Biological Interactions and Distribution January 21st

Predation Predation – when one organism consumes another –Animal-animal predation –Animal-plant predation Stenophagous – selective predators –80% of butterfly species –90% of plant-eating insects Euryphagous – non-selective predators –Most terrestrial birds and mammals

Reasons for Stenophagy Optimal foraging theory Toxins Microenvironment Neural capabilities

Lotka-Volterra model – explains the fluctuations in populations of stenophagous predators and their prey species

Keystone Species A keystone species is a species whose very presence contributes to a diversity of life and whose extinction would consequently lead to the extinction of other forms of life. Keystone species help to support the ecosystem (entire community of life) of which they are a part.

Keystone Species

Competition Interspecific competition Intraspecific competition Two forms of competition –Resource exploitation –Interference competition Allelopathy

Creosote Black Walnut

Competition

Diffuse Competition

Predator Medicated Competition

Mutualism Both species benefit Pollinators Ants and aphids Acacias and ants