BIS 2B Community Ecology/ Ecosystems Exam Questions with Correct Answers Latest Update 2026/2027

BIS 2B Community Ecology/ Ecosystems Exam Questions with Correct Answers Latest Update 2026/2027 Competition - Answers Individuals require the same shared, limiting resource, reducing growth & survival for both competitors. Intraspecific competition - Answers Competition within the same species. Interspecific competition - Answers Competition between different species. Competitive Exclusion Principle - Answers Two species requiring the exact same limiting resource cannot coexist; one outcompetes the other. Fundamental niche - Answers Where a species could live without competitors. Realized niche - Answers Where a species actually lives with competition. Resource partitioning - Answers Species use different parts or different locations of the resource to coexist. Examples of resource partitioning - Answers Warblers feeding at different parts of a tree; Bats using different habitat zones & prey sizes. Lotka-Volterra predator-prey model - Answers Shows how predator & prey abundances cycle over time. Prey equation (LV model) - Answers dV/dt = rV - pVP; Growth minus predation. Predator equation (LV model) - Answers dP/dt = cpVP - dpP; Births depend on prey; predators die without prey. Key assumption of LV model - Answers Predators go extinct without prey; prey grow exponentially without predators. Oscillations - Answers Prey increase → predators increase → prey decrease → predators decrease. Herd immunity - Answers When enough of a population is immune (via vaccination or prior infection), susceptible individuals are protected indirectly. R₀ (basic reproductive number) - Answers Average number of people one infected person will infect. Character displacement - Answers Competing species evolve divergent traits to reduce competition (e.g., beak sizes in finches). Reproductive character displacement - Answers Traits related to mating diverge in sympatric populations to reduce hybridization. Trait matching - Answers Mutualistic partners evolve complementary traits (moth tongue & orchid spur length). Evolutionary arms race - Answers Predators & prey co-evolve escalating defenses and counter-defenses (e.g., toxic newts vs resistant snakes). Trade-offs in arms races - Answers Higher defense often comes with a cost (e.g., more toxin but lower reproduction; more resistance but slower movement). Adaptive radiation - Answers Rapid speciation into many ecological niches when: Many new habitats, Little competition, Ecological opportunity (e.g., Hawaiian honeycreeper beak diversification). Gross Primary Productivity (GPP) - Answers Total rate of photosynthesis.