Designing an ecosystem

Creating life

You are asked to create several species in a unique ecosystem. You will
describe your species' niche as well as their reproductive habits. You will
then prepare an Environmental Impact Report (EIR) describing the
expected effects of an environmental disturbance (e.g. Flood, paving over
the ecosystem to make a parking lot for a shopping mall, Snark hunting,
introduction of a foreign species, etc.).


1. Keep it simple. Since the end of the term is near, you won't have a
billion years to do this activity.
2. Look ahead. Consider the conditions associated with species
endangerment while you plan your ecosystem. That way your EIR will be
more interesting.
3. This activity could be recommended as a term homework topic.

Materials: Poster paper, color markers, notebook paper, pen/pencil.


1. Form a group of 2-4 students.
2. Your mission is to design and artistically depict an ecosystem.
3. Here are some hints:

     A. Location: Your ecosystem may be anywhere, including other

     B. Biological community: Imaginary organisms are very welcome.

     Include at least one species of each of these:
           i. Producers,
           ii. Primary consumers,
           iii. Secondary and higher level consumers,
           iv. Decomposers.

     For each species be sure to include its:
           i. Range,
           ii. Population size,
           iii. Reproductive behavior (mating rituals, fertilization
           method, number of offspring, care of offspring, etc.),
                  a. Nutritional requirements, if an animal; or soil and
                  water requirements, if a plant,
                  b. Position in food web,
           iv. Sensitivity to environmental hazards,
           v. Any known usefulness/attractiveness to humans.

     C. Physical components: Your species must be appropriate for their
     physical environment. Be sure to consider:

           i. Climate: temperature, seasons, humidity and precipitation,
           ii. Surface conditions: soil minerals, soil texture, water,
           grade (slope).

4. Now that you have created a beautiful ecosystem, add a disturbance.
Your disturbance may be spontaneous or man-made, intentional or
unintentional, or a combination of these. You are not limited to the

     A. Climate change: warming, cooling, change in water availability,
     B. Direct human interference: hunting/harvesting, land clearing,
     pesticides/herbicides, introduction of a foreign species, etc.

5. Identify the effect of the disturbance on the species in your ecosystem.
Use the list below to help you make the following declarations:

     A. Extinct: Species which are completely decimated,
     B. Endangered: Species which are in imminent danger of extinction,
     C. Threatened: Species which are at significant risk of becoming
     endangered but are not in immediate danger of becoming extinct,
     D. No expected change: Species with moderate to large
     populations, whose numbers are expected to remain stable,
     E. Increased: Species whose populations increase. May be potential

6. Prepare your EIR describing what happens to each species.
The EIR should also state why you are making your predictions.
Include ideas for mitigation (lessening) of the environmental impact.
Be prepared to share your results with the rest of the class.
Report: Poster, one to two page EIR, classroom presentation.

Conditions Associated with Species Endangerment

1. Limited Range: Species is found in only a small, specific area.

2. Small Population or Rarity: Species is rare within its range. High-level
consumers are usually rare. Other species may also have small

3. High Specificity: Species has very specific requirements for:
    Food (e.g. Pandas only eat bamboo; animals which eat only one
      type of food, or a few specific foods, are prone to extinction if the
      food supply disappears.),
    Reproduction (e.g. Spotted Owls only nest in old coniferous tree
      hollows, rabbit fleas use female rabbit reproductive hormones
      and don't make their own),
    Habitat (e.g. there are fungi which are found only in gopher tortoise
      burrows), etc.

4. High Sensitivity: Species is extremely vulnerable to environmental
disturbances. Examples include:
    Birds are very sensitive to DDT and related pesticides which cause
      thinning of their eggshells. Compare birds with cockroaches, which
      are not very sensitive.
    Some plants have very specific requirements for light; too much or
      too little sunshine will kill them.

5. Low Fecundity: Species produces few offspring. Note: Species that care
for its young either before birth (long pregnancy) and/or afterwards have
fewer offspring than those who do not.

6. High Human Value: Species has characteristics that make it valuable to
humans. Many animals have been hunted to endangerment, or even
extinction, for their beautiful plumage or fur. Wild plants and fungi may
also be over-harvested if they are particularly tasty or contain useful
Sample Ecosystem: The Valley*

PRODUCER: Norse Sea Lily

i. Range: many reservoirs such as Lake Perris,
ii. Pop size: large,
iii. Reproduction: flowering plant pollinated by mead bees, flowers
in early summer,
iv. Nutrition:
       a. Autotroph,
       b. eaten by Go Fish (roots), Vikings (leaves), Mead Bees
       (nectar), Lily Weevil (immature fruit),
v. Sensitivity: the more minerals in the water the better, needs
full sunlight,
vi. Humans’ use: artificial poi & glue (roots), fibers for fabric
(stems), snack food (seeds), decoration (flowers), roofing
material (leaves),
vii. Climate: cool winters with foggy mornings, warm and sunny
viii. Surface: lives in water.

1 CONSUMER: Mead Bee

i. Range: many reservoirs such as Lake Perris,
ii. Pop size: small,
iii. Reproduction: a single queen lays many eggs which are tended
by her daughters,
iv. Nutrition:
       a. Eats nectar and pollen of the Norse Sea Lily,
       b. Eaten by some birds,
v. Sensitivity: low sensitivity, but only one food source,
vi. Humans’ use: often considered a pest,
vii. Climate: active during warm months, hibernates in winter,
viii. Surface: flying insect: hives on land, food flower floats on surface of

i. Range: many reservoirs such as Lake Perris,
ii. Pop size: moderate,
iii. Reproduction: following a mating ritual in clear water the
females lay eggs & the males fertilize the eggs externally,
males guard nest until eggs hatch, babies receive no care nor
iv. Nutrition:
       a. Norse Sea Lily & other plant roots,
       b. Eaten by MoVal Vikings who like them better than Lilies
       but not as much as mead,
v. Sensitivity: eggs are sensitive to chemical pollutants, adults
are pretty tough,
vi. Humans’ use: sport and food fish,
vii. Climate: any temp above freezing and below 50 C,
viii. Surface: lives in water.


i. Range: Southern California,
ii. Pop size: many 1000s,
iii. Reproduction: life-long pair bonds, internal fertilization, low
birth rate, extensive care of young,
iv. Nutrition:
       a. Go Fish, mead, lilies, eagles, cougars and broccoli,
       b. Top level predator,
v. Sensitivity: low chemical sensitivity, sudden temperature
change can harm them,
vi. Humans’ use: extremely attractive exotic pets,
vii. Climate: warm and sunny weather with plenty of water,
viii. Surface: amphibious.


i. Range: very limited, only in Mead Bee hives,
ii. Pop size: moderate in hives, zero elsewhere,
iii. Reproduction: high fecundity, usually asexual budding,
iv. Nutrition:
       a. Eats nectar and pollen brought to hive by bee excretes mead,
       b. Vikings drink mead. Vikings really like that mead,
v. Sensitivity: low sensitivity to chemicals,
vi. Humans’ use: no known use,
vii. Climate: warm & moist,
viii. Surface: live in hive which protects them from climate extremes.

i. Range: many reservoirs such as Lake Perris,
ii. Pop size: large
iii. Reproduction: hermaphroditic, lay many eggs, external
fertilization, no care of young,
iv. Nutrition:
        a. Eats dead organic matter,
        b. Eats anything and everything, once it's dead,
v. Sensitivity: low sensitivity to chemicals, light, temp or
salinity change,
vi. Humans’ use: no known use, humans think they are ugly,
vii. Climate: any temperature above freezing,
viii. Surface: lives in water.

* Some students may need examples, advanced classes may not.

Sample EIR


A gravid (pregnant) Lily Weevil is inadvertently introduced into the valley.
The Lily Weevil eats immature Norse Sea Lily fruit. Worse yet are its
reproductive habits. It parasitizes hymenopterans by stinging them into
paralysis and laying a single egg in the abdomen of each insect. The
Weevil larva then feeds upon its host from the inside out! Needless to say,
this is an experience which a Mead Bee does not survive.


At this time it is not possible to tell whether any of these organisms would
actually go extinct. However endangerment, by definition, means that a
species might go extinct in the near future.

Mead Bee: Bees are being massacred by the Lily Weevil, a newly
introduced species.

Yeast Beast: Yeast Beasts are totally dependent on Mead Bees. If the
Mead Bee dies out, so will the Yeast Beast.
Norse Sea Lily: Not only do Weevils eat their fruit before their seeds have
formed, they also parasitize the Lily's only pollinator. The Lily may not be
able to reproduce in the presence of the Weevil. Finally, human predation
may also contribute to their demise.

MoVal Viking: The Vikings could lose three important food sources: Lilies,
Go Fish, and mead. Fortunately, Vikings have other food sources available
to them.

Go Fish: Go Fish would loose a major food source. Also Vikings may
predate more heavily upon the fish since the Vikings no longer have Lilies
and mead.

No Change:
Ship Worm: One way or the other, there will be plenty of dead for the
Ship Worm to eat.

Lily Weevil: Since the valley is full of food (Lilies) and reproductive
opportunities (Bees), Weevils may increase in population. Contributing to
their increase is the lack of natural predators such as Leaping Lizards
which eat them.


Prevent entry of the Lily Weevil:
Prevent, or at least delay entry, of this dreaded pest. Recommended
practices include: Do not import, or import only after quarantine,
agricultural products, such as aquarium and pond plants, which may be
infested with the Lily Weevil. While this idea is sound, it may be difficult to
carry out. Backyard pond enthusiasts may not understand the need for
not smuggling various exotic plants which they would like to grow at

Population control for the Lily Weevil:
If entry cannot be prevented, methods of limiting Weevil population must
be explored.

Some pesticides kill Lily Weevil effectively, but others are no longer
effective since the Lily Weevil has evolved resistance to them. Also, the
same pesticides that kill Weevils, kills Mead Bees. This solution has only
limited viability.

Introduction of Weevil predator:
A population of Leaping Lizards could be introduced to the valley. Lizards
would keep the Weevil population low. They would not completely
eradicate the Weevil. Prior to their introduction, extensive research is
recommended as it is not known what other organisms would be effected
by the Lizards. For example: Would Leaping Lizards eat Mead Bees, out
compete the local Friendly Frog for insect food, or in some other way
become a pest?


To top