Life Abounds
Abiotic/Biotic Factors
& Energy Flow through Ecosystems
http://quest.arc.nasa.gov/projects/astrobiology/astroventure/index.html
Today’s Objectives
By the end of class today, you will be able to:
 distinguish the difference between biotic and abiotic
factors and the role they play in environmental
communities
 to identify the 4 mains parts of energy flow through an
ecosystem
Changing Gears—Abiotic vs. Biotic Factors
Abiotic Factors
The growth and survival of organisms depends on the
physical conditions and chemical factors in the
environment on which life depends—they themselves
are not living.
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Changing Gears—Abiotic vs. Biotic Factors
Biotic Factors
Includes all the living components of the environment
that affects the ecological community either directly or
indirectly, and helps to limit the species that inhabit
that area
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Abiotic Factors
 Light intensity for photosynthesis
 Temperature range
 Amount of moisture available
 Types of rock under the soil
 Mineral availability
 Presence of atmospheric gases
 pH of the system
Abiotic Factors
 Subject to the physical laws of nature
 Sunlight—affected by filtering of the atmosphere
protecting us from harmful radiation
 Water—expands and becomes less dense when freezes
Biotic Factors
 Population levels of a particular species
 Food requirements for a particular species
 Interactions one species has with another
 Waste produced by the species
Biotic Factors
 Abide by natural biological laws that govern ALL life
forms
 All living things composed of cells (organism’s
functional unit)
 Living things MUST carry out their life functions to
survive
 Living things depend on the activities of other living
things to provide them with nutrients and essential
components.