Studying
Ecology
Chapter 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 .
Individual
Species
Population
Community
Cells
Tissue
Organs
Atoms
Simple
Molecules
Macromolecules
Ecosystem
Biosphere
Organ
Systems
Individual
Species
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.
2.
3.
4.
Plants and trees
Other animals
Fungus
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.
2.
3.
4.
5.
Air
Trees
Soil
Nutrients
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. Abiotic
Biotic Factors
Abiotic Factors
• Living parts of ecosystem or
were “recently” alive.
• Examples: leaves, trees,
fallen logs, carrion
(decomposing animals)
• 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.