BIOL 140 — Lecture 28 Community Ecology Flashcards

This set of 35 vocabulary flashcards covers key concepts in community ecology, including interspecific interactions, niches, mimicry, trophic structures, diversity measures, and ecological succession.

Interspecific Interactions

Interactions that occur between two different species, which can be categorized as competitive, exploitative, or positive.

Competition ($-/-$)

An interaction where both species are harmed by competing for the same limited resource in the same area.

Exploitative Interactions ($+/-$)

A category of interactions where one species benefits while the other is harmed; includes predation, herbivory, and parasitism.

Mutualism ($+/+$)

An interaction where both species benefit, such as the relationship between mycorrhizae and plants or angiosperms and pollinators.

Commensalism ($+/0$)

An interaction where one species benefits while the other is neither helped nor harmed, such as cattle egrets riding on African buffalo.

Ecological Niche

The specific set of biotic and abiotic resources that an organism uses within its environment.

Competitive Exclusion

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

Resource Partitioning

The process by which species reduce competition by using different parts of the environment or different resources to occupy different niches.

Fundamental Niche

The entire range of spaces and resources in the environment a species could potentially use in the absence of competition.

Realized Niche

The actual spaces and resources a species occupies or uses after competition with other species narrows down its options.

Character Displacement

Evolutionary divergence in traits, such as Galapagos finch beak sizes, between sympatric species resulting from natural selection for resource partitioning.

Sympatric

A term describing species that live in the same geographical area.

Predation

A $+/-$ interaction where one organism, the predator, kills and eats another organism, the prey.

Herbivory

A $+/-$ interaction involving the consumption of plants or algae without killing the organism.

Parasitism

A $+/-$ interaction where a parasite lives in or on a host, using the host's resources to survive and reproduce.

Endoparasite

A parasite that lives inside the body of its host, such as Plasmodium which causes malaria.

Ectoparasite

A parasite that lives on the external surface of its host, such as ticks.

Cryptic Coloration

A type of camouflage that enables prey to avoid being detected by predators.

Batesian Mimicry

When a harmless species evolves to mimic the appearance of a harmful or unpalatable species, such as a hawkmoth larva mimicking a venomous snake.

Mullerian Mimicry

When two or more harmful or unpalatable species evolve to mimic each other, such as yellow jackets and cuckoo bees, to reinforce predator avoidance.

Trophic Structure

The system of feeding relationships between species in a community that determines the flow of energy.

Food Chain

A linear sequence showing the transfer of chemical energy through trophic levels from producers to primary and secondary consumers.

Food Web

A network consisting of multiple interconnected food chains that provide a more realistic representation of community feeding relationships.

Energetic Hypothesis

The theory that food chain length is limited by the inefficiency of energy transfer between successive trophic levels.

$10\%$ Rule

The ecological principle stating that only about $10\%$ of energy is transferred to the next trophic level, with the rest lost as heat.

Species Diversity

A measure of the variety of species in a community, comprised of two components: species richness and species evenness.

Species Richness

The total count of different species present within a specific community.

Species Evenness

The measure of how equally individuals are distributed among the various species in a community.

Foundation Species

Species that significantly influence community structure due to their high abundance, such as the American chestnut tree.

Keystone Species

Species with a disproportionately large impact on community structure relative to their abundance, such as the sea star Pisaster.

Intermediate Disturbance Hypothesis

The concept that moderate levels of disturbance result in higher species diversity than very high or very low levels of disturbance.

Ecological Succession

The observed process by which the species composition of a community changes and replaces other species over time following a disturbance.

Primary Succession

Community development starting in a previously lifeless area without soil, such as bare rock exposed after a glacier retreats.

Secondary Succession

The recolonization of an area after a major disturbance has removed most members but left the soil intact, such as regrowth after a forest fire.

Trophic Level

The position an organism occupies in a food chain, such as producer, primary consumer, or secondary consumer.