1. Niches and Interactions
Heather Galloway

2. The niche of a species includes:
The mode of existence of a species in an ecosystem is its ecological niche.
The niche of a species includes:
Habitat: where the species lives in the ecosystem.
Nutrition: how the species obtains its food.
Relationships: the interactions with other species in the ecosystem.

3. breeding sites breeding sites food shelter shelter

4. breeding sites food shelter

5. Competitive exclusion principle:
Only one species can occupy a niche in an ecosystem.
Competitive exclusion happens when a species in unable to occupy any part of its fundamental niche in an area, so it has no realized niche in that area.
Gause’s Law

6. Fundamental vs. Realized
Differences between the fundamental and realized niches are due to competition.
Niche that a species Niche that a species could occupy actually occupies

7. The fundamental niche of a species is how it could potentially live, given its adaptations.
The realized niche of a species is how it actually lives, due to its adaptations and competition from other species.

8. Interactions
A situation in which two species affect each other is called an interaction.
There are five classifications of interactions:
Herbivory
Predation
Parasitism
Competition
Mutualism

9. Herbivory
A primary consumer feeding on a plant or other producer. The producer’s growth affects food availability for the herbivore.

10. Predation
A consumer feeding on another consumer. The numbers and behaviour of the prey affect the predator.

11. Parasitism
A parasite is an organism that lives on or in a host and obtains food from it. The host is always harmed by the parasite.

12. Competition
Two species using the same resource compete if the amount of the resource used by each species reduces the amount available to the other species.

13. Mutualism
Mutualists are members of different species that live together in a close relationship, from which both benefit.

14. Bibliography
Allott, Andrew. Biology for the IB Diploma: Standard and Higher Level. Oxford: Oxford UP, Print.
"Competitive Exclusion in Ecology." ScienceDaily. ScienceDaily, n.d. Web. 21 Apr < clusion_principle.htm>.