Homework # _____ DUE: ______
Name _______________________________per ____ date _____
Fundamentals of Ecology: INTERPRETING ECOLOGICAL DATA
Graph 1: Rabbits Over Time
a. This graph shows what kind of population growth curve?
b. What is a carrying capacity for a population in an ecosystem?
c. According to the graph, the carrying capacity for rabbits of this
population is ______ rabbits.
d. What type of factors, density-dependent or density-independent,
likely caused this population growth curve? EXPLAIN.
Graph 2: Gazelle and Lion populations
a. Over how many years does this data span (do the math to
change months to years)? ____________
How many years between gazelle population high points?
_______
How many years between lion population high points?
______
b. Which population rises first, gazelles or lions? Is it always so?
Number of animals in
population
d. During which month were the rabbits in exponential growth?
Which population hits their lowest point first, gazelles or lions?
c. Why do these population curves happen like this? Make a claim to
answer this question and justify this claim with evidence (WIS) and
explain each piece of evidence with reasoning (WIM).
Graph 3: Mexico and US: Age Distribution
a. In Mexico, what percentage of the population
is between 0-4 years of age? _______
In the US? ______
b. Which population is growing the fastest?
________________
What evidence supports this (WIS)?
d. What would the growth rate curves
look like for each country? Justify your claim.
FOOD CHAINS & WEBS
Food Chain – A food chain is the series of organisms in a line to show feeding relationships (energy and matter transfer). Energy flows
through an ecosystem in one direction- from producers to consumers. The stability of an ecosystem depends on the presence of
producers, since they convert sunlight into energy the whole ecosystem can use- stored in organic molecules (sugars, starch, glucose).
A food chain begins with an organism that can photosynthesize to gain energy (producer), which is then eaten by an organism as their
source of energy (primary consumer). The arrow means ‘energy transfer’ i.e. is eaten by, and shows the direction of matter and
energy flow along the food chain. A significant amount of energy is lost every time energy is transferred, due to laws of
thermodynamics (i.e. that is just how the world works). Decomposers are essential to every ecosystem as well but not shown in a food
chain (more on them later too). Trophic level: Each different ‘link’ in a food chain is a trophic level, Producers are the first trophic level
and each level after that is less and less energy efficient, by a lot. Example of a Food Chain: Grass (Producer) Grasshopper
(primary Consumer)  Kookaburra (secondary consumer)
Comprehension Questions
In the food chains below, identify the producer, the primary consumer and the secondary consumer, write this on the line
below each organism.
1. PHYTOPLANKTON  PRAWN (shrimp)  TUNA
_______________ _________________ ________________
2. Now list your own food chain (producer  primary consumer  secondary consumer  tertiary consumer?) in each
of the following biomes (use any organisms you know to live there, try to be specific and accurate as you can, use the
internet if not sure):
Desert
_______
Rainforest
Tundra ______________________________________________________
Freshwater stream _____________________________________________
3. From the food web left, write down 2
different food chains:
dragonfly larva
mussel
caddisfly larva
zooplankton
phytoplankton
small fish
snail
_____
____________
a. Name the producer __________________
b. Name the primary consumers
______________________________________
______________________________________
a. Name the secondary consumers
b. Name the tertiary consumer
_____
c. Are any organisms in more than one trophic level? If so, which ones and in which trophic levels are they?
____________________________
d. Explain how the organisms would be affected if the snail population died out.
_________________________________________
Heron
Pelican
4. From the food web, write down 2 different food chains:
Large fish
Crab
Zooplankton
Small fish
Prawn
5. What effect would overfishing of crabs, both male and
female, have on the other organisms?
Mud whelk
Phytoplankton
Eel grass
5. Boat anti-rotting paint contains lead- the heavy toxic element which biologically accumulates along a food chain in the
same way as does mercury and DDT. Which organism would suffer the greatest effect if large quantities of anti-rotting
paint were released into the waterways? Claim: ________________________________________________________
Evidence & reasoning:
________________________
___________________________________________________________________