Community Ecology, Biodiversity, and Disturbances - Flashcards

Vocabulary-style flashcards covering key terms from notes on community ecology, biodiversity, disturbances, and biogeography.

Community

A group of populations of different species living closely and capable of interacting.

Habitat

A place or part of an ecosystem occupied by an organism.

Ecological niche

The role and position a species has in its environment.

Fundamental niche

The niche a species could potentially occupy in the absence of limiting factors.

Realized niche

The portion of the fundamental niche actually occupied by the species.

Interspecific interactions

Interactions of individuals from one species with individuals of another species.

Competition

A -/- relationship where species compete for limited resources.

Competitive exclusion principle

Two species competing for the same resource cannot coexist permanently; the better competitor can eliminate the other.

Niche partitioning

Natural selection drives competing species to use different resources or occupy different niches.

Predation

A +/- relationship where a predator kills and eats the prey.

Cryptic coloration

Camouflage that helps prey avoid detection by predators.

Batesian mimicry

A harmless species mimics a harmful one to deter predators.

Müllerian mimicry

Two or more harmful species resemble each other to reinforce predator avoidance.

Herbivory

A +/- relationship where an organism eats part of a plant or alga.

Symbiosis

Two or more species live in direct contact with one another.

Parasitism

+/- relationship where a parasite derives nourishment from a host.

Mutualism

+/+ relationship where both organisms benefit from the interaction.

Commensalism

+/0 relationship where one benefits and the other is unaffected.

Facilitation

A positive effect (+/+ or 0/+) on another's survival and reproduction without intimate symbiosis; common in plants.

Species diversity (biodiversity)

The variety of different organisms within a community; includes species richness and relative abundance.

Species richness

The number of different species present.

Relative abundance

The proportion each species represents of all individuals.

Simpson's diversity index

A measure of diversity based on species richness and relative abundance; higher index means higher biodiversity.

Keystone species

A species with a pivotal ecological role; not usually abundant but many others rely on it.

Disturbance

An event that changes a community by removing organisms or altering resource availability.

Ecological succession

The gradual change in species composition of a community over time after a disturbance.

Primary succession

Succession on an entirely new, lifeless habitat with no soil.

Secondary succession

Succession in a disturbed area where soil remains.

Human disturbances

Disturbances caused by humans that threaten biodiversity (habitat loss, invasive species, overharvesting, global change).

Habitat loss

The single greatest threat to biodiversity; caused by agricultural development and urbanization.

Invasive species

A nonnative species that can occupy many habitats and outcompete native species.

Overharvesting

Harvesting organisms faster than they can rebound (e.g., ivory, overfishing).

Global change

Climate, atmospheric chemistry, and ecological systems changes that reduce Earth's capacity to sustain life.

Endangered species

Species at risk of extinction; many may provide resources like food, medicine, or fibers.

Biogeographical factors

Large-scale factors contributing to diversity, including latitude and area.

Latitude

Species are more diverse in the tropics than at the poles due to climate.

Area

Larger areas tend to harbor greater diversity due to more habitat variety.

Pathogens

Disease-causing organisms and viruses; often have strong effects in new or low-diversity habitats.