Download Chapter 13: Principles of Ecology

Section One: Ecologists Study
Relationships
 Ecology: the study of interactions among living things
 Ecologists study the relationships between the levels of
organization
 Levels of Organization (ordered from smallest to
largest)
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Organism: an individual living thing
Population: a group of organisms of the same species that live
in the same area
Community: a group of different species that live in the same
area
Ecosystem: all organisms and abiotic factors in an area
Biome: major regional or global community of organisms
Section One: Ecologists Study
Relationships
 Ecologists use different tools to conduct research on
these relationships
 Observation
 Experimentation ( in the lab or field)
 Modeling

Computer and Mathematic Models
Section Two: Biotic and Abiotic
Factors
 Components of an Ecosystems
 Biotic Factors: living things in an ecosystem
 Abiotic Factors: nonliving things in an ecosystems such
as temperature, sunlight, wind, and soil
Section Two: Biotic and Abiotic
Factors
 Everything is interconnected
 If you change one thing in an ecosystem you change
everything
 Biodiversity: the variety of living things in an ecosystem
Section Two: Biotic and Abiotic
Factors
 Everything is interconnected
 Keystone Species: a species that has an unusually large
effect on the ecosystem
Section Three: Energy in
Ecosystems
 Energy Flow in Ecosystems
 Producers: organisms that get their energy from
nonliving resources and provide energy for other
organisms in the ecosystem

Can also be called autotrophs
 Consumers: organisms that get their energy by eating
other living or once-living sources

Can also be called heterotrophs
Section Four: Food Chains and
Food Webs
 Food Chains: a sequence that links species by their
feeding relationships
 Always flows in one direction
Section Four: Food Chains and
Food Webs
 Types of Consumers
 Herbivores: organisms that eat only plants
 Carnivores: organisms that eat only animals
 Omnivores: organisms that eat plants and animals
 Detritivores: organisms that eat dead organic matter
 Decomposers: detritivores that break down organic
matter into simple compounds
 Specialists: eats only one specific organism
 Generalists: eats many different organisms
Section Four: Food Chains and
Food Webs
 Trophic Levels: the levels
of nourishment in a food
chain
 Energy flows up the
food chain from the
lowest trophic level to
the highest
Section Four: Food Chains and
Food Webs
 Food Web: a model that
shows the complex
network of feeding
relationships and the
flow of energy within an
ecosystem
 Flow many different
ways
Section Five: Cycling of Matter
 The Water Cycle
 Also called the hydrologic cycle
Section Five: Cycling of Matter
 The Oxygen Cycle
 Most organism need oxygen to live
Section Five: The Cycling of Matter
 The Carbon Cycle
Section Five: The Cycling of Matter
 The Nitrogen Cycle
 Most organism can only
use nitrogen in two
forms

Ammonium and Nitrate
 Nitrogen Fixation: a
process in which certain
types of bacteria convert
gaseous nitrogen in to
ammonia
Section Five: The Cycling of Matter
 The Phosphorus Cycle
 Most of the cycle takes
place underground
 Phosphate is released by
the weathering of rocks
 Plants and fungi take up
the phosphate
Section Six: Pyramid Models
 Energy Pyramid: a diagram
that compares energy used
by producers, primary
consumers, and other
trophic levels
 Biomass: the measure of
the total dry mass of
organisms in a given area
 Biomass (or energy) is lost
as you go up the pyramid