Study Notes on Competition

Key Concepts of Competition

• Competition can be direct or indirect, varying in intensity, and occurs between similar or dissimilar species.

• Coexistence is more likely if competing species utilize resources differently.

• Competition outcomes can be affected by environment, disturbances, and predation.

Types of Competition

• Interspecific Competition: Between different species.

• Intraspecific Competition: Within a single species.

• Exploitation Competition: Indirectly reducing resource supply.

• Interference Competition: Direct interference with competitors.

• Examples include plant shading and allelopathy.

Niches in Competition

• Fundamental Niche: Full resource potential.

• Realized Niche: Restricted due to interspecific competition.

Competition Intensity

• Varies by resource availability and type, with greater intensity in nutrient-poor/environments with limited resources.

• Intensity effects are often asymmetrical; some species may be more negatively affected than others.

Competitive Exclusion Principle

• Two species competing for the same resource cannot coexist indefinitely.

• Competitive coexistence is the ability to share resources despite competition (e.g., through resource partitioning).

Character Displacement

• Occurs when natural selection favors traits that reduce competition (e.g., beak sizes of finches).

External Factors Influencing Competition

• Physical Environment: Soil type, availability of light, etc.

• Disturbances: Can create opportunities for coexistence by temporarily reducing dominant competitors.

• Herbivores and Predators: Change competition outcomes by affecting resource access.

Case Studies

• Studies show competitive impacts across various species; examples include the documented effects of competition in Paramecium and barnacle distribution as influenced by competition and environment.

• Invasive species interactions may shift competitive dynamics in response to climate change.