Natural Selection
Subject/Grade: Biology 9th grade
Lesson #: Introduce new ideas and
reconcile them with students’
ideas: 4
Lesson Overview: Students will create timelines using two different simulated fossil records. One
timeline demonstrates gradualism, and the other demonstrates punctuated equilibrium. Students
then answer discussion questions about their results. The lesson is adapted from ENSI at The
University of Indiana (http://www.indiana.edu/~ensiweb/lessons/peek.html).
Prerequisite Skills: Students should have a basic understanding of fossils, geological timeframe, and
speciation.
Content Standards – National/State
Standard #
Standard
Evaluate the evidence supporting claims that changes in environmental conditions
HS-LS4-5
may result in: (1) increases in the number of individuals of some species, (2) the
emergence of new species over time, and (3) the extinction of other species.
[Clarification Statement: Emphasis is on determining cause and effect relationships for
how changes to the environment such as deforestation, fishing, application of
fertilizers, drought, flood, and the rate of change of the environment affect
distribution or disappearance of traits in species.]
B.12
Describe protective adaptations of animals, including mimicry, camouflage, beak type,
migration, and hibernation.
 Identifying ways in which the theory of evolution explains the nature and
diversity of organisms
 Describing natural selection, survival of the fittest, geographic isolation, and
fossil record
Major Concepts: Biological Evolution: Unity and Diversity
Performance Objectives. The student will: explain the difference between the theories of gradualism
and punctuated equilibrium.
Materials and Resources: See accompanying material. The handouts for the lesson plan can be found
here: http://www.indiana.edu/~ensiweb/lessons/peek.html
Assessment Timeline
Diagnostic –
Formative –
Summative –
Before student work begins.
During lesson.
After lesson is completed.
Informal assessment of
Informal assessment of student
Informal assessment of student
student’s prior knowledge
understanding.
understanding.
gained from previous lessons
in the unit.
Title: Looking at the Fossil Record
Time Allotment: 1-50 minute class
Teaching/Learning Process
Step and time
allocation
(min)
Engage/
Motivation
(5-10 min)
Teaching/Learning Activities
Handouts, supplies,
points to remember.
EQ: Using what you remember about speciation,
do you think that new species come about
quickly, or do you think they arise slowly over
time?
 Record question in science notebook
 Have students record their answer
Students should be able
to provide general
answers to the
question. Remind
students of the
salamander exercisedo they think that
speciation was fast or
Evaluation.
Assessments
for each
activity.
Check that the
students are
writing down
the question
and their
answer.

Learning
Activities
(20 min)
Learning
Activities
(15 min)
Closure
(5 min)
As a large group, ask students about their
answers.
 Discuss together what might cause rapid
changes.
 Remind students that fossils can provide a
record of change over time, based on how
deep they are in the earth.
 After recording their thoughts above,
students should begin the activity described
in the accompanying material.
 Students (in pairs) are arranging simulated
fossils along a timeline, and deciding how
each fossil looks relative to the ones below
and above them. Half of the student should
have a record that represents gradualism,
and half punctuated equilibrium, although
the students shouldn’t have been instructed
in these theories yet.
 Have students construct an explanation
around their fossil timeline.
 Have some groups share their timeline via
document viewer, and see if all groups with
the same fossils agree.
 Have groups share their explanations- do
other groups with the same fossils agree or
disagree?
 After students have shared their timelines,
ask them to record what they think they
would find if they were able to find fossils
slightly above or below where they see a
shift in species.
 Have students read the information on
punctuated equilibrium and gradualism.
Have students reflect on the explanation they
constructed for their timeline- would they label
theirs as gradualism or punctuated equilibrium?
Why would they choose the one they did? Do
they agree with one theory more than the
other? Why? Can both theories be right?
slow?
Students should be able
to differentiate the
species within the
timeline, and then
describe the change
between species as
either gradual or quick.
Walk around to
each group and
make sure the
activity is going
as planned.
Students should be able
to describe, in general
terms, the difference in
gradualism and
punctuated
equilibrium, and the
arguments for and
against each.
Students should
be writing in
their science
notebook.
Students should be able
to agree with one view
or the other with some
supportive statements.
Students should
be participating
in the
discussion.
Differentiation
Pair students with IEPs with students who are able to explain the assignment.
Homework Assignments:
None.