Download Chapter 6 Notes

APES
Chapter 6: Population and Community Ecology
Population Characteristics: Write a definition for each term.
1. Population size:
2. Population density:
3. Population distribution: The following three examples show how individuals are distributed
with respect to one another. Next to each picture, write a description of the distribution and
why organisms might be distributed in this manner. You may use the following wikipedia site to
help you: http://en.wikipedia.org/wiki/Species_distribution
4. Use the following website to take notes on the difference between density dependent and
density independent factors that influence population size.
https://www.tracy.k12.ca.us/sites/mitrajuarez/Shared%20Documents/chapter05_section02.ht
m
 Limiting Factors:
 Density Dependent Factors:
 Competition
 Predation
 Parasitism and Disease:
 Density Independent Factors:
 Answer the multiple-choice questions at the end of the page. Write your answers below.
5. Population Growth Models: Explain the two different growth models including under what
conditions growth would occur. What letters of the alphabet are associated with each graph?
Go to hippocampus.org, on the left toolbar, click on “Earth Science” and then on “Environmental
Science for AP.” Scroll down to “Carrying Capacity” and watch the video “Population Crash” to
assist you in learning about the two curves below.
 Exponential Growth: E
 Logistic Growth: What does the “K” represent on this graph?
6. K-selected versus r-selected species: the following chart shows the traits of these two types of
species. While most species fall somewhere in between these two extremes, write down
examples of organisms for both types of species.
Examples of K- selected species:
Examples of r-selected species:
7. Survivorship Curves: The following graph shows the three different survivorship curves found in
nature. Look closely at the units of the x and y-axes and then explain each curve. Give an
example of a few organisms that would be classified as Type I, II or III.
Type I:
Type II:
Type III:
8. Competitive Exclusion Principle: G.F. Gause, a Russian ecologist, performed an experiment to
demonstrate the competitive exclusion principle. He used two closely related species of
paramecium as his subjects. Look at the three graphs. In the first two graphs, the species were
grown separately. In the third graph, they were grown in the same test tube. Explain the
difference between the first two graphs and the third graph and how the third graph
demonstrates competitive exclusion.
9. Resource Partitioning: The first graph below shows the concept of interspecific competition,
which is where two different species compete for resources. Notice the overlap in the two
curves. Explain the second graph using the concept of evolution to define resource partitioning.
10. Types of Resource Partitioning: There are three main ways that species reduce their
competition, which are shown in the pictures below. Explain each of these types of resource
partitioning.
11. Define the following terms. Give examples of each of the three types of symbiosis and of
keystone and foundation species.
 Symbiosis:
 Parasitism:
 Mutualism:
 Commensalism:
 Keystone Species:
 Foundation Species:
 Intraspecific Competition:
12. Look at the following two pictures that show primary versus secondary succession. Succession is
the change in the species composition of a community over time. What is the difference
between these two types of succession? Watch the following video to assist you. Take notes on
the different types of succession. http://education-portal.com/academy/lesson/ecologicalsuccession-from-pioneer-to-climax-communities.html#lesson
Primary Succession
Secondary succession
Define pioneer community and give examples of the organisms that are pioneer organisms.
Define a climax community.
Click the tab labeled “Quiz” and take the quiz to check your learning.