Ecology Unit: pt. 1 revised

General Ecology Terms
1. Biotic Factor of or relating to life; caused or produced by living beings. Ex. plants,
animals, any organism.
2. Community all the populations of organisms living in a given area.
3. Consumer There are two kinds: Primary consumers are organisms that eat
plants. Secondary consumers are organisms that eat animals that eat plants. Also
called carnivores.
4. Decomposers An organism that feeds on dead material and causes its mechanical
or chemical breakdown. For example: Fungi and bacteria are decomposers.
5. Ecosystem All the living organisms interacting with each other and the non-living
characteristics of an area.
6. Habitat A native environment of an animal or plant which provides food, water,
shelter and space suitable to its needs.
7. Limiting factor The condition which inhibits the expansion of a species.
8. Populations individuals of one species that occupies a particular geographic area
9. Producer Green plants that produce their own food from soil and sunlight.
10. Succession The gradual change of one community by another.
More Ecology Terms
11. organic Pertaining to compounds containing carbon plus hydrogen. Also refers to
living things or the materials made by living things.
12. inorganic Not containing carbon and hydrogen in combination. Not from living
things. Ex., minerals, water, oxygen, carbon dioxide etc.
13. biosphere The portion of the earth and its atmosphere in which living organisms
exist or that is capable of supporting life.
14. heterotroph "eats others." An organism that must consume other organisms to
fuel its metabolism
15. autotroph "self eater." Organisms capable of producing their own food.
16. Niche the way in which an organism uses its environment.
17. Detritus particles of organic material that provide food for organisms at the base
of a food web Ex: leaf litter
18. Abiotic Factor physical, or nonliving, factor that shapes an ecosystem.
branch of science concerned with the interrelationship of organisms
and their environments.
Photosynthesis & Chemosynthesis
Producer Green plants that produce their own food from soil and sunlight
autotroph "self eater." Organisms capable of producing their own food.
Food Chain
food chain/food web All
the interactions of predator
and prey, included along
with the exchange of
nutrients into and out of the
soil. These interactions
connect the various
members of an ecosystem,
and describe how energy
passes from one organism
to another.
Food Web
Ecological Pyramids
Ecologist use
ecological pyramids
to represent the
energy relationships
among trophic levels.
 There are 3
types of
Pyramid of Energy
A pyramid of
energy the total
amount of
energy at each
successive level.
 Notice that
energy (in the
form of heat) is
lost going from
one trophic
level to another.
Pyramid of Biomass
A pyramid of biomass
show the total mass of
living tissue at each
 This pyramid of
biomass shows for
example, that a large
amount of grass is
needed to feed a single
rabbit and a large
number of rabbits is
needed to nourish a
single hawk.
Pyramid of Numbers
A pyramid of numbers
illustrates the total number of
organisms at each level
 In a grassland, for
example, a large amount of
grass (producers) is needed to
support the herbivores (primary
2000 grass plants
25 voles
1 barn owl
Pyramid of Numbers
pyramids of numbers do not
always appear as pyramids.
Look at this one
 If the producer (in this
example an oak tree) is a
large plant, then the
number of primary
consumers which feed on
the producer (caterpillars in
this example) will be much
larger in numbers.
Water Cycle
Carbon and Oxygen Cycle
Phosphorus cycle
Nitrogen Cycle
79% of the air is nitrogen
Denitrification: When nitrogen in
compounds is released into the air
fixation the
nitrogen by
soil bacteria
and its
release for
plant use
Nitrification the oxidation of ammonium compounds in dead organic material into
nitrates and nitrites by soil bacteria (making nitrogen available to plants)
Biogeochemical Cycles
All of the matter that cycles
through the earth and living
things. Ex. Carbon, Oxygen,
Nitrogen, Phosphorous, Water,
 The difference between matter
and energy flow is that energy
can flows in one direction but
matter (or nutrients) is neither
created nor destroyed it gets
Biological Magnification
The process by which concentrations
of a harmful substance increases in
organisms at higher trophic levels in a
food chain or food web.
It affects the entire food web but toplevel carnivores are at highest risk.
1962 Rachel Carson wrote Silent
Spring about the dangers of a
pesticide called DDT, which was
banned in 1970. One effect of DDT
was to make the eggs of large fish
eating birds so fragile that they could
not survive intact.
Biotic Factors
Biotic relating to, or
caused by living
 Biotic factor Factors such
as parasitism, disease,
competition and predation
(one animal eating
another) would also be
classified as biotic factors.
Abiotic Factors
refers to nonliving
objects, substances or
 : The abiotic factors of
the environment include
light, temperature, and
atmospheric gases.
Symbiosis - Organisms and their
interactions with other organisms
in which one species, the
parasite, benefits at the
expense of the other, the
Symbiosis- Mutualism
An association between
organisms of two different
species in which each
member benefits
Symbiosis - Commensalism
relationship between two
organisms of different
species in which one
derives some benefit while
the other is unaffected.
The gradual and
orderly process of
change in an ecosystem
brought about by the
replacement of one
community by another
until a stable climax
community is
* Lichens*
Pond Succesion
Mount St. Helens
Growth of Populations
To study the
relationships between
organisms, ecologists
need to know how
organisms change over
time. How many
individuals are born?
How many die? How
many organisms live in
an area at any given
time? To answer these
questions, ecologist
study populations.
Exponential growth
Growth is
accelerating. When
introduced into a
environment with an
abundance of
resources, a small
population may
undergo geometric,
or exponential
Logistic Growth
When growth encounters
environmental resistance,
(competition, predation,
parasitism, crowding and
death due to natural
disasters) populations
experience an S-shaped
or logistic growth curve.
Limiting Factors
Density Dependent Factors
Become limiting only when the population density (the number
of organism per unit area) reaches a certain level.
These factors operate most strongly when a population is large
and dense
They do not affect small, scattered populations greatly.
Density Independent Factors
Affect all populations in
similar ways, regardless of
the population size
Unusual weather, natural
disasters, seasonal cycle, and
certain human activities,
such as damming rivers and
clear-cutting forests are all
examples of densityindependent limiting factors
Using Your Conservation Project
Answer the following Questions.
Identify four different populations.
Identify four biotic factors.
Name one primary consumer.
Identify two autotrophs.
Identify two heterotrophs.
Identify four abiotic factors.
Identify four organic items.
Name one secondary consumer.
9. Identify two producers.
10. Identify four inorganic items.
11. Identify two decomposers.
12. Using 4 organisms illustrate a basic food chain.
13. Using 10 organisms illustrate a basic food web.
14. Using 4 organisms illustrate a energy pyramid.
15. Explain the problem that is causing your
environment to be destroyed. (at least 20 words)