Chapter 5:
Evolution and
Community Ecology
Mr. Manskopf
Notes Can Also Be Found at
http://www.manskopf.com
Section 3: Ecological
Communities
► Explain
the difference between producer and
consumer.
► Explain the effect of inefficient energy
transfer on community structure.
► TERMS: primary producer, photosynthesis,
consumer, cellular respiration, herbivore,
carnivore, omnivore, detritivore,
decomposer, trophic level, food chain,
biomass, food web, keystone species.
What makes an ecosystem like this “work?”
Life Depends ENERGY, LOTS OF
ENERGY…from the Sun
• Average
Star
• 93 million
miles away
• Nuclear
Fusion
• No Sun,
No Life
Life Depends on the Sun
ALL
organisms
need a
constant
supply of
energy or
they die
Why do
plants
grow
upwards?
Life Depends on the Sun
► The
Mmmm, solar
energy tastes
good!
ultimate source
of almost all energy
for organisms is the
SUN.
► What did you eat?
(Nuclear Powered?)
► Only some deep sea
creatures do not get
energy from sun
Life Depends on the Sun
►Photosynthesis:
plants use the
suns energy,
water and CO2,
to make energy.
►Base of ALL food
chains
Almost all
organisms depend
either directly or
indirectly on
photosynthesis
From Producer to Consumer
► Producer:
an
organism that makes
it own food
► Plants
►Autotrophs,
feeders
► Use
sunlight
► Base of all food
chains
self-
From Producer to Consumer
► Consumer:
gets it
energy by eating
producers or other
consumers
►Heterotrophs
► Indirectly
powered
solar
Types of Consumers
► Herbivore:
eats only producers (vegetarian)
► Cows, sheep, deer, grasshopper, mice,
rabbits
Types of Consumers
► Carnivore:
eats
other consumers
► Lion, hawks,
snakes, alligator,
whales
Types of Consumers
► Omnivore:
eats
both producers and
consumers
► Bears, pigs,
raccoons and most
humans
Types of Consumers
► Decomposer:
breaks down dead
decaying organisms
► Critical to
ecosystem health
► Returns nutrients
► Fungus, bacteria
Detritivores and decomposers: recycle nutrients
within the ecosystem by breaking down nonliving
organic matter
How do Organisms Use Energy
Most organisms spend large
amounts of time/energy in
search of food and a mate.
How do Organisms Use Energy
► Cellular
Respiration:
processes of
breaking down food
to yield energy
► Gives energy to
walk, read, grow,
think, run, fight
diseases
► Excess stored as fat
Glucose (sugar) + Oxygen
REACTANTS
yields
carbon dioxide, water and energy
PRODUCTS
Energy Transfer
Each time one
organism eats another,
energy is transferred
Ecosystems are all
about energy flowing
from one organism to
another
Energy Transfer
► Who
are the
producers?
► Consumers?
► Herbivores?
► Carnivores?
► Omnivores?
► Decomposers?
► Where does the
energy start?
Energy Transfer
► Food
Chain:
sequence in which
energy is
transferred from
one organism to
another
► Starts with
producers
Energy Flow
► Food
Web:
shows many
feeding
relationships
that are possible
in a ecosystem
► More complex
and realistic
Energy Flow
► Trophic
Level: each
step which energy
is transferred
Energy Pyramid
Energy Flow
►Why
are there
fewer organisms at
the top? (Why
fewer bears than
the fruit they feed
on)
►Why aren’t there
more than 4-5
trophic levels in a
energy pyramid?
Energy Flow
► At
each trophic level
about 90% of
energy is lost
► Cellular respiration
► Lost to heat body
and carry out living
Energy Flow
► Why
are there fewer
organisms at the top?
(Why fewer bears than
the fruit they feed on)
► Why aren’t there more
than 4-5 trophic levels
in a energy pyramid?
What does this diagram show?
Keystone Species
►Species
that have
strong and/or widereaching effects on a
community
►Removal
of a
keystone species can
significantly alter the
structure of a
community.
Keystone Species
http://www.youtube.com
/watch?v=Xg62WKwA47
0 (Otter Keystone
Species)
Prairie Dogs:
Keystone species
http://www.youtube.com
/watch?v=kEh4r4iQiBU
NATURE's "Silence of the
Bees“
http://www.youtube.com
/watch?v=dIUo3STj6tw
Section 3 Review
► Explain
the difference between producer
and consumer.
► Explain the effect of inefficient energy
transfer on community structure.
► TERMS: primary producer, photosynthesis,
consumer, cellular respiration, herbivore,
carnivore, omnivore, detritivore,
decomposer, trophic level, food chain,
biomass, food web, keystone species.
Section 3 Quiz
1) The ultimate source of energy in an
ecosystem in which deer eat grass and
coyotes eat deer is
A. the grass.
B. the sun.
C. the deer.
D. chemosynthesis.
B. The SUN
2) When energy is transferred between
trophic levels, the amount of available
energy lost is about
A. 90 percent.
B. 50 percent.
A. 90%
C. 25 percent.
D. 10 percent.
3) Humans are generally
A. carnivores.
B. herbivores.
C. omnivores.
D. detrivores.
C. Omnivores
4) Any being that uses the sun’s energy
to create sugars is a
A. primary producer.
B. secondary producer.
C. primary consumer.
D. secondary consumer.
A. primary producer.
5) In a food web that consists of grass,
mice, deer, coyotes, and hawks, which
species is likely to have the greatest
biomass?
A. grass
B. mice
C. coyotes
D. hawks
A.
grass
6) The first level of all food pyramids
A. consists of primary producers.
B. consist of primary consumers.
C. is chemosynthesis.
D. is photosynthesis.
A.
consists of primary producers.
7) Short Answer: In a meadow
community, you observe a high biomass
of plants, a fairly high number of
rodents, but only a single fox. Explain.
This is due to inefficient energy transfer
through the food web. Only about 10
percent of energy is available from one
level to the next, so a high biomass of
plants will support only a few predators.
8) Short Answer: Grasslands are generally
considered highly productive ecosystems, and
we see some of the largest and most diverse
assemblages of mammal species on
grasslands such as the Serengeti. Why do you
think this is, as opposed to an ecosystem like
a northern pine forest, for example?
Grasslands produce a huge amount of available plant
energy, which in turn supports a large number of
herbivores, and a higher concentration of carnivores. A
forest contains a lot of biomass as unavailable woody
material that animals cannot easily consume, so energy
remains locked at the producer level.
9) Short Answer: Explain why a food
web is a better representation of energy
flow in a community than a food chain.
A chain represents a single avenue of
energy transfer. In reality, there are
numerous relationships between a single
species and the other species in its
community, so energy might travel along
any of several paths.
10) Identify a
producer, a primary
consumer, and a
secondary consumer
from the illustration.
Plants are producers.
Deer, crayfish,
moorhens, raccoons,
shrimp, and flagfish are
primary consumers. Pin
frogs, bobcats,
alligators, crayfish,
killfish, largemouth
bass, anhingas, and
alligators are secondary
consumers.
11) If an anhinga
consumes a crayfish,
what percentage of
the energy of the
crayfish’s original
plant-based meal will
reach the anhinga?
One percent of
the original
energy of the
plants will be
available to the
anhinga.
12) Which
populations in this
ecosystem would you
expect to have the
fewest members, and
why?
The anhingas, bobcats,
and alligators would
probably be fewer in
number than other
species, since they are
secondary or tertiary
consumers and much of
the ecosystem’s energy
has been lost by the
time it reaches them.
13) What would happen
if alligators were
removed from the
ecosystem? Explain the
effects on each level of
the food web.
The alligator’s prey
species might increase,
which might put pressure
on plant resources and on
other species that the
alligator’s prey species
eat. On the other hand,
competitors of the
alligator would most likely
flourish, so anhingas
might also experience an
increase in population.
14) Identify two
species in this web
that might compete
with each other, and
explain which
resources they
compete for.
Alligators and bobcats are
competing for food in the form
of moorhens. Raccoons,
moorhens, white-tailed deer,
crayfish, glass shrimp, and
flagfish compete for plant foods.
Anhingas and alligators compete
for pin frogs. Pin frogs and
anhingas compete for crayfish.
Bass and anhingas compete for
killfish. Bass and killfish compete
for grass shrimp and worms.
Section 4 How Ecosystems Change
► Describe
the types of ecological succession
► Explain what pioneer species are
► Explain the conditions necessary for a
species to become invasive.
► Terms:
ecological succession, primary
succession, secondary succession, pioneer
species
Ecological Succession
► Ecosystems
constantly are
changing (some
fast some slowly)
► Young Forests
vs. Old Forest
► Quick change like
fire, or volcanic
eruption
Ecological Disturbances
A community in equilibrium is
generally stable and
balanced, with most
populations at or around
carrying capacity.
Disturbances or changes in
the environment can throw a
community into
disequilibrium.
Severe disturbances can
cause permanent changes to
a community and initiate a
predictable series of changes
called succession
Ecological Succession
► Ecological
Succession: the
gradual change and
replacement of
some or all species
in a community
► Neighborhood
changes over time
Ecological Succession
► Primary
Succession:
occurs on a surface
where no
ecosystem existed
before (FIRST)
► Rocks, sand dunes
► Uncommon!
Primary Succession
► Occurs
when there are no traces of the original
community remaining, including vegetation and
soil
Ecological Succession
► Secondary
Succession: occurs on
a surface where an
ecosystem has
previously existed
► More common
► Land Disturbed by
humans, other
animals
► Flood, fire, volcano
Secondary Succession
►
►
►
Occurs when a
disturbance
dramatically alters a
community but does
not completely destroy
it
Common after
disturbances such as
fire, logging, or farming
Occurs significantly
faster than primary
succession
Secondary ecological succession after a fire on the left
Fires are a
natural part
of many
forest
ecosystems
Ecological Succession
► Pioneer
Species:
first organisms to
colonize a newly
available land
► Lichens, bacteria,
small plants often
pioneers
Pioneer
species in a
parking lot
crack
Ecological Succession
Climax Community: final stable community.
•
Continues to change in small ways, but fairly stable if
undisturbed
Invasive Species
• Nonnative organisms
that spread widely in a
community
• A lack of limiting
factors such as
predators, parasites, or
competitors enables Did You Know? Although
their population to
the European honeybee is
grow unchecked.
invasive to North America,
Not all invasive species it is beneficial because it
pollinates our agricultural
are harmful
crops.
►A
2010 report on
invasive species
suggests that they
cost the U.S. $120
billion a year in
environmental losses
and damages.
Invasive kudzu
► The
zebra mussel has
completely displaced 20
native mussel species in
Lake St. Clair.
Invasive Species
► In
the Great Lakes
http://www.youtube.com
/watch?v=-V5513w1XSk
► San Francisco Bay
http://www.youtube.com
/watch?v=iu1z5Mo1wkA
► In Your Backyard
http://www.youtube.com
/watch?v=3MtYtx4geV8
► Invasive
Phragmites
http://vimeo.com/30526
20
Section 4 Ecosystem Changes
Review
► Describe
the types of ecological succession
► Explain what pioneer species are
► Explain the conditions necessary for s
species to become invasive.
► Terms:
ecological succession, primary
succession, secondary succession, pioneer
species
Section 4 Quiz
1) In the years immediately after a fire,
a forest will experience
A. primary succession.
B. secondary succession.
C. tertiary succession.
D. a climax community.
B. Secondary Succession
2) A landslide causes part of a
mountainside to fall away, leaving bare
rock. In the years immediately following
the landslide, the area will experience
A. primary succession.
B. secondary succession.
C. tertiary succession.
D. a climax community.
A. Primary Succession
3) If these are present in a new environment,
a species is unlikely to become invasive.
A. predators, parasites, and competitors
B. cane toads, kudzu, and zebra mussels
C. exotic species
D. symbiotic and commensalist species
A. predators, parasites, and
competitors
Fill in blank
4) A species introduced to a new
environment without limiting factors
could become
____________________.
Invasive
True or False
5) An invasive species is a species that
has been introduced to a new area and
lacks limiting factors.
TRUE