Name___________________________________ Block_________ Date____________________ #________
Chapter 16 – Ecosystems Reading Guide
What is an Ecosystem (pgs. 340-344)
1. Ecology is
2. The place where a particular population of a species lives is its ________________.
3. What is a community?
4. What does an ecosystem, or ecological system, consist of?
5. The physical aspects of a habitat are called ______________ factors, and the organisms in a habitat are
called ____________ factors.
6. Define biodiversity:
7. The first organisms to live in a new habitat where soil is present to be small, fast-growing plants, called
_______________ _____________.
8. What do pioneer species do for other species? Will the pioneer species survive indefinitely in the new
habitat? Why or why not?
9. What is succession?
10. How is primary succession different from secondary succession?
11. Ecologists now recognize that __________ __________________ and ___________ play roles in the
process of succession.
12. Glacier Bay Succession:
a. Primary succession begins with exposed areas or piles of ___________ and __________ that lack
the usable _______________ essential to plant and animal life.
b. The seeds and spores of ___________ species are carried by the wind. These plants grow
____________ to the _____________, severely stunted by mineral deficiency.
c. Alder roots with __________-__________ ____________ and dead leaves and fallen branches add
more useable nitrogen to the soil.
d. Over time, as the soil deepens and is nitrified, species of trees out-compete or _________one
another, growing taller and denser than previous species.
Energy Flow in Ecosystems (pgs. 345-349)
1. Most life on Earth depends on _______________________ organisms, which capture some of the sun’s
______________ ______________ and store it as chemical energy in ______________ molecules.
2. What is primary productivity and what does it determine about an ecosystem?
3. Organisms that first capture energy, the ________________ (autotrophs), include ____________, some
kinds of _____________ and ________________.
4. Define consumers (heterotrophs):
5. Ecologists study how energy moves through an ecosystem by assigning organisms in that ecosystem to a
specific level, called a _______________ _______________, in a graphic organizer based on the
organism’s source of energy.
6. The path of energy through the trophic levels of an ecosystem is called a _________ ____________.
7. What is the lowest trophic level of an ecosystem occupied by?
8. At the second trophic level are _____________, animals that eat ______________ or other
_______________ _________________.
9. What are herbivores also known as in the trophic levels?
10. What must herbivores be able to digest?
11. Most herbivores rely on _____________________, such as _____________ and _____________, in
their gut to help digest ____________________.
12. At the third trophic level are __________________ _________________, animals that eat other
animals.
13. What is a carnivore?
14. What is an omnivore?
15. Omnivores use the simple _______________ and _______________ stored in plants as food, but they
cannot digest _______________.
16. What are detritivores?
17. What organisms to they include?
18. ____________________ and _____________ are known as ___________________ because they cause
decay. Decomposition of bodies and wastes releases ___________________ back into the environment
to be __________________ by other organisms.
19. What are tertiary or top consumers?
20. Why do food webs better show the feeding interactions within an ecosystem?
21. During every transfer of energy within an ecosystem, energy is lost as _______________.
22. What limits the number of trophic levels an ecosystem can support?
23. How much energy does photosynthesis harness from sunlight available to the leaves of the plant?
24. How much energy is passed from a producer into the herbivore?
25. At each trophic level, the energy stored by the organisms in a level is about _________-_____________
of that stored by the organisms in the level below.
26. What does an energy pyramid illustrate?
27. What does each block in an energy pyramid represent?
28. Diagram and label a trophic pyramid below:
29. Define biomass: