1. Principles of Ecology

2. Biotic vs. Abiotic Factors
What is Ecology?
Ecology is the study of interactions between organisms and their environment.
Biotic vs. Abiotic Factors
Biosphere – portion of the Earth supporting life
Biotic factors
a. All organisms inhabiting the environment
b. Each organism adapts to its part of the biosphere
Abiotic factors
a. Nonliving parts of the environment
b. Can determine which species will survive
examples: rainfall, temperature, light, soil

3. Abiotic Factors
Biotic Factors
ECOSYSTEM

4. C. Levels of Biological Organization
Populations
a. A group of organisms of the same species living together
b. Must compete for resources
Community
a. Several populations that interact
b. Changes in one population will cause changes in the others
Ecosystem
a. Interactions between populations and their surroundings
b. 2 main types:
1. Terrestrial – land
2. Aquatic – fresh or salt water

5. Levels of Biological Organization

6. D. Niche vs. Habitat Niche Habitat Place where an organism lives
The role an organism plays in the environment
(Its “job” in the community)
Habitat
Place where an organism lives
Three Species of Warblers and their niches
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Yellow-Rumped Warbler
Feeds in the lower part of the tree and
at the bases of the middle branches
Spruce tree

7. E. Types of Feeding Relationships
Autotrophs
a. Self-feeders, produce their own food
b. Example: plants, algae
Heterotrophs
a. Depend on other organisms for food
b. Herbivore – eats only plants
c. Carnivore – eats only meat
d. Omnivore – eats both

8. a. Break down and absorb nutrients from dead organisms
Decomposers
a. Break down and absorb nutrients from dead organisms
b. Example: mushrooms, bacteria
Commensalism
a. Relationship in which one species benefits and the other is not affected
b. Example: remoras that live on/around a shark’s mouth
bacteria
Remora on a Ray

9. a. One organism benefits and the other is harmed
tickbirds
Mutualism
a. Both species benefit
b. Example: tickbirds eat parasites off of a rhino
Parasitism
a. One organism benefits and the other is harmed
b. Example: tapeworm living inside a person’s intestine
oxpeckers

10. F. Compare Food Chains and Food Webs
a. Model showing movement of energy through the ecosystem
b. Uses arrows to show “what eats what”
Grass  Cow  Human
Food Web
Food Web
a. More complicated than a food chain
b. Shows more than one food source for each organism
c. More realistic view of energy transfer