Ecology and Human Impact
 Ch.
14: Ecosystems (pg. 253-262)
 Ch. 16: The Fragile Earth (pg. 289-307)
What is Ecology?
Ecology – the study of the interactions of
organisms with one another and with their
physical environment.
Biotic Factors – Organisms that are living (or
WERE living at one time….paper, steak)
ex) animals, plants, bacteria, fungus
Abiotic Factors – Physical Environment
(non-living) ex) water, air, dirt, rocks
Ch. 14: Ecosystems
What is an Ecosystem?
A self-sustaining collection
of organisms and their
physical environment.
ex) forest, river, lake.
Food Webs and
Energy Transfer
 Organisms
obtain the energy they need to live by
eating or taking in other sources of energy.
 If the flow of energy is disrupted, it can have
disastrous results on the entire ecosystem
 What is the first source of energy for the planet?
Important Terms
 Producer/Autotroph

(Auto = self, troph = feeder)
organisms that produce their own food directly from
the sun’s energy.
 Take
in energy from their surroundings and and store
it in complex molecules such as carbohydrates.
 Use the process of photosynthesis to make complex
molecules
 Consumers/Heterotrophs (hetero = other)
Organisms that obtain energy by
consuming other organisms.

 Feed
on producers & other consumers
Can be:
 herbivores
 carnivores
 omnivores
 Decomposers
**Be able to define
These terms from
your Chapter 14
Vocabulary homework
Important Terms
 Primary
Consumer – Feeds on plants. All are
herbivores.
 Secondary Consumer – Feeds on primary
consumers. May be omnivore or carnivore
 Tertiary Consumer – Feeds on secondary
consumer. May be omnivore or carnivore
 Quaternary Consumer – Feeds on tertiary
consumer. May be omnivore or carnivore.
Food Chain vs. Food Web
Food Chain
 Food
chain is one
series of energy
transfers in an
ecosystem
Food Web
 Food
web is the
interconnected
food chains in an
ecosystem
Food Chain
or
Food Web?
Important Terms
 Trophic
Level – group of organisms who's energy
source (the sun) is the same number of steps away
from the sun.
 Energy flows from producer  consumer.
 Producers are always the 1st trophic level
 Heterotrophs (consumers) are always at least the
2nd trophic level
Trophic
levels are
different
than
consumer
levels
 Level
5
 Level
4
 Level
3
 Level
2
 Level
1
Ecological Pyramids:
graphs which
illustrate the
trophic levels in
a community.
Most ecological pyramids are large at the
base and narrow at the top.
This is because every time
that an organism is eaten
by the next trophic level,
some of the energy is lost
as heat.
Less Energy
More Energy
Pyramid of Energy:
 Shows


the energy available at each trophic level.
The size of the blocks represents the proportion of energy
Measured in Joules or Calories
Pyramid of Numbers:
 Illustration
each level
of the number of organisms at