Principles of Ecology

1
Chapter 13

• Principles of Ecology

2
KEY CONCEPT 1 Ecology is the study of the
relationships among organisms and their
environment.
3
Ecologists study environments at different levels
of organization.

• Definition Ecology is the study of the
  interactions among living things, and between
  living things and their surroundings.

4

• An organism is an individual living thing, such
  as an alligator.

5

• A population is a group of the same species that
  lives in one area.

6

• A community is a group of different species that
  live together in one area.

7

• An ecosystem includes all of the organisms as
  well as the climate, soil, water, rocks and other
  nonliving things in a given area.

8

• A biome is a major regional or global community
  of organisms characterized by the climate
  conditions and plant communities that thrive
  there.

9
The Environment Levels of Organization from
Simplest to Most Complex
10
KEY CONCEPT 2Every ecosystem includes both
living and nonliving factors.
11
An ecosystem includes both biotic and abiotic
factors.

• Biotic factors are living things.
• plants
• animals
• fungi
• bacteria

12

• Abiotic factors are nonliving things.

• moisture
• temperature
• wind
• sunlight
• soil

13
Changing one factor in an ecosystem can affect
many other factors.

• Biodiversity is the assortment, or variety, of
  living things in an ecosystem.
• Rain forests have more biodiversity than other
  locations in the world, but are threatened by
  human activities.

14

• A keystone species is a species that has an
  unusually large effect on its ecosystem.

15

• Keystone species form and maintain a complex web
  of life.