1. Symbiosis is a relationship between different species in which at least one species depends upon the relationship to survive

2. Symbiotic relationships
Symbiosis
Mutualism (+ +)
Commensalism (+ 0)
Antagonism (+ -)
Parasitism
Predation
Competition
Amensalism (- 0)

3. Antagonism - Predation
One individual (predator) captures, kills, and consumes another individual (prey)
Common Defenses Against Predation
Flight
Mimicry
Camouflage
Chemicals/Physical Structures
Bright Colors

4. Herbivore-Plant Interactions
An herbivore grazing on a plant is another example of predation.
Usually, only part of the prey is eaten by the predator.
Photo Credit: Rhett A. mongabay.com

5. Antagonism - Competition
Competition in an interaction between two organisms that are using the same resources
Competition within the same species= intraspecific
Competition between different species= interspecific
One organism better uses a resource leaving less for other species

6. Example: Interspecific Competition
Two species of barnacles on rocky coasts often compete for space.
The smaller species (Chthamalus) is unable to compete as well as the larger species (Balanus).
However, Chthamalus can survive drying better than Balanus, so it can live higher up on the rocks.

7. Experiment: Interspecific Competition
In Scotland, Joseph Connell studied interspecific competition in these two barnacles.
In places where both barnacles were present, he removed the Balanus barnacles from the rocks.

8. Experiment: Interspecific Competition
When Balanus barnacles were removed, the Chthamalus barnacles moved down into the vacant area.
This showed that Balanus was outcompeting Chthamalus in the lower zone.

9. Experiment: Interspecific Competition
At other sites where both barnacles were present, he removed Chthamalus barnacles from the rocks.
The vacant areas remained unoccupied.
This showed that Balanus was not able to survive in the upper zone.

10. Antagonism - Parasitism
One individual is harmed and one benefits
Parasite feeds on the host
No immediate death

11. Mutualism
Both species benefit
Pollination

12. Commensalism One species benefits and the other is not affected
Cattle Egrets and Livestock

13. Ammensalism
one species is harmed or inhibited and the other species is unaffected
shading out of one plant by a taller and wider one
the inhibition of one plant by the secretions of another

14. Species Interactions Symbiotic Relationship Species 1 Species 2
Mutualism +
Benefits
Commensalism
Neutral
Antagonism (Parasitism, competition, predations) -
Harmed
Ammensalism

15. http://education. nationalgeographic
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