Ecology
The study of the interactions
between organisms and their
environment.
Biotic Factors
All of the living organisms that
inhabit an environment.
Abiotic Factors
All of the nonliving parts of the
environment.
List the biotic “things” that
inhabit this environment.
List the abiotic “things” that
inhabit this environment.
List the biotic “things” that
inhabit this environment.
List the abiotic “things” that
inhabit this environment.
List the biotic “things” that
inhabit this environment.
List the abiotic “things” that
inhabit this environment.
List the biotic “things” that
inhabit this environment.
List the abiotic “things” that
inhabit this environment.
An organism- ex. deer
A population- more than one deer
that live in the same place at the
same time.
A community- more than one
population that live in the same
place at the same time.
An ecosystem- a community along
with the abiotic factors that
influence the community.
•Biosphere – the area of the
Earth where all life exists.
the place where an organism lives.
Habitat
Niche
the role a species plays in a community-feeding
relationships, space, etc. It tells how a species
uses and affects its environment.
Ways Organisms Interact
•Autotrophs-organisms that use energy
from the sun or energy stored in chemical
compounds to manufacture their own
food.
•Also known as Producers- all other organisms in
the community depend on the producers. Ex.
Plants, algae
Ways Organisms Interact
•Heterotrophs-organisms that depend on
other organisms for their source of food
and energy.
•Also known as Consumers.
Herbivores- eat only producers.
Carnivores- kill and feed on other
animals
Omnivores – eat either plants or
animals
Scavengers-feed on dead organisms
that they did not kill
Scavengers-feed on dead organisms
that they did not kill
Decomposers - break down and absorb
the nutrients into basic molecules so that
the nutrients can be recycled back into
the ecosystem. Ex. many of the bacteria,
some protozoans, and most fungi.
Relationships
•Symbiosis - a
relationship where
there is a close and
permanent
relationship between
organisms of
different species.
Commensalism – a relationship where one
species is benefited and the other is neither
harmed nor benefited.
Commensalism – a relationship where one
species is benefited and the other is neither
harmed nor benefited.
Commensalism – a relationship where one
species is benefited and the other is neither
harmed nor benefited.
mutualism – a relationship where both
species benefit.
mutualism – a relationship where both
species benefit.
parasitism – a relationship where one
organism is harmed (but usually not killed)
and the other organism is benefited.
parasitism – a relationship where one
organism is harmed (but usually not killed)
and the other organism is benefited.
parasitism – a relationship where one
organism is harmed (but usually not killed)
and the other organism is benefited.
Competitors
*Competition – ecological interaction
between two or more species that use the
same limited resource such as food, light,
and water. No two organisms can occupy
exactly the same niche without one of the
organisms becoming extinct.
Predator-prey relationships
•Predator – an organism that kills and feeds on
that organism
•Prey – the organism that is killed
Energy Relationships
Food Chains
•Shows the simple relationship of what organism
consumes what organism. This relationship very
seldom exists in nature since it represents only
one way that energy can be transferred in an
ecosystem.
•2 Rules for food chain or food web.
–1. Always start with a producer organism.
–2. The arrows always go in the direction of energy
flow.
•Food chains can consist of no more than two to five
links.
Food Chains
•*10% rule in food chains – As energy is
transferred from one trophic level to the
next, 90% of the energy is lost as heat to
the environment and only 10% is
transferred as tissue in the next trophic level
for the next trophic level to use. This is a
rough rule of thumb to show what happens
to energy in a food chain.
HeterotrophHeterotrophHeterotroph
Herbivore1
st
Carnivore2
nd
Carnivore
*only 10 C of the original 10,000 C in the grass is left in the food chain
for the rat snake. If food chains are any more than five links long, there is not enough
energy left for organisms at higher levels. It also explains why one sees so few top carnivores in
the environment. There are not very many hawks in the environment because they are at the top
of the food chain.
Food Webs
Tries to explain all of the feeding
relationships at each trophic level in a
community. A food web is more realistic
than a food chain since most organisms
feed on more than one organism.
Ecological Pyramids
• Shows relationships in food chains and food webs.
–The bottom - represents the producers,
–2
nd
level- the herbivores
–3
rd
level- the 1st carnivore
–4
th
level- top carnivore.
*The shape of the pyramid indicates that it is largest on the bottom
and gets smaller toward the top.
• pyramid of energy – shows energy relationships between trophic levels in
the form of calories
• pyramid of numbers – shows number relationships between numbers of
organisms at different trophic levels
• pyramid of biomass – shows the living mass at each trophic level in a food
web or food chain.
Biomes
Bring colors, markers, or colored
pencils tomorrow!!