Download Ecology Review Sheet Answers

Name: ___________________________
date: ____________
Honors Review for Test on Ecology and Scientific Method
Directions: Answer each question as a review for the test. Use complete sentences.
1. What is the ultimate source of energy for almost every living thing on earth?
The sun
2. Are there any organisms/ecosystems that do not rely on your answer to number 1 for
energy? If so, provide examples.
Yes, tube worms in the deep ocean, extremophile bacteria in caves
3. What is the difference between a food chain, and a food web? Explain. (understand what the
arrows show)
A food web shows one possible flow of energy from prey to predators, while a food web is
composed of many food chains within an ecosystem. The arrows show the direction of energy
flow; from prey to predator.
4. Which group of organisms is missing from a food web? How do they obtain energy? Explain.
Decomposers are usually not shown on a food web. They can get their energy from any dead
organism within the food web.
5. Fill in the chart below
Term
Producer
Define the term
Uses sunlight to make its own food
List at least two examples
Plants, algae
Herbivore
Obtains energy by eating producers
Deer, grasshopper
Omnivore
Consumes plants and meat
Humans, bears
Decomposer
Obtains energy from dead organisms
Fungi, some bacteria
6. Define limiting factor? Provide at least five examples of limiting factors.
A limiting factor is anything that restricts the size of a population, such as space, food, water,
shelter, predators, competitors
7. Under each graph below, identify what type of growth is occurring, and describe what
conditions could make the graph.
Population of desert gecko over
5 decades
Exponential - No limiting factors in place
Logistic - limiting factor or factors in place
8. What is carrying capacity? How does it relate to limiting factors?
Carrying capacity describes the maximum population that an environment can support. Limiting
factors are what cause a population to reach its carrying capacity. For example, bacteria in a
Petri dish will reach carrying capacity when the population hits the edge of the Petri dish
because space, a limiting factor, restricts them from growing larger
9. Fill in the chart below.
Type of symbiosis
definition
example
A close association between two species in Flowers and Bees, Humans and
mutualism
which both species benefit
Dogs
commensalism
parasitism
A close association between two species in
which one benefits and the other is
unaffected
A close association between two species in
which the parasite benefits, and its host
is harmed
Barnacles and Whales
Tapeworm, Hooke Worm,
Ticks
10. What is biodiversity? Explain how biodiversity is a measure for how healthy an ecosystem
is. Biodiversity refers to the number of different species living in an ecosystem. The greater
the biodiversity, the healthier the ecosystem. Greater biodiversity means a larger food web,
which means that, if any species goes extinct, the species that rely on that one will still have
other options.
11.
Refer to the worksheet I gave you for this chart above
12. Design an experimental setup to test the following scientific question: How do different
colors of light affect the rate of plant growth?
Question: Refer to above
Hypothesis: If plants are exposed to red, blue, and green light, then they will grow at the
fastest rate in green light
Test: Controlling for as many constants as you can, set up four containers, each with five of the
same species and maturity of plants in them. One container is exposed to red, another blue, a
third green, and the last is the control (pitch black). Measure the height of each plant to start,
and take height measurements over several months.
Conclusion: Discuss whether results support your hypothesis or not.
What should a scientist do if his conclusion does not support his hypothesis? Explain.
Change your hypothesis, and test again
13. Answer the chart based upon your notes
14. Based on the energy pyramid, explain why there are significantly less lions in the African
Savanna than there are grasses.
The energy pyramid shows us that only 10% of the energy available at one trophic level can be
accessed by the next trophic level. This means that there is many times less energy avaiable
for the lions (top of the food chain) than the grasses (bottom of food chain), and therefore
many less lions can be supported
15. According to the energy pyramid, each trophic level going up the food chain receives only
__ 10______ % of the available energy from the trophic level below it.
16. If a mouse stores 1000 units of energy in its body, how much energy will the snake extract
from it when it east and digests it? _____ 100_____ units
17. Why can’t all the energy in one trophic level be transferred to the next? Provide examples.
Energy can't be transferred with 100% efficiency in any process in our universe. In this case,
much of the energy is lost as heat as it is used by one trophic level before the next level eats
it. There are parts of an organism, like hair, nails, and bones, that energy can't be extracted
from either.
18. Why do biotic factors interact? Explain.
Organisms must have a regular source of energy. For this reason, all consumers must interact
with other living organisms to gain that energy.
19. Describe the relationship between the concepts of niche and resource partitioning.
A niche is the role that a species occupies in its specific habitat. All the behaviors, and ways
that it affects its environment is part of its niche. No two species can occupy the very same
niche. If this occurs, one will be outcompeted. Resource partitioning is a behavior that some
species exhibit, in which two or more species will divide up a resources (like the warbler birds),
preventing them from competing so fiercely in the same niche.
20. How do the concepts of the competitive exclusion principle and niche help to describe the
Biogeography Theory of Species Equilibrium?
Competitive Exclusion refers to the concept that, if two species occupy the same niche, one will
outcompete the other, often to extinction. The "BTSE" states that an area can support a
certain maximum number of species. Larger islands can support greater number of species, and
smaller ones can support less. This is because there is a certain number of niches in a given
environment, so larger islands will contain more niches than smaller ones.
21. Explain what is wrong with the following statement: “Both matter and energy can be cycled
through an ecosystem many times”
Matter is reused again and again in an ecosystem (the atoms in your last meal might have once
been part of a dinosaur), but energy can only flow in one direction (usually from sun throught he
trophic levels).
22. What is biological magnification? Explain how the concept is relevant to you as a member
of the human species.
BM refers to fact that some substances can't be broken down by organisms. These substances
can accumulate in larger and larger concentrations in the tissues of organisms as you go up the
trophic levels of a food chain. For example, mercury is a toxic metal that can;t be broken down
by organisms. Top level predators will have higher mercury levels in their tissues than lower
trophic levels due to BM.
23. Provide an example to demonstrate each concept for the acronym HIPPO.
Answers will vary.