CPES 2014-15
NAME____________________________________________
Unit 2A Online Homework- Paper Edition
1) Which factors of an ecosystem are not part of a community?
a. Abiotic
b. Keystone
c. Native
d. Biotic
2) Why would it be incorrect to describe ecosystems as being isolated from each other?
a. All ecosystems have different species
b. Things can move from one ecosystem onto another because ecosystems do not have clear boundaries
c. Ecosystems have biotic and abiotic factors
d. Both ecosystems and communities have biotic and abiotic factors
3) List three biotic factors and three abiotic factors found in the ecosystem surrounding Livingston High
School.
Biotic Factors
Abiotic Factors
Trees, grass, squirrels, humans, chipmunks, worms, bugs,
Air, rocks, sunlight, rain, weather, temperature
poison ivy, (there are probably many more)
4) How do producers and consumers get their food energy? (be specific and name the process when
appropriate)
Producers are autotrophs and can perform photosynthesis to make their own food. Consumers eat or absorb their
nutrition from other living things.
5) Describe how energy is transferred from one organism to another? What happens to the energy when it
transfers?
Energy is transferred when one organism eats another organism. It is transferred as chemical energy. Only 10% of the
energy is passed from one trophic level to the next. 90% is lost as either heat or unconsumed/undigestable matter.
6) Describe how each of the following type of organism obtains their food. Decide where it is an autotroph or a
heterotroph. Give an example for each.
Describe how it obtains food
Autotroph or
Example(s)
Heterotroph
Producer
Produces food through photosynthesis
auto
Trees, grass,
phytoplankton(algae)
Herbivore
Eats plants/producers
Hetero
Deer, Rodents, Insects,
Zooplankton
Omnivore
Eats BOTH producers and other consumers
Hetero
Bears, Skunks,
Raccoons, Humans
Carnivore
Eats other consumers (Carnivores include
Hetero
Owl, Snake, Coyote,
insectivores)
Predatory Fish (tuna)
Scavenger
Eats other consumers that have already been
Hetero
Vultures
killed
Detritivore
Eats dead things that are rotting/decomposing
Hetero
Worms
Decomposer
Breaks down the molecules of dead things and
releases the nutrients and matter back into the
environment
Hetero
Mushrooms, Bacteria
7) Identify natural processes and human processes in the carbon cycle.
Natural
Human
Cellular respiration, photosynthesis, decomposition,
Mining/Drilling for Fossil Fuels, Slash and Burn
depositing of sediments at the bottoms of lakes/oceans,
Deforestation, Burning Fossil Fuels
storing carbon in mineral deposits and trees, dissolving
oxygen into the air/oceans
8) Explain how the excessive use of fertilizers affects the nitrogen cycle.
Excessive fertilizer can run-off into bodies of water and cause eutrophication of those bodies of water
9) How is secondary succession different from primary succession?
Secondary succession happens when and established ecosystem is destroyed (by a fire/volcano, etc). Primary
succession happen on an area of land that has never been colonized by living things before.
10) Describe the role a pioneer species plays during the process of ecological succession.
Pioneer species are the first organisms to colonize an area of land. They make the area habitable for other
organisms that will come later.
11) Which of the following is correctly arranged from the lowest trophic level to the highest trophic level?
a. Bacteria, Frog, Eagle, Raccoon
b. Algae, deer, wolf, hawk
c. Grass, Mouse, Snake, Eagle
d. grass, bass, minnow, snake
12) The energy lost between trophic levels
a. can be captured only by parasitic organisms
b. cools the surrounding environment
c. is used in the course of normal living
d. evaporates in the atmosphere
13) Which of the following statements about the nitrogen cycle is NOT true?
a. animals get their nitrogen by eating plants or other animals
b. plants generate nitrogen in their roots *(the bacteria do)
c. nitrogen moves back and forth between the atmosphere and living things
d. decomposers break down waste to yield ammonia
17) Math Practice: Consider the following food chain: Grass  Grasshopper Lizard  Owl. If 100 calories is
available to the grasshopper from eating grass, how many calories are available to the owl? (Hint- remember, only
10% of energy available is passed up each level of the food chain).
100 calories *.10*.10 = 1 Calorie