13: Species Interactions

What are the different types of species interactions

Competition (-/-)

Exploitation (Predation, Herbivory, Parasitism) (+/-)

Mutualism (+/+)

Commensalism/Facilitation (+/0 or +)

Types of Competition

Exploitative: eat the same resources/etc, not physical fighting

Interference: direct, physical interaction

Mutualism

Increases fitness for both partners

Potential consequences: increases per-capita demographic rates, rates of population growth, or population size (mutualism might be TOO GOOD, the dynamic duo)

Food chain

In ecosystem, energy passes through steps/links

Trophic/Feeding Level

The levels in the food chain

What do food chains show?

ONE POSSIBLE path of the flow of energy in an ecosystem

Food web

Links all food chains in an ecosystem together

Apex predator

animal at the top of the food chain with no natural predators

Nonexclusive consumers/Omnivores

Species that can weave into the food web at more than one trophic level

Trophic cascades

changing predators changes the food web

Keystone species

an organism that defines a whole ecosystem, no other species can fill their niche

Mutualism, commensalism, and parasitism

Can shift from each other