Name:________________________________
Biology20–MarineBiology
ENERGYPYRAMIDSANDCOMMUNITYINTERACTIONS
SLOs:
• Sketch the flow of energy & matter through higher levels of biological organization
• Identify factors that affect ecological organization at the community and ecosystem level
• Assess the role of humans in natural systems
Food Chains, Food Webs, and Energy Pyramids
1. Use the following food chain to answer the questions below: GRASS – RABBIT- FOX
a. What type of organism is the grass? _______________________
b. Which animal is an herbivore or primary consumer? _______________________
c. What would happen to the population of rabbits if the population of foxes increases?
d. Humans decide to take the grassy area and develop it into a shopping mall. What will happen to
the population of rabbits and foxes?
2. Label the parts of the food web:
a. Label each animal: H= herbivore C= Carnivore O= Omnivore.
b. Label the Producers (P)
c. In the box to the right of the food web, draw a food chain and label the different trophic levels
(Primary Producer, Primary Consumer, Secondary Consumer, Tertiary Consumer, etc.)
d. What elements are missing from this food web?
TakenandmodifiedfromM.Anduri,CSUF
3. A common food chain for developed nations is illustrated by the pyramid below. Humans eat beef
(cows). Cows graze on plant material. Study the pyramid and answer the questions below.
a. Who is the secondary consumer in this food chain? Who is the primary consumer? What is the
producer?
b. During this time (one year) a 150-pound person would eat one cow of what weight? (Assume the
person ate only beef).
c. How many pounds of plants were needed to sustain the person who ate only beef?
d. If a snake weighs 7 pounds and eats only mice, how many pounds of mice must the snake eat in
a year? How many pounds of grain are required to sustain this many pounds of mice in the same
period?
Draw this food pyramid below, including the numbers you came up with above:
TakenandmodifiedfromM.Anduri,CSUF
Symbiotic Relationships: Read about each Organism Interaction and identify what type of symbiotic
relationship exists between the two organisms (Predation, Commensalism, or Mutualism). Briefly explain why.
ORGANISMS
Brief Overview of Relationship
Symbiotic
Explanation
Relationship
Barnacle/ Whale Barnacles create home sites by attaching themselves to
whales. As the barnacle is a filter feeder, it also gets
access to more water (and more food) due to the
relationship. Whale is unaffected.
Cuckoo/Warbler A cuckoo lays its eggs in the nest of the warbler. The
cuckoo’s eggs hatch first and the young kick the
warbler eggs out of the nest. The warbler raises the
cuckoo babies and the warbler babies aren’t hatched.
Remora/Shark
Remoras attach themselves to a shark’s body. They
travel with the shark and feed on the leftover food
scraps after the shark has finished its meal. The shark
is unaffected as it’s done eating anyway.
Ostrich/Gazelle
Ostriches and gazelles feed next to each other. They
both watch for predators. Because the visual abilities
of the two species are different, they can each identify
threats that the other animal may not see as readily.
Mistletoe/Spruce Mistletoe extracts water and nutrients from the spruce
tree to the detriment (ill effect) to the spruce.
Silverfish/ Army Silverfish live and hunt with army ants and share the
Ant
prey. They neither help nor harm the ants.
Oxpecker/
Oxpeckers (bird) feed on the ticks found on a
Rhinoceros
rhinoceros. The oxpecker, therefore, gets food and the
rhino gets rid of a parasite.
Mouse/ Flea
A flea feeds on a mouse’s blood to the mouse’s
detriment.
Honey Guide
Honey guide birds alert and direct badgers to bee
Bird/ Badger
hives. The badgers then expose the hives and feed on
the honey first. Next the honey guide birds eat.
Wrasse Fish/
Wrasse fish feed on the parasites found on the black
Black Sea Bass
sea bass’s body (usually in the mouth). Dental floss
for fish!
1. None of the relationships above involve competition. Although competition is a symbiotic relationship,
it is rarely seen in nature. Define the term “competition” and explain why we rarely observe it in nature
(think about how long these organisms have been living in the habitat they are in and why we might not
see competition).
TakenandmodifiedfromM.Anduri,CSUF