Studying EcologyChapter 4 Section 1

Levels of Ecological Organization• Ecologists study life at many levels.• Ecology is the study of how organisms interact

with each other and their environments .

IndividualSpecies

Population Community Ecosystem Biosphere

Cells Tissue Organs Organ Systems

Individual Species

Atoms Simple Molecules

Macro-molecules

Organelles Cells

Individual Species/Organism

• Basic level of study for an ecologist is an individual organism.

• Ecology describes the relationship between organisms and their environment.

• A species is a group of individuals that…– interbreed and produce fertile offspring. – have genetic similarity

Populations

• Population: members of the same species that live in the same area at the same time.

• The fleas living on your dog = a population.

• All of the golden toads in the Costa Rican rainforest = a population.

Communities• All of the populations in a particular area.• PA bears’ community includes:

1. Plants and trees2. Other animals3. Fungus4. Stream life

Ecosystems• An ecosystem includes all of the living things in an area AND their

physical environment. • Back to the bears…Their ecosystem would including the following…

1. Air2. Trees3. Soil4. Nutrients5. Rivers

Biosphere• All of the parts of Earth that host

life. – all of the organisms and

environments in which they live. • Ecologists rarely study this

“grand” of a scale!

Let’s Fill Out Our Diagram With Examples!

Biotic vs. AbioticBiotic Factors

• Living parts of ecosystem or were “recently” alive.

• Examples: leaves, trees, fallen logs, carrion (decomposing animals)

Abiotic Factors

• Ecosystem parts that have never been living.

• Many are used or consumed by living things.

• Examples: oxygen, sunlight, water, carbon.

Habitat• The environment in which an organism lives• Includes all the resources needed to

survive. • Include both abiotic and biotic factors,

because both are required for living things to survive.

Review Questions

1. Would all of the different kinds of organisms in a pond be considered a population or a community? Explain.

2. For each level of ecological organization (refer to your chart) state whether it contains only biotic factors, only abiotic factors, or both.