1. Community
Interactions

2. KEY CONCEPT Every organism has a habitat and a niche.

3. A habitat differs from a niche.
A habitat is all aspects of the area in which an organism lives.
biotic factors
abiotic factors
An ecological niche includes all of the factors that a species needs to survive, stay healthy, and reproduce.
A “role” in their community
food
abiotic conditions
behavior

4. Ecological equivalents are species that occupy similar niches but live in different geographical regions.
Madagascar
South America

5. when organisms live together in an ecological community they interact constantly.
Three types of interactions
Competition
Predation
Symbiosis

6. Competition- competing for resources
occurs due to a limited number of resources
Intraspecific competition
Interspecific competition
Resource- any necessity of life. water, nutrients, light, food.
Competitive exclusion principle- no two species can occupy the same niche in the same habitat at the same time

7. Competitive exclusion has different outcomes.
One species is better suited to the niche and the other will either be pushed out or become extinct.
The niche will be divided.
The two species will further diverge.

8. Predation
Predation- when an organism captures and feeds on another organism.
Predator- hunter
Prey- hunted

9. Symbiosis
Symbiosis- any relationship where two species live closely together.
(3 types)
Mutualism
Commensalism
Parasitism

10. Symbiosis Mutualism- both species benefit from a relationship.
Lichens (fungus and Algae)
One example is the lichens, little non-descript patches of stuff you see growing on rocks and tree bark. This is a symbiosis, consisting of a fungus and an alga. The fungus provides a protective home for the algae, and gathers mineral nutrients from rainwater and from dissolving the rock underneath. The alga gathers energy from the sun. There are thousands of species of lichen in the world; actually thousands of species of fungi with just a few species of algae which can form a partnership with almost any of them.

11. Symbiosis
Commensalism – One member of a symbiotic relationship benefits and the other is neither helped or harmed
Ex. Holes used by bluebirds in a tree were chiseled out by woodpeckers after it has been abandoned

12. + Ø Human Our eyelashes are home to tiny mites
that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle.
Demodicids Eyelash mites find all they need to survive in the tiny follicles
of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. +
Organism benefits Ø
Organism is not affected
Commensalism

13. Symbiosis Parasitism- One creature benefits and one creature is harmed
Ex tapeworm. Feeds in a humans intestines absorbing his/her nutrients.

14. _ + Organism benefits Organism is affected Hornworm caterpillar
The host hornworm will eventually die as its organs are consumed
by wasp larvae.
Braconid wasp
Braconid larvae feed on their host and release themselves shortly before reaching
the pupae stage of development.
Parasitism

15. Relationships:
Symbiosis = Living Together
a) commensalism
b) mutualism
c) parasitism

16. Identify these relationships