Ecology
Branch of Biology that studies
interactions between organisms
and the environment
Abiotic Factors
Nonliving things that affect an
ecosystem
Examples of Abiotic
Factors
Sunlight, temperature, soil,
precipitation, pH, O2
Concentration
Biotic Factors
Living things that affect an
ecosystem
Examples of Biotic
Factors
Competition, predation,
decomposition, symbiosis,
disease
Population
All of the individuals of one
species living in a specific area
Community
All of the populations of
different organisms living in a
specific area
Ecosystem
All living organisms (biotic) and
their physical environment
(abiotic)
Niche
Intraspecific
Interactions
The full range of biotic and abiotic
conditions in which an organism
lives and the way it uses those
conditions
Interactions between individuals
of the same species
Interspecific
Interactions
Interactions between individuals
of different species
Neutralism
A relationship between two
species that interact but do not
affect each other
Symbiosis
Relationship between organisms
of different species that benefits
one or both of the organisms
Mutualism
A symbiotic relationship
between two or more species
where both organisms benefit
Commensalism
A symbiotic relationship in
which one organism benefits and
the other is neither benefited nor
harmed
Parasitism
A symbiotic relationship in
which one organism benefits and
the other is harmed
Predation
A relationship between
organisms in which one captures
and feeds on the other
Competition
A relationship between
organisms in which they
compete for limited resources
Intraspecific
Competition
Competition between organisms
of the same species
Interspecific
Competition
Competition between organisms
of different species
Competitive Exclusion
Principle
No two species can occupy the
exact same niche, in the same
place, at the same time
Limiting Factors
When a nutrient limits the
growth (productivity) of
organisms in an ecosystem
Exponential Growth
When a population multiple by a
constant factor at a constant time
because of unlimited resources
Logistic Growth
An S shaped curved population
that starts exponentially, then
slows and finally stops growing
Carrying Capacity
The maximum number of
individuals that the environment
can support
Producers
Organisms that make their own
food from inorganic compounds
Autotrophs
Organisms that make their own
food through photosynthesis or
chemosynthesis
Consumers
Organisms that must obtain their
food from other organisms
Heterotrophs
Organisms that must obtain their
food from their environment
Decomposers
Organisms that break down the
remains of dead organisms
Food Chain
A series of organisms though
which food energy is passed
How Energy Flows
through an Ecosystem
In a straight line through food
chains
Food Webs
Many food chains connected at
different points
Effect of removing a
producer from a food
web
Collapse of the whole system
Effect of removing a
consumer from a food
web
Increase of the individuals that the
consumer eats, and reduction of
the individuals which eat the
consumer
Primary Consumer
Herbivores or omnivores that
consume the producers
Secondary Consumer
Omnivores and carnivores that
consume primary consumers
Tertiary Consumer
Omnivores and carnivores that
consume secondary consumers
Quaternary Consumer
Omnivores and carnivores that
consume tertiary consumers
10% Rule
Only 10% of available energy, at one
tropic level, is transferred to
organisms at the next tropic level
Pyramid of Energy
Diagram which shows that the
energy available to organisms
decreases with each tropic level
Pyramid of Biomass
Diagram which shows that the
total amount of living tissue
(biomass) decreases with each
trophic level
Pyramid of Numbers
Diagram which shows that the
number of organisms decreases
with each tropic level
Carbon Cycle
The movement of Carbon and
Oxygen through the biosphere
Nitrogen Cycle
The movement of Nitrogen
through the biosphere
Nitrogen Fixation
The process that changes free
nitrogen in the atmosphere to
compounds that can be used by
living things
Denitrification
The process of breaking down
nitrogen compounds into free
nitrogen
Ecological Succession
The series of changes that occur
in communities over time
Primary Succession
Changes that occur on surfaces
where there is no soil
Secondary Succession
Changes that occur on surfaces
where soil is already present
Pioneer Species
The first species to populate an
area
Pioneer Species in
Primary Succession
Lichens and Mosses
Seral Communities
Different communities between
the pioneer species and the
climax community
Climax Community
The mature, stable community
of organisms, which is the end
result of succession