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Chapter 12
Ecosystems
Mr. McCloskey
College Bound Biology
The State of Our World
• Population:
6,446,131,400 and
increasing rapidly.
• Global warming
• Habitat destruction
• Species extinction
• Ozone depletion
Ecology and Ecosystems
• Ecology = The study
of the interactions of
organisms with one
another and with their
physical environment.
Ecology and Ecosystems
• Community = The organisms that live in a particular
place, such as a stream.
Ecology and Ecosystems
• Ecologists = The
scientists who
specialize in ecology.
• Salary : $36,384 $66,108.
Ecology and Ecosystems
• Habitat = The
physical location of a
community.
Ecology and Ecosystems
• Ecosystem = The
self-sustaining
collection of
organisms and their
physical environment.
Ecology and Ecosystems
• Diversity = The number of species living in an
ecosystem and how common each species is.
– 10 Crayfish
– 5 dragonflies
2 Mayflies
1 Black fly
Why Study Ecology?
To prevent pollution
Conserve resources
Help your children
Why Study Ecology?
• Ecosystems are very complex.
• They could contain hundreds or thousands of
interacting species.
Why Study Ecology?
• Understanding
ecosystems by asking
2 questions.
• #1 Where does the
energy for organisms
come from?
• #2 Where do minerals
and inorganic
substances come from
for organisms?
Why Study Ecology?
• So what happens to
an ecosystem if one
organism where to be
removed? (Lets say
the crayfish)
Energy in Ecosystems
• Producers = The
organisms that take in
energy from their
surroundings and
store it in complex
molecules.
– Plants
– Algae
– Bacteria
Energy in Ecosystems
Consumers = Organisms
that obtain their energy
by consuming other
organisms.
Animals
Protists
Fungi
Bacteria
Energy in Ecosystems
• Decomposers =
Organisms that obtain
energy by consuming
organic wastes
(feces, urine, dead
plants and animals)
• Fungi
• Bacteria
The Food Chain
Energy in Ecosystems
• Trophic Level = A
group of organisms
whose energy
sources are the same
number of steps away
from the sun.
Energy in Ecosystems
• Autotrophs = Plants
and other organisms
that make their own
food.
Energy in Ecosystems
• Herbivores = Are
plant eaters.
• Usually found in the
second trophic level.
Energy in Ecosystems
• Carnivores = Flesh
eaters
• Usually found in the
third trophic level or
above.
Energy in Ecosystems
• Omnivores =
organisms that eat
both plants and
animals.
Energy in Ecosystems
• Heterotrophs =
Organisms living in
trophic levels above
the first trophic level
(above the
autotrophs).
Energy in Ecosystems
• Food web = The
movement of energy
through an ecosystem
in a complex network
of feeding
relationships.
• Notice the arrows
show the flow of
energy, not who is
eating who.
Ecological Pyramid
• This shows the loss of overall energy from one trophic level to
the next.
• Also, think about the numbers of each organism.