occurrences

Uniform (regular) Dispersion

Pattern in which individuals tend to be evenly spread out within a habitat

Anadromous (fish)

A fish that spends much of its life at sea, and moves into freshwater to breed

Accumulation curve

For estimating population size, a curve formed by plotting the number of individuals sampled on the x-axis versus the number of unique individuals in the sample on the y-axis. The estimated population size is the value at which the number of unique individuals is projected to reach an asymptote

Age structure (population)

The proportion of individuals in different age groups

Carrying capacity (K)

The maximum population size that can be supported or sustained by the environment

Density-dependent factor

A factor that reduces a population's growth rate as population density increases, by decreasing the birth rate and/or increasing the death rate at high population density

Density-independent factor

A factor that influences a population's growth rate in the same manner regardless of population density

Exponential growth model

For a population with a continuous reproductive life history, the change in population size by a constant proportion over a vanishingly small time interval

Geometric growth model

For a population with a discrete reproductive life history, the change in abundance by a constant proportion from one time period to the next

Intrinsic growth rate

The per individual birth rate minus the per individual death rate when there is no competition or predation

Logistic model of population growth

A model of population growth that is nearly exponential at low abundance but that levels out as population abundance approaches the carrying capacity

Mark–recapture study

A type of population analysis in which individuals are captured, marked, and released into the environment, allowed to mix back into the source population, and then recaptured a second time.

Metapopulation

A group of local populations inhabiting networks of somewhat discrete habitat patches

Modular organisms

Species that develop an undetermined number of repeated copies of similar structures, so it can be difficult to distinguish individual organisms.

Percent cover

The percent of a substrate covered by organisms when viewed from above

Per capita growth rate

Per individual birth rate minus the per individual death rate

Population density

The number of individuals within a population per unit area

Quadrat

A small (often rectangular) sampling plot

Seed bank

The collection of viable seeds stored in the soil

Unitary organisms

Species in which each individual is an easily distinguished unit.