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5.3 Life Science: Life science principles are powerful conceptual tools for making sense of the complexity, diversity, and
interconnectedness of life on Earth. Order in natural systems arises in accordance with rules that govern the physical world, and the
order of natural systems can be modeled and predicted through the use of mathematics.
C. Interdependence: All animals and most plants depend on both other organisms and their environment to meet their basic needs.
Essential Questions
Enduring Understandings
How are organisms
dependent on each other?
The survival of organisms is
affected by interactions with each
other and their environment, and
can be altered by human
manipulation.
Content Statements
Biological communities in
ecosystems are based on
stable interrelationships
and interdependence of
organisms.
Cumulative Progress
Indicators
Analyze the interrelationships and
interdependencies among different
organisms, and explain how these
relationships contribute to the
stability of the ecosystem.
(5.3.12.C.1)
Labs, Investigation, and Student Experiences
5.3.12.C.1
(1) View and then discuss the PBS Documentary: Crash: A
Tale of Two Species. The documentary focuses on the
interrelationship between the horseshoe crabs, red knots,
and humans.
http://www.pbs.org/wnet/nature/episodes/crash-a-tale-oftwo-species/introduction/592/
(2) Complete virtual lab on modeling ecosystems- How does
energy flow through an ecosystem?
http://glencoe.mcgrawhill.com/sites/dl/free/0078757134/383926/BL_02.html
(3) Conduct a lab to determine the interrelationship of plants
and animals by using snails and elodea. The resource can be
found by doing an Internet search of the following: UCLA,
GK-12 Science & Mathematics in Los Angeles Urban
Schools
http://www.nslc.ucla.edu/STEP/GK12/ & Plant and Animal
Interrelationships
Developed by: K. Thomas, C. Davis & J. Thomas
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Desired Results
Students will be able to...
1. Understand that an ecosystem is a community of organisms
that interact with one another and with their physical
environment by a one-way flow of energy and a cycling of
materials.
2. Describe how changes in one ecosystem, (for example, due to
a natural disaster or extinction of a species) can have
consequences on local ecosystems as well as global ecosystems.
3. Categorize populations of organisms according to the roles
(producers, consumers, and decomposers) they play in an
ecosystem.
4. Define the following ecological terms: habitat, niche,
population, community, symbiotic, competition, predation,
parasitism, commensalism and mutualism.
5. Be able to distinguish the physical, chemical, geologic and
biological features of habitats.
6. Explain how niches help to increase the diversity within an
ecosystem and maximize the number of populations that can live
in the same habitat.
7. Using models or graphic representations, demonstrate how
changes in biotic and abiotic factors affect interactions within an
ecosystem.
8. Describe how the biotic and abiotic factors can act as selective
pressures on a population and can alter the diversity of the
ecosystem over time.
9. Using graphs of population data of a predator and its prey,
describe the patterns observed. Explain how the interactions of
predator and prey generate these patterns, and predict possible
future trends in these populations.
10. Construct and analyze population growth curves to show
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changes in a species over time.
11. Be able to recognize logistic versus exponential population
growth patterns in a graph.
12. Define the term "carrying capacity" and identify the carrying
capacity for a population in an ecosystem using graphical
representations of population data.
13. Describe how birth rate, death rate, emigration, and
immigration contribute to a population’s growth rate
14. Identify limiting factors in an ecosystem and explain why
these factors prevent populations from reaching biotic potential.
Predict the effects on a population if these limiting factors were
removed.
15. Explain why a population reaching unlimited biotic potential
can be detrimental to the ecosystem.
16. Describe some factors that contribute to species becoming
“endangered.”
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PERFORMANCE ASSESSMENT
“Ecology”
OVERVIEW
Pronunciation note: Zooxanthella is pronounced: zoh-uh-zan-thel-uh
Coral reefs are beautiful places in the sea that are home to many different types of fish. Coral reefs contain corals, which are a type of
animal that do not move around. Corals need lots of sun to survive because they have little organisms in them, called zooxanthella,
that use the sun’s energy to create food for the coral (much like plants do).
Healthy corals in a reef
In many places around the world, coral reefs are dying. The little zooxanthella in the corals die and the corals are left with no food and
therefore die as well.
Scientists want to find out why so many of the corals are dying.
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Scientists noticed that there are a lot of algae in the reefs that are dying. The algae in reefs are tiny plants that you may need a
microscope to see. When there are a lot of algae in a reef, the water becomes green.
The scientists wonder what causes the algae to grow so much in some reefs, and they wonder how the algae might contribute to the
deaths of the coral.
Some scientists are considering this explanation:
1. Chemicals from farms or factories get into the water.
2. These chemicals cause plants such as algae to grow in the water.
3. Large amounts of algae turn the water cloudy and less sun can penetrate.
4. Without sunlight the little zooxanthella in corals can’t make food and die.
5. The corals die too because their zooxanthella are dead and no food is made.
We can show this explanation as a diagram. The arrows show that one event causes the next event.
Chemicals
get in
water
This
Algae
This
No sunlight
causes to grow causes penetrates into

in water 
the water
This
Zooxanthella
And
causes don’t have
this
Corals

enough sunlight causes to die.

and die
Now scientists got some more information. Scientists did a study. They examined more than 30 reefs around the world to find out
more about coral deaths. This is what they found:
Most of the dead coral reefs have been overfished in recent years. That means that fisherman have caught most of the fish in these
coral reefs, so that there were not a lot of fish left.
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YOUR TASK
1. How should scientists change their explanation to fit this new information? You can use words; draw diagrams, or both to show
how scientists should change their explanation.
2. Explain why the scientists should make these changes.
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