Community Ecology Quiz

Community Ecology

• Community: An assemblage of populations of various species living close enough for potential interaction. Affected by environmental conditions, including invasive species.

Interspecific Interactions

• Interspecific Interactions: Relationships between species in a community. Examples include: competition, predation, herbivory, and symbiosis. Categorized by their effect on the involved species (e.g., positive, negative, or neutral).

• Competition: (Negative/Negative) Occurs when two+ species compete for a limited resource. Potentially leads to competitive exclusion (local elimination of a competing species) – a concept proposed by Georgy Gause.

Ecological Niche

• Ecological Niche: An organism's ecological role or function.

• Fundamental Niche: The potential niche a species could occupy without competition.

• Realized Niche: The actual niche a species occupies due to interactions with other species. Realized niche is influenced by community interactions.

Resource Partitioning

• Resource Partitioning: Differentiation of ecological niches, allowing similar species to coexist. Example: Anolis lizard species differentiate their perching locations (sun vs. shade). Acomys rusatus and Mus spretus exhibit temporal partitioning by active times of day.

Character Displacement

• Character Displacement: Sympatric populations of species exhibit more divergent characteristics than allopatric populations of the same species. Example: beak size variation in Galapagos finches.

Predation

• Predation: (Positive/Negative) One species (predator) kills and eats another (prey).

• Camouflage/Cryptic Coloration: Prey adaptation where they blend into their environment, avoiding predators. Example: Canyon tree frogs.

• Aposematic Coloration: Warning coloration in prey to signal danger. Example: Poison dart frogs.

• Batesian Mimicry: A harmless species mimics a harmful one. Example: Hawkmoth larva mimicking a snake.

• Mullerian Mimicry: Two unpalatable (harmful) species mimic each other.

Herbivory

• Herbivory: (Positive/Negative) Interaction where an herbivore consumes plant or algal parts. Influences plant diversity and species composition.

Symbiosis

• Symbiosis: Close, long-term relationships between two+ species.

  • Parasitism: (Positive/Negative) One organism (parasite) benefits at the expense of another (host).

• Endoparasites: Live inside the host.

• Ectoparasites: Live on the host's surface.

  • Mutualism: (Positive/Positive) Win-win relationship benefiting both species.

• Obligate Mutualism: One species cannot survive without the other (e.g., ants and acacia trees).

• Facultative Mutualism: Both species can survive independently but benefit from the interaction (e.g., bees and flowering plants)

  • Commensalism: (Positive/Neutral) One species benefits, the other is unaffected. Difficult to prove in nature. (e.g., barnacles and whales)

Facilitation

• Facilitation: One species positively affects another without direct contact.

Species Diversity

• Species Diversity: Variety of organisms in a community.

  • Species Richness: Total number of different species.

  • Relative Abundance: Proportion of each species in the community.

• Shannon Diversity Index: An index to compare species diversity in communities. High diversity relates to higher community productivity, greater stability, and greater resistance to environmental stressors/invasive species.

Trophic Structure