Chapter 2 Principles of Ecology

I. Organisms and their environments

Main Idea: The interactions of biotic & abiotic factors in a community or ecosystem form a tight web

A. What is Ecology?• 1. The scientific study of interactions

among organisms and their environment.

*Ecology comes from the greek word oikos meaning house and ology-to study*

2. Reveals interdependence3. Scientist who study it = Ecologist

B. Aspects of Ecological Study

1. -the portion of earth that supports life

-scientist study

the diversity

of organisms

& factors

that effect

them

2. Abiotic Factors

• a. air currents

• b. temperature

• c. moisture

• d. light

• e. soil

• f. rainfall

• g. available nutrients

3. Biotic Factors• a. plants

• b. animals

• c. bacteria

• d. fungi

• e. protists

C. Levels of Organization

• 1. Ecologist study interactions among organisms at several different levels.

• Know list on page 36

2. Levels include:

• a. Organism- one individual living thing

• b. Population- group of one species that interbreed and live in the same place.

• c. Biological Community- collection of interacting populations that occupy the same geographic area

d. Ecosystems- interactions among populations in a community and the physical surroundings.

Mobile, AL

D. Organisms in Ecosystems

1. Habitat-place an organism lives.

2. Niche-role and position a species has in its environment.

3. Living Relationships

• a. Symbiosis- Living together

b. Symbiotic relationships include:

• (1) Commensalism-one species benefits and the other species is unaffected.

(2) Mutualism- both species benefit.

Termites and intestinal flagellates: Sea anemone and the clown fish

(3) Parasitism- one organism derives benefit at the expense of another.

II. Flow of energy in an Ecosystem

Main Idea: Autotrophs capture energy, making it available for all members of a food web

A. How organisms obtain energy• 1. Autotrophs-make their own nutrients

from an energy source.

• 2. Heterotrophs- cannot make their own energy-they must feed on other organisms.

3. Heterotrophs include:

• a. herbivores-plant eaters

b. carnivores-kill and eat meat

c. Scavengers-eat already dead animals (don’t kill)

d. Omnivores- eat meat and plants

e. Decomposers- breakdown complex molecules. (detrivores)

B. Models of Energy Flow

1. Food Chain

• a. Shows how matter and energy move

through an ecosystem.

• b. Simple-shows one possible route.

• c. Algae fish heron

• d. Consist of 3-5 steps.

2. Trophic Levels• a. Trophic levels = feeding step

• b. Feeding = energy transfer

3. Food Webs

A model representing the many interconnected food chains and pathways in which energy can flow.

4. Ecological Pyramids

• a. Energy Pyramid- shows how

energy flows through an ecosystem.

b. Numbers pyramid

*number of individuals at each level decreases b/c there is less energy to support them

c. Biomass Pyramid• Expresses weight of living material at each

trophic level

III. Cycles in the Biosphere• Biogeochemical Cycles- exchange of matter

through the biosphere

• - Matter, in the form of nutrients moves through the organisms at each trophic level.

• - Matter cannot be replenished by sunlight.

• - Matter must be constantly recycled.

-Nutrient Cycles include:

A. Water Cycle

B. Carbon/Oxygen Cycle

c. Nitrogen Cycle

d. Phosphorus Cycle