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DESIGN AN ECOSYSTEM

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					DESIGN AN ECOSYSTEM
Student requirements:
The lesson does not assume a specific vocabulary base, but concepts suggested by the
following terms should be understood: food chain/food web; producer; primary, secondary
and tertiary consumer; decomposer; pyramids of energy, mass and number; community;
population; niche; threatened species; endangered species; extinction.
This activity is deceptively complex. Students usually require at least two hours preparing
their ecosystems. Additional time is then needed for the discussion.

DESIGN AN ECOSYSTEM
Introduction:
You are 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 Wal-Mart parking lot, hunting, introduction of a
foreign species, etc.).
Hints:
1. Keep it simple.
2. Look ahead. Consider the conditions associated with species endangerment while you
   plan your ecosystem. That way your EIR will be more interesting.

Method :
1. Your mission is to design and artistically depict an ecosystem.
2. Here are some hints:
   A. Location: Your ecosystem may be anywhere, including other planets!
   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.)
       iv. a. nutritional requirements, if an animal, or soil and water requirements, if a
            plant b. position in food web
       v. sensitivity to environmental insults/degradations
       vi. 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)

3. 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 following:
   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.

4. 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 pests.
5. 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 : one page EIR, and 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 populations.
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);
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 which care for their 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
     medicine.
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 summers
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 water




1 CONSUMER: Go Fish
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 assistance
iv. nutrition:
      a. Norse Sea Lily & other plant roots
      b. are 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 & below 50 C
viii. surface: lives in water

1 CONSUMER/2 CONSUMER: MoVal Viking**
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 & 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


1 CONSUMER/DECOMPOSER:
Yeast Beast
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

DECOMPOSER: Ship Worm
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 & everything, once it’s died
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


SAMPLE EIR
ENVIRONMENTAL CHANGE:
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.


IMPACT ON SPECIES:
Extinct : 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.
Endangered:
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.
Threatened:
MoVal Viking: The Vikings could loose 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.
Increased:
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.




MITIGATION :
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 home.
Population control for the Lily Weevil:
If entry cannot be prevented, methods of limiting Weevil population must be explored. For example:
Pesticides: 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?

				
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posted:10/5/2011
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