Biological Interactions and Distribution

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. Allelopathy Black Walnut Creosote

11. Competition

12. Competition

13. Competition

14. Diffuse Competition

15. Predator Medicated Competition

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