Topic 1.1 – The Food Chain
A. Members of the Ecosystem
Ecosystem = all ______________________ parts of a __________________ community and their
_______________________ through which ______________ and __________________ are passed. To
be maintained, there must be a continual _____________ of energy from the ________.
1. Producers –
2. Primary Consumers –
3. Secondary Consumers –
4. Decomposers:
• scavengers –
• detritovores-
• decomposers-
• decomposers are ________________________ because they _________ _______ dead plants and
animals and return the _____________________ back to the _________
B. Trophic Levels
• the _____________________________ in a food web
• only a small amount of __________________ is transferred from one ______________ level to the
next. Why? Most of the ______________ that enters each ______________ ___________ is used by
the ___________________ at this level just to stay _____________. Some of the energy ____________
be used and passes out of the organism as _____________. Only a ___________ amount of energy is
________________ in each organism and this is the energy that is available as potential __________ for
_____________________ at the next level.
• _____________________ show the transfer of energy from one trophic level to the next
• many organisms may eat a _________________ of foods and may consume organisms from more than
one ______________________ (__________________ = eats plants and animals). Food chains in an
ecosystem ___________________________ to form a complex ____________________.
Flowchart of Connecting Links:
C. Ecological Pyramids
1. Pyramid of Numbers
• relative ____________________ sizes of organism ________________ as you move up the food chain
• usually more ________________ are needed to ____________ fewer organisms along the food chain
2. Pyramid of Biomass
• biomass: how
• biomass _______________________ further up the pyramid (less organisms = less biomass)
3. Pyramid of Energy
• measures the total ___________ _____________ that flows through each trophic level
• both numbers and biomass have exceptions, but this pyramid is always ___________________.
• worksheets A and B (do not hand in- we will correct in class)
• textbook questions (hand in)
Worksheet A : Chains and Webs
Become familiar with the relationships among organisms in food chains and food webs.
Study the diagram of feeding relationships. Then answer the questions that follow.
* Note: a paramecium is a microscopic herbivore
1. What does the diagram show? __________________________________________________________
2. Which organisms are the producers? _____________________________________________________
3. Give an example of an aquatic herbivore. _________________________________________________
4. Give an example of a terrestrial herbivore. ________________________________________________
5. Give an example of a secondary consumer. _______________________________________________
6. Which organisms is the top carnivore in the terrestrial ecosystem? ____________________________
7. Give an example of an organism that would be in the second trophic level. ______________________
8. What is another term for “vegetarian organisms”? __________________________________________
9. In which trophic level is the snake? ______________________________________________________
10. Define the term “top carnivore”: _______________________________________________________
11. Define the term “omnivore”: __________________________________________________________
12. Which organism is clearly an omnivore? _________________________________________________
13. Use words and arrows to identify two aquatic and two terrestrial food chains in the food web.
Aquatic Food Chain 1:
Aquatic Food Chain 2:
Terrestrial Food Chain 3:
Terrestrial Food Chain 4:
Worksheet B : Ecology Terms
Goal: Assess your knowledge of ecology terms that describe feeding relationships.
Match each description in column A with the correct term in column B. Place the letter for the term on
the line beside the description. You will not use all the terms in column B.
____ 1. organism in the highest tropic level of a food chain
____ 2. linear feeding relationship between organisms
____ 3. feeding level
____ 4. something captured by producers from the Sun
____ 5. organism that eats plants and animals
____ 6. organism that is able to make its own food
____ 7. organism that eats only meat
____ 8. organism that is hunted and eaten
____ 9. interconnected network of food chains
____ 10. organisms that help recycle valuable nutrients
____ 11. organism that relies on other organisms for food
____ 12. organism that eats only plants
(a) trophic level
(b) omnivore
(c) carnivore
(d) food chain
(e) top carnivore
(f) herbivore
(g) producer
(h) food web
(i) consumer
(j) prey
(k) energy
(l) decomposer
(m) ecosystem
(n) biomass
Use the terms below to complete the sentences that follow. You may use a term more than once.
food chain
food web
top carnivore
pyramid of biomass
pyramid of energy flow
pyramid of numbers
1. A ______________________ is the part of a food chain that captures energy from the sun.
2. An interconnected relationship of the feeding patterns of different organisms in a specific area is a
3. ______________________ include organism, such as bacteria and fungi, that feed on dead plant and
animal matter.
4. An organism that does not make its own food and relies on other animals for food is a
5. A structure that illustrates the total chemical energy being passed along each trophic is a
6. A linear representation of feeding patterns between different organisms in a specific area is a
7. The organism in the highest trophic level at the end of a food chain is the ______________________.
8. An organism that uses sunlight, water, and carbon dioxide to make its own food is a
9. A vegetarian is an example of a ______________________.
10. Another term for meat eater is ______________________.
11. A ______________________ shows that organisms in lower trophic levels are usually more
abundant that organisms in higher trophic levels.
12. A ______________________ shows that biomass decreases from each trophic level to the one

Topic 1.1 – The Food Chain A. Members of the Ecosystem