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
A morphological character is part of the phenotype of a
species, often (but not always) determined by genotype
e.g., beak size and seed size in birds

6. Adaptive Radiation

7. Figure B, p. 283

8. Quiz What is Gause’s Principle and the concept of the ‘niche’?
Write and explain the Lotka-Volterra equations for the effect of species 1 on species 2 in interspecific competition and vice versa? What is the competition coefficient?
What is meant by an unstable and stable equilibrium?
What is the ‘Ghost of Competition Past’ and give an example?
How does the experiment by Joseph Connell relate to the concepts of competitive release, interference competition, predator mediated competition, and realized vs. fundamental niches?