1. Community Interactions
EQ: How do the three types of symbiosis differ?

2. Types of Interactions Competition Predation Symbiosis Mutualism
Commensalism
Parasitism

3. Competition (-/-)
Organisms of the same or different species compete for the same resource in the same place at the same time.
Elk Herd
Bison
Moose

4. Tiger Swallowtail butterfly
Competition
Intraspecific competition: Competition among members of the same species
Tiger Swallowtail butterfly
Interspecific competition: Competition between members of different species
Blue Butterfly

5. Competitive exclusion principle:
No two species can occupy exactly the same niche in exactly the same habitat at exactly the same time. One will always exclude the other.

6. Predation (+/-)
predator
Interaction in which one organism captures and feeds on another organism
Falcon
prey
Herbivory:
Type of predation
Interaction in which an herbivore feeds on producers.
Ground Squirrel

7. Predation
Keystone species: a single species that is vital to the ecosystem stability.
Ex. Otters/kelp/sea urchins

8. Predation
Arctic Hare
Rabbit and Coyote
Coyote
rabbit
coyote

9. Symbiosis Any relationship in which two species live closely together.
Mutualism
Commensalism
Parasitism

10. Mutualism (+/+) Both organisms benefit Examples: Flowers and insects
Bee on Purple Flower
Examples:
Flowers and insects
Ants and aphids
Ant and Aphid

11. Mutualism (+/+)
Lichen
Algae and fungus living together
Lichen

12. Commensalism (+/0)
One organism benefits and the other is neither helped nor harmed.
Spanish Moss

13. Commensalism (+/0)
Whales & Barnacles
Barnacles on Whale

14. Commensalism (+/0)
Epiphytes
“air plants”
Epiphyte in Tree
Epiphyte

15. Parasitism (+/-) One organism benefits while the other is harmed
Examples: tapeworms inside mammals; fleas, ticks, and lice on mammals
Female head louse
Female Head Lice 15

16. Parasitism (+/-) Ticks
The parasite obtains all or part of its nutritional needs from the other organism, the host.
Ticks
Before
After
Blacklegged Tick: An adult female blacklegged tick, engorged after a blood meal, rests on a leaf.
Black Legged Tick