1. Interactions in Ecosystems

2. Habitat
All of the biotic and abiotic factors in the area where an organism lives
Lion habitat

3. Ecological Niche
All of the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduce
Food
Abiotic conditions
Behavior

4. Competitive Exclusion
When two species are competing for the same resources, one species will be better suited to the niche, and the other species will be pushed into another niche or become extinct
Invasive species may outcompete organisms that are native to a particular region

5. Predation
The process by which one species captures and feeds upon another
Heterotrophs can prey on autotrophs and other heterotrophs

6. Predator – Prey Cycles Prey outnumber predators
Increasing numbers of prey promote increases in predator populations

7. Symbiosis
A close ecological relationship between two or more organisms of different species that live in direct contact with one another
Mutualism
Commensalism
Parasitism

8. Mutualism An interspecies interaction in which both species benefit
Flowers and pollinating insects
Humans and intestinal E. coli
Clown fish and anemones

9. Commensalism
A relationship between two organisms in which one receives an ecological benefit from another, while the other neither benefits or is harmed
Many ecologists believe that commensalism is rare, and that most such relationships are probably subtle mutualism or parasitism

10. Parasitism
A relationship in which one species benefits while the other is harmed.
Many parasites have complex lifecycles involving more than one host
Seen “Alien” ?

11. The Parasitic Life Cycle of the Tse-Tse Fly

12. Tapeworm lifecycle