1. What Shapes an Ecosystem?

2. Review of Biotic and Abiotic Factors
Ecosystems are influenced by a combination of biological and physical factors.
Biotic factors
include all the living things with which an organism might interact.
Abiotic Factors
Physical, or nonliving, factors that shape ecosystems.

3. Habitat and Niche Habitat
all aspects of the area in which an organism lives (includes both biotic and abiotic).
Habitats may change or disappear due to natural causes or interference by man.

4. Habitat and Niche Niche
the role or place and position a species has in its environment.
An ecological niche includes all of the factors that a species needs to survive, stay healthy, and reproduce.
food
abiotic conditions
behavior

5. Habitat and Niche
Why do you think no two species can share the same niche.
One species is better suited to the niche and the other will either be pushed out or become extinct.

6. Community Interactions
When organisms live together in ecological communities, they interact constantly.
Community interactions include:
Competition
Predation
Symbiosis

7. Community Interactions
Competition:
occurs when two organisms fight for the same limited resource.
Direct competition in nature often results in a winner and a loser—with the losing organism failing to survive.

8. How species avoid Competition
The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree.

9. Community Interactions
Predator
Predation:
occurs when one organism captures and eats another.
Prey

10. Community Interactions
Symbiosis:
Any relationship in which two species live closely together
Includes:
mutualism
commensalism
parasitism

11. Community Interactions
Mutualism:
both species benefit from the relationship.

12. Community Interactions
Commensalism
one member of the association benefits and the other is neither helped nor harmed.
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. Community Interactions
Parasitism
one organism lives on or inside another organism and harms it.
Organism benefits _
Organism is not 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 +

14. Ecological Succession
Succession occurs following a disturbance in an ecosystem and regenerates or creates a community after a disturbance.
a sequence of biotic changes
damaged communities are regenerated
new communities arise in previously uninhabited areas

15. Ecological Succession
There are two types of succession.
primary succession — started by pioneer species

16. Ecological Succession
There are two types of succession.
secondary succession — started by remaining species