Basic Food Web Practice
1) List the organisms that are producers.
2) List the organisms that are primary consumers.
3) What is another name for an organism that is only a
primary consumer?
4) List the organisms that are secondary consumers.
5) What is another name for an animal that is only a
secondary consumer?
6) List the consumers that eat both plants and animals.
7) What is another name for an animal that eats both
plants and animals?
8) What elements are missing from this food web?
9) What would happen to the food web if all the plants
were removed? Explain your answer.
10) Describe how 3 animals might be affected if owls
were removed from the food web.
11) Draw an energy pyramid of one food chain in the food web shown.
12) If 2000 kcal of energy are available in berries, how much energy would be available to the grasshopper?
To the mouse? To the fox?
13) Which organism in this food web has the greatest influence on the ecosystem? Justify your answer.
14) The table below lists the average amount of energy (in kilojoules per square meter of land per year) in
different organisms that people use for food.
Organism
Energy (KJ/m2/year)
Ranking
Wheat cereal
3,400
Oranges and grapefruits
4,200
Peanuts
3,850
Rice
5,200
Potatoes
6,700
Carrots
3,400
Other vegetables
840
Apples
6,300
Peaches
3,800
Beet sugar
8,300
Cane sugar
14,650
Corn
6,700
Milk (cow)
1,800
Eggs (chicken)
840
Chicken
800
Pork (pig)
800
Beef (cow)
550
Fish
8
15) Organize the data from LEAST energy to MOST energy. (Do this under the “Ranking” column in the table
above)
16) Calculate the AVERAGE energy of all the producers
17) Calculate the AVERAGE energy of all the consumers.
18) Which organisms (producers or consumers) can offer more energy (on average)?
19) Do you think it is more efficient for people to eat plant products or animal products? Why?
20) Below is a list of organisms from a marine biome and what they eat. Using the chart below, draw both the
organisms and arrows to show the direction of energy transfer between these organisms in the food web.
Sea otter
Squid
Killer whale
Sea urchins
Crab
eats
eats
eats
eats
eats
sea urchin
crab, kelp
sea otter, squid
kelp
kelp
21) Use the information in the chart above to create a food web for this community in the space below:
22) Write the following next to each organism:
A) If it is an autotroph or heterotroph
B) If it is a producer or consumer. If it is a consumer, label it as a primary consumer, secondary consumer,
etc. Keep in mind, some organisms might fall into more than one trophic level.
23) Why is a pyramid a good shape to represent how matter and energy transfer in an ecosystem? Why not
use circle or a square?
24) What happens to the energy that is not passed on to the next trophic level?
25) What trophic level is the most important? Defend your answer.
26) Explain why the producers have to be the biggest trophic level. Then explain what would happen if you
had more herbivores than plants in an ecosystem.
Marine Biomes Practice
Marine biomes are aquatic biomes found in the salt water of the ocean. Major marine biomes include
neritic, oceanic, and benthic biomes. Neritic and oceanic biomes are described in the rest of this
passage.
Neritic Biomes
Neritic biomes occur in ocean water over the continental shelf. They extend from the low-tide water
line to the edge of the continental shelf. The water here is shallow, so there is enough sunlight for
photosynthesis. The water is also rich in nutrients, which are washed into the water from the nearby
land. Because of these favorable conditions, large populations of phytoplankton live in neritic biomes.
They produce enough food to support many other organisms, including both zooplankton and
nekton. As a result, neritic biomes have relatively great biomass and biodiversity. They are occupied by
many species of invertebrates and fish. In fact, most of the world’s major saltwater fishing areas are in
neritic biomes.
Oceanic biomes occur in the open ocean beyond the continental shelf. There are lower
concentrations of dissolved nutrients away from shore, so the oceanic zone has a lower density of
organisms than the neritic zone. The oceanic zone is divided into additional zones based on water
depth.
 The epipelagic zone is the top 200 meters of water, or the depth to which enough sunlight can
penetrate for photosynthesis. Most open ocean organisms are concentrated in this zone, including
both plankton and nekton.
 The mesopelagic zone is between 200 and 1,000 meters below sea level. Some sunlight
penetrates to this depth but not enough for photosynthesis. Organisms in this zone consume food
drifting down from the epipelagic zone, or they prey upon other organisms in their own zone.
Some organisms are detrivores, which consume dead organisms and organic debris as they drift
down through the water.
 The bathypelagic zone is between 1,000 and 4,000 meters below sea level. No sunlight penetrates
below 1,000 meters, so this zone is completely dark. Most organisms in this zone either consume
dead organisms drifting down from above or prey upon other animals in their own zone. There
are fewer organisms and less biomass here than in higher zones. Some animals are
bioluminescent, which means they can give off light. This is an adaptation to the total darkness.
 The abyssopelagic zone is between 4,000 and 6,000 meters below sea level and is completely
dark. It has low biomass and low species diversity.
 The hadopelagic zone is found in the water of deep ocean trenches below 6,000 meters. It is
totally dark and has very low biomass and very low species diversity.
1) Describe a neritic biome.
2) Why do oceanic biomes generally have a lower density of organisms than neritic biomes?
3) Why are most open ocean organisms found in the epipelagic zone?
4) Name three oceanic biomes that are located in the aphotic zone.
5) What types of organisms are found in aphotic ocean biomes?
6) Name and describe the other two aquatic biomes that are not marine.
Match the term with correct definition.
1) ______ part of the ocean floor that makes up the continental slope
2) ______ narrow strip along the coastline of the ocean that is exposed to air
at low tide
3) ______ part of the ocean floor that is under the deep ocean
4) ______ part of the pelagic zone over the continental shelf
5) ______ bottom surface of the ocean or a lake
6) ______ water between 200 and 1,000 meters below sea level in the
oceanic zone
7) ______ interface between running freshwater and land
8) ______ deep water where too little sunlight penetrates for photosynthesis
to occur
9) ______ part of the ocean floor that is in deep ocean trenches
10) ______ shallow water near the shore of a lake or the ocean
A. abyssal zone
B. aphotic zone
C. bathyal zone
D. benthic zone
E. hadal zone
F. intertidal zone
G. littoral zone
H. mesopelagic zone
I. neritic zone
J. riparian zone