CH.54 Community Ecology Flashcards

A set of vocabulary flashcards covering the key concepts, interactions, and ecological models of community ecology from the Chapter 54 lecture.

Interspecific interactions

Any interactions that occur between individuals belonging to different species within a community.

Competition ($-/--$)

An interaction where individuals of different species use a resource that limits the survival and reproduction of both groups.

Competitive exclusion

The local elimination of an inferior competitor that occurs when two species compete for the same limited resources.

Ecological niche

The specific set of biotic and abiotic environmental resources that an organism uses.

Resource partitioning

The differentiation of niches that enables ecologically similar species to coexist within the same community.

Fundamental niche

The full niche that a species could potentially occupy in the absence of factors like competition.

Realized niche

The actual portion of the fundamental niche that a species occupies in its environment.

Character displacement

The tendency for characteristics to diverge more in sympatric populations (living together) than in allopatric populations (living separately) of two species.

Exploitation ($+/-$)

A category of ecological interactions including predation, herbivory, and parasitism where one species benefits by feeding on another.

Aposematic coloration

Bright warning colors exhibited by animals with chemical defenses to signal danger to predators.

Cryptic coloration

Camouflage that makes prey difficult to see against their environmental background.

Batesian mimicry

A type of mimicry where a harmless or palatable species resembles a harmful or unpalatable model.

Müllerian mimicry

A defensive strategy where two or more unpalatable species resemble each other.

Endoparasites

Parasites that live and feed within the internal body of their host.

Ectoparasites

Parasites that reside and feed on the external surface of a host organism.

Mutualism ($+/+$)

An interspecific interaction where individuals from both participating species benefit.

Commensalism ($+/0$)

An interaction where one species benefits while the other is neither helped nor harmed.

Species richness

The total number of different species present within a community.

Relative abundance

The proportion that each species represents out of the total number of individuals in the community.

Shannon diversity index ($H$)

A widely used index to calculate and compare species diversity between communities based on richness and relative abundance.

Biomass

The total mass of all individual organisms living within a specific community or ecosystem.

Trophic structure

The feeding relationships between organisms that determine energy flow and community dynamics.

Energetic hypothesis

The concept that food chain length is limited by inefficient energy transfer, typically allowing only about $10\%$ of energy to pass to the next level.

Foundation species

Species that have a large impact on community structure due to their high abundance or large physical size, often providing habitat or food.

Keystone species

Species that exert strong control on community structure through their pivotal ecological roles rather than their numerical abundance.

Ecosystem engineers

Organisms, such as beavers, that influence community structure by physically altering or creating their environment.

Bottom-up control

A model of community organization where the abundance of each trophic level is limited by nutrient supply or food availability from lower levels.

Top-down control

A model where the abundance of organisms at each trophic level is controlled by the consumers at higher trophic levels.

Intermediate disturbance hypothesis

The theory that moderate levels of disturbance foster greater species diversity than either high or low levels of disturbance.

Primary succession

The process of species colonization and replacement starting in a virtually lifeless area where soil has not yet formed.

Secondary succession

The recolonization of an area after a major disturbance has removed most organisms but left the soil intact.

Evapotranspiration

The combined evaporation of water from soil and transpiration from plants, which correlates with species richness.

Species-area curve

The biogeographic principle stating that, all other factors being equal, a larger geographic area will contain more species.

Island equilibrium model

A model developed by MacArthur and Wilson that predicts species richness on islands as a balance between immigration and extinction rates.

Zoonotic pathogens

Disease-causing agents that are transferred from animals to humans, often via an intermediate species called a vector.