2. Principle of Competitive Exclusion or Gause’s Principle No two species can coexist and share the same space if they compete for the same resources within that space Coexistence possible only if resource needs do not overlap or only slightly overlap Niche All ecological parameters under which a species lives and grows --abiotic and biotic resources No two species can share the same niche

3. Resource partitioning

4. Character displacement When related species coexist by exhibiting differences in morphology of one or more characters that reduces niche overlap e.g., beak size and seed size in birds A morphological character is part of the phenotype of a species, often (but not always) determined by genotype

6. Adaptive Radiation

7. Figure B, p. 283