1. Biological Interactions and Distribution January 21st

2. 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

4. Reasons for Stenophagy Optimal foraging theory Toxins Microenvironment Neural capabilities

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

7. 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.

8. Keystone Species

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

10. Creosote Black Walnut

11. Competition

14. Diffuse Competition

15. Predator Medicated Competition

16. Mutualism Both species benefit Pollinators Ants and aphids Acacias and ants