Download Mechanisms of Evolution

Biology
HS/Science
Unit: 09
Lesson: 01
Suggested Duration: 9 days
Mechanisms of Evolution
Lesson Synopsis:
Students will learn that evolution does not occur in individuals but in populations. They will explore various
agents of microevolution including: natural selection, genetic drift, gene flow, mutation, recombination, nonrandom mating, artificial selection, and reproductive isolation. This lesson will focus on the process and results of
natural selection, as it is the key mechanism for evolution.
NOTE: The curriculum in this CSCOPE unit is based upon the Texas Essential Knowledge and Skills (TEKS),
which are the teaching standards required under the provisions of the Texas Education Code. During the course
of instruction, students may voice diverse viewpoints regarding the topic of evolution. Educators are encouraged
to consult with district administration to determine how they should best address these varying perspectives so
that all viewpoints are respected and district expectations are met.
TEKS:
B.6
Scientific concepts. The student knows the mechanisms of genetics including the role of nucleic acids and the
principles of Mendelian Genetics. The student is expected to:
B.6A
Identify components of DNA, and describe how information for specifying the traits of an organism is carried in the
DNA. Readiness Standard
B.7
Scientific concepts. The student knows evolutionary theory is a scientific explanation for the unity and diversity of
life. The student is expected to:
B.7C
B.7D
B.7E
B.7F
B.12
B.12B
Analyze and evaluate how natural selection produces change in populations, not individuals. Supporting Standard
Analyze and evaluate how the elements of natural selection, including inherited variation, the potential of a
population to produce more offspring than can survive, and a finite supply of environmental resources, result in
differential reproductive success. Supporting Standard
Analyze and evaluate the relationship of natural selection to adaptation and to the development of diversity in and
among species. Readiness Standard
Analyze and evaluate the effects of other evolutionary mechanisms, including genetic drift, gene flow, mutation, and
recombination. Supporting Standard
Science concepts. The student knows that interdependence and interactions occur within an environmental
system. The student is expected to:
Compare variations and adaptations of organisms in different ecosystems. Supporting Standard
Scientific Process TEKS:
B.2
Scientific processes. The student uses scientific methods during field and laboratory investigations. The student is
expected to:
B.2C
Know scientific theories are based on natural and physical phenomena and are capable of being tested by multiple
independent researchers. Unlike hypotheses, scientific theories are well-established and highly reliable
explanations, but they may be subject to change as new areas of science and new technologies are developed.
Plan and implement descriptive, comparative, and experimental investigations, including asking questions,
formulating testable hypotheses, and selecting equipment and technology.
Collect and organize qualitative and quantitative data and make measurements with accuracy and precision using
tools such as calculators, spreadsheet software, data-collecting probes, computers, standard laboratory glassware,
microscopes, various prepared slides, stereoscopes, metric rulers, electronic balances, gel electrophoresis
apparatuses, micropipettors, hand lenses, Celsius thermometers, hot plates, lab notebooks or journals, timing
devices, cameras, Petri dishes, lab incubators, dissection equipment, meter sticks, and models, diagrams, or
samples of biological specimens or structures.
B.2E
B.2F
B.3
B.3A
©2012, TESCCC
Scientific concepts. The student uses critical thinking and scientific problem solving to make informed decisions
within and outside the classroom. The student is expected to:
In all fields of science, analyze, evaluate, and critique scientific explanations by using empirical evidence, logical
reasoning, and experimental and observational testing, including examining all sides of scientific evidence of those
scientific explanations, so as to encourage critical thinking.
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Biology
HS/Science
Unit: 09 Lesson: 01
B.3E
B.3F
Evaluate models according to their limitations in representing biological objects or events.
Research and describe the history of biology and contributions of scientists.
GETTING READY FOR INSTRUCTION
Performance Indicator(s):
• “Natural selection is usually thought of as an agent of change in populations, but it can also act to
•
maintain the status quo.” Create and present a media presentation analyzing and evaluating this
statement. Include the range of responses of a population to changes in the environment, such as
differential reproductive success, the adaptation and development of diversity in and among species,
and change in populations. (B.7C, B.7D, B.7E)
1C; 5B, 5G
Analyze evolutionary mechanisms including genetic drift, gene flow, mutation, and recombination with
respect to natural selection. Within each analysis, include a written evaluation of the mechanism,
appropriate labeled drawings, and examples of the mechanism’s effects. (B.3A, B.3E; B.7F)
5E, 5G
Key Understandings and Guiding Questions:
•
•
Natural selection produces change in populations, not individuals.
— In what ways does natural selection produce change in populations, not individuals?
Natural selection and other evolutionary mechanisms lead to the unity and diversity of life.
— What are the mechanisms of evolution?
— How does speciation occur?
— What are the effects of evolutionary mechanisms?
Vocabulary of Instruction:
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•
•
•
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evolution
natural selection
genetic drift
gene flow
non-random mating
mutation
sympatric speciation
polyploidy
©2012, TESCCC
•
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recombination
artificial selection
microevolution
adaptation
diversity
disruptive selection
directional selection
stabilizing selection
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• extinction
• geographic isolation
• behavioral isolation
• inherited variation
• selection advantage
• differential
reproductive success
• gene variation
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Biology
HS/Science
Unit: 09 Lesson: 01
Materials:
Refer to Notes for Teacher section for materials.
©2012, TESCCC
05/24/13
page 3 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Advance Preparation:
1. Prior to Day 1:
• Copy the Teacher Resource: Biological Evolution Definition Cards, and cut out the cards. You will
need one card for each student, and there are two cards per page.
Print and copy the Handout: Mechanisms of Evolution Graphic Organizer on legal-size paper.
You will need one per student.
• Some students may benefit from hard copies of handouts of the Teacher Resource: PowerPoint:
Mechanisms of Evolution. Using the handouts with three slides per page will allow for students to
add their own notes.
• Note: The University of California at Berkeley has an extensive library of online resources and
teaching materials related to understanding evolution.
Prior to Day 2:
• Locate and preview a video clip(s) or use district approved resources to present the following topics
to students for discussion:
•
Who was Darwin
•
2.
•
•
•
•
Darwin’s findings on the Galapagos Islands
Darwin’s ideas about natural selection
Descent with modification
Examples of evolution and natural selection
•
3.
4.
5.
For ease of presentation, you may wish to embed a hyperlink to your choice of video(s) into the
Teacher Resource: Mechanisms of Evolution on slide 11. The Public Broadcasting Service has a
library of related instructional resources, including videos, that may be helpful for this purpose. Be
sure to preview any selected videos to ensure they are appropriate for your community and district’s
needs.
Prior to Day 3:
• Copy the Teacher Resource: Candy Pictures in color, and cut out the pictures. There should be
enough pictures for one per student in the class plus several extras of each variety in your class set.
Consider copying these on card stock and then laminating for durability. Note: Make sure you note
how many of each picture you start with, as you will need these initial numbers for the activity.
• For each group of four students, cut out 30 small, black, construction paper shapes and 30 small,
newspaper shapes (30 black and 30 newspaper) and place them in a resealable, plastic bag per
group. The types of shapes are not important (square or circle for example), so consider using a
paper cutter or die cut machine if available.
Prior to Day 4, locate and preview an animation to assist students in understanding the three different
modes of natural selection. Embed the hyperlink for the animation on slide 19 of the Teacher Resource:
Mechanisms of Evolution for ease of projection during the presentation. Note: Several textbook
publishers have online animations available for this purpose.
Prior to Day 6:
• Arrange for access to student computers/Internet for student research for the Natural Selection in
the Real World activity.
• Preview and determine research websites appropriate for your community and student needs.
Alternatively, you may wish to project the websites and conduct the activity as a whole group
discussion.
©2012, TESCCC
05/24/13
page 4 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
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6.
7.
8.
You will also need to locate and preview a website with information on natural selection in human
beings (specifically the hemoglobin gene). Consider conducting an Internet search for an article
entitled, “Sickle Cell Anemia & Malaria Resistance (subsection, “Taking the Good With the Bad –
The Malaria Hemoglobin Connection.”). You will need to either print the article or provide the website
for students to read during the activity.
Prior to Day 7:
• Print in color the Teacher Resource: Mechanisms of Evolution Model Boards. Each group of two
students will need one set of boards. There are six boards, but they may be printed front/back so
that each group gets a set of three pages. If you are preparing the activity for multiple classes, you
could use card stock and then laminate.
• Each group will need a resealable, plastic bag with approximately 40 green, 40 red, and 40 blue
hole-punched dots. Using card stock, rather than thin paper, will make handling the punched dots
much easier. Note: Other colored objects, such as very small die cut shapes, may be substituted for
the hole-punched dots.
• Locate and preview appropriate websites with a real world examples of the mechanisms of
evolution: mutations, gene flow, genetic drift, artificial selection, non-random mating, and
recombination and genetic shuffling. Possible websites to consider are from the University of
California at Berkeley and the University of Utah. These libraries have many resources which you
may find appropriate for your students and your district. Embed the websites onto the appropriate
slides in the PowerPoint: slide 33: Mutations; slide 37: Gene Flow; slide 41: Genetic Drift; slide 44:
Artificial Selection; slide 47: Non-random mating; and slide 49: Recombination and Genetic
Shuffling.
Prior to Day 9:
• Review types of media presentations to determine which software you wish your students to use for
the assessments. Consider online poster programs in addition to PowerPoint presentations, if
applicable for your students. Create a sample media presentation to guide students in completing
the Performance Indicators. Arrange for access to student computers/Internet.
Prepare attachment(s) as necessary.
Background Information:
This unit bundles student expectations that address the theory of evolution by natural selection and other
mechanisms.
Prior to this unit, in Biology, students learned that all organisms are made of chemicals that combine to form
cells. This unit explores the theory of evolution and its relationship to the diversity of species on Earth. During
this lesson, students analyze and evaluate the mechanism of natural selection as well as other mechanisms of
evolution. After this unit, students will build on these concepts in their study of taxonomy and the domains of life
on Earth covered in the classification unit.
STAAR Note:
This unit introduces the content for Readiness Standards B.7A and B.7E and Supporting Standards B.7BCDF
and B.7G, which will be assessed on the STAAR Biology Assessment. It also reinforces Supporting Standards
B.9D and B.12B, which were introduced in previous units.
NOTE: The curriculum in this CSCOPE unit is based upon the Texas Essential Knowledge and Skills (TEKS),
which are the teaching standards required under the provisions of the Texas Education Code. During the course
of instruction, students may voice diverse viewpoints regarding the topic of evolution. Educators are encouraged
to consult with district administration to determine how they should best address these varying perspectives so
that all viewpoints are respected and district expectations are met.
©2012, TESCCC
05/24/13
page 5 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
GETTING READY FOR INSTRUCTION SUPPLEMENTAL PLANNING DOCUMENT
Instructors are encouraged to supplement and substitute resources, materials, and activities to differentiate instruction to address the needs
of learners. The Exemplar Lessons are one approach to teaching and reaching the Performance Indicators and Specificity in the
Instructional Focus Document for this unit. Instructors are encouraged to create original lessons using the Content Creator in the Tools
Tab located at the top of the page. All originally authored lessons can be saved in the “My CSCOPE” Tab within the “My Content” area.
INSTRUCTIONAL PROCEDURES
Instructional Procedures
Notes for Teacher
ENGAGE – Defining Biological Evolution
1. Distribute a card from the Teacher Resource: Biological Evolution
NOTE: 1 Day = 50 minutes
Suggested Day 1
Definition Cards to each student (see Advance Preparation).
2. Project the discussion questions from the Teacher Resource:
PowerPoint: Mechanisms of Evolution.
• Read through these three scientific definitions of biological
evolution. As you read, analyze and evaluate the scientific
meaning of biological evolution. Be prepared to share your
responses to the statements projected on the board.
3. Allow a few minutes for students to read and analyze the three
definitions of biological evolution. Ask students to respond to the following
prompts.After students write their answers in their notebooks, you may
wish to have students discuss in groups or partners and then share out
with the class.
• Biological evolution happens at the ______________________
level, not the individual level.
• All three definitions mention genetic changes or changes in allele
frequency within a population from one generation to the next.
• Based on what you have learned about evolution and genetics in
the past, list 2–3 things that could cause these changes.
4. Reinforce that biological evolution happens at the population level over
many generations and not in individual organisms.
5. As students share, make a list on the board of key terms, processes,
or mechanisms that are involved in biological evolution. For example, a
student might share that they believe changes in populations are caused
by natural selection. You should add natural selection to the list.
Responses may include terms such as: mutations, mixing genetic material
in reproduction, natural selection (as students learned about this
mechanism in Grade 7), lack of resources, migration, competition,
variation, fitness, etc.
Materials:
• scissors (1 per student)
• glue or tape (per group)
Attachments:
• Teacher Resource: Biological
Evolution Definition Cards (see
Adv. Prep., 1 card per student)
• Teacher Resource: PowerPoint:
Mechanisms of Evolution (slides
1–9)
• Handout: Mechanisms of
Evolution Graphic Organizer (see
Adv. Prep., 1 per student)
Instructional Notes:
The curriculum in this CSCOPE unit is
based upon the Texas Essential
Knowledge and Skills (TEKS), which are
the teaching standards required under
the provisions of the Texas Education
Code. During the course of instruction,
students may voice diverse viewpoints
regarding the topic of evolution.
Educators are encouraged to consult
with district administration to determine
how they should best address these
varying perspectives so that all
viewpoints are respected and district
expectations are met.
6. Distribute the Handout: Mechanisms of Evolution Graphic
Organizer, scissors, and glue or tape to students (see Advance
Preparation). Trim, fold, and glue the graphic organizer according to the
instructions on the PowerPoint (slides 3 – 8).
7. Explain to students that the upcoming lesson focuses on the various
©2012, TESCCC
05/24/13
Check for Understanding:
Students should understand by the end
of class that biological evolution
happens at the population level over
many generations and not in individual
page 6 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
mechanisms that cause biological evolution. Some of the mechanisms are
already familiar to them, based on the list compiled during the class
discussion.
organisms.
8. Assist students in filling in the eight mechanisms on their folding
Misconceptions:
• Students may think that the theory
of evolution explains the origin of
life.
• Students may think that evolution
implies that organisms are evolving
toward perfection.
graphic organizer. Use the list compiled during the class discussion to
point out the mechanisms they were able to come up with from their
previous knowledge, but inform students they will be using the graphic
organizer to record additional information and organize their thoughts
during the upcoming lesson (slide 9).
9. Emphasize that although there are many mechanisms that lead to
evolution, natural selection is the most influential and key mechanism.
This is why the box for natural selection is bigger on the student graphic
organizers.
10. Instruct students to affix the trimmed and folded organizer in their
notebooks.
EXPLORE – Darwin’s Idea of Natural Selection
1. Project the questions that will be discussed after the upcoming video (see
Advance Preparation) by using slide 10 of the Teacher Resource:
PowerPoint: Mechanisms of Evolution. Allow students time to read the
questions before beginning.
Science Notebooks:
Students affix biological evolution
definitions and write responses in their
notebooks.
Suggested Day 2
Attachments:
• Teacher Resource: PowerPoint:
Mechanisms of Evolution (from
previous activity, slides 10–11)
2. Remind students there will be a discussion relating to these questions after
a video (see Instructional Notes or Advance Preparation).
3. Instruct students to take brief notes in their science notebooks.
4. Show a video clip or use district approved resources to present the
following concepts (see Advance Preparation):
• Who was Darwin
•
•
•
•
Darwin’s findings on the Galapagos Islands
Darwin’s ideas about natural selection
Descent with modification
Examples of evolution and natural selection
5. Facilitate a discussion in which students reflect on the following questions
that should have been addressed in the video presented:
• What explains the explosion of living creatures on Earth—1.4
million different species discovered so far?
• To what prediction did the finches collected on the Galapogos
lead Darwin?
• What did Darwin predict causes one species to evolve into other
species?
©2012, TESCCC
05/24/13
Check for Understanding:
Students should be able to make the
connection between Darwin’s findings
and natural selection. They should also
see that the process of natural selection
is the major mechanism in evolution.
Instructional Notes:
The curriculum in this CSCOPE unit is
based upon the Texas Essential
Knowledge and Skills (TEKS), which are
the teaching standards required under
the provisions of the Texas Education
Code. During the course of instruction,
students may voice diverse viewpoints
regarding the topic of evolution.
Educators are encouraged to consult
with district administration to determine
how they should best address these
varying perspectives so that all
viewpoints are respected and district
expectations are met.
page 7 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
• What domesticated animal helped lead Darwin to the idea of
•
natural selection? Explain.
What questions did Darwin’s insight about evolution raise?
6. Check for and briefly correct any misconceptions throughout the
discussion. Explain to students that in the next section of the lesson, they
will explore how the process of natural selection works.
Notes for Teacher
Prior to instruction, locate and preview a
video clip(s) or use district approved
resources to present the following topics
to students for discussion:
•
Who was Darwin
•
Darwin’s findings on the
Galapagos Islands
•
Darwin’s ideas about
natural selection
•
Descent with
modification
•
Examples of evolution
and natural selection
For ease of presentation, you may wish
to embed a hyperlink to your choice of
video(s) into the Teacher Resource:
Mechanisms of Evolution on slide 11.
The Public Broadcasting Service has a
library of related instructional resources,
including videos, that may be helpful for
this purpose. Be sure to preview any
selected videos to ensure they are
appropriate for your community and
district’s needs.
STAAR Note:
Student Expectation B.3F requires
students to “research and describe the
history of biology and contributions of
scientists.”
EXPLORE/EXPLAIN 1 – Differential Reproductive Success
1. Provide a selection of colored pictures of candies (from the Teacher
Resource: Candy Pictures) from which students will choose one as they
come into the room. Place each variety in a different stack so students can
observe the selections. Note: Make sure you note how many of each
picture with which you start the activity.
2. Ask students to choose their favorite candy as they enter the
classroom and to take that card with them to their desk.
3. Explain to students that the candies represent a population of
organisms and they, the students, represent predators that feed on
organisms in that population.
Suggested Day 3
Attachments:
• Teacher Resource: PowerPoint:
Mechanisms of Evolution (from
previous activity, slides 12–14)
• Teacher Resource: Candy Pictures
(see Adv. Prep., class set with 1
colored picture per student and a
few extras of each variety)
Check for Understanding:
©2012, TESCCC
05/24/13
page 8 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
4. Make a list, on the board, of all the candies that you originally had
available. Record how many were in the original stack and how many
“survived” after predation occurred.
5. Begin a discussion by mentioning that many times there is a large
amount of variation between indivduals of one animal species. Ask
students to list some of the variations seen in the candy population.
6. Then, ask the students why variation is important in populations. (One
reason variety within a population is important is because variation permits
different individuals to survive.).
7. Ask students to list some of the variations in traits that made the candy
organisms more fit for survival. For example: Some students didn’t prefer
the strong flavor of licorice or were allergic to nuts. Explain that these traits
allow certain organisms to survive and reproduce.
Students should be able to make the
connection between genetic variations
and reproductive success. They should
see how differential reproductive
success is not possible without
variations in a population.
Science Notebooks:
Students draw and fill in the concept
map of differential reproductive success
in their notebooks.
8. Introduce students to the term differential reproductive success.
Facilitate a discussion of the following concepts:
• The wide variation of characteristics in the candy population
resulted in some candies being selected (eaten) and others not
selected (surviving).
• Each individual has unique traits; some traits will help an
individual survive and reproduce, and some traits do not.
• Variation occurs in all populations and because of this, some
individuals will be more fit to reproduce than others. This is
known as differential reproductive success.
9. Using the Teacher Resource: PowerPoint: Mechanisms of Evolution,
project the differential reproductive success concept map “skeleton” (slide
12).
10. Instruct students to draw the concept map in their science notebooks.
11. Explain to students that the map is designed to help them understand
the components of differential reproductive success and how it relates to
natural selection.
12. It is important to assist students in thinking through the concept map
before filling in all of the technical information. Using the concept map filled
in with A–F (slide 13), continue the discussion:
• According to the concept map, which letters represent the
components that lead to differential reproductive success?
(D,E,F)
• According to the concept map, to what does differential
reproductive success lead? (Natural selection)
• Based on what we learned from the candy activity, what
concept/term belongs in D? (Variation)
©2012, TESCCC
05/24/13
page 9 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
13. Take time to discuss and explain differential reproductive success as
you fill in the rest of the concept map (slide 14).
14. Ensure students understand the following terms: genetic variation,
fitness, competition, resources, and environmental factors.
15. Ask students to return the pictures of the candy to use with the next
class.
EXPLORE – Natural Selection Simulation
Suggested Days 3 (continued) and 4
1. Divide the class into groups of four. Distribute the Handout: Peppered
Moth Simulation to students and materials for the simulation.
2. Ask students to read the procedure and answer any questions they
may have regarding the instructions.
3. Note: To make the simulation model work more effectively, you should
make sure students are following the rules of predations. This means no
scooping up shapes or grabbing more than one at a time. They should go
as fast as possible, which forces them to pick up the easily seen shapes
more frequently. Slightly dimming the lights in your classroom may help
camouflage the shapes a bit better.
4. Allow time for student groups to complete the activity, monitoring
groups to make sure they are following the procedure.
5. Use the post-investigation questions to discuss how this simulation
models the process of natural selection. Include the following concepts in
the disuccsiondiscussion:
• Genetic variation was present in the population.
•
•
•
•
Variation led to differential reproductive success.
Traits/variations were passed from one generation to the next.
Individual moths did not change.
The population did change over several generations.
6. Collect the materials to reuse with the next class.
7. Instruct students to affix the handouts pages in their notebooks.
Materials:
• newspaper pieces (see Advance
Preparation, 30 small pieces per
group)
• construction paper pieces (black,
see Advance Preparation, 30 small
pieces per group)
• resealable plastic bag (1 per group)
• construction paper (black, 1–2 large
sheets per group)
• newspaper sheets (several per
group)
• timing device (1 per group)
• index cards (4” x 6”, 1 per student)
• glue or tape (per group)
Attachments:
• Handout: Peppered Moth
Simulation (1 per student)
Instructional Note:
Now that students have a working
definition of reproductive success, the
lesson continues by exploring the
important role it plays in the process of
natural selection.
Check for Understanding:
The post-simulation discussion provides
an opportunity for formative
assessment.
©2012, TESCCC
05/24/13
page 10 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
STAAR Notes:
Supporting Standard B.7C requires
students to “analyze and evaluate how
natural selection produces change in
populations, not individuals.”
Standard B.3A requires the following of
students: “in all fields of science,
analyze, evaluate, and critique scientific
explanations by using empirical
evidence, logical reasoning, and
experimental and observational testing,
including examining all sides of scientific
evidence of those scientific
explanations, so as to encourage critical
thinking.”
Science Notebooks:
Students affix the handout pages in their
science notebooks.
EXPLAIN – Components and Types of Natural Selection
1. Ask students to refer back to their Mechanisms of Evolution Graphic
Suggested Days 4 (continued) and 5
Organizer (from previous activity).
2. Explain to students that we are focusing on one particular mechanism
at this point in the lesson and that is natural selection. Other mechanisms
will be discussed later in the lesson.
3. Distribute the Handout: A Formula for Natural Selection, scissors,
and glue sticks to students.
4. Instruct students to cut out the graphic organizer on page 1 of the
Handout: Formula for Natural Selection. Instruct students to fold along
the middle line and then cut the tabs on the dotted lines.
5. Instruct students to then cut out the images, definitions, and terms on
page 2 that will be glued onto the graphic organizer. Note: The definitions,
images, and terms are in no particular order on the student handout.
6. Instruct students to work with a partner to determine where the terms,
definitions, and images fit on/in the graphic organizer. Explain that images
and definitions will go under the tabs and terms fit in the “formula” on the
front.
7. The term “natural selection” has already been correctly placed in the
©2012, TESCCC
05/24/13
Materials:
• scissors (1 per student)
• glue sticks (1 per pair of students)
Attachments:
• Handout: Mechanisms of
Evolution Graphic Organizer (from
previous activity)
• Handout: A Formula for Natural
Selection (1 per student)
• Teacher Resource: PowerPoint:
Mechanisms of Evolution (from
previous activity, slides 15–23)
Instructional Notes:
The curriculum in this CSCOPE unit is
based upon the Texas Essential
Knowledge and Skills (TEKS), which are
the teaching standards required under
the provisions of the Texas Education
Code. During the course of instruction,
students may voice diverse viewpoints
page 11 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
“formula”. Students will build and add to it based on what they have
learned from the previous activities.
8. Note: By this point in the lesson, students should know enough about
natural selection to complete this with minimal teacher input.
9. As students sort and glue, circulate around the room and check for
understanding.
10. The final product should have the following formula on the front:
Variation + Differential Reproductive Success + Heredity = Natural Selection  Evolution
(causes)
11. After students have completed their graphic organizers, facilitate a
discussion including the following questions (also noted on slide 15 of the
Teacher Resource: PowerPoint: Mechanisms of Evolution):
•
What is the purpose of using a “formula” type graphic
organizer to help explain natural selection?
•
What three things are needed for the process of natural
selection?
•
What sorts of things cause variation in a population?
•
Is evolution best defined as:
•
or
Individuals changing and adapting to their environment
•
Changes in allele frequencies or traits within a population
over many generations?
regarding the topic of evolution.
Educators are encouraged to consult
with district administration to determine
how they should best address these
varying perspectives so that all
viewpoints are respected and district
expectations are met.
Prior to instruction, locate and preview
an animation to assist students in
understanding the three different modes
of natural selection. Embed the
hyperlink for the animation on slide 19
of the Teacher Resource: Mechanisms
of Evolution for ease of projection
during the presentation. Note: Several
textbook publishers have online
animations available for this purpose.
Check for Understanding:
Students must be able to evaluate and
analyze the relationship between natural
selection and adaptations as well as the
relationship between natural selection
and the development of diversity in and
among species. These are key concepts
in Readiness Standard B.7E.
12. Note: Students should be able to evaluate and analyze the relationship
between natural selection and adaptations as well as the relationship
between natural selection and the development of diversity in and among
species. Continue using the Teacher Resource: PowerPoint: Mechanisms
of Evolution (slides 15–18) to assist students in making these
connections.
13. Instruct students to affix the graphic organizers in their notebooks.
14. Project your choice of an animation to assist students in understanding
the three different modes of natural selection (See the Advance
Preparationsection. It may be helpful to embed your choice of animation on
slide 19 of the Teacher Resource: PowerPoint: Mechanisms of
Evolution).
15. Be sure to point out that one type of selection actually maintains the
status quo rather than causing changes.
16. Instruct students to draw and label the Types of Selection Table in their
notebooks and fill in the information from the Teacher Resource:
©2012, TESCCC
05/24/13
Misconception:
• Students may think that an
individual organism can evolve new
characteristics in response to
environmental change, rather than
understanding that evolution occurs
at the population level over the
course of generations.
STAAR Notes:
Supporting Standard B.7D requires
students to “analyze and evaluate how
the elements of natural selection,
including inherited variation, the
potential of a population to produce
page 12 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
PowerPoint: Mechanisms of Evolution (slides 20–23).
more offspring than can survive, and a
finite supply of environmental resources,
result in differential reproductive
success.”
Readiness Standard B.7E requires
students to “analyze and evaluate the
relationship of natural selection to
adaptation and to the development of
diversity in and among species.”
Science Notebooks:
Students affix graphic organizers in their
notebooks. Additionally, students draw
the Types of Selection Table in their
notebooks and notes from the
PowerPoint presentation.
Elaborate 1 – Real-World Examples of Natural Selection
1. Distribute the Handout: Natural Selection in the Real World to each
student (see Advance Preparation and Instructional Notes). Divide the
class into groups of 2–3 to accommodate computer/Internet limitations.
2. Instruct students to use the URLs you provide to find information about
examples of natural selection occurring in various species today.
3. Instruct students to work through the steps on the handout to complete
the assignment. Note: Although an example is given on how to fill in the
table, it maybe helpful to discuss what is needed in each column.
4. Instruct students to find one additional example of evolution by means
of natural selection. This example will be added to the table included on
the handout.
5. Monitor and assist students as they complete the handout.
6. Conclude the activity by facilitating a discussion on the role of variation
and differential reproductive success in natural selection.
Suggested Day 6
Materials:
• glue or tape (per group)
Attachments:
• Handout: Natural Selection in
the Real World (1 per student)
• Teacher Resource: Natural
Selection in the Real World KEY
Instructional Notes:
Prior to instruction, preview and
determine websites appropriate for your
community and student needs.
Alternatively, you may wish to project
the sites and conduct the activity as a
whole group activity.
7. Reinforce the fact that all changes were seen at the population/species
level.
8. Instruct students to affix the handouts in their notebooks.
©2012, TESCCC
05/24/13
Misconception:
• Students may think that an
individual organism can evolve new
characteristics in response to
environmental change, rather than
understanding that evolution occurs
page 13 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
at the population level over the
course of generations.
Science Notebooks:
Students affix the handout pages in their
notebooks.
EXPLORE/EXPLAIN 3 – Mechanisms of Microevolution Models
1. Ask students to refer back to their Mechanisms of Evolution Graphic
Organizer (from previous activity). Explain that in portions of the lesson,
they will be exploring how other mechanisms of evolution cause change in
populations over many generations.
2. Ask students to find a partner or to work with the person next to them.
Distribute a set of six Mechanisms of Evolution Models Boards (see
Advance Preparation) and a resealable, plastic bag with red, green, and
blue dots (see Advance Preparation) to each partner group.
3. Using the Teacher Resource: PowerPoint: Mechanisms of Evolution,
explain the components of the models. Ask students to think in terms of
percentages of individuals rather than exact number of individuals. Note:
Do not spend time trying to calculate exact numbers as students predict
outcomes.
4. Use the presentation to help students work through each mechanism
one at a time. PowerPoint slide 25 shows students how to set up the
original population.
5. Instruct students to read the scenario on their board and predict and
build what the population would look like after the “event” has taken place
as well as many generations later.
6. Circulate around the room checking for understanding. Note: The
Suggested Days 7 and 8
Materials:
• bag of hole-punched dots (see
Advance Preparation, red, green
and blue, 40 each color, per pair of
students)
• colored pencils (optional, per group)
• scissors (1 per student)
• glue (per student)
Attachments:
• Handout: Mechanisms of
Evolution Graphic Organizer (from
previous activity)
• Teacher Resource: Mechanisms of
Evolution Model Boards (see Adv.
Prep., 1 set per pair of students)
• Teacher Resource: PowerPoint:
Mechanisms of Evolution (from
previous activity, slides 24–57)
• Handout: Mechanism Match
Cards (1 per student)
PowerPoint includes the predictions, so be careful not to click too far and
give the students the answers before they have time to think, predict, and
build understanding (slides 26–47).
7. Explain to students that this activity is designed to model the various
mechanisms of evolution. As with any model, there are limits to accuracy.
Ask students what some of the limits are to the models they have
constructed.
8. Use the PowerPoint to discuss the limitations of the models (slide 48).
9. Explain the other two mechanisms, recombination and reproductive
isolation (slides 49–57). Note: Make sure students know the role of
©2012, TESCCC
05/24/13
STAAR Notes:
According to Standard B.3E, students
are required to “evaluate models
according to their limitations in
representing biological objects or
events.”
Supporting Standard B.7F requires
students to “analyze and evaluate the
page 14 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
reproductive isolation in the formation of new species as well as the
various types of isolation.
10. Instruct students to record notes on reproductive isolation and
effects of other evolutionary
mechanisms, including genetic drift,
gene flow, mutation, and
recombination.”
speciation in their science notebooks.
11. Distribute the Handout: Mechanism Match Cards to each student.
Inform students they will be creating a tabbed book to help them organize
information about other mechanisms of evolution. Note: If the colors or
shades of color are not clear on the graphics, assist students in coloring
them to match the colors that were lost by printing and coping in black and
white. Instruct students to cut out the cards.
12. With their partner, instruct students to read and analyze each card.
They should determine where the card fits in their graphic organizer. Each
mechanism has a definition and a graphic.
13. Explain to students that once they have checked with you to make
sure they have the correct information in the correct locations, they should
glue the cards into their graphic organizer tab book. Additionally, students
should affix the tabbed book in their notebooks.
14. Conclude the lesson with a discussion of the following concepts with
students:
• Biological evolution happens at the population level, not
individual.
• Genetic variation is a key force in evolution.
•
•
•
Natural selection cannot happen without variation, differential
reproductive success, and heredity.
Natural selection plays a major role in the formation of an
adaptation in a population and in the development of diversity in
and among species.
Natural selection is the key mode to evolution but there are many
other mechanisms that play important roles in the evolutionary
process.
EVALUATE – Performance Indicator
Performance Indicator
• “Natural selection is usually thought of as an agent of change in
populations, but it can also act to maintain the status quo.” Create and
present a media presentation analyzing and evaluating this statement.
Include the range of responses of a population to changes in the
environment, such as differential reproductive success, the adaptation
and development of diversity in and among species, and change in
populations. (B.7C, B.7D, B.7E)
©2012, TESCCC
05/24/13
Instructional Notes:
Locate and preview appropriate
websites with a real world examples of
the mechanisms of evolution: mutations;
gene flow, genetic drift, artificial
selection, non-random mating, and
recombination and genetic shuffling.
Possible websites to consider are the
Berkeley Evolution website and the
Learn Genetics Utah website. it has
many resources which you may find
appropriate for your students and
district. Embed the websites onto the
appropriate slides in the PowerPoint:
slide 33: Mutations; slide 37: Gene
Flow; slide 41: Genetic Drift; slide 44:
Artificial Selection; slide 47: Nonrandom mating; and slide 49:
Recombination and Genetic Shuffling.
Check for Understanding:
Students should know the importance of
reproductive isolation in the formation of
new species as well as the various
types of isolation.
Science Notebooks:
Students record notes on recombination
and speciation and affix tabbed books in
their notebooks.
Suggested Days 8 (continued) and 9
Attachments:
• Teacher Resource:
Performance Indicator
Instructions KEY
page 15 of 16
Biology
HS/Science
Unit: 09 Lesson: 01
Instructional Procedures
Notes for Teacher
1C; 5B, 5G
•
Analyze evolutionary mechanisms including genetic drift, gene
flow, mutation and recombination. Within each analysis, include a
written evaluation of the mechanism, appropriate labeled drawings,
and examples of the mechanism’s effects.(B.3A, B.3E; B.7F)
5E,
5G
1. Refer to the Teacher Resource: Performance Indicator Instructions KEY
for information on administering the assessment.
©2012, TESCCC
05/24/13
page 16 of 16